Gyroscope-like platinum and palladium complexes with trans-spanning bis(pyridine) ligands

Article

pubs.acs.org/Organometallics

Gyroscope-Like Platinum and Palladium Complexes with

Trans-Spanning Bis(pyridine) Ligands

Paul D. Zeits,^†,§Giovanni Pietro Rachiero,^‡,§Frank Hampel,^‡Joseph H. Reibenspies,^†

and John A. Gladysz*^,†

^†Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States

^‡Institut fur Organische Chemie and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universitat

̈

Erlangen-Nurnberg, Henkestraße 42, 91054 Erlangen, Germany

̈

S

* Supporting Information

ABSTRACT: Pyridines with one or two substituents terminating in vinyl groups are prepared. Intramolecular ring-closing

metatheses of trans-MCl₂adducts and hydrogenations supply the title compounds. Williamson ether syntheses using the alcohols

HO(CH₂)_nCHCH₂(n = 1 (a), 2 (b), 3 (c), 4 (d), 5 (e), 6 (f), 8 (h), 9 (i)) and appropriate halides give the pyridines

2-NC₅H₄(CH₂O(CH₂)_nCHCH₂) (1a,b), 3-NC₅H₄(CH₂O(CH₂)_nCHCH₂) (2a−e,h,i), and 2,6-NC₅H₃(CH₂O-

(CH₂)_nCHCH₂)₂(4a−d) in 92−45% yields. Reactions of 3,5-NC₅H₃(COCl)₂and HO(CH₂)_nCHCH₂afford the diesters

3,5-NC₅H₃(COO(CH₂)_nCHCH₂)₂(5a−f,h, 90−41%). The reaction of 3,5-NC₅H₃(4-C₆H₄OH)₂, Br(CH₂)₅CHCH₂, and

Cs₂CO₃yields 3,5-NC₅H₃(4-C₆H₄O(CH₂)₅CHCH₂)₂(8; 32%). Reactions of PtCl₂with 1a,b, 2a−e,h,i, 4a,b (but not 4c,d),

5a,c−f,h, and 8 afford the corresponding bis(pyridine) complexes trans-10a,b (40−12%), trans-12a−e,h,i (84−46%), trans-17a,b

(88−22%), trans-19a,c−f,h (94−63%), and trans-22 (96%). Selected adducts are treated with Grubbs’ catalyst and then H₂(Pd/

C) to give trans-PtCl₂[2,2′-(NC₅H₄(CH₂O(CH₂)_2n+2OCH₂)H₄C₅N)] (trans-11a,b; 79−63%), trans-PtCl₂[3,3′-(NC₅H₄(CH₂O-

(CH₂)_2n+2OCH₂)H₄C₅N)] (trans-13,d,h,i; 93−80%), trans-PtCl₂[2,6,2′,6′-(NC₅H₃(CH₂O(CH₂)_2n+2OCH₂)₂H₃C₅N)] (trans-

18a,b; 22−10%), trans-PtCl₂[3,5,3′,5′-(NC₅H₃(COO(CH₂)_2n+2OCO)₂H₃C₅N)] (trans-20d−f,h; 45−14%), and trans-

PtCl₂[3,5,3′,5′-(NC₅H₃(4-C₆H₄O(CH₂)₁₂O-4-C₆H₄)₂H₃C₅N)] (40%). A previously reported ring-closing metathesis of trans-

PdCl₂[2,6-NC₅H₃(CH₂CH₂CHCH₂)₂]₂is confirmed, and the new hydrogenation product trans-PdCl₂[2,6,2′,6′-

(NC₅H₃((CH₂)₆)₂H₃C₅N)] (trans-16; 62%) is isolated. Additions of CH₃MgBr to 12b,h and 13d,h afford the corresponding

PtClCH₃species (94−41%), but analogous reactions fail with 2-substituted pyridine adducts. The reaction of trans-19c with

PhCCH and CuI/i-Pr₂NH gives the corresponding PtCl(CCPh) adduct (18%). The crystal structures of trans-17a, trans-

11b, trans-13d, trans-13h·CH₂Cl₂, trans-16, trans-18a,b, and trans-20e·2CHCl₃are determined. Steric effects in the preceding

data, especially involving 2-substituents and the MCl₂or MCl(X) rotators, are analyzed in detail.

coordination geometries have proved accessible, as illustrated

by III−V.

We have also sought systems based upon other types of trans

donor atoms. Arsenic analogues of some of the species in

Scheme 1 have been realized.¹¹However, we were particularly

interested in establishing new donor atom coordination

INTRODUCTION

■

As summarized in a review, the term “gyroscope” has been

applied to a variety of molecules.¹The most intensive efforts to

craft functional molecular analogues of macroscopic gyros-

copes have been described by Garcia-Garibay.^2,3In our research

group, we have sought to develop transition-metal-based

gyroscopes in which trans phosphorus donor atoms are bridged

by three methylene chains or related linkers.⁴⁻¹⁰All of these

have been prepared via 3-fold intramolecular ring-closing

metatheses, as sketched in Scheme 1 (I → II). A variety of

Special Issue: F. Gordon A. Stone Commemorative Issue

Received: November 16, 2011

Published: March 9, 2012

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Scheme 1. Syntheses of Gyroscope-Like Complexes with

Trans Phosphorus Donor Atoms and (CH₂)_nLinkers

RESULTS

■

1. Syntheses of Alkene-Containing Pyridines. For

initial studies, monosubstituted pyridines were sought. Thus,

commercial 2-(chloromethyl)pyridine hydrochloride was com-

bined with excesses of the alcohols HO(CH₂)_nCHCH₂(n =

1 (a), 2 (b)) and 3.0−2.3 equiv of sodium to generate the

corresponding alkoxide bases. As shown in Scheme 3, workups

Scheme 3. Syntheses of Complexes with 2-Substituted Trans-

Spanning Bis(pyridine) Ligands

numbers. Toward this end, our attention was drawn to pyridine

ligands. An additional motivation was the possibility of

introducing functionality in the para or 4-position, which

could allow for surface mounting, a subject of much interest

within the broad field of molecular rotors.¹²

Further impetus derived from an intriguing preliminary

communication by Lambert and Ng.¹³They reported the

synthesis of the palladium bis(2,6-dihomoallylpyridine) com-

plex, VI shown in Scheme 2, and its 2-fold intramolecular

Scheme 2. Lambert's Initial Synthesis of a Complex with a

Doubly Trans-Spanning Bis(pyridine) Ligand

gave the alkene-containing monoethers 2-NC₅H₄(CH₂O-

(CH₂)_nCHCH₂) (1a,b) as yellow or brown oils in 61−

59% yields. Compounds 1a,b have previously been prepared

from 2-pyridinemethanol and the corresponding chlorides

Cl(CH₂)_nCHCH₂.^15,16However, these building blocks are

more costly.

Given the course of results below, 3-substituted pyridines

were also desired. As shown in Scheme 4, analogous reactions

of commercial 3-(chloromethyl)pyridine hydrochloride, alco-

hols HO(CH₂)_nCHCH₂(n = 1 (a), 2 (b), 3 (c), 4 (d), 5 (e),

8 (h), 9 (i)), and sodium were conducted. Workups gave

the new monoethers 3-NC₅H₄(CH₂O(CH₂)_nCHCH₂)

(2a−e,h,i) as yellow-brown oils in 98−42% yields.

Disubstituted pyridines were sought next. As shown in

Scheme 5, commercial 2,6-bis(bromomethyl)pyridine, 2,6-

NC₅H₃(CH₂Br)₂, was combined with 2.5 equiv of the Grignard

reagent H₂C=CHCH₂MgBr in THF. A chromatographic

workup gave the doubly butenylated pyridine 2,6-

NC₅H₃(CH₂CH₂CHCH₂)₂(3) as a yellow oil in 60%

yield. This compound was previously prepared by a similar

route by Lambert, but no synthetic details or characterization

were given.¹³

ring-closing metathesis with Grubbs’ catalyst to give the doubly

bridged trans-spanning bis(pyridine) complex VII. The crystal

structure of VII, which can be viewed as an adduct of a diaza-m-

cyclophane, was mentioned, but the data were not deposited

with the Cambridge Crystallographic Data Centre. We sought

to explore the generality of this type of process, including

extensions to pyridines with other substitution patterns.

In this paper, we report (1) syntheses of a variety of 2-, 3-,

2,6-, and 3,5- mono- and disubstituted pyridine ligands in

which the substituents terminate with vinyl groups, (2) the

preparation of the corresponding trans-dichloroplatinum or

trans-dichloropalladium bis(pyridine) complexes, (3) intra-

molecular ring-closing metatheses that lead to a variety of

singly and doubly trans-spanning systems, (4) chloride ligand

substitutions that lead to dipolar rotors, (5) crystal structures of

representative species, and (6) analyses of numerous steric

effects manifested in these data. Additional details can be found

elsewhere.¹⁴

Ether-containing analogues were desired. Accordingly, 2,

6-NC₅H₃(CH₂Br)₂and the alcohols HO(CH₂)_nCHCH₂

(a−d) were refluxed in the presence of the quaternary ammo-

nium salt C₆H₅CH₂N(CH₃)₃Cl⁻(20 mol %), as shown in

+

Scheme 6. A related procedure has been previously applied to

benzyl halides.¹⁷Workups gave the dialkenylated diethers 2,

6-NC₅H₃(CH₂O(CH₂)_nCHCH₂)₂(4a−d) as light yellow

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inexpensive building block, and the bis(acid chloride) 3,5-

NC₅H₃(COCl)₂was prepared in quantitative yield as

previously described.²⁰As shown in Scheme 7, this material

was combined with a slight excess of HO(CH₂)_nCHCH₂

(a−f,h) in dry CH₂Cl₂. After basic workups, the dialkenylated

diesters 3,5-NC₅H₃(COO(CH₂)_nCHCH₂)₂(5a−f,h) were

isolated as viscous yellow oils in 90−41% yields. Compounds

5d,h have been previously synthesized by similar routes.^19,21

Given certain results below, expanded 3,5-disubstituted

pyridine frameworks were also desired. Two known reactions

were conducted first. As shown in Scheme 8, the cross coupling

of 3,5-dichloropyridine and (4-methoxyphenyl)magnesium

bromide, 4-CH₃OC₆H₄MgBr, using the nickel catalyst (dppp)-

NiCl₂(dppp = Ph₂P(CH₂)₃PPh₂), afforded 3,5-bis(4-

methoxyphenyl)pyridine (6) or 3,5-NC₅H₃(4-C₆H₄OCH₃)₂in

73% yield.²²Subsequent reaction with BBr₃gave the bis-

(phenol) 3,5-NC₅H₃(4-C₆H₄OH)₂(7)²³in 66% yield. Treat-

ment with Br(CH₂)₅CHCH₂and Cs₂CO₃base (DMF,

100 °C) afforded the new dialkenylated diether 3,5-NC₅H₃(4-

C₆H₄O(CH₂)₅CHCH₂)₂(8) as a white powder in 32% yield.

2. Syntheses of trans-Bis(pyridine) Complexes. 2.1.

Singly Bridged Complexes. As shown in Scheme 3, reactions of

1a,b with PtCl₂in refluxing benzene afforded the correspond-

ing trans-dichloroplatinum bis(pyridine) complexes trans-10a,b

as light yellow solids in 40−12% yields after workup. These and

all other new complexes below were characterized by NMR and

IR and (in most cases) microanalyses, as summarized in the

Experimental Section. In particular, the sp^{2 1}H and ¹³C NMR

signals of the free and coordinated pyridines could be assigned

on the basis of well-established chemical shift trends.^24,25

Coordination shifts have been tabulated elsewhere.^14aSome

DSC/TGA and mass spectral data are also reported.

Scheme 4. Syntheses of Complexes with 3-Substituted Trans-

Spanning Bis(pyridine) Ligands

Scheme 5. Additional Chemistry Relating to Scheme 2

Interestingly, CDCl₃solutions of trans-10a exhibited two

1

NCCH₂O H NMR signals (singlets, 1:1 ratio) at room tem-

perature. These were presumed to arise from atropisomers

(rotamers) with syn/anti dispositions of the two 2-pyridyl

substituents, as shown in Scheme 9 (VIII, VIII′). The 2-

methylpyridine analogue of trans-10a gives a 65:35 mixture of

atropisomers, and similar phenomena have been found for

closely related complexes.²⁴The two signals coalesced be-

tween 35 and 40 °C. The coalescence temperature (T_c) was

extrapolated as 311 K, giving a ΔG^⧧(T_c) value of 16.6 kcal/mol.

Next, CH₂Cl₂solutions of trans-10a,b (0.0019−0.0021 M)

and Grubbs’ catalyst (4 and 8 mol %) were refluxed for

18−42 h as described in the Experimental Section. The crude

metathesis products were treated with H₂(balloon pressure) in

the presence of Pd/C (5 mol %). Chromatography gave

trans-11a,b as light yellow and off-white solids in 79−63%

overall yields. These feature 8- and 10-atom linkers connecting

the pyridine ligands, or 13- and 15-membered macrocycles.

Single crystals of trans-11b were obtained as described in

the Experimental Section. A crystal structure, described in the

following section, confirmed the formulation.

Attention was turned to the analogous 3-substituted pyri-

dines in Scheme 4. Under conditions comparable to those in

Scheme 3, the corresponding platinum complexes trans-12a−

e,h,i were obtained in higher yields (80−46%) as yellow solids.

On the basis of additional data below, this was attributed to the

absence of a 2-substituent, diminishing steric hindrance. In two

cases (12b,h), comparable amounts of cis isomers formed, but

these more polar adducts were readily separated by silica gel

chromatography.

oils in 55−45% yields. Compounds 4a,d had been previously

prepared by other Williamson ether syntheses.^18,19

Next, 3,5-disubstituted systems were sought. Pyridine-3,

5-dicarboxylic acid, 3,5-NC₅H₃(COOH)₂, was seen as an

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Scheme 6. Syntheses of Complexes with 2,6-Disubstituted Doubly Trans-Spanning Bis(pyridine) Ligands

Scheme 7. Syntheses of Complexes with 3,5-Disubstituted

Doubly Trans-Spanning Bis(pyridine) Ligands

2.2. Doubly Bridged Complexes. An initial objective was to

round out and extend the fragmentary data of Lambert

(Scheme 2). As shown in Scheme 5, the reaction of trans-

(PhCN)₂PdCl₂and 3 (2.3 equiv) afforded the dichloropalla-

dium bis(pyridine) complex trans-14 (VI) in 15% yield

following chromatography. A CH₂Cl₂solution of trans-14

(0.0301 M) was treated with Grubbs’ catalyst (15 mol % added

in three equal charges over 24 h). Chromatography gave the

metathesis product trans-15 (VII) in 58% yield. Lambert

obtained an 80% yield and assigned a Z CC stereochemistry

on the basis of the incompletely reported crystal structure

mentioned above.¹³

In a new reaction, this material was hydrogenated (balloon

pressure, PtO₂catalyst). Chromatography afforded the satu-

rated analogue trans-16 as a light yellow solid in 62% yield.

Single crystals were obtained as described in the Experimental

Section, and the crystal structure is detailed below. Complex

trans-16 features 6-atom linkers connecting the pyridine

ligands, making for an 11-membered cyclethe smallest ring

system in this study.

Analogous sequences were attempted with the 2,6-disub-

stituted ether containing pyridines, as summarized in Scheme 6.

Reactions with PtCl₂with 4a,b gave the dichloroplatinum

bis(pyridine) complexes trans-17a,b as yellow solids in 88−26%

yields after chromatography. The lower yield with 4b appeared

to relate to the size of the 2,6-substituents; the ligands 4c,d did

not give detectable amounts of complexes under comparable

conditions, and the yield of trans-14 was also modest. The

crystal structure of trans-17a, which is detailed in the following

section, shows that both pyridine ligands are roughly coplanar

and orthogonal to the Cl−Pt−Cl vector.

Ring-closing metatheses of trans-17a,b were carried out

under more dilute conditions (0.001 99−0.002 01 M) with

10 mol % of Grubbs’ catalyst. Reactions were monitored by ¹H

NMR to ensure that all of the vinyl groups were consumed.

However, following hydrogenations and chromatography, the

cyclized products trans-18a,b were obtained as white or off-

white solids in only 22−10% yields. When the synthesis of

Similar reactions of Grubbs’ catalyst with trans-12d,h,i and

subsequent hydrogenations gave the ring-closing metathesis

products trans-13d,h,i as light yellow to off-white solids in 93−

80% overall yields. These feature 14-, 22-, and 24-atom linkers

connecting the pyridine ligands, or 21-, 29-, and 31-membered

macrocycles. The attempted metathesis of trans-12c, which

would have given a 19-membered macrocycle, did not give any

products that could be chromatographed, implicating polymer

formation. Single crystals of trans-13d and the solvate trans-

13h·CH₂Cl₂were obtained as described in the Experimental

Section. The crystal structures, described in the following

section, confirmed the formulations.

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Scheme 8. Synthesis of a Complex with an Expanded 3,5-Disubstituted Doubly Trans Spanning Bis(pyridine) Ligand

Scheme 9. Atropisomeric Equilibrium (Top) and Exchange

of Diastereotopic Groups via MLL′ Rotation (Bottom)

molecules trans-20d−f,h as light yellow solids in 45−14%

overall yields following chromatography. When the synthesis of

trans-20d was repeated with Grubbs’ second-generation

catalyst, a 12% yield was obtained. This series of complexes

features 14-, 16-, 18-, and 22-atom tethers connecting the two

pyridine rings. This corresponds to 21-, 23-, 25-, and 29-

membered macrocycles. Single crystals of a solvate of the 23-

membered macrocycle trans-20e were obtained, and the crystal

structure is described in the following section.

Finally, PtCl₂and the expanded 3,5-disubstituted pyridine

framework 8 were similarly reacted as shown in Scheme 8.

Workup gave the dichloroplatinum bis(pyridine) complex 22 as

a light yellow solid in 96% yield. Ring-closing metathesis and

hydrogenation as above gave 23 as a yellow solid in 40% yield

after chromatography. This complex features a 14-atom tether

connecting the 3,5-diarylpyridine moieties, making for two 29-

membered macrocycles.

3. Crystal Structures. Bond lengths and angles around

platinum or palladium for the seven crystal structures

mentioned above are summarized in Table 1. Additional tables

of crystallographic data are presented in the Supporting

Information. All bond angles are quite similar, and indicate

nearly idealized square-planar coordination geometries. The

bond lengths are very close to those found earlier for trans-

PtCl₂adducts of pyridine, 3-methylpyridine, 4-methylpyridine,

and 2,6-bis(hydroxymethyl)pyridine^24a,26and are not analyzed

further.

Figure 1 illustrates two views of the molecular structure of

the unbridged complex trans-17a. There is a 2-fold symmetry

axis that contains the N−Pt−N vector and an orthogonal mirror

plane containing the Cl−Pt−Cl vector. One methylene carbon

atom (C3) was disordered, but this could not be resolved.

trans-18a was repeated with Grubbs’ second-generation

catalyst, an 8% yield was obtained. Complexes trans-18a,b

feature 8- and 10-atom linkers connecting the pyridine ligands,

or 13- and 15-membered macrocycles. The crystal structures of

both adducts could be determined, as described below.

As shown in Scheme 7, reactions of PtCl₂with the 3,5-

disubstituted ester containing pyridines 5a,c−f,h gave dichloro-

platinum bis(pyridine) complexes trans-19a,c−f,h as yellow

solids in 94−63% yields after chromatography. These yields are

much higher than those for most of the 2,6-disubstituted

adducts in the preceding section.

Ring-closing metatheses of trans-19d−f,h were carried out

under dilute conditions (0.002 00−0.002 02 M) comparable to

those used for trans-17a,b. Hydrogenations afforded the target

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a

Table 1. Key Bond Lengths (Å) and Angles (deg) in Crystallographically Characterized Complexes

b

trans-17a

trans-11b

trans-13d

trans-13h·CH₂Cl₂

trans-16

trans-18a

trans-18b

trans-20e·2CHCl₃

Bond Lengths

2.2968(16)

M−Cl1

M−Cl2

M−N1

M−N2

2.2926(14)

2.033(5)

2.3204(9)

2.3091(9)

2.028(2)

2.021(2)

2.299(2)

2.3082(19)

2.293(2)

2.288(2)

2.026(5)

2.027(6)

2.018(5)

2.019(6)

2.3126(4)

2.0637(12)

2.3048(8)

2.050(3)

2.3060(7)

2.048(2)

2.2824(17)

2.2919(16)

2.004(4)

2.2985(16)

1.998(5)

2.002(5)

2.033(5)

2.011(4)

Bond and Other Angles

178.22(18)

N1−M−N2

Cl1−M−Cl2

Cl1−M−N1

Cl2−M−N2

Cl1−M−N2

Cl2−M−N1

pyridine/pyridine

180.0

90.0

178.4(8)

179.17(2)

90.49(7)

89.81(7)

90.15(7)

90.4(2)

27.9

177.9(2)

178.4(2)

177.77(7)

177.80(9)

89.54(18)

89.38(19)

90.64(18)

90.65(19)

89.43(18)

89.50(19)

90.47(18)

90.50(19)

1.7

180.0

180.000(1)

180.00(2)

90.64(7)

89.36(7)

0.0

179.20(16)

178.71(6)

90.00(3)

90.78(12)

89.35(13)

89.85(13)

0.1

178.73(6)

90.25(14)

89.76(14)

89.44(14)

90.59(14)

12.4

180.000(3)

90.84(3)

90.84(3))

89.16(3)

0.0

180.00(3)

90.66(8)

89.34(8)

0.0

90.0

90.000(1)

0.0

c

6.1

d

Cl−M−Cl/pyridine

89.2

86.7

52.8

54.9

76.4

79.1

79.2

63.3

50.3

a

b

c

M = Pt except for trans-16 (Pd). The doubled values are for two independent molecules in the unit cell. The angle defined by the planes of the

d

two pyridine ligands. Angle defined by the Cl−M−Cl vector and the plane or average plane of the two pyridine ligands.

proposed for the atropisomers in Scheme 9 (top). This mini-

mizes steric interactions between the chloride ligands and the

2,6-substituents and in turn “preorganizes” the CHCH₂

moieties with respect to intramolecular metathesis.

The crystal structure of the 13-membered macrocycle trans-

11b is depicted in Figure 2. The pyridine rings are no longer

coplanar and define an angle of 27.9°. However, the Cl−Pt−Cl

vectors remain approximately orthogonal (86.6−86.7°) to the

“average” of the two planes (Figure 2, bottom).

The crystal structure of the 21-membered macrocycle trans-

13d revealed two independent molecules in the unit cell. In

one, two of the methylene groups in the O(CH₂)₁₀O segment

were disordered (80:20 occupancies), and in the other, six

((70−50):(30−50) occupancies). In the former, which is

depicted in Figure 3, the C−CH₂−O−CH₂bonds are nearly

perpendicular to the planes of the pyridine rings, as reflected by

torsion angles of 84.0−89.2°. In the latter, the same bonds are

nearly coplanar with the pyridine rings, with torsion angles of

4.8−6.6°. The pyridine rings in both molecules are nearly

coplanar (6.1−1.7° angles). However, the Cl−Pt−Cl vectors

show the greatest deviations from orthogonality in this series of

complexes (52.8−50.3°), as readily seen in Figure 3 (bottom).

The crystal structure of the 29-membered macrocycle trans-

13h·CH₂Cl₂is depicted in Figure 4. The pyridine rings are

approximately coplanar (middle view), defining a quite small

angle (12.4°). However, the Cl−Pt−Cl vector again shows a

large deviation from orthogonality (54.9°). Interestingly, the

solvate molecule lies within the macrocycle and, as shown in

the bottom view, fills a substantial portion of the enclosed

space.

Figure 1. Thermal ellipsoid plots (50% probability level) of trans-17a: (top)

view along the Cl−Pt−Cl axis; (bottom) view along the N−Pt−N axis.

Importantly, the pyridine rings are coplanar and essentially

orthogonal to the Cl−Pt−Cl vector (89.2°; see Table 1), as

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Figure 3. Thermal ellipsoid plots (50% probability level) of trans-13d

(dominant conformation of one of two independent molecules in the

unit cell): (top) view of the coordination plane; (bottom) view along

the N−Pt−N axis.

OC linkages of all four ester groups are anti to the C^...C^...N

moieties, as reflected by O−C−C−C(N) torsion angles of

176.5−163.4°. Furthermore, all of the OC−O−CH₂linkages

exhibit Z conformations, as reflected by torsion angles of 4.0−

0.1°. The pyridine rings are essentially coplanar (0.1° angle),

but the Cl−Pt−Cl vector shows a large deviation from ortho-

gonality (63.3°). In contrast to trans-13h·CH₂Cl₂, only one

chlorine atom of each solvate molecule projects (partially) into

the macrocycle cavity.

Figure 2. Thermal ellipsoid plots (50% probability level) of trans-11b:

(top) view in the general direction of the Cl−Pt−Cl axis; (bottom)

view along the N−Pt−N axis.

4. Other Reactions. For reasons amplified in the

Discussion, the substitution chemistry of several complexes

was briefly explored. In response to some unanticipated results

below, the unbridged 3-substituted pyridine complexes trans-

12b,h were combined with the Grignard reagent CH₃MgBr

(2.5−3.0 equiv), as shown in Scheme 10. Chromatography gave

the monosubstituted chloroplatinum methyl complexes trans-

24b,h as white solids in 94−67% yields. Analogous reactions of

the monobridged analogues trans-13d,h afforded the chloro-

platinum methyl complexes trans-25d,h, albeit in slightly lower

yields of 65−41%. The methyl ligands gave characteristic

The molecular structure of the doubly bridged 11-membered

cycle trans-16, derived from the hydrogenation of Lambert's

trans-15 (VII), is depicted in Figure 5. It exhibits an inversion

center at palladium, rendering many of the bond lengths and

angles in Table 1 identical. The pyridine rings are coplanar, but

the Cl−Pd−Cl vector is not orthogonal (76.4°).

The molecular structures of the 13- and 15-membered

macrocycles trans-18a,b are illustrated in Figures 6 and 7,

respectively. Both exhibit an inversion center at platinum. For

the latter, three methylene groups are disordered and refine to

a 81:19 occupancy ratio. Only the dominant conformation is

depicted. For both molecules, the pyridine rings are coplanar,

and the angles with the Cl−Pt−Cl vectors (79.1 and 79.2°) are

close to that of trans-16.

1

upfield H and ¹³C NMR signals (δ 0.87 to 0.93 and −6.4

to −6.6 ppm).

In contrast, the 2,6-disubstituted pyridine complex trans-17a

(Scheme 6) was recovered in at least 80% yield when treated

with CH₃MgBr, various cyanide ion sources, or phenylace-

tylene in the presence of the catalyst CuI and base i-Pr₂NH.

However, the 3,5-disubstituted pyridine complex trans-19c and

Three methylene groups of the 23-membered macrocycle

trans-20e·2CHCl₃were disordered (65:35 to 73:27 occupancy

ratios). The dominant conformation is shown in Figure 8. The

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Figure 5. Thermal ellipsoid plots (50% probability level) of trans-16:

(top) view along the Cl−Pd−Cl axis; (bottom) view along the N−

Pd−N axis.

As shown in Scheme 11, reaction of the 2,6-disubstituted

pyridine 4a and the rhodium bis(cyclooctene) complex

[RhCl(coe)₂]₂under CO afforded the trans rhodium carbonyl

chloride bis(pyridine) complex trans-27a as an orange solid in

26% yield after chromatography. However, in contrast to the

platinum analogues in Scheme 6, reactions of 0.017−0.0020 M

CH₂Cl₂solutions with Grubbs’ catalyst never gave a detectable

quantity of a monorhodium metathesis product, although

the starting material was consumed. Unsuccessful attempts to

improve the yield of trans-27a, or prepare analogous adducts of

4b−d, are described elsewhere.^14a

1

Nonetheless, the H NMR spectrum of trans-27a proved

relevant. The two protons on the methylene group between the

Figure 4. Structural representations of trans-13h·CH₂Cl₂: thermal

ellipsoid plots (50% probability level) with the solvate molecule

omitted in the general direction of the Cl−Pt−Cl axis (top) and along

the N−Pt−N axis (middle); space-filling model (bottom).

pyridine ring and ether oxygen atom (NCCH₂O) gave two

2

significantly separated doublets (δ 5.76 and 5.64 ppm; J_HH

=

15 Hz), indicating a diastereotopic relationship. This is

highlighted in the partial structure IX in Scheme 9 (bottom).

Importantly, the diasteretopic protons (H_a/H_b) would be

exchanged when the Cl−Rh−CO moiety rotates by 180°.²⁷

Apparently, this is slow on the NMR time scale, even in this

unbridged system.

phenylacetylene reacted in the presence of CuI and i-Pr₂NH

to give the phenylacetylide complex trans-26c (Scheme 10,

bottom) as a pale yellow solid in 18% yield after

chromatography.

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Figure 7. Thermal ellipsoid plots (50% probability level) of trans-18b:

(top) view along the Cl−Pt−Cl axis; (bottom) view along the N−Pt−

N axis. The three disordered atoms are depicted in their dominant

conformations.

Figure 6. Thermal ellipsoid plots (50% probability level) of trans-18a:

(top) view along the Cl−Pt−Cl axis; (bottom) view along the N−Pt−

N axis.

DISCUSSION

■

1. Scope of Syntheses. Schemes 3−8 establish that a

variety of platinum and palladium complexes with macrocyclic

singly and doubly trans-spanning bis(pyridine) ligands can be

accessed by ring-closing alkene metatheses of precursors with

appropriately functionalized trans pyridine ligands. Although

the one rhodium species studied, trans-27a (Scheme 11), could

not be similarly cyclized, phosphine analogues have been

successfully converted to gyroscope-like complexes of the type

IV in Scheme 1.^6,7Note that the platinum analogue of trans-

27a, trans-17a, gives the lowest yield of all the bis-macro-

cyclizations reported (10%; Scheme 6). Hence, we believe

that rhodium adducts of other disubstituted pyridine ligands

employed above would give reasonable yields of doubly trans-

spanning bis(pyridine) complexes.

In relevant earlier work, van Koten, Kang, and Ko have

studied metatheses of platinum pincer complexes of dialkeny-

lated pyridines.^28,29Three of many examples are collected in

Scheme 12. The first two involve intraligand metatheses of 3,5-

and 2,6-disubstituted systems (eqs i and ii). The third example

features a 3-fold interligand metathesis to a metacyclophane-like

macrocycle.

Equation i of Scheme 12 features the same ligand as in trans-

19d (Scheme 7), but we observed only interligand metathesis to

trans-20d (one chromatographically mobile product). Impor-

tantly, no special attempt has been made to establish thermo-

dynamic control in any of our reactions, although this has been

unambiguously reached in certain cases.³⁰Furthermore, Fogg

Figure 8. Thermal ellipsoid plots (50% probability level) of trans-

20e·2CHCl₃with the solvate molecules omitted: (top) view along

the Cl−Pt−Cl axis; (bottom) view along the N−Pt−N axis. The

disordered atoms are depicted in their dominant conformations.

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Scheme 10. Substitution Reactions

Scheme 11. Synthesis of a Rhodium 2,6-Disubstituted Bis(pyridine) Complex

has emphasized that oligomers sometimes dominate kinetically

in ring-closing metatheses but can convert to monocyclic pro-

ducts given sufficient time, catalyst, and ethylene coproduct.³¹

Thus, there remains much potential for optimization in the

preceding chemistry.

The preparative data in Schemes 3−8 and 10 suggest a

myriad of steric effects. For example, the yields of the 3-

substituted pyridine complexes in Scheme 4 are higher than

those of the 2-substituted homologues in Scheme 3. Similarly,

the yields of the 2,6-disubstituted pyridine complexes in

Schemes 5 and 6 are generally lower than those of the related

3,5-disubstituted pyridine complexes in Schemes 7 and 8.

All attempts to effect substitution of the chloride ligands in

2,6-disubstituted pyridine complexes were unsuccessful, in con-

trast to the examples involving 3-substituted or 3,5-disubsti-

tuted pyridine complexes in Scheme 10.

The congestion inherent in the 2,6-disubstituted pyridine

complexes is readily seen in the fragment IX in Figure 9, which

is taken from the crystal structure of the unbridged adduct

trans-17a, including the coplanar pyridine rings (Figure 1).

Projection IXa highlights the distance between the carbon

atoms bound to the 2,6-positions on opposite pyridine ligands,

ca. 3.83 Å. This is somewhat greater than twice the van der

Waals radius of an sp³carbon atom (1.70 Å),³²as illustrated by

projection IXc, a perpendicular view with the carbon and

chlorine atoms shown at van der Waals radii. The difference,

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Scheme 12. Other Alkene Metatheses Involving Pyridine Ligands in Metal Coordination Spheres

greater clearance for the 2-monosubstituted complex trans-11b

(0.87 Å) arises from the noncoplanarity or skewing of the

pyridine rings (Table 1).

2. Feasibility of MCl₂Rotation. The long-term goal of this

project is to synthesize molecular rotors¹²in which a transition-

metal-based rotator can turn within a macrocyclic cage (stator)

with as low an energy barrier as possible. In this context, a

key issue is the interior space available within the macrocycles

̀

vis-a-vis the sizes of the ligands on the metal. Analyses of

the type in Figure 10 have proven to be particularly helpful

Figure 9. Steric relationships between the carbon atoms bound to the

2,6-pyridine positions and the chlorine atoms in trans-17a.

0.43 Å, can be viewed as a “top−bottom clearance”. As summa-

rized in Table 2, comparable values are found for the other

2,6-disubstituted complexes, all of which have coplanar pyridine

rings (0.45−0.63 Å; trans-16, trans-18a,b). The somewhat

Table 2. Distances (Å) Relevant to Rotator Rotation in

Crystalline Complexes

closest

intermolecular

contact

MCl₂

bridge

top−bottom

b

a

complex

trans-17

radius height

clearance

c

4.04

0.43

3.38

2.62

2.51

c

trans-11

4.06

4.05

4.06

4.05

4.06

4.04

3.40

5.37

5.00

7.58

2.58

2.49

4.38

0.87

d

e

trans-13d

1.90

e

1.91

e

trans-13h·CH₂Cl₂

trans-16

1.92

1.87

3.59

3.13

2.89

3.21

f

c

0.58

Figure 10. Estimation of “horizontal clearance” or “bridge height” in

Table 2, illustrated for trans-18b.

c

trans-18a

0.63

c

trans-18b

0.45

e

trans-20e·2CHCl₃

7.66

1.93

in correlating properties of the bis(phosphine) systems in

Scheme 1. First, the radius of the MCl₂moiety is calculated by

adding the crystallographically determined metal−chlorine

bond distance (Table 1) and the van der Waals radius of

a

b

c

d

See Figure 10. See Figure 9. 2- or 2,6-substitution. The two sets of

values correspond to the two independent molecules in the unit cell.

e

f

3- or 3,5-substitution. PdCl₂radius; other values are PtCl₂radii.

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Figure 11. Space-filling representations of the molecular structures of trans-18a, trans-18b, and trans-20e.

chlorine (1.75 Å).³²As summarized in Table 2, essentially the

same value is obtained for all the platinum and palladium com-

plexes (average 4.05 Å).

processes that readily occur in organic molecules despite

van der Waals interactions involving hydrogen atoms and/or

not being able to execute them with space-filling models.

Hence, only non-hydrogen atoms have been considered in this

admittedly qualitative analysis.

Figure 11 provides side-by-side comparisons that illustrate

the preceding concepts. In 2,6-disubstituted trans-18a, the

bridge height is smaller than the PtCl₂radius, and the top−

bottom clearance is much smaller than the diameter of chlorine.

In trans-18b, the latter still holds, but the bridge height is larger

than the PtCl₂radius. With 3,5-disubstituted trans-20e, the

bridge height is much larger than the PtCl₂radius, and the

top−bottom clearance is the maximum possible for this series

of compounds. Complexes trans-20h and trans-23 (Schemes 7

and 8), in which the macrocycles are even larger (29 vs the 23

atoms in trans-20e), would make a still more spacious visual

impression.

In any case, the top−bottom clearance in trans-20e is

admittedly snug with respect to a chlorine ligand, especially

in view of the hydrogen atoms that have been neglected.

However, this can to some extent be ameliorated if the pyridine

ligands skew away from coplanarity, as reflected by the trend

with trans-11b in Table 2. In effect, this would replace an

energy maximum with two closely spaced but lower energy

maxima. Interactions might also be attenuated by employing

second- or third-row donor atoms, which would feature longer

metal−heteroatom bonds.

The distances between the metal atom and the remote

carbon atoms of each macrocycle chain are then calculated,

utilizing the two carbon atoms closest to the plane that would

be defined by MCl₂rotation. As shown in Figure 10, these vary,

and the shortest distance among the four possibilities is taken.

The van der Waals radius of carbon is then subtracted, giving a

“horizontal clearance” or “bridge height”. The resulting dis-

tances are summarized in Table 2. However, it should be kept

in mind that an equilibrium ensemble of macrocycle con-

formations would be expected in solution, and any impression

of a rigid steric barrier is unintended.

In any case, the PtCl₂radii in trans-13d, trans-13h·CH₂Cl₂,

trans-18b, and trans-20e·2CHCl₃are less than the respective

bridge heights (Table 2), fulfilling one steric condition

for PtCl₂rotation. These complexes represent the largest

macrocycle based upon a 2,6-disubstituted pyridine (trans-18b,

15-membered), and all of the macrocycles based upon 3-sub-

stituted (trans-13d, trans-13h·CH₂Cl₂, 21- and 29-membered)

and 3,5-disubstituted pyridines (trans-20e·2CHCl₃, 23-mem-

bered). However, in the 2,6-disubstituted complex trans-18b,

the top−bottom clearance is much less than the van der Waals

diameter of a chlorine atom (0.45 Å vs 3.50 Å). This is depicted

in projection IXc in Figure 9 and would render rotation a very

high energy process.

For the 3-substituted and 3,5-disubstituted complexes, the

top−bottom clearance can be estimated as follows. First, the

shortest distance between the 2,2′- or 6,6′-carbon atoms is

identified. In the case of reference molecule trans-17a, this is

5.44 Å (Figure 9, IXa). Next, two times the van der Waals

radius of carbon is subtracted. As summarized in Table 2,

this gives distances in the range of 1.90−1.98 Å. In the absence

of any skewing of the pyridine rings, this would have to

accommodate the full diameter of a chlorine atom: ca. 3.50 Å.

Obviously, this steric requirement is poorly fulfilled, and none

of the compounds in this first-generation synthetic study pro-

vide an experimental test of MCl₂rotation. Per the analysis

Apart from these intramolecular issues, another question is

whether any of the MCl₂moieties would be able to undergo

rotation in the crystal lattice. It is a simple matter to calculate

the distance between the metal and the closest atom in a

neighboring molecule, and these are summarized in Table 2. In

every case, the closest contact is less than the MCl₂radius.

Hence, the rotational barriers should be extremely high, even in

the absence of intramolecular contacts. In principle, the onset

of any rotation in the solid state could be evidenced by a phase

transition. Out of all the macrocyclic complexes for which

DSC data were recorded (trans-18b, trans-20d,e,f,h), only one

showed an endotherm considerably below the melting or

decomposition point (trans-20e).

1

in Scheme 9 (bottom), the H NMR properties of rhodium

carbonyl chloride analogues of any of these complexes would

be diagnostic of Cl−Rh−CO rotation.

Furthermore, note that the hydrogen atoms in the 2,2′- or

6,6′-positions have not been taken into accountas was also

the case for complexes with 2,6-substituents (Figure 9).

Hydrogen atoms have also been omitted in all space-filling

representations in this paper. There are many conformational

We note in passing that, for doubly bridged trans-18b and

trans-20e·2CHCl₃, all molecules exhibit parallel Cl−M−Cl

axes in the crystal lattice. In contrast, trans-16 and trans-18a

show two sets of molecules with parallel axes. These axes

define angles of 44 and 82°, respectively, as calculated from

six atom planes generated from two parallel Cl−M−Cl seg-

ments. Representative packing diagrams are given elsewhere.¹⁴

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solvents were purified by simple distillation or used as received. Silica

(Acros, 60 A) and alumina (neutral, Macherey-Nagel) were used as

received.

Trigonal-bipyramidal systems such as III (Scheme 1)

commonly pack in layers with all P−M−P axes parallel,⁴but

other coordination geometries do not appear to exhibit strong

preferences.

The CDCl₃was stored over molecular sieves (Deutero GmbH) or

used as received (Cambridge Isotope Laboratories). Other chemicals

were used as received: DMSO-d₆(Aldrich), sodium (J. T. Baker, ACS

reagent), allyl alcohol (Alfa Aesar, 98%), 3-buten-1-ol (TCI or Acros

Organics, 96−95%), 4-penten-1-ol (TCI or Acros Organics, 98−97%),

5-hexen-1-ol (TCI, 95%), 6-hepten-1-ol (TCI, 95%), 7-octen-1-ol

(TCI, >96%), 9-decen-1-ol (TCI or Aldrich, 97%-95%), 10-undecen-

1-ol (TCI, 95%), 3-(chloromethyl)pyridine hydrochloride (Alfa Aesar,

97%), 2-(chloromethyl)pyridine hydrochloride (TCI, 98%),

3. Toward Molecular Gyroscopes. The singly bridged bis

(pyridine) complexes belong to a class of compounds that have

been referred to as rope-skipping rotors,¹²and the doubly

bridged bis(pyridine) complexes belong to a class of com-

pounds that have been termed molecular turnstiles.³⁴The

former are in principle quite numerous, whereas the latter are

less common if required to closely approximate “revolving

door” symmetry. The prototype would be Moore's system X in

Figure 12, but the descriptor has also been applied to molecules

in the rope-skipping category³⁵and other assemblies.³⁶

+

C₆H₅CH₂N(CH₃)₃Cl⁻(Aldrich, 97%), 2,6-bis(bromomethyl)-

pyridine (Aldrich, 98%), PtCl₂(ABCR, 99.9%), trans-(PhCN)₂PtCl₂

(Alfa Aesar, 98%), trans-(PhCN)₂PdCl₂(Acros, 99%), [RhCl(coe)₂]₂

(Acros, 97%), Grubbs’ catalyst (Ru(CHPh)(PCy₃)₂(Cl)₂; Aldrich),

CuI (Acros, 99.9%), i-Pr₂NH (Fluka, 99%), PhCCH (Acros, 98%),

PtO₂(Aldrich), Pd/C (Lancaster or Acros, 10%), pyridine-3,5-

dicarboxylic acid (Aldrich), 3,5-dichloropyridine (TCI or Aldrich,

98%), 4-bromoanisole (Alfa Aesar, 99%), BBr₃(Aldrich, 1.0 M in

CH₂Cl₂), Cs₂CO₃(Alfa Aesar, 99.9%), 7-bromo-1-heptene (Aldrich,

97%), CH₃MgBr (Acros, 3.0 M in diethyl ether; titration vs I₂gave

2.94 M),³⁷H₂CCHCH₂MgBr (Fluka, 1.0 M in diethyl ether),

magnesium (Alfa Aesar, 99.8%), NH₄Cl (Mallinckrodt, 99.5%), and

(dppp)NiCl₂(Strem, 99%). The bis(acid chloride) 3,5-NC₅H₃-

(COCl)₂³⁸and Grubbs’ second-generation catalyst Ru(CHPh)-

(H₂IMes)(PCy₃)(Cl)₂³⁹were synthesized by literature procedures.

NMR spectra were recorded on 500−300 MHz spectrometers and

1

referenced as follows: H, residual internal CHCl₃(δ, 7.26 ppm) or

DMSO-d₅(δ, 2.50 ppm); ¹³C, internal CDCl₃(δ, 77.23 ppm). The ¹H

and ¹³C NMR signals of the free and coordinated nitrogen donor

ligands were assigned on the basis of literature generalizations.^24,25IR

spectra were recorded using ATR accessories. DSC data were treated

by standard methods.⁴⁰Instrument models are detailed elsewhere.¹⁴

2-NC₅H₄(CH₂OCH₂CHCH₂) (1a). A Schlenk flask was charged

with sodium (0.8942 g, 36.94 mmol) and allyl alcohol (15.6510 g,

269.47 mmol). The mixture was stirred at 80 °C (oil bath) until the

sodium was consumed and cooled to room temperature. Then 2-

(chloromethyl)pyridine hydrochloride (2.4870 g, 15.161 mmol) was

added and the mixture kept at 80 °C for 16 h. The excess alcohol was

removed by oil pump vacuum at 80 °C. Water and CH₂Cl₂were added

to the residue. The phases were separated and the aqueous phase

extracted with CH₂Cl₂(2 × 50 mL). The combined CH₂Cl₂layers

were dried (MgSO₄). The solvent was removed by oil pump vacuum.

The residue was eluted through a silica column (8 × 1.5 cm) with

ethyl acetate (300 mL). The solvent was removed from the product

fraction by oil pump vacuum to give spectroscopically pure 1a as a

Figure 12. Other relevant molecular rotors.

Regardless of the MCl₂rotational barriers associated with our

complexes, the MCl₂moieties of individual molecules would

exhibit both clockwise and counterclockwise motion. However,

in order to attain functional gyroscopic properties, unidirec-

tional rotation is required. One strategy for controlling the

direction of a rotator involves introducing a dipole moment,

such that it can be oriented by a static applied electric field or

driven by a rotating electric field.^12,33Both substitution reac-

tions of the types in Scheme 10, and ring-closing metatheses of

less symmetrical substratessuch as rhodium carbonyl chloride

analogues of the preceding platinum dichloride complexes

should provide practical routes to such species, especially now

that certain limitations of these processes have been defined.

Macroscopic gyroscopes are almost always found within

housings to shield the moving parts. The rotators in our doubly

bridged bis(pyridine) adducts are somewhat more exposed than

those in the diphosphine systems in Scheme 1. However, this

renders them superior for other purposes such as gearing, i.e.

the coupling of rotation between rotors in ordered arrays. In

summary, this study has established much valuable baseline

data pertaining to the synthesis of molecular rotors based upon

bridged trans bis(pyridine) complexes. Key structural, steric,

and conformational properties have also been elucidated.

Additional studies, including full papers detailing the types of

complexes in Scheme 1, will be reported shortly.

1

brown oil (1.3682 g, 9.1776 mmol, 61%). NMR (δ, CDCl₃): H 8.54

(m, 1H, o-HC_6pyr), 7.68 (m, 1H, p-HC_4pyr), 7.45 (m, 1H, m-HC_3pyr),

3

7.17 (m, 1H, m-HC_5pyr), 6.01−5.92 (ddt, 1H, J_HHtrans= 17.3 Hz,

³J_HHcis= 10.3 Hz, ³J_HH= 5.5 Hz, CH), 5.35−5.19 (m, 2H, CH₂),

4.64 (s, 2H, CH₂O), 4.11 (m, 2H, OCH₂CH); ¹³C{¹H} 158.7 (s, o-

C_2pyr), 149.2 (s, o-C_6pyr), 136.8 (s, CH), 134.6 (s, p-C_4pyr), 122.5 (s,

m-C_3pyr), 121.5 (s, m-C_5pyr), 117.5 (s, CH₂), 73.1 (s, CH₂O), 72.0 (s,

OCH₂CH). These data agreed with those previously reported for an

alternative synthesis.¹⁵IR (cm⁻¹, neat oil): 3076 (w), 2859 (w), 1717

(m), 1591 (m), 1306 (m), 1244 (m), 1107 (s), 1084 (s), 993 (s), 926

(s), 758 (s).

2-NC₅H₄(CH₂O(CH₂)₂CHCH₂) (1b). 3-Buten-1-ol (14.0023 g,

194.19 mmol), sodium (0.6338 g, 27.57 mmol), and 2-

(chloromethyl)pyridine hydrochloride (1.9507 g, 11.892 mmol)

were combined in a procedure similar to that for 1a (12 h reac-

tion time at 80 °C). An analogous workup gave 1b as a yellow oil

1

(1.8179 g, 11.138 mmol, 59%). NMR (δ, CDCl₃): H 8.53 (m, 1H,

o-HC_6pyr), 7.68 (m, 1H, p-HC_4pyr), 7.44 (m, 1H, m-HC_3p3yr), 7.17 (m,

EXPERIMENTAL SECTION

3

■

1H, m-HC_5pyr), 5.90−5.81 (ddt, 1H, J_HHtrans= 17.1 Hz, J_HHcis= 10.1

3

General Considerations. All reactions were carried out under

inert atmospheres using standard Schlenk and vacuum line techniques.

Workups were conducted in air. Reaction solvents were dried and

deoxygenated by standard protocols detailed elsewhere.¹⁴Workup

Hz, J_HH= 6.9 Hz, CH), 5.14−5.03 (m, 2H, CH₂), 4.64 (s, 2H,

3

CH₂O), 3.62 (t, 2H, J_HH= 6.9 Hz, OCH₂CH₂), 2.41 (m, 2H,

OCH₂CH₂); ¹³C{¹H} 158.9 (s, o-C_2pyr), 149.2 (s, o-C_6pyr), 136.9

(s, CH), 135.3 (s, p-C_4pyr), 122.5 (s, m-C_3pyr), 121.5 (s, m-C_5pyr),

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116.7 (s, CH₂), 73.9 (s, CH₂O), 70.6 (s, OCH₂CH₂), 34.4 (s,

CH₂CH). These data agreed with those previously reported for an

alternative synthesis.¹⁶IR (cm⁻¹, neat oil): 2907 (w), 2859 (m), 1717

(m), 1591 (m), 1435 (s), 1121 (s), 1088 (s), 993 (s), 914 (s), 756 (s).

3-NC₅H₄(CH₂OCH₂CHCH₂) (2a). Allyl alcohol (14.1138 g,

243.01 mmol), sodium (0.9319 g, 40.54 mmol), and 3-

(chloromethyl)pyridine hydrochloride (2.2593 g, 13.773 mmol)

were combined in a procedure similar to that for 1a (12 h reaction

time at 80 °C). An analogous workup gave 2a as a yellow-brown oil

(1.7175 g, 11.512 mmol, 84%). NMR (δ, CDCl₃): ¹H 8.58 (m, 1H, o-

HC_2pyr), 8.54 (m, 1H, o-HC_6pyr), 7.69 (m, 1H, p-HC₄₃_pyr), 7.28 (m, 1H,

3-NC₅H₄(CH₂O(CH₂)₅CHCH₂) (2e). 6-Hepten-1-ol (23.7783 g,

208.24 mmol), sodium (0.6665 g, 28.93 mmol), and 2-

(chloromethyl)pyridine hydrochloride (1.9377 g, 11.813 mmol)

were combined in a procedure similar to that for 1a (sodium

dissolved at 100 °C; 12 h reaction time at 100 °C). An analogous

workup gave 2e as a yellow-brown oil (1.9577 g, 9.5358 mmol, 81%).

NMR (δ, CDCl₃): ¹H 8.56 (m, 1H, o-HC_2pyr), 8.52 (m, 1H, o-HC_6pyr),

7.68 (m, 1H, p-HC_4pyr), 7.28 (m, 1H, m-HC_5pyr), 5.86−5.73 (ddt, 1H,

³J_HHtrans= 17.1 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.6 Hz, CH), 5.03−4.90

3

(m, 2H, CH₂), 4.50 (s, 2H, CH₂O), 3.48 (t, 2H, J_HH= 6.6 Hz,

OCH₂CH₂), 2.04 (m, 2H, CH₂CHCH₂), 1.62 (m, 2H, OCH₂CH₂),

1.44−1.34 (m, 4H, CH₂); ¹³C{¹H} 149.2 and 149.0 (2 s, o-C_2pyrand o-

C_6pyr), 139.1 (s, CH), 135.6 (s, p-C_4pyr), 134.3 (s, m-C_3pyr), 123.6 (s,

m-C_5pyr), 114.6 (s, CH₂), 71.0 (s, CH₂O), 70.5 (s, OCH₂CH₂), 33.9,

29.7, 28.9, and 25.8 (4 s, 4CH₂). IR (cm⁻¹, neat oil): 2932 (m), 2859

(m), 1722 (s), 1420 (m), 1281 (s), 1113 (s), 1024 (m), 910 (m), 743

(s), 702 (s).

3-NC₅H₄(CH₂O(CH₂)₈CHCH₂) (2h). 9-Decen-1-ol (16.7254 g,

107.03 mmol), sodium (0.3096 g, 13.47 mmol), and 3-

(chloromethyl)pyridine hydrochloride (0.8856 g, 5.399 mmol) were

combined in a procedure similar to that for 1a (sodium dissolved at

100 °C; 16 h reaction time at 125 °C). An analogous workup gave 2h

as a yellow-brown oil (1.1231 g, 4.5400 mmol, 84%). NMR (δ,

CDCl₃): ¹H 8.57 (m, 1H, o-HC_2pyr), 8.53 (m, 1H, o-HC_6pyr), 7.68 (m,

3

m-HC_5pyr), 6.01−5.88 (ddt, 1H, J_HHtrans= 17.3 Hz, J_HHcis= 10.4 Hz,

³J_HH= 5.6 Hz, CH), 5.32 (dt, 1H, ³J_HH= 17.3 Hz, ²J_HH= 1.7 Hz, 

CH_EH_Z), 5.23 (dt, 1H, ³J_HH= 10.4 Hz, ²J_HH= 1.7 Hz CH_EH_Z), 4.53

3

4

(s, 2H, CH₂O), 4.05 (dt, 2H, J_HH= 5.6 Hz, J_HH= 1.4 Hz,

OCH₂CH); ¹³C{¹H} 149.4 and 149.3 (2 s, o-C_2pyrand o-C_6pyr), 135.6

(s, CH), 134.5 (s, p-C_4pyr), 133.9 (s, m-C_3pyr), 123.6 (s, m-C_5pyr),

117.8 (s, CH₂), 71.8 (s, CH₂O), 69.7 (s, CH₂CH). IR (cm⁻¹, neat

oil): 2857 (w), 1724 (w), 1578 (m), 1425 (m), 1082 (s), 1026 (m),

926 (m), 791 (m), 712 (s).

3-NC₅H₄(CH₂O(CH₂)₂CHCH₂) (2b). 3-Buten-1-ol (23.1913 g,

321.62 mmol), sodium (1.0569 g, 45.973 mmol), and 3-

(chloromethyl)pyridine hydrochloride (2.4873 g, 15.163 mmol)

were combined in a procedure similar to that for 1a (12 h reaction

time at 80 °C). An analogous workup gave 2b as a yellow-brown oil

(2.2722 g, 13.921 mmol, 92%). NMR (δ, CDCl₃): ¹H 8.57 (m, 1H, o-

HC_2pyr), 8.53 (m, 1H, o-HC_6pyr), 7.67 (m, 1H, p-HC₄₃_pyr), 7.27 (m, 1H,

1H, p-HC_4pyr), 7.27 (m, 1H, m-HC_5pyr), 5.87−5.73 (ddt, 1H, ³J_HHtrans

=

17.1 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.6 Hz, CH), 5.02−4.89 (m, 2H,

CH₂), 4.51 (s, 2H, CH₂O), 3.48 (t, 2H, ³J_HH= 6.6 Hz, OCH₂CH₂),

2.03 (m, 2H, CH₂CHCH₂), 1.61 (m, 2H, OCH₂CH₂), 1.45−1.27

(m, 10H, CH₂); ¹³C{¹H} 149.4 and 149.2 (2 s, o-C_2pyrand o-C_6pyr),

139.4 (s, CH), 135.5 (s, p-C_4pyr), 134.2 (s, m-C_3pyr), 123.6 (s, m-

C_5pyr), 114.3 (s, CH₂), 71.1 (s, CH₂O), 70.5 (s, OCH₂CH₂), 34.0,

29.9, 29.6 (2×), 29.3, 29.1, and 26.3 (6 s, 7CH₂). IR (cm⁻¹, neat oil):

2926 (s), 2854 (s), 1724 (s), 1281 (s), 1111 (s), 1024 (m), 908 (s),

743 (s), 710 (s).

3

m-HC_5pyr), 5.90−5.76 (ddt, 1H, J_HHtrans= 17.0 Hz, J_HHcis= 10.2 Hz,

³J_HH= 6.8 Hz, CH), 5.14−5.02 (m, 2H, CH₂), 4.53 (s, 2H,

3

CH₂O), 3.54 (t, 2H, J_HH= 6.8 Hz, OCH₂CH₂), 2.38 (apparent qt,

3

2H, J_HH= 6.6 Hz, J_HH= 1.4 Hz, OCH₂CH₂); ¹³C{¹H} 149.34 and

149.28 (2 s, o-C_2pyrand o-C_6pyr), 135.5 (s, CH), 135.2 (s, p-C_4pyr),

134.0 (s, m-C_3pyr), 123.6 (s, m-C_5pyr), 116.8 (s, CH₂), 70.6 (s,

CH₂O), 70.1 (s, OCH₂CH₂), 34.3 (s, CH₂). IR (cm⁻¹, neat oil): 2860

(w), 1722 (s), 1591 (m), 1427 (m), 1283 (s), 1096 (s), 1024 (s), 916

(s), 791 (m), 743 (s), 712 (s).

3-NC₅H₄(CH₂O(CH₂)₉CHCH₂) (2i). 10-Undecen-1-ol (23.3818 g,

137.31 mmol), sodium (0.4430 g, 19.27 mmol), and 2-(chloromethyl)-

pyridine hydrochloride (1.4139 g, 8.6195 mmol) were combined in a

procedure similar to that for 1a (sodium dissolved at 100 °C; 16 h

reaction time at 125 °C). An analogous workup gave 2i as a yellow-

3-NC₅H₄(CH₂O(CH₂)₃CHCH₂) (2c). 4-Penten-1-ol (27.3842 g,

39.793 mmol), sodium (1.0307 g, 44.833 mmol), and 2-

(chloromethyl)pyridine hydrochloride (2.9548 g, 18.013 mmol)

were combined in a procedure similar to that for 1a (12 h for sodium

consumption at 80 °C; 12 h reaction time at 100 °C). An analogous

workup gave 2c as a yellow oil (2.2281 g, 12.571 mmol, 70%). NMR

1

brown oil (1.7982 g, 6.8791 mmol, 80%). NMR (δ, CDCl₃): H 8.57

(m, 1H, o-HC_2pyr), 8.53 (m, 1H, o-HC_6pyr), 7.68 (m, 1H, p-HC_4pyr),

3

7.28 (m, 1H, m-HC_5pyr), 5.85−5.76 (ddt, 1H, J_HHtrans= 17.1 Hz,

³J_HHcis= 10.3 Hz, ³J_HH= 6.8 Hz, CH), 5.01−4.91 (m, 2H, CH₂),

1

(δ, CDCl₃): H 8.57 (m, 1H, o-HC_2pyr), 8.53 (m, 1H, o-HC_6pyr), 7.68

3

4.51 (s, 2H, CH₂O), 3.48 (t, 2H, J_HH= 6.5 Hz, OCH₂CH₂), 2.03

(m, 1H, p-HC_4pyr), 7.28 (m, 1H, m-HC_5pyr), 5.87−5.73 (ddt, 1H,

(m, 2H, CH₂CHCH₂), 1.61 (m, 2H, OCH₂CH₂), 1.40−1.24 (m,

12H, CH₂); ¹³C{¹H} 148.9 and 148.8 (2 s, o-C_2pyrand o-C_6pyr), 139.2

(s, CH), 135.5 (s, p-C_4pyr), 134.1 (s, m-C_3pyr), 123.4 (s, m-C_5pyr),

114.1 (s, CH₂), 70.9 (s, CH₂O), 70.3 (s, OCH₂CH₂), 33.8, 29.7,

29.4 (2×), 29.4, 29.1 (2×), and 26.1 (6 s, 8CH₂). IR (cm⁻¹, neat oil):

2924 (s), 2853 (s), 1724 (s), 1427 (m), 1281 (s), 1098 (s), 908 (s),

712 (s).

³J_HHtrans= 17.1 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.6 Hz, CH), 5.05−4.93

3

(m, 2H, CH₂), 4.51 (s, 2H, CH₂O), 3.50 (t, 2H, J_HH= 6.5 Hz,

OCH₂CH₂), 2.14 (m, 2H, CH₂CHCH₂), 1.71 (m, 2H, OCH₂CH₂);

¹³C{¹H} 149.2 and 149.1 (2 s, o-C_2pyrand o-C_6pyr), 138.3 (s, CH),

135.6 (s, p-C_4pyr), 134.2 (s, m-C_3pyr), 123.6 (s, m-C_5pyr), 115.1 (s, 

CH₂), 70.5 (s, CH₂O), 70.3 (s, OCH₂CH₂), 30.5 (s, CH₂), 29.0

(s, CH₂). IR (cm⁻¹, neat oil): 2938 (m), 2860 (m), 1722 (s), 1427

(m), 1281 (s), 1097 (s), 912 (s), 712 (s).

2,6-NC₅H₃(CH₂CH₂CHCH₂)₂(3).¹³A round-bottom flask was

charged with 2,6-bis(bromomethyl)pyridine (2000 g, 7.549 mmol)

and THF (76 mL). The solution was cooled to 0 °C with stirring.

After 15 min, H₂CCHCH₂MgBr (1.0 M in diethyl ether; 19 mL,

19.0 mmol) was added dropwise over 20 min. The cold bath was

removed. After 18 h, cold saturated aqueous NH₄Cl (20 mL) was

added dropwise over 20 min. The organic layer was collected, washed

with water (3 × 20 mL), and dried (MgSO₄). The solvent was

removed by rotary evaporation. The orange residue was chromato-

graphed on a silica column (40 × 3 cm, 5/1 v/v hexanes/ethyl

acetate). The solvents were removed from the product-containing

fractions by rotary evaporation and oil pump vacuum to give 3 as a

3-NC₅H₄(CH₂O(CH₂)₄CHCH₂) (2d). 5-Hexen-1-ol (12.9850 g,

129.64 mmol), sodium (0.7838 g, 34.09 mmol), and 3-

(chloromethyl)pyridine hydrochloride (1.9432 g, 11.846 mmol)

were combined in a procedure similar to that for 1a (sodium

dissolved at 100 °C; 12 h reaction time at 100 °C). An analogous

workup gave 2d as a yellow-brown oil (1.0806 g, 5.6496 mmol, 48%).

NMR (δ, CDCl₃): ¹H 8.56 (m, 1H, o-HC_2pyr), 8.53 (m, 1H, o-HC_6pyr),

7.67 (m, 1H, p-HC_4pyr), 7.27 (m, 1H, m-HC_5pyr), 5.87−5.72 (ddt, 1H,

³J_HHtrans= 17.0 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.6 Hz, CH), 5.04−4.91

3

(m, 2H, CH₂), 4.50 (s, 2H, CH₂O), 3.49 (t, 2H, J_HH= 6.5 Hz,

1

yellow oil (0.847 g, 4.52 mmol, 60%). NMR (δ, CDCl₃): H 7.50 (t,

OCH₂CH₂), 2.06 (m, 2H, CH₂CHCH₂), 1.63 (m, 2H, OCH₂CH₂),

1.46 (m, 2H, OCH₂CH₂CH₂); ¹³C{¹H} 152.7 and 152.5 (2 s, o-C_2pyr

and o-C_6pyr), 138.8 (s, CH), 137.4 (s, p-C_4pyr), 136.8 (s, m-C_3pyr),

125.1 (s, m-C_5pyr), 114.9 (s, CH₂), 71.2 (s, CH₂O), 69.3

(s, OCH₂CH₂), 33.7, 29.2, and 25.6 (3 s, 3CH₂). IR (cm⁻¹, neat

oil): 2934 (m), 2859 (m), 1639 (m), 1429 (m), 1097 (s), 1028 (m),

933 (m), 791 (m), 712 (s).

1H, ³J_HH= 7.7 Hz, p-HC_4pyr), 6.96 (d, 2H, ³J_HH= 7.7 Hz, m-HC_3,5pyr),

3

5.88 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis= 10.3 Hz, J_HH= 6.6 Hz,

3

2

CH), 5.05 (dd, 2H, J_HHtrans= 17.1 Hz, J_HH= 1.9 Hz, CH_EH_Z),

4.97 (dd, 2H, ³J_HHcis= 10.2 Hz, ²J_HH= 1.3 Hz, CH_EH_Z), 2.87 (t, 4H,

³J_HH= 7.8 Hz, CH₂), 2.49 (q, 4H, ³J_HH= 7.4 Hz, CH₂); ¹³C{¹H} 160.9

(s, o-C_2,6pyr), 137.9 (s, CH), 136.4 (s, p-C_4pyr), 120.0 (s, m-C_3,5pyr),

2867

dx.doi.org/10.1021/om201145x | Organometallics 2012, 31, 2854−2877

Organometallics

Article

3

2

114.9 (s, CH₂), 37.8 (s, CH₂), 34.0 (s, CH₂). IR (cm⁻¹, oil film):

3076 (w), 2922 (m), 2853 (w), 1640 (m), 1579 (s), 1455 (s), 996 (s),

911 (s), 804 (m), 749 (m). MS:⁴¹188 ([21 + H]⁺, 80%), 133 ([21 −

CH₂CH₂CHCH₂]⁺, 100%).

Hz, J_HH= 6.7 Hz, CH), 4.98 (dd, 2H, J_HHtrans= 17.1 Hz, J_HH

=

1.8 Hz, CH_EH_Z), 4.93 (dd, 2H, ³J_HHcis= 10.2 Hz, ²J_HH= 1.6 Hz, 

CH_EH_Z), 4.59 (s, 4H, CH₂O), 3.54 (t, 4H, ³J_HH= 6.5 Hz, OCH₂CH₂),

2.09−2.01 (m, 4H, CH₂), 1.68−1.62 (m, 4H, CH₂), 1.51−1.45 (m,

4H, CH₂); ¹³C{¹H} 157.8 (s, o-C_2,6pyr), 138.5 (s, p-C_4pyr), 136.8 (s,

CH), 120.8 (s, m-C_3,5pyr), 115.1 (s, CH₂), 74.5 (s, CH₂O), 70.2 (s,

OCH₂CH₂), 33.8, 30.3, and 28.7 (3 s, CH₂). These data agreed

reasonably well with those previously reported (in acetone-d₆) for an

alternative synthesis.¹⁹IR (cm⁻¹, oil film): 3078 (w), 2941 (m), 2870

(m), 1645 (s), 1600 (s), 1448 (s), 1350 (s), 1120 (s), 994 (s), 915 (s),

785 (s). MS:⁴²304 ([4d + H]⁺, 100%).

2,6-NC₅H₃(CH₂OCH₂CHCH₂)₂(4a). A Schlenk flask was

charged with 2,6-bis(bromomethyl)pyridine (3.300 g, 12.45 mmol),

+

allyl alcohol (3.620 g, 62.32 mmol), and C₆H₅CH₂N(CH₃)₃Cl⁻

(0.464 g, 2.50 mmol, 20 mol %) and fitted with a condenser. The

solution was refluxed with stirring (24 h), cooled to room temperature,

and poured into water (20 mL). The organic layer was separated. The

aqueous layer was extracted with CH₂Cl₂(4 × 10 mL). The organic

layer and the extracts were combined, washed with water (3 × 20 mL)

and saturated aqueous NaHCO₃(4 × 20 mL), and dried (MgSO₄).

The solvent was removed by rotary evaporation. The yellow residue

was chromatographed on a silica column (40 × 3 cm, 4/1 v/v

hexanes/ethyl acetate). The solvents were removed from the product-

containing fractions by rotary evaporation and oil pump vacuum to

give 4a as a light yellow oil (1.503 g, 6.86 mmol, 55%). Continued

elution of the column afforded the byproduct 2,6-NC₅H₃(CH₂Br)-

(CH₂OCH₂CHCH₂), identified from an ¹H NMR spectrum

3,5-NC₅H₃(COOCH₂CHCH₂)₂(5a). A round-bottom flask was

charged with 3,5-NC₅H₃(COCl)₂(1.224 g, 6.002 mmol) and CH₂Cl₂

(20 mL) and cooled to 0 °C. Allyl alcohol (0.7442 g, 13.16 mmol) was

added dropwise over 20 min with stirring. The cold bath was removed.

After 1 h, the flask was fitted with a condenser. The solution was

refluxed (5 h) and cooled to room temperature. The solvent was

removed by rotary evaporation. Hexanes was added (10 mL). The off-

white residue was collected by filtration and washed with hexanes until

a white solid was obtained (8 × 5 mL). The solid was dissolved in

CH₂Cl₂(20 mL), washed with aqueous NaOH (1.0 M, 4 × 5 mL),

and dried (MgSO₄). The solvent was removed by oil pump vacuum to

give spectroscopically pure 5a as a light yellow oil (0.8732 g, 3.535

reported elsewhere.^14aNMR (δ, CDCl₃): H 7.68 (t, 1H, J_HH= 7.7

Hz, p-HC_4pyr), 7.33 (d, 2H, ³J_HH= 7.7 Hz, m-HC_3,5pyr), 5.98 (ddt, 2H,

³J_HHtrans= 17.2 Hz, ³J_HHcis= 10.4 Hz, ³J_HH= 5.6 Hz, CH), 5.34 (dd,

1

3

2

mmol, 59%). NMR (δ, CDCl₃): ¹H 9.35 (d, 2H, J_HH= 2.1 Hz,

4

2H, J_HHtrans= 17.2 Hz, J_HH= 1.6 Hz, CH_EH_Z), 5.23 (dd, 2H,

³J_HHcis= 10.4 Hz, ²J_HH= 1.5 Hz, CH_EH_Z), 4.64 (s, 4H, CH₂O), 4.12

4

o-HC_2,6pyr), 8.85 (t, 1H, J_HH= 2.1 Hz, p-HC_4pyr), 6.02 (ddt, 2H,

3

4

(dt, 4H, J_HH= 5.6 Hz, J_HH= 1.4 Hz, OCH₂CH); ¹³C{¹H} 157.9

(s, o-C_2,6pyr), 137.2 (s, p-C_4pyr), 134.4 (s, CH), 119.8 (s, m-C_3,5pyr),

117.3 (s, CH₂), 72.9 and 71.8 (2 s, CH₂OCH₂). These data agreed

with those previously reported for an alternative synthesis.¹⁸IR (cm⁻¹,

oil film): 3084 (w), 2918 (s), 2853 (m), 1648 (w), 1594 (m), 1459

(m), 1347 (m), 1100 (s), 992 (s), 922 (s), 787 (m). MS:⁴¹220 ([4a +

H]⁺, 100%).

³J_HHtrans= 17.2 Hz, ³J_HHcis= 10.4 Hz, ³J_HH= 5.8 Hz, CH), 5.40 (dd,

3

2

2H, J_HHtrans= 17.2 Hz, J_HH= 1.4 Hz, CH_EH_Z), 5.30 (dd, 2H,

³J_HHcis= 10.4 Hz, J_HH= 1.2 Hz, CH_EH_Z), 4.85 (dt, 4H, J_HH= 5.8

Hz, ⁴J_HH= 1.3 Hz, OCH₂); ¹³C{¹H} 163.9 (s, CO), 154.1 (s, o-C_2,6pyr),

137.9 (s, p-C_4pyr), 131.4 (s, CH), 125.9 (s, m-C_3,5pyr), 119.0 (s, 

CH₂), 66.2 (s, OCH₂). IR (cm⁻¹, oil film): 3080 (w), 2931 (m), 2863

(w), 1727 (s), 1312 (m), 1240 (s), 1112 (m), 912 (m), 747 (s). MS:⁴¹

248 ([5a + H]⁺, 100%).

2

3

2,6-NC₅H₃(CH₂O(CH₂)₂CHCH₂)₂(4b). 2,6-Bis(bromomethyl)-

pyridine (2.000 g, 7.548 mmol), 3-buten-1-ol (2.721 g, 37.74 mmol),

3,5-NC₅H₃(COO(CH₂)₂CHCH₂)₂(5b). 3,5-NC₅H₃(COCl)₂

(0.400 g, 1.96 mmol), CH₂Cl₂(6.5 mL), and 3-buten-1-ol (0.423 g,

5.88 mmol) were combined in a procedure similar to that for 5a. An

analogous workup gave 5b as a light yellow oil (0.482 g, 1.75 mmol,

+

and C₆H₅CH₂N(CH₃)₃Cl⁻(0.280 g, 1.51 mmol, 20 mol %) were

combined in a procedure similar to that for 4a. An analogous workup

gave 4b as a light yellow oil (1.020 g, 4.326 mmol, 55%). NMR (δ,

CDCl₃): ¹H 7.73 (t, 1H, ³J_HH= 7.7 Hz, p-HC_4pyr), 7.36 (d, 2H, ³J_HH

=

1

4

89%). NMR (δ, CDCl₃): H 9.33 (d, 2H, J_HH= 2.1 Hz, o-HC_2,6pyr),

3

7.7 Hz, m-HC_3,5pyr), 5.87 (ddt, 2H, J_HHtrans= 17.1 Hz, J_HHcis= 10.3

4

3

8.82 (t, 1H, J_HH= 2.1 Hz, p-HC_4pyr), 5.84 (ddt, 2H, J_HHtrans= 17.1

3

2

Hz, J_HH= 6.8 Hz, CH), 5.09 (dd, 2H, J_HHtrans= 17.2 Hz, J_HH

=

Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.8 Hz, CH), 5.22 (dd, 2H, ³J_HHtrans

=

3

2

1.6 Hz, CH_EH_Z), 4.99 (dd, 2H, J_HHcis= 10.2 Hz, J_HH= 1.3 Hz,

2

3

17.1 Hz, J_HH= 1.3 Hz, CH_EH_Z), 5.11 (dd, 2H, J_HHcis= 10.2 Hz,

3

2 CH_EH_Z), 4.64 (s, 4H, CH₂O), 3.63 (t, 4H, J_HH= 6.7 Hz,

²J_HH= 1.1 Hz, CH_EH_Z), 4.42 (t, 4H, ³J_HH= 6.7 Hz, OCH₂), 2.53 (q,

OCH₂CH₂), 2.44 (q, 4H, J_HH= 6.7 Hz, CH₂); ¹³C{¹H} 158.0 (s, o-

3

4H, J_HH= 6.7 Hz, CH₂CH); ¹³C{¹H} 165.2 (s, CO), 153.2 (s, o-

C_2,6pyr), 137.2 (s, p-C_4pyr), 135.1 (s, CH), 119.7 (s, m-C_3,5pyr), 116.5 (s,

CH₂), 73.7 (s, CH₂O), 70.3 (s, OCH₂CH₂), 34.2 (s, CH₂). IR (cm⁻¹,

oil film): 3080 (w), 2910 (s), 2860 (m), 1640 (w), 1455 (m), 1351 (m),

1112 (s), 992 (s), 915 (s), 787 (s). MS:⁴¹248 ([4b + H]⁺, 100%).

2,6-NC₅H₃(CH₂O(CH₂)₃CHCH₂)₂(4c). 2,6-Bis(bromomethyl)-

pyridine (3.000 g, 11.32 mmol), 4-penten-1-ol (5.860 g, 68.03 mmol),

C_2,6pyr), 138.0 (s, p-C_4pyr), 135.7 (s, CH), 126.0 (s, m-C_3,5pyr), 115.4

(s, CH₂), 64.3 (s, OCH₂), 33.5 (s, CH₂CH). IR (cm⁻¹, oil film):

3082 (w), 2940 (m), 2865 (w), 1730 (s), 1312 (m), 1242 (s), 1112

(m), 913 (m), 746 (s). MS:⁴¹276 ([5b + H]⁺, 100%).

3,5-NC₅H₃(COO(CH₂)₃CHCH₂)₂(5c). 3,5-NC₅H₃(COCl)₂

(1.500 g, 7.349 mmol), CH₂Cl₂(24 mL), and 4-penten-1-ol (1.392 g,

16.16 mmol) were combined in a procedure similar to that for 5a. An

analogous workup gave 5c as a light yellow oil (1.865 g, 6.148 mmol,

+

and C₆H₅CH₂N(CH₃)₃Cl⁻(0.420 g, 2.26 mmol, 20 mol %) were

combined in a procedure similar to that for 4a. An analogous workup

gave 4c as a colorless oil (1.412 g, 5.127 mmol, 45%). NMR (δ,

1

4

CDCl₃): ¹H 7.71 (t, 1H, ³J_HH= 7.7 Hz, p-HC_4pyr), 7.35 (d, 2H, ³J_HH

7.7 Hz, m-HC_3,5pyr), 5.83 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis= 10.3

=

84%). NMR (δ, CDCl₃): H 9.33 (d, 2H, J_HH= 2.1 Hz, o-HC_2,6pyr),

4

3

8.81 (t, 1H, J_HH= 2.1 Hz, p-HC_4pyr), 5.87 (ddt, 2H, J_HHtrans= 17.2

Hz, ³J_HHcis= 11.0 Hz, ³J_HH= 5.9 Hz, CH), 5.03 (dd, 2H, ³J_HHtrans

=

3

2

Hz, J_HH= 6.7 Hz, CH), 5.03 (dd, 2H, J_HHtrans= 17.2 Hz, J_HH

=

2

3

2.0 Hz, CH_EH_Z), 4.99 (dd, 2H, ³J_HHcis= 10.2 Hz, ²J_HH= 2.0 Hz, 

CH_EH_Z), 4.60 (s, 4H, CH₂O), 3.57 (t, 4H, ³J_HH= 6.5 Hz, OCH₂CH₂),

2.20−2.14 (m, 4H, CH₂), 1.79−1.72 (m, 4H, CH₂); ¹³C{¹H} 158.2 (s,

o-C_2,6pyr), 138.2 (s, p-C_4pyr), 137.2 (s, CH), 119.7 (s, m-C_3,5pyr),

114.8 (s, CH₂), 73.7 (s, CH₂O), 70.6 (s, OCH₂CH₂), 30.3 (s, CH₂),

28.9 (s, CH₂). IR (cm⁻¹, oil film): 3076 (w), 2937 (m), 2864 (m),

1640 (s), 1594 (s), 1445 (s), 1347 (s), 1116 (s), 992 (s), 911 (s), 787

(s). MS:⁴¹276 ([4c + H]⁺, 100%).

17.1 Hz, J_HH= 1.7 Hz, CH_EH_Z), 4.98 (dd, 2H, J_HHcis= 10.2 Hz,

²J_HH= 1.2 Hz, CH_EH_Z), 4.41 (t, 4H, ³J_HH= 6.7 Hz, OCH₂), 2.25−

2.20 (m, 4H, CH₂), 1.93−1.86 (m, 4H, CH₂); ¹³C{¹H} 164.8 (s, CO),

154.4 (s, o-C_2,6pyr), 138.0 (s, p-C_4pyr), 137.9 (s, CH), 126.6 (s, m-

C_3,5pyr), 115.4 (s, CH₂), 65.5 (s, OCH₂), 30.4 (s, CH₂), 28.1 (s,

CH₂). IR (cm⁻¹, oil film): 3076 (w), 2932 (m), 2858 (w), 1720 (s),

1312 (m), 1231 (s), 1103 (m), 913 (m), 749 (s). MS:⁴¹304 ([5c +

H]⁺, 100%).

3,5-NC₅H₃(COO(CH₂)₄CHCH₂)₂(5d). 3,5-NC₅H₃(COCl)₂

(2.000 g, 9.799 mmol), CH₂Cl₂(32 mL), and 5-hexen-1-ol (2.160 g,

21.57 mmol) were combined in a procedure similar to that for 5a.

An analogous workup gave 5d as a light yellow oil (2.917 g, 8.802

2,6-NC₅H₃(CH₂O(CH₂)₄CHCH₂)₂(4d). 2,6-Bis(bromomethyl)-

pyridine (1.000 g, 3.774 mmol), 5-hexen-1-ol (1.512 g, 15.10 mmol),

+

and C₆H₅CH₂N(CH₃)₃Cl⁻(0.140 g, 0.754 mmol, 20 mol %) were

combined in a procedure similar to that for 4a. An analogous workup

gave 4d as a light yellow oil (0.542 g, 1.79 mmol, 47%). NMR (δ,

4

mmol, 90%). NMR (δ, CDCl₃): ¹H 9.37 (d, 2H, J_HH= 2.1 Hz,

4

CDCl₃): ¹H 7.68 (t, 1H, ³J_HH= 7.7 Hz, p-HC_4pyr), 7.32 (d, 2H, ³J_HH

7.7 Hz, m-HC_3,5pyr), 5.79 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis= 10.3

=

o-HC_2,6pyr), 8.85 (t, 1H, J_HH= 2.1 Hz, p-HC_4pyr), 5.80 (ddt, 2H,

³J_HHtrans= 17.0 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.7 Hz, CH), 5.02 (dd,

3

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3

2

2H, J_HHtrans= 17.1 Hz, J_HH= 1.5 Hz, CH_EH_Z), 4.97 (dd, 2H,

cooled to 0 °C. The Grignard mixture from the round-bottom flask

was then added dropwise with stirring over 10 min. The cold bath was

removed. After 15 h, the sample was refluxed (oil bath). After 2 h, the

mixture was cooled (0 °C), and methanol (10 mL) was added. The

volatiles were removed by oil pump vacuum. Water (200 mL) was

added, which was extracted with CH₂Cl₂(3 × 200 mL). The

combined extracts were washed with water (150 mL) and brine

(150 mL) and dried (MgSO₄). The solvent was removed by oil pump

vacuum. The residue was recrystallized from toluene to afford 6 as

colorless plates (1.8531 g, 6.3606 mmol, 73%). Mp (capillary): 228−

231 °C; lit.⁴³mp 233−235 °C. NMR (δ, CDCl₃): ¹H 8.75 (br s, 2H, o-

³J_HHcis= 10.2 Hz, J_HH= 1.1 Hz, CH_EH_Z), 4.41 (t, 4H, J_HH= 6.7

Hz, OCH₂), 2.18−2.13 (m, 4H, CH₂), 1.87−1.80 (m, 4H, CH₂),

1.61−1.54 (m, 4H, CH₂); ¹³C{¹H} 164.6 (s, CO), 154.1 (s, o-C_2,6pyr),

138.7 (s, p-C_4pyr), 137.6 (s, CH), 126.3 (s, m-C_3,5pyr), 114.7 (s, 

CH₂), 65.7 (s, OCH₂), 33.6, 25.8, and 25.3 (3 s, 3CH₂). These data

agreed reasonably well with those previously reported in other solvents

for a similar synthesis.¹⁹IR (cm⁻¹, oil film): 3078 (w), 2937 (m), 2860

(w), 1724 (s), 1309 (m), 1235 (s), 1107 (m), 909 (m), 745 (s). MS:⁴¹

332 ([5d + H]⁺, 100%).

3,5-NC₅H₃(COO(CH₂)₅CHCH₂)₂(5e). 3,5-NC₅H₃(COCl)₂

(1.500 g, 7.349 mmol), CH₂Cl₂(24 mL), and 6-hepten-1-ol (1.850 g,

16.20 mmol) were combined in a procedure similar to that for 5a. An

analogous workup gave 5e as a light yellow oil (1.838 g, 5.113 mmol,

2

3

HC_2,6pyr), 7.97 (s, 1H, p-HC_4pyr), 7.58 (d, 4H, J_HH= 8.6 Hz,

3

MeOCCH), 7.04 (d, 4H, J_HH= 8.6 Hz, MeOCCHCH), 3.88 (s, 6H,

CH₃). These data agreed with those previously reported.⁴³

3,5-NC₅H₃(4-C₆H₄OH)₂(7).^23bA round-bottom flask was charged

with 6 (10944 g, 3.7564 mmol), CH₂Cl₂(25 mL), and BBr₃(1.0 M in

CH₂Cl₂; 16.0 mL, 16.0 mmol) with stirring. After 14 h, methanol (10

mL) was added. The volatiles were removed by oil pump vacuum, and

the residue was chromatographed on a silica column (37 × 4 cm, 1/9

v/v petroleum ether/ethyl acetate). The solvent was removed from a

faint yellow band by rotary evaporation to give 7 as an off-white solid

1

4

70%). NMR (δ, CDCl₃): H 9.36 (d, 2H, J_HH= 2.1 Hz, o-HC_2,6pyr),

4

3

8.85 (t, 1H, J_HH= 2.1 Hz, p-HC_4pyr), 5.80 (ddt, 2H, J_HHtrans= 17.0

Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.7 Hz, CH), 5.01 (dd, 2H, ³J_HHtrans

=

2

3

17.1 Hz, J_HH= 1.7 Hz, CH_EH_Z), 4.96 (dd, 2H, J_HHcis= 10.2 Hz,

²J_HH= 1.0 Hz, CH_EH_Z), 4.39 (t, 4H, ³J_HH= 6.7 Hz, OCH₂), 2.10−

2.08 (m, 4H, CH₂), 1.84−1.77 (m, 4H, CH₂), 1.50−1.45 (m, 8H,

CH₂); ¹³C{¹H} 164.5 (s, CO), 154.1 (s, o-C_2,6pyr), 138.5 (s, p-C_4pyr),

137.9 (s, CH), 126.2 (s, m-C_3,5pyr), 114.6 (s, CH₂), 65.8 (s,

OCH₂), 33.5, 28.5, 28.3, and 25.3 (4 s, 4CH₂). IR (cm⁻¹, oil film):

3076 (w), 2934 (m), 2860 (w), 1725 (s), 1309 (m), 1235 (s), 1104

(m), 911 (m), 745 (s). MS:⁴¹360 ([5e + H]⁺, 100%).

1

(0.6539 g, 2.484 mmol, 66%). NMR (δ, DMSO-d₆): H 10.06 (br s,

4

2H, OH), 9.37 (br s, 2H, o-HC_2,6pyr), 8.90 (t, 1H, J_HH= 2.0 Hz, p-

HC_4pyr), 7.77 (m, 4H, HOCCH), 6.99 (m, 4H, HOCCHCH). These

data agreed with those previously reported.^23b

3,5-NC₅H₃(4-C₆H₄O(CH₂)₅CHCH₂)₂(8). A round-bottom flask

was charged with 7 (0.5179 g, 1.967 mmol), Cs₂CO₃(1.5166 g, 4.6549

mmol), and DMF (50 mL). The flask was fitted with a septum

connected by a needle to an oil bubbler and purged with N₂(10 min).

Then 7-bromo-1-heptene was added by syringe with stirring. The

mixture was kept at 100 °C for 1 h. The solvent was removed by oil

pump vacuum. Water (100 mL) and CH₂Cl₂(100 mL) were added

and the phases separated. The aqueous phase was extracted with

CH₂Cl₂(2 × 100 mL). The combined CH₂Cl₂layers were dried

(MgSO₄). The solvent was removed by oil pump vacuum. The residue

was chromatographed on a silica column (37 × 4 cm, 1/1 v/v ethyl

acetate/CH₂Cl₂). The solvent was removed from the product-

containing fraction by rotary evaporation to give 8 as a colorless

solid (0.2902 g, 0.6369 mmol, 32%). Mp (capillary): 151−154 °C.

3,5-NC₅H₃(COO(CH₂)₆CHCH₂)₂(5f). 3,5-NC₅H₃(COCl)₂

(1.800 g, 8.819 mmol), CH₂Cl₂(29 mL), and 7-octen-1-ol (2.488 g,

19.42 mmol) were combined in a procedure similar to that for 5a.

After workup, the yellow residue was chromatographed on a silica

column (45 × 3 cm, 4/1 v/v hexanes/ethyl acetate). The solvent was

removed from the product-containing fractions by rotary evaporation

to give 5f as a light yellow oil (1.408 g, 3.633 mmol, 41%). NMR (δ,

CDCl₃): ¹H 9.36 (d, 2H, ⁴J_HH= 2.1 Hz, o-HC_2,6pyr), 8.85 (t, 1H, ⁴J_HH

=

2.1 Hz, p-HC_4pyr), 5.81 (ddt, 2H, ³J_HHtrans= 17.0 Hz, ³J_HHcis= 10.2 Hz,

³J_HH= 6.7 Hz, CH), 5.00 (dd, 2H, ³J_HHtrans= 17.2 Hz, ²J_HH= 2.1 Hz,

3

2

CH_EH_Z), 4.94 (dd, 2H, J_HHcis= 10.2 Hz, J_HH= 2.1 Hz, 

3

CH_EH_Z), 4.39 (t, 4H, J_HH= 6.7 Hz, OCH₂), 2.07−2.03 (m, 4H,

CH₂), 1.85−1.76 (m, 4H, CH₂), 1.45−1.51 (m, 12H, CH₂); ¹³C{¹H}

164.5 (s, CO), 154.1 (s, o-C_2,6pyr), 138.8 (s, p-C_4pyr), 137.9 (s, CH),

126.2 (s, m-C_3,5pyr), 114.4 (s, CH₂), 65.9 (s, OCH₂), 33.6, 28.7, 28.6,

28.5, and 25.8 (5 s, 5CH₂). IR (cm⁻¹, oil film): 3076 (w), 2930 (s),

2856 (m), 1725 (s), 1309 (s), 1235 (s), 1104 (s), 911 (s), 745 (s).

MS:⁴¹388 ([5f + H]⁺, 100%).

1

4

NMR (δ, CDCl₃): H 8.73 (br s, 2H, o-HC_2,6pyr), 7.97 (t, 1H, J_HH

=

2.3 Hz, p-HC_4pyr), 7.56 and 7.01 (2 m, 2 × 4H, pyr-CCH and pyr-

3

CCHCH), 5.87−5.79 (ddt, 2H, J_HHtrans= 17.3 Hz, J_HHcis= 10.3 Hz,

³J_HH= 6.4 Hz, CH), 5.05−4.94 (m, 4H, CH₂), 4.02 (t, 4H, ³J_HH

=

6.7 Hz, OCH₂), 2.10 (m, 4H, CH₂CHCH₂), 1.83 (m, 4H,

OCH₂CH₂), 1.52−1.47 (m, 8H, CH₂); ¹³C{¹H} 159.6 (s, COCH₂),

145.8 (s, o-C_2,6pyr), 139.0 (s, CH), 136.6 (s, m-C_3,5pyr), 132.3 (s, p-

C_4pyr), 130.1 (s, pyr-C(CH)₂), 128.5 (s, pyr-C(CH)₂), 115.4 (s,

(CH)₂CO), 114.7 (s, CH₂), 68.3 (s, C₆H₄OCH₂), 33.9, 29.3, 28.8,

and 25.8 (4 s, 4CH₂). IR (cm⁻¹, powder film): 2936 (m), 2864 (w),

1715 (w), 1605 (m), 1510 (m), 1287 (m), 1246 (s), 1180 (m), 910

(m), 824 (s), 716 (m).

3,5-NC₅H₃(COO(CH₂)₈CHCH₂)₂(5h). 3,5-NC₅H₃(COCl)₂

(1.480 g, 7.251 mmol), CH₂Cl₂(24 mL), and 9-decen-1-ol (2.503 g,

16.02 mmol) were combined in a procedure similar to that for 5a.

An analogous workup gave 5h as a light yellow oil (2.152 g, 4.858

1

4

mmol, 67%). NMR (δ, CDCl₃): H 9.36 (d, 2H, J_HH= 2.1 Hz, o-

HC_2,6pyr), 8.86 (t, 1H, ⁴J_HH= 2.1 Hz, p-HC_4pyr), 5.81 (ddt, 2H, ³J_HHtrans

3

= 17.0 Hz, J_HHcis= 10.3 Hz, J_HH= 6.7 Hz, CH), 5.23 (dd, 2H,

³J_HHtrans= 17.1 Hz, J_HH= 1.8 Hz, CH_EH_Z), 4.99 (dd, 2H, J_HHcis

=

2

3

trans-PtCl₂(2-NC₅H₄(CH₂OCH₂CHCH₂))₂(trans-10a). A

round-bottom flask was charged with PtCl₂(0.8468 g, 3.183 mmol)

and benzene (50 mL) and fitted with a condenser. Then 1a (1.2956 g,

8.6841 mmol) was added with stirring. The mixture was refluxed (oil

bath). After 14 h, the solvent removed by oil pump vacuum. The resi-

due was chromatographed on a silica column (32 × 2.5 cm, 1/4 v/v

ethyl acetate/CH₂Cl₂). The solvent was removed from the product-

containing fraction by oil pump vacuum to give trans-10a (0.7258 g,

1.286 mmol, 40%) as a light yellow solid and a mixture of atropisomers

(ca. 50:50; see text). Mp (capillary): 160−162 °C. Anal. Calcd for

C₁₈H₂₂Cl₂N₂O₂Pt: C, 38.31; H, 3.93; N, 4.96. Found: C, 38.35; H,

3.93; N, 4.97. NMR (δ, CDCl₃): ¹H 8.92 (m, 2H, o-HC_6pyr), 7.77 (m,

2H, m-HC_4pyr), 7.69 (m, 2H, p-HC_3pyr), 7.24 (m, 2H, m-HC_5pyr),

6.13−5.98 (m, 2H, CH), 5.65 and 5.63 (2 s, 4H, atropiso-

mers, NC₅H₄CH₂O), 5.50−5.26 (m, 4H, CH₂), 4.27 (m, 4H,

OCH₂CH). VT-NMR data (NC₅H₄CH₂O signal): −50 °C, 5.605 and

5.584 (Δ = 6.2 Hz); −30 °C, 5.617 and 5.597 (Δ = 6.0 Hz); −10 °C, 5.624

and 5.606 (Δ = 5.9 Hz); 0 °C, 5.631 and 5.613 (Δ = 5.4 Hz); 10 °C, 5.638

and 5.620 (Δ = 5.2 Hz); 30 °C, 5.650 and 5.636 (Δ = 4.1 Hz); 35 °C,

2

3

10.2 Hz, J_HH= 1.2 Hz, CH_EH_Z), 4.39 (t, 4H, J_HH= 6.7 Hz,

OCH₂), 2.06−2.02 (m, 4H, CH₂), 1.81−1.76 (m, 4H, CH₂), 1.46−

1.33 (m, 20H, CH₂); ¹³C{¹H} 164.5 (s, CO), 154.1 (s, o-C_2,6pyr), 139.1

(s, p-C_4pyr), 137.9 (s, CH), 126.2 (s, m-C_3,5pyr), 114.2 (s, CH₂),

65.9 (s, OCH₂), 33.7, 29.3, 29.1, 29.0, 28.8, 28.6, and 25.9 (7 s, 7CH₂).

These data agreed reasonably well with those previously reported for a

similar synthesis.²⁰IR (cm⁻¹, oil film): 3076 (w), 2926 (s), 2856 (m),

1729 (s), 1309 (s), 1235 (s), 1100 (s), 907 (s), 745 (s). MS:⁴¹444

([5h + H]⁺, 100%).

3,5-NC₅H₃(4-C₆H₄OCH₃)₂(6).^23aA 100 mL three-necked round-

bottom flask was charged with magnesium (0.5821 g, 23.95 mmol)

and fitted with a septum, a stopper, and a condenser capped with a

180° glass needle valve. The flask was evacuated and back-filled with

N₂. THF (30 mL) was added via cannula. Then 1,2-dibromoethane

(0.30 mL) was added with stirring. After 10 min, 4-bromoanisole

(2.50 mL, 20.0 mmol) was added by syringe. A Schlenk flask was

charged with 3,5-dichloropyridine (1.3697 g, 9.2552 mmol), (dppp)-

NiCl₂(0.0503 g, 0.0928 mmol, 1.0 mol %), and THF (20 mL) and

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5.650 and 5.642 (Δ = 3.0 Hz); 40 °C, 5.648 (Δ = 0 Hz). On the basis

of the visual appearance of the spectra at 35 and 40 °C, the

coalescence temperature (T_c) was extrapolated as 311 K. The

ΔG^⧧(T_c) value was calculated by standard methods⁴⁴as detailed

elsewhere.^14bIR (cm⁻¹, powder film): 3073 (w), 2868 (w), 2837 (w),

1611 (m), 1483 (m), 1431 (m), 1340 (m), 1123 (s), 1094 (s), 926

(m), 768 (s), 719 (s).

combined in a procedure similar to that for trans-10a. An analogous

workup gave trans-12a as a yellow solid (1.8265 g, 3.236 mmol, 86%).

Mp (capillary): 120−121 °C. Anal. Calcd for C₁₈H₂₂Cl₂N₂O₂Pt: C,

38.31; H, 3.93; N, 4.96. Found: C, 38.28; H, 3.81; N, 4.96. NMR (δ,

CDCl₃): ¹H 8.84 (m, 2H, o-HC_2pyr), 8.80 (m, 2H, o-HC_6pyr), 7.80 (m,

2H, p-HC_4pyr), 7.29 (m, 2H, m-HC_5pyr), 6.00−5.87 (ddt, 2H, ³J_HHtrans

=

17.0 Hz, ³J_HHcis= 10.4 Hz, ³J_HH= 6.8 Hz, CH), 5.32−5.18 (m, 4H,

CH₂), 4.54 (s, 4H, CH₂O), 4.07 (m, 4H, OCH₂CH); ¹³C{¹H}

152.8 and 152.6 (2 s, o-C_2pyrand o-C_6pyr), 137.6 (s, CH), 136.6

(s, p-C_4pyr), 134.1 (s, m-C_3pyr), 125.1 (s, m-C_5pyr), 118.3 (s, CH₂),

72.0 (s, CH₂O), 68.4 (s, OCH₂CH₂). IR (cm⁻¹, powder film):

2924 (w), 2857 (w), 1609 (w), 1423 (m), 1096 (s), 924 (s), 800 (s),

696 (s).

trans-PtCl₂(2-NC₅H₄(CH₂O(CH₂)₂CHCH₂))₂(trans-10b). Pyr-

idine 1b (1.4989 g, 9.1833 mmol) and PtCl₂(1.1470 g, 4.3120 mmol)

were combined in a procedure similar to that for trans-10a. An

analogous workup gave trans-10b as a light yellow solid (0.3065 g,

0.5174 mmol, 12.0%). Mp (capillary): 188−191 °C dec. The

broadened CH₂O ¹H NMR signal suggested a mixture of

atropisomers. Anal. Calcd for C₂₀H₂₆Cl₂N₂O₂Pt: C, 40.55; H, 4.42;

N, 4.73. Found: C, 40.27; H, 4.35; N, 4.49. NMR (δ, CDCl₃): ¹H 8.92

(m, 2H, o-HC_6pyr), 7.77 (m, 2H, m-HC_4pyr), 7.67 (m, 2H, p-HC_3pyr),

7.24 (m, 2H, m-HC_5pyr), 5.96−5.87 (m, 2H, CH), 5.64 (br s, 4H,

PtCl₂(3-NC₅H₄(CH₂O(CH₂)₂CHCH₂))₂(12b). Pyridine 2b

(1.3203 g, 8.0891 mmol) and PtCl₂(1.0233 g, 3.8471 mmol) were

combined in a procedure similar to that for trans-10a. An analogous

workup gave trans-12b (1.1204 g, 1.8912 mmol, 49%; mp (capillary)

118−119 °C) and cis-12b (0.9764 g, 1.648 mmol, 43%; mp (capillary)

54−56 °C) as yellow solids. Anal. Calcd for C₂₀H₂₆Cl₂N₂O₂Pt: C,

40.55; H, 4.42; N, 4.73. Found (trans-12b): C, 40.50; H, 4.37; N, 4.71.

3

CH₂O), 5.20−5.09 (m, 4H, CH₂), 3.80 (t, 4H, J_HH= 6.4 Hz,

OCH₂CH₂), 2.50 (m, 4H, OCH₂CH₂). IR (cm⁻¹, powder film): 2164

(w), 2012 (w), 1981 (w), 1611 (w), 1477 (w), 1439 (w), 1356 (m),

1130 (s), 1099 (s), 1001 (m), 924 (m), 773 (s), 721 (m).

1

Data for trans-12b are as follows. NMR (δ, CDCl₃): H 8.83 (m,

2H, o-HC_2pyr), 8.80 (m, 2H, o-HC_6pyr), 7.78 (m, 2H, p-HC_4pyr), 7.29

trans-PtCl₂[2,2′-(NC₅H₄(CH₂O(CH₂)₄OCH₂)H₄C₅N)] (trans-11a).

A two-necked round-bottom flask was charged with trans-10a (0.4344

g, 0.7697 mmol) and CH₂Cl₂(382 mL), fitted with a condenser, and

flushed with N₂(5 min). A solution of Grubbs’ catalyst (0.0251 g,

0.0305 mmol, 4.0 mol %) in CH₂Cl₂(5 mL) was added dropwise with

stirring (the resulting solution is 0.002 01 M in trans-10a). The

mixture was refluxed (24 h) and cooled to room temperature. The

solvent was removed by rotary evaporation. The residue was

chromatographed on a silica column (15.5 × 1.5 cm, 1/4 v/v ethyl

acetate/CH₂Cl₂). The solvent was removed by rotary evaporation and

oil pump vacuum. A round-bottom flask was charged with the residue

(metathesis product), 10% Pd/C (0.0325 g of 10% w/w, 0.0305 mmol

Pd, 4.0 mol %), toluene (30 mL), and ethanol (30 mL), flushed with

H₂, and fitted with a balloon of H₂(1.0 atm). After 23 h, CHCl₃(40

mL) was added and the mixture filtered through a Celite column (5 ×

2 cm). The column was washed with CHCl₃(2 × 40 mL). The solvent

was removed from the filtrate by oil pump vacuum, and the residue

was chromatographed on a silica column (29 × 1.5 cm, 1/4 v/v ethyl

acetate/CH₂Cl₂) to give trans-11a as a light yellow solid (0.2593 g,

0.4187 mmol, 63%). Mp (capillary): 227−229 °C dec. Anal. Calcd for

3

(m, 2H, m-HC_5pyr), 5.91−5.76 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis

=

3

10.4 Hz, J_HH= 6.8 Hz, CH), 5.16−5.04 (m, 4H, CH₂), 4.53 (s,

3

4H, CH₂O), 3.56 (t, 4H, J_HH= 6.6 Hz, OCH₂CH₂), 2.39 (apparent

qt, 4H, ³J_HH= 6.6 Hz, ³J_HH= 1.4 Hz, CH₂CHCH₂); ¹³C{¹H} 152.8

and 152.5 (2 s, o-C_2pyrand o-C_6pyr), 137.5 (s, CH), 136.7 (s, p-C_4pyr),

135.0 (s, m-C_3pyr), 125.1 (s, m-C_5pyr), 117.0 (s, CH₂), 70.5 (s,

CH₂O), 69.3 (s, OCH₂CH₂), 34.3 (s, CH₂). IR (cm⁻¹, powder film):

2943 (w), 2870 (m), 1641 (m), 1477 (m), 1436 (s), 1364 (m), 1101

(s), 927 (s), 799 (s).

Data for cis-12b are as follows. NMR (δ, CDCl₃): ¹H 8.85 (m, 4H,

o-HC_2,6pyr), 7.75 (m, 2H, p-HC_4pyr), 7.27 (m, 2H, m-HC_5pyr), 5.84−

3

5.70 (ddt, 2H, J_HHtrans= 17.3 Hz, J_HHcis= 10.3 Hz, J_HH= 6.6 Hz,

CH), 5.12−5.01 (m, 4H, CH₂), 4.47 (s, 4H, CH₂O), 3.50 (t, 4H,

³J_HH= 6.6 Hz, OCH₂CH₂), 2.32 (apparent qt, 4H, ³J_HH= 6.6 Hz, ³J_HH

= 1.4 Hz, CH₂CHCH₂); ¹³C{¹H} 152.1 and 151.7 (2 s, o-C_2pyr

and o-C_6pyr), 137.9 (s, CH), 137.5 (s, p-C_4pyr), 134.9 (s, m-C_3pyr),

126.2 (s, m-C_5pyr), 117.0 (s, CH₂), 70.6 (s, CH₂O), 69.0

(s, OCH₂CH₂), 34.2 (s, CH₂). IR (cm⁻¹, powder film): 3068 (w),

2904 (w), 2860 (w), 1608 (m), 1479 (m), 1437 (m), 1098 (s),

912 (s), 702 (s).

C₁₆H₂₀Cl N₂O₂Pt: C, 35.70; H, 3.74; N, 5.20. Found: C, 35.39; H,

2

trans-PtCl₂(3-NC₅H₄(CH₂O(CH₂)₃CHCH₂))₂(trans-12c). Pyr-

idine 2c (1.6721 g, 9.4338 mmol) and PtCl₂(1.1893 g, 4.4711 mmol)

were combined in a procedure similar to that for trans-10a. An

analogous workup gave trans-12c as a yellow solid (2.3537 g, 3.793

mmol, 85%). Mp (capillary): 77−79 °C. Anal. Calcd for

C₂₂H₃₀Cl₂N₂O₂Pt: C, 42.59; H, 4.87; N, 4.51. Found: C, 43.00; H,

4.78; N, 4.10. NMR (δ, CDCl₃): ¹H 8.84 (m, 2H, o-HC_2pyr), 8.81 (m,

2H, o-HC_6pyr), 7.78 (m, 2H, p-HC_4pyr), 7.29 (m, 2H, m-HC_5pyr), 5.86−

3.81; N, 5.12. NMR (δ, CDCl₃): ¹H 9.01 (m, 2H, o-HC_6pyr), 7.76 (m,

2H, p-HC_4pyr), 7.54 (m, 2H, m-HC_3pyr), 7.28 (m, 2H, m-HC_5pyr), 5.63

(s, 4H, CH₂O), 3.90 (m, 4H, OCH₂CH₂), 2.10 (m, 4H, OCH₂CH₂);

¹³C{¹H} 160.4 (s, o-C_2pyr), 154.7 (s, o-C_6pyr), 138.6 (s, p-C_4pyr), 126.7

(s, m-C_3pyr), 124.8 (s, m-C_5pyr), 72.2 (s, CH₂O), 69.8 (s, OCH₂CH₂),

24.6 (s, CH₂). IR (cm⁻¹, powder film): 2966 (w), 2911 (w), 2851 (w),

2149 (w), 1981 (w), 1607 (m), 1437 (m), 1225 (m), 1109 (s), 930

(m), 789 (s), 772 (s).

3

5.78 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis= 10.1 Hz, J_HH= 6.4 Hz,

CH), 5.07−4.97 (m, 4H, CH₂), 4.52 (s, 4H, CH₂O), 3.52 (t, 4H,

³J_HH= 6.4 Hz, OCH₂CH₂), 2.16 (m, 4H, CH₂CHCH₂), 1.74 (m,

4H, OCH₂CH₂); ¹³C{¹H} 152.8 and 152.6 (2 s, o-C_2pyrand o-C_6pyr),

138.2 (s, CH), 137.4 (s, p-C_4pyr), 136.8 (s, m-C_3pyr), 125.1 (s, m-

C_5pyr), 115.2 (s, CH₂), 70.7 (s, CH₂O), 69.3 (s, OCH₂CH₂), 30.4 (s,

CH₂), 29.0 (s, CH₂). IR (cm⁻¹, powder film): 2938 (m), 2872 (m),

1643 (m), 1611 (m), 1441 (m), 1366 (m), 1096 (s), 1078 (s), 988

(m), 926 (m), 816 (s), 698 (s), 638 (m).

trans-PtCl₂[2,2′-(NC₅H₄(CH₂O(CH₂)₆OCH₂)H₄C₅N)] (trans-

11b). Grubbs’ catalyst (two charges 24 h apart, 0.0132 and 0.0126

g, 0.0314 mmol, 8.0 mol %), CH₂Cl₂(197 mL), trans-10b (0.2334 g,

0.3940 mmol), and Pd/C (0.0174 g of 10% w/w, 0.0164 mmol Pd, 4.2

mol %) were combined in a procedure similar to that for trans-11a. An

analogous workup gave trans-11b as an off-white solid (0.1761 g,

0.3109 mmol, 79%). Mp (capillary): 242−244 °C dec. Anal. Calcd for

C₁₈H₂₄Cl₂N₂O₂Pt: C, 38.17; H, 4.27; N, 4.95. Found: C, 38.57; H,

4.29; N, 4.96. NMR (δ, CDCl₃): ¹H 8.91 (m, 2H, o-HC_6pyr), 7.76 (m,

2H, p-HC_4pyr), 7.63 (m, 2H, m-HC_3pyr), 7.24 (m, 2H, m-HC_5pyr), 5.77

(s, 4H, CH₂O), 3.87 (t, 4H, ³J_HH= 6.4 Hz, OCH₂CH₂), 1.89 (m, 4H,

OCH₂CH₂), 1.68 (m, 4H, OCH₂CH₂CH₂); ¹³C{¹H} 161.7 (s, o-

C_2pyr), 153.5 (s, o-C_6pyr), 138.5 (s, p-C_4pyr), 124.1 (s, m-C_3pyr), 124.0 (s,

m-C_5pyr), 71.8 (s, CH₂O), 70.2 (s, OCH₂CH₂), 27.3 (s, CH₂), 23.9 (s,

CH₂). IR (cm⁻¹, powder film): 3061 (w), 2941 (m), 2859 (m), 1607

(m), 1570 (m), 1477 (m), 1229 (m), 1126 (s), 1101 (s), 787 (s), 768

(s), 719 (s).

trans-PtCl₂(3-NC₅H₄(CH₂O(CH₂)₄CHCH₂))₂(trans-12d). Pyr-

idine 2d (2.2421 g, 11.722 mmol) and PtCl₂(1.4588 g, 5.4844 mmol)

were combined in a procedure similar to that for trans-10a. An analo-

gous workup gave trans-12d as a yellow solid (2.9313 g, 4.5199 mmol,

82%). Mp (capillary): 85−87 °C. Anal. Calcd for C₂₄H₃₄Cl₂N₂O₂Pt:

C, 44.45; H, 5.28; N, 4.32. Found: C, 44.71; H, 4.97; N, 4.24. NMR

1

(δ, CDCl₃): H 8.83 (m, 2H, o-HC_2pyr), 8.80 (m, 2H, o-HC_6pyr), 7.78

(m, 2H, p-HC_4pyr), 7.29 (m, 2H, m-HC_5pyr), 5.88−5.74 (ddt, 2H,

³J_HHtrans= 17.0 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.6 Hz, CH), 5.06−4.93

3

trans-PtCl₂(3-NC₅H₄(CH₂OCH₂CHCH₂))₂(trans-12a). Pyridine

(m, 4H, CH₂), 4.51 (s, 4H, CH₂O), 3.50 (t, 4H, J_HH= 6.4 Hz,

2a (1.2028 g, 8.0620 mmol) and PtCl₂(1.0038 g, 3.7738 mmol) were

OCH₂CH₂), 2.08 (m, 4H, CH₂CHCH₂), 1.65 (m, 4H, OCH₂CH₂),

2870

dx.doi.org/10.1021/om201145x | Organometallics 2012, 31, 2854−2877

Organometallics

Article

1.48 (m, 4H, OCH₂CH₂CH₂); ¹³C{¹H} 152.7 and 152.5 (2 s, o-C_2pyr

and o-C_6pyr), 138.8 (s, CH), 137.4 (s, p-C_4pyr), 136.8 (s, m-C_3pyr),

125.1 (s, m-C_5pyr), 114.9 (s, CH₂), 71.2 (s, CH₂O), 69.3 (s,

OCH₂CH₂), 33.7, 29.2, and 25.6 (3 s, 3CH₂). IR (cm⁻¹, powder film):

2934 (m), 2872 (m), 1641 (w), 1611 (w), 1483 (w), 1439 (m), 1369

(m), 1084 (s), 995 (m), 920 (s), 808 (s), 698 (s), 650 (m).

trans-PtCl₂[3,3′-(NC₅H₄(CH₂O(CH₂)₁₀OCH₂)H₄C₅N)] (trans-

13d). Grubbs’ catalyst (0.0254 g, 0.0306 mmol, 3.9 mol %), CH₂Cl₂

(398 mL), trans-12d (0.5158 g, 0.7953 mmol), and Pd/C (0.0423 g of

10% w/w, 0.0398 mmol Pd, 5.0 mol %) were combined in a procedure

similar to that for trans-11a. An analogous workup gave trans-13d as a

light yellow solid (0.4615 g, 0.7414 mmol, 93%). Mp (capillary): 204−

208 °C. Anal. Calcd for C₂₂H₃₂Cl₂N₂O₂Pt: C, 42.45; H, 5.18; N, 4.50.

Found: C, 42.52; H, 4.78; N, 4.45. NMR (δ, CDCl₃): ¹H 9.05 (m, 2H,

o-HC_2pyr), 8.82 (m, 2H, o-HC_6pyr), 7.54 (m, 2H, p-HC_4pyr), 7.23 (m,

trans-PtCl₂(3-NC₅H₄(CH₂O(CH₂)₅CHCH₂))₂(trans-12e). Pyr-

idine 2e (1.5794 g, 7.6913 mmol) and PtCl₂(0.9657 g, 3.630 mmol)

were combined in a procedure similar to that for trans-10a. An

analogous workup gave trans-12e as a yellow solid (2.2861 g, 3.3789

mmol, 93%). Mp (capillary): 86−88 °C. Anal. Calcd for

C₂₆H₃₈Cl₂N₂O₂Pt: C, 46.16; H, 4.91; N, 4.14. Found: C, 46.21; H,

4.91; N, 4.11. NMR (δ, CDCl₃): ¹H 8.83 (m, 2H, o-HC_2pyr), 8.80 (m,

2H, o-HC_6pyr), 7.78 (m, 2H, p-HC_4pyr), 7.28 (m, 2H, m-HC_5pyr), 5.85−

3

2H, m-HC_5pyr), 4.53 (s, 4H, CH₂O), 3.54 (t, 4H, J_HH= 5.7 Hz,

OCH₂CH₂), 1.64 (m, 4H, OCH₂CH₂), 1.56 (m, 4H, O(CH₂)₂CH₂),

1.45−1.35 (m, 8H, CH₂); ¹³C{¹H} 153.1 and 152.5 (2 s, o-C_2pyrand o-

C_6pyr), 136.8 (s, p-C_4pyr), 136.5 (s, m-C_3pyr), 124.5 (s, m-C_5pyr), 71.3 (s,

CH₂O), 69.6 (s, OCH₂CH₂), 30.1, 29.8, 29.4, and 26.5 (4 s, 4CH₂). IR

(cm⁻¹, powder film): 2922 (m), 2853 (m), 1609 (w), 1439 (m), 1358

(m), 1315 (m), 1103 (s), 802 (s), 698 (s).

3

5.77 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis= 10.1 Hz, J_HH= 6.9 Hz,

CH), 5.02−4.92 (m, 4H, CH₂), 4.51 (s, 4H, CH₂O), 3.49 (t, 4H,

³J_HH= 6.4 Hz, OCH₂CH₂), 2.06 (m, 4H, CH₂CHCH₂), 1.63 (m,

4H, OCH₂CH₂), 1.44−1.36 (m, 8H, CH₂); ¹³C{¹H} 152.7 and 152.5

(2 s, o-C_2pyrand o-C_6pyr), 139.1 (s, CH), 137.4 (s, p-C_4pyr), 136.9 (s,

m-C_3pyr), 125.0 (s, m-C_5pyr), 114.6 (s, CH₂), 71.4 (s, CH₂O), 69.3 (s,

OCH₂CH₂), 33.9, 29.7, 28.9, and 25.8 (4 s, 4CH₂). IR (cm⁻¹, powder

film): 2931 (m), 2872 (m), 2851 (m), 1643 (w), 1610 (w), 1440 (m),

1089 (s), 986 (m), 924 (s), 816 (s), 698 (s), 648 (m).

trans-PtCl₂[3,3′-(NC₅H₄(CH₂O(CH₂)₁₈OCH₂)H₄C₅N)] (trans-

13h). Grubbs’ catalyst (0.0237 g, 0.0288 mmol, 5.0 mol %), CH₂Cl₂

(290 mL), trans-12h (0.4409 g, 0.5796 mmol), and Pd/C (0.0316 g of

10% w/w, 0.0297 mmol Pd, 5.1 mol %) were combined in a procedure

similar to that for trans-11a. An analogous workup gave trans-13h as a

yellow solid (0.3398 g, 0.4625 mmol, 80%). Mp (capillary): 131−

134 °C. Anal. Calcd for C₃₀H₄₈Cl₂N₂O₂Pt: C, 49.04; H, 6.59; N, 3.81.

PtCl₂(3-NC₅H₄(CH₂O(CH₂)₈CHCH₂))₂(12h). Pyridine 2h

(1.0658 g, 4.3084 mmol) and PtCl₂(0.5188 g, 1.950 mmol) were

combined in a procedure similar to that for trans-10a. An analogous

workup gave trans-12h (0.6785 g, 0.8919 mmol, 46%; mp (capillary)

101−102 °C) and cis-5h (0.6558 g, 0.8621 mmol, 44%) as yellow

solids. Anal. Calcd for C₃₂H₅₀Cl₂N₂O₂Pt: C, 50.52; H, 6.62; N, 3.68.

Found (trans-12h): C, 50.64; H, 5.78; N, 3.53.⁴⁵

Found: C, 49.16; H, 5.82; N, 3.75.⁴⁵NMR (δ, CDCl₃): H 8.93 (m,

1

2H, o-HC_2pyr), 8.82 (m, 2H, o-HC_6pyr), 7.71 (m, 2H, p-HC_4pyr), 7.28

3

(m, 2H, m-HC_5pyr), 4.51 (s, 4H, CH₂O), 3.50 (t, 4H, J_HH= 6.7 Hz,

OCH₂CH₂), 1.63 (m, 4H, OCH₂CH₂), 1.41−1.24 (m, 28H, CH₂);

¹³C{¹H} 153.1 and 152.8 (2 s, o-C_2pyrand o-C_6pyr), 137.5 (s, p-C_4pyr),

136.8 (s, m-C_3pyr), 124.9 (s, m-C_5pyr), 71.4 (s, CH₂O), 69.5 (s,

OCH₂CH₂), 29.7, 29.4 (5 × ), 29.3, and 26.1 (4 s, 8CH₂). IR (cm⁻¹,

powder film): 2924 (s), 2851 (s), 1611 (w), 1435 (m), 1364 (m),

1103 (s), 800 (s), 692 (s).

1

Data for trans-12h are as follows. NMR (δ, CDCl₃): H 8.83 (m,

2H, o-HC_2pyr), 8.80 (m, 2H, o-HC_6pyr), 7.79 (m, 2H, p-HC_4pyr), 7.29

3

(m, 2H, m-HC_5pyr), 5.88−5.74 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis

=

3

10.4 Hz, J_HH= 6.6 Hz, CH), 5.03−4.89 (m, 4H, CH₂), 4.51 (s,

trans-PtCl₂[3,3′-(NC₅H₄(CH₂O(CH₂)₂₀OCH₂)H₄C₅N)] (trans-

13i). Grubbs’ catalyst (two charges 24 h apart, 0.0219 and 0.0196 g,

0.0505 mmol, 7.6 mol %), CH₂Cl₂(334 mL), trans-12i (0.5273 g.

0.6685 mmol), and Pd/C (0.0363 g of 10% w/w, 0.0341 mmol Pd, 5.1

mol %) were combined in a procedure similar to that for trans-11a. An

analogous workup gave trans-13i as an off-white solid (0.4581 g,

0.6006 mmol, 90%). Mp (capillary): 134−136 °C. Anal. Calcd for

C₃₂H₅₂Cl₂N₂O₂Pt: C, 50.39; H, 6.87; N, 3.67. Found: C, 50.40; H,

6.75; N, 3.55. NMR (δ, CDCl₃): ¹H 8.91 (m, 2H, o-HC_2pyr), 8.81 (m,

2H, o-HC_6pyr), 7.72 (m, 2H, p-HC_4pyr), 7.28 (m, 2H, m-HC_5pyr), 4.52

(s, 4H, CH₂O), 3.49 (t, 4H, ³J_HH= 6.4 Hz, OCH₂CH₂), 1.63 (m, 4H,

OCH₂CH₂), 1.40−1.22 (m, 32H, CH₂); ¹³C{¹H} 153.0 and 152.8 (2

s, o-C_2pyrand o-C_6pyr), 137.5 (s, p-C_4pyr), 136.8 (s, m-C_3pyr), 124.9 (s,

m-C_5pyr), 71.3 (s, CH₂O), 69.4 (s, OCH₂CH₂), 29.7, 29.5 (5 × ), 29.4,

29.3, and 26.1 (5 s, 9CH₂). IR (cm⁻¹, powder film): 2922 (s), 2851

(s), 2341 (w), 2160 (w), 2039 (w), 1981 (w), 1476 (w), 1458 (w),

1435 (m), 1103 (s), 800 (s), 692 (s).

3

4H, CH₂O), 3.49 (t, 4H, J_HH= 6.6 Hz, OCH₂CH₂), 2.04 (m, 4H,

CH₂CHCH₂), 1.62 (m, 4H, OCH₂CH₂), 1.44−1.25 (m, 24H,

CH₂); ¹³C{¹H} 152.7 and 152.5 (2 s, o-C_2pyrand o-C_6pyr), 139.4 (s,

CH), 137.5 (s, p-C_4pyr), 136.9 (s, m-C_3pyr), 125.1 (s, m-C_5pyr), 114.3

(s, CH₂), 71.5 (s, CH₂O), 69.3 (s, OCH₂CH₂), 34.0, 29.8, 29.6

(2×), 29.3, 29.1, and 26.3 (6 s, 7CH₂). IR (cm⁻¹, powder film): 2918

(m), 2849 (m), 2357 (w), 1641 (w), 1464 (w), 1439 (w), 1369 (m),

1258 (w), 1227 (w), 1093 (s), 926 (s), 810 (s), 698 (s), 644 (m).

Data for cis-12h are as follows. NMR (δ, CDCl₃): ¹H 8.89 (m, 2H,

o-HC_2pyr), 8.86 (m, 2H, o-HC_6pyr), 7.73 (m, 2H, p-HC_4p₃_yr), 7.26 (m,

3

2H, m-HC_5pyr), 5.85−5.71 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis= 10.2

3

Hz, J_HH= 6.6 Hz, CH), 5.00−4.87 (m, 4H, CH₂), 4.42 (s, 4H,

3

CH₂O), 3.41 (t, 4H, J_HH= 6.6 Hz, OCH₂CH₂), 2.06−1.97 (m, 4H,

CH₂CHCH₂), 1.59−1.48 (m, 4H, OCH₂CH₂), 1.40−1.22 (m, 24H,

CH₂); ¹³C{¹H} 152.1 and 151.7 (2 s, o-C_2pyrand o-C_6pyr), 139.3 (s,

CH), 138.0 (s, p-C_4pyr), 137.4 (s, m-C_3pyr), 126.1 (s, m-C_5pyr), 114.3

(s, CH₂), 71.5 (s, CH₂O), 68.9 (s, OCH₂CH₂), 33.9, 29.7, 29.5

(2×), 29.2, 29.0, and 26.2 (6 s, 7CH₂).

trans-PdCl₂[2,6-NC₅H₃(CH₂CH₂CHCH₂)₂]₂(trans-14).⁸

A

Schlenk flask was charged with trans-(PhCN)₂PdCl₂(0.527 g, 1.37

mmol), benzene (15 mL), and 3 (0.565 g, 3.02 mmol) and fitted with

a condenser. The solution was refluxed (40 min). A black precipitate

formed after 5 min. The mixture was cooled to room temperature and

filtered. The solvent was removed by rotary evaporation. The residue

was chromatographed on a silica column (30 × 1 cm, 3/1 v/v

hexanes/CH₂Cl₂). The solvents were removed from the product-

containing fractions by rotary evaporation and oil pump vacuum to

give trans-14 as a yellow solid (0.112 g, 0.203 mmol, 15%). NMR (δ,

trans-PtCl₂(3-NC₅H₄(CH₂O(CH₂)₉CHCH₂))₂(trans-12i). Pyri-

dine 2i (1.4690 g, 5.6196 mmol) and PtCl₂(0.7101 g, 2.670 mmol)

were combined in a procedure similar to that for trans-10a. An

analogous workup gave trans-12i as a yellow solid (1.8760 g, 2.3783

mmol, 89%). Mp (capillary): 102−103 °C. Anal. Calcd for

C₃₄H₅₄Cl₂N₂O₂Pt: C, 51.77; H, 6.90; N, 3.55. Found: C, 51.71; H,

6.00; N, 3.40.⁴⁵NMR (δ, CDCl₃): H 8.83 (m, 2H, o-HC_2pyr), 8.80

1

(m, 2H, o-HC_6pyr), 7.79 (m, 2H, p-HC_4pyr), 7.29 (m, 2H, m-HC_5pyr),

3

5.85−5.77 (ddt, 2H, J_HHtrans= 17.0 Hz, J_HHcis= 10.1 Hz, J_HH= 6.9

CDCl₃): ¹H 7.61 (t, 2H, ³J_HH= 7.7 Hz, p-HC_4pyr), 7.12 (d, 4H, ³J_HH

=

Hz, CH), 5.01−4.91 (m, 4H, CH₂), 4.51 (s, 4H, CH₂O), 3.49 (t,

3

7.7 Hz, m-HC_3,5pyr), 6.05 (ddt, 4H, J_HHtrans= 17.0 Hz, J_HHcis= 10.4

4H, J_HH= 6.4 Hz, OCH₂CH₂), 2.03 (m, 4H, CH₂CHCH₂), 1.62

3

2

(m, 4H, OCH₂CH₂), 1.40−1.26 (m, 24H, CH₂); ¹³C{¹H} 152.7 and

152.5 (2 s, o-C_2pyrand o-C_6pyr), 139.5 (s, CH), 137.4 (s, p-C_4pyr),

136.9 (s, m-C_3pyr), 125.1 (s, m-C_5pyr), 114.3 (s, CH₂), 71.5

(s, CH₂O), 69.3 (s, OCH₂CH₂), 34.0, 29.8, 29.7, 29.6 (2×), 29.3,

29.1, and 26.3 (7 s, 8CH₂). IR (cm⁻¹, powder film): 2920 (s), 2847

(s), 2324 (w), 1641 (w), 1611 (w), 1462 (m), 1366 (m), 1096 (s),

920 (s), 810 (s), 700 (s).

Hz, J_HH= 6.5 Hz, CH), 5.23 (dd, 4H, J_HHtrans= 17.1 Hz, J_HH

=

1.6 Hz, CH_EH_Z), 5.14 (dd, 4H, ³J_HHcis= 10.2 Hz, ²J_HH= 1.1 Hz, 

CH_EH_Z), 4.42 (t, 8H, ³J_HH= 7.5 Hz, CH₂), 2.85 (q, 8H, ³J_HH= 7.2 Hz,

CH₂); ¹³C{¹H} 163.3 (s, o-C_2,6pyr), 138.2 (s, p-C_4pyr), 136.8 (s, CH),

122.2 (s, m-C_3,5pyr), 116.4 (s, CH₂), 38.7 (s, CH₂), 32.1 (s, CH₂). IR

(cm⁻¹, powder film): 3080 (m), 2964 (m), 2868 (m), 2934 (m), 2856

(m), 1644 (m), 1606 (m), 1575 (m), 1471 (s), 1262 (s), 1096 (s),

2871

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915 (s), 807 (s). MS:⁴¹517 ([14 − Cl]⁺, 30%), 292 (unknown,

100%), 188 ([3 + H]⁺, 80%).

The mixture was refluxed with stirring (7 days; after 4 days, a yellow

solution had formed) and cooled to room temperature. The solvent

was removed by rotary evaporation, and the residue was chromato-

graphed on a silica column (20 × 2 cm, 4/1 v/v hexanes/ethyl

acetate). The solvents were removed by rotary evaporation from the

product-containing fractions. Hexanes was added (15 mL). The

residue was collected by filtration, washed with hexanes (10 × 3 mL),

and dried overnight by oil pump vacuum to give trans-17b as a yellow

solid (0.354 g, 0.465 mmol, 26%). Mp (capillary): 106−108 °C. DSC

(T_i/T_e/T_p/T_c/T_f): 90.7/109.9/110.8/112.1/135.3 °C (endotherm).

TGA: onset of mass loss, 167.9 °C. Anal. Calcd for C₃₀H₄₂Cl₂N₂O₄Pt:

C, 47.37; H, 5.57; N, 3.68. Found: C, 47.25; H, 5.55; N, 3.62. NMR

trans-PdCl₂[2,6,2′,6′-(NC₅H₃((CH₂)₂CHCH(CH₂)₂)₂H₃C₅N)]

(trans-15).⁸A two-necked round-bottom flask was charged with trans-

14 (0.108 g, 0.196 mmol) and CH₂Cl₂(5 mL). A solution of Grubbs’

catalyst (0.0081 g, 0.098 mmol, 5.0 mol %) in CH₂Cl₂(1.5 mL) was

added dropwise over 10 min with stirring (the resulting solution is

0.0301 M in trans-14). A precipitate formed after 20 min. After 6 h, a

second charge of Grubbs’ catalyst (0.0081 g, 5.0 mol %) was added

as a solid. After 18 h, a final charge of Grubbs’ catalyst (0.0081 g,

5.0 mol %) was added. The mixture was stirred for an additional 6 h.

Water (15 mL) and CH₂Cl₂(15 mL) were added. After 30 min, the

organic layer was separated. The aqueous layer was extracted with

CH₂Cl₂(3 × 15 mL). The organic layer and the extracts were

combined, dried (MgSO₄), and concentrated by rotary evaporation.

The residue was chromatographed on a silica column (25 × 1 cm,

7/3 v/v hexanes/ethyl acetate). The solvents were removed from the

product-containing fractions by rotary evaporation and oil pump

vacuum to give trans-15 as a light yellow solid (0.0563 g, 0.114 mmol,

1

3

(δ, CDCl₃): H 7.78 (t, 2H, J_HH= 7.9 Hz, p-HC_4pyr), 7.58 (d, 4H,

³J_HH= 7.9 Hz, m-HC_3,5pyr), 5.94 (ddt, 4H, ³J_HHtrans= 17.1 Hz, ³J_HHcis

=

3

10.3 Hz, J_HH= 6.8 Hz, CH), 5.81 (s, 8H, CH₂O), 5.19 (dd, 4H,

2

3

³J_HHtrans= 17.2 Hz, J_HH= 1.8 Hz, CH_EH_Z), 5.12 (dd, 4H, J_HHcis

=

2

3

10.2 Hz, J_HH= 1.8 Hz, CH_EH_Z), 3.84 (t, 8H, J_HH= 6.6 Hz,

OCH₂), 2.55−2.50 (m, 8H, CH₂); ¹³C{¹H} 161.3 (s, o-C_2,6pyr), 138.9

(s, p-C_4pyr), 134.8 (s, CH), 121.5 (s, m-C_3,5pyr), 116.9 (s, CH₂),

71.9 (s, CH₂O), 70.9 (s, OCH₂CH₂), 34.2 (s, CH₂). IR (cm⁻¹, powder

film): 3074 (w), 2981 (w), 2866 (m), 1613 (m), 1475 (m), 1352 (m),

1120 (s), 1027 (m), 911 (s), 796 (s). MS:⁴¹760 (17b⁺, 5%), 725

([17b − Cl]⁺, 30%), 248 ([4b + H]⁺, 100%).

1

3

58%). H NMR (δ, CDCl₃): 7.62 (t, 2H, J_HH= 7.7 Hz, p-HC_4pyr),

3

7.12 (d, 4H, J_HH= 7.7 Hz, m-HC_3,5pyr), 6.05−5.97 (m, 4H, CH),

3

4.00 (t, 8H, J_HH= 7.5 Hz, CH₂), 3.28−3.18 (m, 8H, CH₂).

trans-PdCl₂[2,6,2′,6′-(NC₅H₃((CH₂)₆)₂H₃C₅N)] (trans-16). A

round-bottom flask was charged with 15 (0.0702 g, 0.142 mmol),

PtO₂(0.0048 g, 0.021 mmol, 15 mol %), and CH₂Cl₂(14 mL),

flushed with H₂, and fitted with a balloon of H₂(1.0 atm). The mixture

was stirred (3 days). The solvent was removed by rotary evaporation.

The residue was chromatographed on alumina (10 × 2 cm column,

CH₂Cl₂). The solvent was removed from the product-containing

fractions by rotary evaporation and oil pump vacuum to give trans-16

as a light yellow solid (0.044 g, 0.088 mmol, 62%). The sample slightly

darkened at 150 °C. TGA: onset of mass loss, 159.6 °C. Anal. Calcd

for C₂₂H₃₀Cl₂N₂Pd: C, 52.87; H 6.05; N 5.60. Found: C, 52.42; H,

trans-PtCl₂[2,6,2′,6′-(NC₅H₃(CH₂O(CH₂)₄OCH₂)₂H₃C₅N)]

(trans-18a). A two-necked round-bottom flask was charged with

trans-17a (0.250 g, 0.355 mmol) and CH₂Cl₂(173 mL), fitted with a

condenser, and flushed with N₂. A solution of Grubbs’ catalyst (0.0292

g, 0.0355 mmol, 10 mol %) in CH₂Cl₂(5 mL) was added dropwise

over 30 min with stirring (the resulting solution is 0.001 99 M in trans-

17a). The mixture was refluxed (24 h). A precipitate formed after

30 min. The mixture was cooled to room temperature, and the solvent

was removed by rotary evaporation. The residue was chromatographed

on alumina (15 × 2 cm column, CH₂Cl₂). A single light yellow band

was collected. The solvent was removed by rotary evaporation and oil

pump vacuum. A round-bottom flask was charged with the crude

metathesis product, 10% Pd/C (0.0263 g, 0.0246 mmol of Pd),

toluene (10 mL), and ethanol (10 mL), flushed with H₂, and fitted

with a balloon of H₂(1.0 atm). The mixture was stirred (3 days) and

passed through a pad of Celite (7 × 2 cm, rinsed with CH₂Cl₂). The

filtrate was concentrated by oil pump vacuum (to ca. 1 mL), carefully

layered with hexanes (20 mL), and kept at −4 °C. After 24 h, the

supernatant was carefully decanted, and the precipitate was dried by oil

pump vacuum to give trans-18a as an off-white solid (0.0221 g, 0.0338

mmol, 10%). The sample slightly darkened at 150 °C. TGA: onset of

mass loss, 160.0 °C. Anal. Calcd for C₂₂H₃₀Cl₂N₂O₄Pt: C, 40.50; H,

4.63; N, 4.29. Found: C, 41.08; H, 4.95; N, 4.04. NMR (δ, CDCl₃): ¹H

1

3

6.60; N, 4.88. NMR (δ, CDCl₃): H 7.54 (t, 2H, J_HH= 7.7 Hz, p-

3

HC_4pyr), 7.11 (d, 4H, J_HH= 7.7 Hz, m-HC_3,5pyr), 3.94−3.89 (m, 8H,

CH₂), 2.72−2.55 (m, 8H, CH₂), 2.02−1.85 (m, 8H, CH₂); ¹³C{¹H}

165.1 (s, o-C_2,6pyr), 139.0 (s, p-C_4pyr), 123.8 (s, m-C_3,5pyr), 40.6 (s,

CH₂), 26.3 (s, CH₂), 25.2 (s, CH₂). IR (cm⁻¹, powder film): 3069 (w),

2961 (m), 2926 (m), 2868 (m), 1644 (m), 1606 (m), 1575 (m), 1463

(s), 1262 (m), 1092 (s), 1019 (s), 915 (s), 791 (s), 757 (s). MS:⁴¹501

(16⁺, 60%), 486 (unknown, 100%), 428 ([16 − 2Cl]⁺, 20%).

trans-PtCl₂[2,6-NC₅H₃(CH₂OCH₂CHCH₂)₂]₂(trans-17a). A

Schlenk flask was charged with PtCl₂(0.513 g, 1.93 mmol), benzene

(19 mL), and 4a (0.930 g, 4.24 mmol) and fitted with a condenser.

The mixture was refluxed with stirring (5 days; after 2 days, a yellow

solution had formed) and cooled to room temperature. The solvent

was removed by rotary evaporation and the residue chromatographed

on a silica column (10 × 2 cm, CH₂Cl₂). A single yellow band was

collected. The solvent was removed by rotary evaporation. Hexanes

was added (10 mL). The residue was collected by filtration, washed

with hexanes (10 × 3 mL), and dried overnight by oil pump vacuum to

give trans-17a as a yellow solid (1.196 g, 1.698 mmol, 88%). Mp

(capillary): 148−150 °C. DSC (T_i/T_e/T_p/T_c/T_f): 107.5/152.0/154.9/

156.5/168.3 °C (endotherm). TGA: onset of mass loss, 163.1 °C.

Anal. Calcd for C₂₆H₃₄Cl₂N₂O₄Pt: C, 44.32; H, 4.86; N, 3.98. Found:

3

7.80 (t, 2H, J_HH= 7.7 Hz, p-HC_4pyr), 7.53 (d, 4H, J_HH= 7.7 Hz, m-

HC_3,5pyr), 5.95 (s, 8H, CH₂O), 3.97−3.94 (m, 8H, OCH₂CH₂), 2.08−

2.13 (m, 8H, CH₂); ¹³C{¹H} 161.0 (s, o-C_2,6pyr), 139.5 (s, p-C_4pyr),

125.6 (s, m-C_3,5pyr), 72.5 and 69.9 (2 s, CH₂OCH₂), 24.5 (s, CH₂). IR

(cm⁻¹, powder film): 2941 (w), 2914 (w), 2856 (m), 1610 (m), 1471

(m), 1370 (m), 1212 (m), 1123 (s), 1108 (s), 984 (s), 803 (s). MS:⁴¹

617 ([18a − Cl]⁺, 30%), 580 (unknown, 100%).

trans-PtCl₂[2,6,2′,6′-(NC₅H₃(CH₂O(CH₂)₆OCH₂)₂H₃C₅N)]

(trans-18b). Solutions of trans-17b (0.250 g, 0.328 mmol) in CH₂Cl₂

(160 mL) and of Grubbs’ catalyst (0.027 g, 0.0328 mmol, 10 mol %)

in CH₂Cl₂(4 mL) were combined in a procedure similar to that for

trans-18a (the resulting solution is 0.002 01 M in trans-17b). After

hydrogenation, an analogous workup gave trans-18b as a white solid

(0.0501 g, 0.0706 mmol, 22% overall). The sample slightly darkened at

200 °C. DSC (T_i/T_e/T_p/T_c/T_f): 126.7/166.3/170.1/174.7/182.0 °C

(endotherm). TGA: onset of mass loss, 231.6 °C. Anal. Calcd for

C₂₆H₃₈Cl₂N₂O₄Pt: C, 44.07; H, 5.41; N, 3.95. Found: C, 43.51; H,

C, 43.39; H, 4.86; N, 3.79.⁴⁵NMR (δ, CDCl₃): ¹H 7.78 (t, 2H, ³J_HH

=

3

7.9 Hz, p-HC_4pyr), 7.58 (d, 4H, J_HH= 7.9 Hz, m-HC_3,5pyr), 6.04 (ddt,

2H, ³J_HHtrans= 17.2 Hz, ³J_HHcis= 10.6 Hz, ³J_HH= 5.4 Hz, CH), 5.82

3

2

(s, 8H, CH₂O), 5.44 (dd, 4H, J_HHtrans= 17.2 Hz, J_HH= 1.6 Hz, 

3

2

CH_EH_Z), 5.30 (dd, 4H, J_HHcis= 10.4 Hz, J_HH= 1.5 Hz, CH_EH_Z),

4.27 (dt, 8H, ³J_HH= 5.5 Hz, ⁴J_HH= 1.5 Hz, OCH₂); ¹³C{¹H} 161.5 (s,

o-C_2,6pyr), 139.0 (s, p-C_4pyr), 134.0 (s, CH), 121.5 (s, m-C_3,5pyr),

117.9 (s, CH₂), 72.2 and 71.3 (2 s, CH₂OCH₂). IR (cm⁻¹, powder

film): 3092 (w), 3015 (w), 2868 (m), 2837 (m), 1613 (m), 1471 (m),

1332 (m), 1239 (w), 1123 (s), 1107 (s), 911 (s), 787 (s). MS:⁴¹705

(17a⁺, 10%), 669 ([17a − Cl]⁺, 40%), 220 ([4a + H]⁺, 100%).

trans-PtCl₂[2,6-NC₅H₃(CH₂O(CH₂)₂CHCH₂)₂]₂(trans-17b). A

Schlenk flask was charged with PtCl₂(0.477 g, 1.79 mmol), benzene

(15 mL), and 4b (0.914 g, 3.70 mmol) and fitted with a condenser.

1

3

5.31; N, 3.66. NMR (δ, CDCl₃): H 7.79 (t, 2H, J_HH= 7.8 Hz,

3

p-HC_4pyr), 7.56 (d, 4H, J_HH= 7.8 Hz, m-HC_3,5pyr), 5.90 (s, 8H,

CH₂O), 3.89 (t, 8H, ³J_HH= 6.5 Hz, OCH₂), 1.92−1.89 (m, 8H, CH₂),

1.70−1.68 (m, 8H, CH₂); ¹³C{¹H} 161.5 (s, o-C_2,6pyr), 138.9 (s, p-

C_4pyr), 121.5 (s, m-C_3,5pyr), 70.7 and 69.6 (2 s, CH₂OCH₂), 26.1 (s,

CH₂), 23.0 (s, CH₂). IR (cm⁻¹, powder film): 2943 (w), 2866 (w),

2872

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1614 (m), 1468 (m), 1367 (m), 1213 (w), 1112 (s), 1012 (m), 965

(m), 811 (s). MS:⁴¹709 (18b⁺, 60%), 673 ([18b − Cl]⁺, 50%), 636

(unknown, 100%).

and benzene (11 mL) were combined in a procedure similar to that for

trans-19a. An analogous workup gave trans-19e as a yellow solid

(1.042 g, 1.058 mmol, 94%). Mp (capillary): 74−76 °C. DSC (T_i/T_e/

T_p/T_c/T_f): 48.5/52.1/53.6/55.6/57.3 °C (endotherm); 70.4/79.3/

81.1/82.9/99.8 °C (endotherm). TGA: onset of mass loss, 165.7 °C.

trans-PtCl₂[3,5-NC₅H₃(COOCH₂CHCH₂)₂]₂(trans-19a). A

Schlenk flask was charged with 5a (0.790 g, 3.198 mmol), PtCl₂

(0.4051 g, 1.523 mmol), and benzene (15 mL) and fitted with a

condenser. The mixture was refluxed with stirring (12 h; after 1 h, a

yellow solution had formed) and cooled to room temperature. The

solvent was removed by rotary evaporation. The residue was

chromatographed on a silica column (20 × 2 cm, 4/1 v/v hexanes/

ethyl acetate). A single yellow band was collected. The solvent was

removed by rotary evaporation. Hexanes was added (15 mL). The

residue was collected by filtration, washed with hexanes (7 × 2 mL),

and dried by oil pump vacuum to give trans-19a as a yellow solid

(1.004 g, 1.321 mmol, 87%). Mp (capillary): 178−180 °C. TGA: onset

of mass loss, 145.3 °C. Anal. Calcd for C₂₆H₂₆Cl₂N₂O₈Pt: C, 41.06; H,

3.45; N, 3.68. Found: C, 40.65; H, 3.18; N, 3.53. NMR (δ, CDCl₃): ¹H

Anal. Calcd for C₄₂H₅₈Cl₂N₂O₈Pt: C, 51.22; H, 5.94; N, 2.84. Found:

1

C, 51.71; H, 6.19; N, 2.93. NMR (δ, CDCl₃): H 9.67 (d, 4H, ⁴J_HH

=

4

1.8 Hz, o-HC_2,6pyr), 8.98 (t, 2H, J_HH= 1.8 Hz, p-HC_4pyr), 5.83 (ddt,

4H, ³J_HHtrans= 17.1 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.7 Hz, CH), 5.04

(dd, 4H, ³J_HHtrans= 18.1 Hz, ²J_HH= 2.5 Hz, CH_EH_Z), 4.99 (dd, 4H,

³J_HHcis= 10.2 Hz, J_HH= 1.2 Hz, CH_EH_Z), 4.43 (t, 8H, J_HH= 6.7

Hz, OCH₂), 2.13−2.09 (m, 8H, CH₂), 1.88−1.81 (m, 8H, CH₂),

1.47−1.50 (m, 16H, CH₂); ¹³C{¹H} 162.1 (s, CO), 157.5 (s, o-C_2,6pyr),

140.0 (s, p-C_4pyr), 138.5 (s, CH), 128.6 (s, m-C_3,5pyr), 114.7 (s, 

CH₂), 66.8 (s, OCH₂), 33.5, 28.4, 28.3, and 25.3 (4 s, 4CH₂). IR

(cm⁻¹, powder film): 3130 (w), 3080 (w), 2926 (m), 2856 (m), 1722

(s), 1447 (m), 1305 (s), 1247 (s), 1127 (s), 984 (s), 907 (s), 741 (s).

MS:⁴¹984 (19e⁺, 4%), 949 ([19e − Cl]⁺, 14%), 360 (5e⁺, 100%).

trans-PtCl₂[3,5-NC₅H₃(COO(CH₂)₆CHCH₂)₂]₂(trans-19f).

Pyridine 5f (1.410 g, 3.641 mmol), PtCl₂(0.440 g, 1.66 mmol), and

benzene (15 mL) were combined in a procedure similar to that for

trans-19a. An analogous workup gave trans-19f as a yellow solid (0.906

g, 0.870 mmol, 63%). Mp (capillary): 66−68 °C. DSC (T_i/T_e/T_p/T_c/

T_f): 60.8/68.5/70.7/72.3/82.7 °C (endotherm). TGA: onset of mass

loss, 171.8 °C. Anal. Calcd for C₄₆H₆₆Cl₂N₂O₈Pt: C, 53.07; H, 6.39;

N, 2.69. Found: C, 52.62; H, 6.44; N, 2.63. NMR (δ, CDCl₃): ¹H 9.66

2

3

4

9.68 (d, 4H, J_HH= 1.8 Hz, o-HC_2,6pyr), 9.02 (t, 2H, J_HH= 1.8 Hz, p-

3

HC_4pyr), 6.05 (ddt, 4H, J_HHtrans= 16.9 Hz, J_HHcis= 10.6 Hz, J_HH

=

3

2

6.2 Hz, CH), 5.47 (dd, 4H, J_HHtrans= 17.2 Hz, J_HH= 1.3 Hz, 

3

2

CH_EH_Z), 5.39 (dd, 4H, J_HHcis= 10.3 Hz, J_HH= 1.1 Hz, CH_EH_Z),

4.92 (dt, 8H, ³J_HH= 5.9 Hz, ⁴J_HH= 1.2 Hz, OCH₂); ¹³C{¹H} 162.1 (s,

CO), 157.6 (o-C_2,6pyr), 140.1 (s, p-C_4pyr), 130.8 (s, CH), 128.4 (s, m-

C_3,5pyr), 120.0 (s, CH₂), 67.1 (s, OCH₂). IR (cm⁻¹, powder film):

3082 (w), 2968 (m), 2895 (m), 1733 (s), 1652 (m), 1598 (m), 1447

(m), 1301 (s), 1251 (s), 1135 (s), 1112 (s), 980 (s), 911 (s), 745 (s).

MS:⁴¹760 (19a⁺, 20%), 725 ([19a − Cl]⁺, 18%).

4

(d, 4H, J_HH= 1.8 Hz, o-HC_2,6pyr), 8.98 (t, 2H, J_HH= 1.8 Hz, p-

HC_4pyr), 5.82 (ddt, 4H, J_HHtrans= 17.1 Hz, J_HHcis= 10.2 Hz, J_HH

trans-PtCl₂[3,5-NC₅H₃(COO(CH₂)₃CHCH₂)₂]₂(trans-19c).

Pyridine 5c (1.000 g, 3.297 mmol), PtCl₂(0.400 g, 1.50 mmol),

and benzene (33 mL) were combined in a procedure similar to that for

trans-19a. An analogous workup gave trans-19c as a yellow solid

(1.098 g, 1.258 mmol, 84%). Mp (capillary): 92−94 °C. DSC (T_i/T_e/

T_p/T_c/T_f): 72.5/95.5/97.6/99.9/133.3 °C (endotherm). TGA: onset

of mass loss, 176.3 °C. Anal. Calcd for C₃₄H₄₂Cl₂N₂O₈Pt: C, 46.79; H,

4.85; N, 3.21. Found: C, 46.23; H, 4.56; N, 3.04. NMR (δ, CDCl₃): ¹H

3

=

3

2

6.8 Hz, CH), 5.01 (dd, 4H, J_HHtrans= 17.0 Hz, J_HH= 2.3 Hz, 

3

2

CH_EH_Z), 4.95 (dd, 4H, J_HHcis= 10.1 Hz, J_HH= 1.1 Hz, CH_EH_Z),

3

4.43 (t, 8H, J_HH= 6.7 Hz, OCH₂), 2.09−2.03 (m, 8H, CH₂), 1.83−

1.81 (m, 8H, CH₂), 1.45−1.42 (m, 24H, CH₂); ¹³C{¹H} 162.1 (s,

CO), 157.5 (s, o-C_2,6pyr), 140.0 (s, p-C_4pyr), 138.8 (s, CH), 128.6 (s,

m-C_3,5pyr), 114.4 (s, CH₂), 66.8 (s, OCH₂), 33.6, 28.7, 28.6, 28.5,

and 25.7 (5 s, 5CH₂). IR (cm⁻¹, powder film): 3127 (w), 3080 (w),

2926 (s), 2856 (m), 1718 (s), 1606 (m), 1447 (s), 1305 (s), 1225 (s),

1127 (s), 968 (s), 911 (s), 741 (s). MS:⁴¹1040 (19f⁺, 2%), 1005 ([19f

− Cl]⁺, 20%), 388 ([5f + H]⁺, 100%).

4

9.68 (d, 4H, J_HH= 1.8 Hz, o-HC_2,6pyr), 8.99 (t, 2H, J_HH= 1.8 Hz, p-

3

HC_4pyr), 5.86 (ddt, 4H, J_HHtrans= 17.0 Hz, J_HHcis= 10.3 Hz, J_HH

=

3

2

6.7 Hz, CH), 5.12 (dd, 4H, J_HHtrans= 17.2 Hz, J_HH= 1.3 Hz, 

3

2

CH_EH_Z), 5.06 (dd, 4H, J_HHcis= 10.3 Hz, J_HH= 1.1 Hz, CH_EH_Z),

trans-PtCl₂[3,5-NC₅H₃(COO(CH₂)₈CHCH₂)₂]₂(trans-19h).

Pyridine 5h (0.652 g, 1.47 mmol), PtCl₂(0.178 g, 0.668 mmol),

and benzene (7 mL) were combined in a procedure similar to that for

trans-19a. An analogous workup gave trans-19h as a yellow solid

(0.600 g, 0.520 mmol, 78%). Mp (capillary): 68−70 °C. DSC (T_i/T_e/

T_p/T_c/T_f): 34.5/39.5/41.6/43.6/47.0 °C (endotherm); 50.6/68.3/

70.3/72.1/87.2 °C (endotherm). TGA: onset of mass loss, 177.5 °C.

3

4.46 (t, 8H, J_HH= 6.7 Hz, OCH₂), 2.28−2.23 (m, 8H, CH₂), 1.98−

1.91 (m, 8H, CH₂); ¹³C{¹H} 162.0 (s, CO), 157.6 (s, o-C_2,6pyr), 140.1

(s, p-C_4pyr), 137.0 (s, CH), 128.5 (s, m-C_3,5pyr), 115.8 (s, CH₂),

66.1 (s, OCH₂), 30.0 (s, CH₂), 27.6 (s, CH₂). IR (cm⁻¹, powder film):

3128 (w), 3082 (w), 2958 (m), 2926 (m), 1722 (s), 1645 (m), 1607

(m), 1447 (s), 1305 (s), 1251 (s), 1112 (s), 981 (s), 911 (s), 742 (s).

MS:⁴¹872 (19c⁺, 30%), 836 ([19c − Cl]⁺, 10%), 304 (5c⁺, 100%).

trans-PtCl₂[3,5-NC₅H₃(COO(CH₂)₄CHCH₂)₂]₂(trans-19d).

Pyridine 5d (1.002 g, 3.018 mmol), PtCl₂(0.382 g, 1.437 mmol),

and benzene (14 mL) were combined in a procedure similar to that for

trans-19a. An analogous workup gave trans-19d as a yellow solid

(1.234 g, 1.329 mmol, 92%). Mp (capillary): 74−76 °C. DSC (T_i/T_e/

T_p/T_c/T_f): 49.4/56.6/58.6/61.8/62.6 °C (endotherm); 63.0/65.7/

67.3/68.5/68.5 °C (endotherm); 75.5/76.7/79.3/80.8/83.2 °C

(endotherm). TGA: onset mass loss, 165.3 °C. Anal. Calcd for

C₃₈H₅₀Cl₂N₂O₈Pt: C, 49.14; H, 5.43; N, 3.02. Found: C, 48.69; H,

Anal. Calcd for C₅₄H₈₂Cl₂N₂O₈Pt: C, 56.24; H, 7.17; N, 2.43. Found:

1

C, 55.93; H, 7.12; N, 2.38. NMR (δ, CDCl₃): H 9.66 (d, 4H, ⁴J_HH

=

4

1.8 Hz, o-HC_2,6pyr), 8.98 (t, 2H, J_HH= 1.8 Hz, p-HC_4pyr), 5.82 (ddt,

4H, ³J_HHtrans= 17.0 Hz, ³J_HHcis= 10.3 Hz, ³J_HH= 6.7 Hz, CH), 5.00

(dd, 4H, ³J_HHtrans= 17.1 Hz, ²J_HH= 2.1 Hz, CH_EH_Z), 4.95 (dd, 4H,

³J_HHcis= 10.2 Hz, J_HH= 2.1 Hz, CH_EH_Z), 4.42 (t, 8H, J_HH= 6.7

Hz, OCH₂), 2.08−2.04 (m, 8H, CH₂), 1.86−1.79 (m, 8H, CH₂),

1.45−1.34 (m, 40H, CH₂); ¹³C{¹H} 162.1 (s, CO), 157.4 (s, o-C_2,6pyr),

140.1 (s, p-C_4pyr), 139.6 (s, CH), 128.6 (s, m-C_3,5pyr), 114.6 (s, 

CH₂), 67.3 (s, OCH₂), 34.2, 29.9, 29.7, 29.6, 29.4, 28.9, and 26.2 (7 s,

7CH₂). IR (cm⁻¹, powder film): 3127 (w), 3080 (w), 2922 (s), 2853

(m), 1733 (s), 1718 (s), 1606 (m), 1447 (m), 1305 (s), 1262 (s),

1127 (s), 1108 (s), 992 (s), 911 (s), 741 (s). MS:⁴¹1152 (19h⁺, 5%),

1117 ([19h − Cl]⁺, 50%), 444 ([5h + H]⁺, 100%).

2

3

1

4

5.42; N, 2.73. NMR (δ, CDCl₃): H 9.67 (d, 4H, J_HH= 1.8 Hz, o-

HC_2,6pyr), 8.99 (t, 2H, ⁴J_HH= 1.8 Hz, p-HC_4pyr), 5.83 (ddt, 4H, ³J_HHtrans

3

= 17.0 Hz, J_HHcis= 10.3 Hz, J_HH= 6.7 Hz, CH), 5.07 (dd, 4H,

³J_HHtrans= 17.1 Hz, J_HH= 1.9 Hz, CH_EH_Z), 5.01 (dd, 4H, J_HHcis

=

2

3

2

3

10.2 Hz, J_HH= 1.9 Hz, CH_EH_Z), 4.44 (t, 8H, J_HH= 6.7 Hz,

OCH₂), 2.19−2.13 (m, 8H, CH₂), 1.89−1.81 (m, 8H, CH₂), 1.61−

1.53 (m, 8H, CH₂); ¹³C{¹H} 162.1 (s, CO), 157.5 (s, o-C_2,6pyr), 140.0

(s, p-C_4pyr), 138.0 (s, CH), 128.5 (s, m-C_3,5pyr), 115.2 (s, CH₂),

66.6 (s, OCH₂), 33.2, 27.9, and 25.1 (3 s, 3CH₂). IR (cm⁻¹, powder

film): 3113 (w), 3075 (w), 2950 (m), 2920 (m), 1730 (s), 1645 (m),

1607 (m), 1452 (s), 1267 (s), 1112 (s), 966 (s), 911 (s), 742 (s).

MS:⁴¹928 (19d⁺, 30%), 893 ([19d − Cl]⁺, 30%), 332 ([5d + H]⁺,

100%).

trans-PtCl₂[3,5,3′,5′-(NC₅H₃(COO(CH₂)₁₀OCO)₂H₃C₅N)] (trans-

20d). A round-bottom flask was charged with trans-19d (0.250 g,

0.269 mmol) and CH₂Cl₂(130 mL), fitted with a condenser, and

flushed with N₂. A solution of Grubbs’ catalyst (0.0220 g, 0.0269

mmol, 10 mol %) in CH₂Cl₂(4 mL) was added dropwise over 30 min

with stirring (the resulting solution is 0.002 01 M in trans-19d).

The mixture was refluxed (24 h) and cooled to room temperature. The

solvent was removed by rotary evaporation. The residue was

chromatographed on an alumina column (20 × 2 cm, CH₂Cl₂). A

single yellow band was collected. The solvent was removed by rotary

trans-PtCl₂[3,5-NC₅H₃(COO(CH₂)₅CHCH₂)₂]₂(trans-19e).

Pyridine 5e (0.853 g, 2.373 mmol), PtCl₂(0.300 g, 1.128 mmol),

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evaporation and oil pump vacuum. A round-bottom flask was charged

with the crude metathesis product, 10% Pd/C (0.0343 g, 0.0322 mmol

of Pd), toluene (10 mL), and ethanol (10 mL), flushed with H₂, and

fitted with a balloon of H₂(1.0 atm). The mixture was stirred (3 days)

and passed through a pad of Celite (7 × 2 cm, CH₂Cl₂). The filtrate

was concentrated by oil pump vacuum (to ca. 1 mL), carefully layered

with hexanes (20 mL), and kept at −4 °C. After 24 h, the supernatant

was carefully decanted, and the precipitate was dried by oil pump

vacuum to give trans-20d as a pale yellow solid (0.0469 g, 0.0535

mmol, 20%). The sample slightly darkened at 190 °C. DSC (T_i/T_e/

T_p/T_c/T_f): 159.5/167.8/194.6/201.7/209.4 °C (endotherm). TGA:

onset of mass loss, 253.2 °C. Anal. Calcd for C₃₄H₄₆Cl₂N₂O₈Pt: C,

46.58; H, 5.29; N, 3.20. Found: C, 45.75; H, 5.41; N, 3.09.⁴⁵NMR (δ,

TGA: onset of mass loss, 202 °C. Anal. Calcd for C₅₀H₇₈Cl₂N₂O₈Pt:

C, 54.54; H, 7.14; N, 2.54. Found: C, 54.13; H, 7.08; N, 2.33. NMR

1

4

(δ, CDCl₃): H 9.65 (d, 4H, J_HH= 1.8 Hz, o-HC_2,6pyr), 9.10 (t, 2H,

⁴J_HH= 1.8 Hz, p-HC_4pyr), 4.45 (t, 8H, J_HH= 5.9 Hz, OCH₂), 1.85−

3

1.82 (m, 8H, CH₂), 1.45−1.29 (m, 56H, CH₂); ¹³C{¹H} 162.2

(s, CO), 157.1 (s, o-C_2,6pyr), 141.6 (s, p-C_4pyr), 128.8 (s, m-C_3,5pyr), 66.9

(s, OCH₂), 29.2, 29.0, 28.9, 28.7, 28.5, 27.8, 26.8, and 25.6 (8 s,

8CH₂). IR (cm⁻¹, powder film): 3080 (w), 2926 (s), 2853 (m), 1737

(s), 1598 (m), 1459 (m), 1266 (s), 1243 (s), 1162 (s), 1112 (s), 973

(s), 930 (s), 749 (s), 683 (s). MS:⁴¹1101 (20h⁺, 25%), 1066 [20h −

Cl]⁺, 35%), 1027 (unknown, 10%).

trans-PtCl₂(3,5-NC₅H₃(4-C₆H₄O(CH₂)₅CHCH₂)₂)₂(trans-22).

PtCl₂(0.0162 g, 0.0609 mmol) and 8 (0.0570 g, 0.125 mmol) were

combined in a procedure similar to that for trans-10a. An analogous

workup gave trans-22 as a light yellow solid (0.0687 g, 0.0584 mmol,

96%). Mp (capillary): 190−192 °C. Anal. Calcd for C₆₂H₇₄Cl₂N₂O₄Pt:

C, 63.25; H, 6.34; N, 2.38. Found: C, 62.59; H, 6.31; N, 2.30.⁴⁵NMR

CDCl₃): ¹H 9.68 (d, 4H, ⁴J_HH= 1.8 Hz, o-HC_2,6pyr), 9.12 (t, 2H, ⁴J_HH

=

3

1.8 Hz, p-HC_4pyr), 4.44 (t, 8H, J_HH= 5.8 Hz, OCH₂), 1.87−1.81 (m,

8H, CH₂), 1.71−1.63 (m, 8H, CH₂), 1.54−1.47 (m, 16H, CH₂);

¹³C{¹H} 162.1 (s, CO), 157.1 (s, o-C_2,6pyr), 141.0 (s, p-C_4pyr), 128.6 (s,

C_3,5pyr), 67.2 (s, OCH₂), 29.3, 28.6, 28.5, and 26.5 (4 s, 4CH₂). IR

(cm⁻¹, powder film): 3074 (w), 2935 (m), 2850 (m), 1738 (s), 1599

(w), 1460 (w), 1390 (w), 1267 (s), 1104 (m), 1004 (m), 958 (s), 749

(s). MS:⁴¹876 (20d⁺, 30%), 840 ([20d − Cl]⁺, 60%), 817 (unknown,

100%).

1

4

(δ, CDCl₃): H 9.01 (d, 4H, J_HH= 1.8 Hz, o-HC_2,6pyr), 8.00 (t, 2H,

⁴J_HH= 1.8 Hz, p-HC_4pyr), 7.57 and 7.01 (2 m, 2 × 8H, pyr-CCH and

3

C_pyrCCHCH), 5.88−5.79 (ddt, 4H, J_HHtrans= 17.0 Hz, J_HHcis= 10.1

3

Hz, J_HH= 6.4 Hz, CH), 5.06−4.94 (m, 8H, CH₂), 4.02 (t, 8H,

³J_HH= 6.4 Hz, OCH₂), 2.11 (m, 8H, CH₂CHCH₂), 1.83 (m, 8H,

OCH₂CH₂), 1.50 (m, 16H, CH₂); ¹³C{¹H} 160.2 (s, COCH₂), 149.6

(s, o-C_2,6pyr), 139.0 (s, CH₂), 138.4 (s, m-C_3,5pyr), 133.9 (s, p-C_4pyr),

128.7 (s, pyr-C(CH)₂), 128.0 (s, pyr-C(CH)₂), 115.5 (s, (CH)₂CO),

114.7 (s, CH), 68.3 (s, C₆H₄OCH₂), 33.9, 29.3, 28.8, 25.7 (4 s,

4CH₂). IR (cm⁻¹, powder film): 3074 (w), 2930 (m), 2857 (m), 1607

(s), 1512 (s), 1449 (s), 1287 (s), 1240 (s), 1180 (s), 995 (m), 908 (s),

823 (s), 696 (m).

trans-PtCl₂[3,5,3′,5′-(NC₅H₃(COO(CH₂)₁₂OCO)₂H₃C₅N)] (trans-

20e). Solutions of trans-19e (0.250 g, 0.253 mmol) in CH₂Cl₂(120

mL) and of Grubbs’ catalyst (0.021 g, 0.0253 mmol, 10 mol %) in

CH₂Cl₂(5 mL) were combined in a procedure similar to that for

trans-20d (the resulting solution is 0.002 02 M in trans-19e). After

hydrogenation, an analogous workup gave trans-20e as a light yellow

solid (0.105 g, 0.113 mmol, 45%). Mp (capillary): 214−216 °C. DSC

(T_i/T_e/T_p/T_c/T_f): 63.5/63.5/69.8/74.0/74.0 °C (endotherm); 75.0/

80.4/86.8/91.8/101.0 °C (endotherm); 208.8/213.9/223.9/229.5/

229.5 °C (endotherm). TGA: onset of mass loss, 220.3 °C. Anal.

Calcd for C₃₈H₅₄Cl₂N₂O₈Pt: C, 48.92; H, 5.84; N, 3.00. Found: C,

48.52; H, 5.83; N, 3.00. NMR (δ, CDCl₃): ¹H 9.66 (d, 4H, ⁴J_HH= 1.8

Hz, o-HC_2,6pyr), 9.12 (t, 2H, ⁴J_HH= 1.8 Hz, p-HC_4pyr), 4.45 (t, 8H, ³J_HH

= 5.9 Hz, OCH₂), 1.82−1.89 (m, 8H, CH₂), 1.60−1.53 (m, 8H, CH₂),

1.48−1.40 (m, 24H, CH₂); ¹³C{¹H} 162.1 (s, CO), 157.0 (s, o-C_2,6pyr),

141.2 (s, p-C_4pyr), 128.9 (s, m-C_3,5pyr), 67.1 (s, OCH₂), 29.0, 28.6, 28.4,

28.3, and 26.3 (5 s, 5CH₂). IR (cm⁻¹, powder film): 3084 (w),

3061(w), 2926 (m), 2853 (m), 1737 (s), 1463 (w), 1444 (w), 1266

(s), 1243 (s), 1112 (m), 1046 (m), 965 (m), 748 (s), 687 (m). MS:⁴¹

932 (20e⁺, 100%), 897 ([20e − Cl]⁺, 80%), 859 (unknown, 70%).

trans-PtCl₂[3,5,3′,5′-(NC₅H₃(4-C₆H₄O(CH₂)₁₂O-4-C₆H₄)₂H₃C₅N)]

(trans-23). Grubbs’ catalyst (0.0287 g, 0.0349 mmol, 15 mol %), trans-

22 (0.2737 g. 0.2325 mmol), and Pd/C (10% w/w; three hydro-

genation cycles using 0.0203, 0.0217, and 0.0217 g or 0.0599 mmol of

Pd, 26 mol %) were combined in a procedure similar to that for trans-

11a. An analogous workup gave trans-23 as a yellow solid (0.1036 g,

0.09207 mmol, 40%). Mp (capillary): 198−204 °C dec. Anal. Calcd

for C₅₈H₇₀Cl ₂N₂O₄Pt: C, 61.91; H, 6.27; N, 2.49. Found: C, 60.58; H,

1

4

6.07; N, 2.42.⁴⁵NMR (δ, CDCl₃): H 8.83 (d, 4H, J_HH= 2.0 Hz, o-

4

HC_2,6pyr), 7.96 (t, 2H, J_HH= 2.0 Hz, p-HC _4pyr), 7.48 and 6.97 (2 m,

2 × 8H, pyr-CCH and C_pyrCCHCH), 4.05 (t, 8H, J_HH= 6.9 Hz,

3

OCH₂), 1.86−1.76 (m, 8H, OCH₂CH₂), 1.54−1.44 (m, 8H, CH₂),

1.44−1.28 (m, 24H, CH₂); ¹³C{¹H} 160.1 (s, COCH₂), 149.2 (s, o-

C_2,6pyr), 137.7 (s, m-C _3,5pyr), 133.1 (s, p-C_4pyr), 128.7 (s, pyr-C(CH)₂),

127.5 (s, pyr-C(CH)₂), 115.4 (s, (CH)₂CO), 68.2 (s, C₆H₄OCH₂),

29.2, 29.1, 29.0 (2×), and 25.8 (4 s, 5CH₂). IR (cm⁻¹, powder film):

2924 (s), 2853 (m), 2359 (w), 1607 (s), 1512 (s), 1449 (s), 1287 (s),

1240 (s), 1180 (s), 1028 (m), 824 (s), 698 (m).

trans-PtCl(CH₃)[3-NC₅H₄(CH₂O(CH₂)₂CHCH₂)]₂(trans-24b).

A round-bottom flask was charged with trans-12b (0.6121 g, 1.033

mmol) and diethyl ether (15 mL) in an argon glovebox. Then

CH₃MgBr (2.94 M in ether; 0.86 mL, 2.5 mmol) was added with

stirring. After 2 h, saturated aqueous NH₄Cl (5 mL), water (45 mL),

and diethyl ether (35 mL) were added, and the phases were separated.

The water layer was extracted with diethyl ether (2 × 50 mL). The

combined ethereal layers were dried (MgSO₄). The solvent was

removed by oil pump vacuum. The residue was chromatographed on a

silica column (39 × 2.5 cm, 1/4 v/v ethyl acetate/CH₂Cl₂) to give

trans-24b as a white solid (0.5549 g, 0.9701 mmol, 94%). NMR (δ,

CDCl₃): ¹H 8.89 (m, 2H, o-HC_2pyr), 8.85 (m, 2H, o-HC_6pyr), 7.74 (m,

trans-PtCl₂[3,5,3′,5′-(NC₅H₃(COO(CH₂)₁₄OCO)₂H₃C₅N)] (trans-

20f). Solutions of trans-19f (0.250 g, 0.240 mmol) in CH₂Cl₂(115

mL) and of Grubbs’ catalyst (0.0197 g, 0.024 mmol, 10 mol %) in

CH₂Cl₂(5 mL) were combined in a procedure similar to that for

trans-20d (the resulting solution is 0.002 00 M in trans-19f). After

hydrogenation, an analogous workup gave trans-20f as a light yellow

solid (0.0420 g, 0.0425 mmol, 18% overall). Mp (capillary): 150−

152 °C. DSC (T_i/T_e/T_p/T_c/T_f): 137.1/146.0/152.4/154.3/154.3 °C

(endotherm). TGA: onset of mass loss, 217.6 °C. Anal. Calcd for

C₄₂H₆₂Cl₂N₂O₈Pt: C, 51.01; H, 6.32; N, 2.83. Found: C, 49.52, H,

1

4

5.78; N, 2.74. NMR (δ, CDCl₃): H 9.65 (d, 4H, J_HH= 1.8 Hz, o-

HC_2,6pyr), 9.10 (t, 2H, ⁴J_HH= 1.8 Hz, p-HC_4pyr), 4.46 (t, 8H, ³J_HH= 5.9

Hz, OCH₂), 1.83−1.81 (m, 8H, CH₂), 1.45−1.40 (m, 40H, CH₂);

¹³C{¹H} 162.1 (s, CO), 157.2 (s, o-C_2,6pyr), 141.0 (s, p-C_4pyr), 128.9 (s,

m-C_3,5pyr), 66.9 (s, OCH₂), 28.9, 28.8, 28.7, 28.6, 28.4, and 25.8 (6 s,

6CH₂). IR (cm⁻¹, powder film): 3127 (w), 3107 (w), 2922 (s), 2853

(m), 1718 (s), 1606 (m), 1447 (m), 1305 (s), 1258 (s), 1108 (s), 799

(s), 741 (s), 683 (s). MS:⁴¹988 (20f⁺, 50%), 953 ([20f − Cl]⁺, 30%),

915 (unknown, 100%).

2H, p-HC_4pyr), 7.23 (m, 2H, m-HC_5pyr), 5.90−5.76 (ddt, 2H, ³J_HHtrans

=

17.0 Hz, ³J_HHcis= 10.2 Hz, ³J_HH= 6.6 Hz, CH), 5.15−5.03 (m, 4H,

CH₂), 4.52 (s, 4H, CH₂O), 3.56 (t, 4H, ³J_HH= 6.6 Hz, OCH₂CH₂),

2.39 (apparent qt, 4H, ³J_HH= 6.6 Hz, ⁴J_HH= 1.4 Hz, CH₂CHCH₂),

0.87 (s, 3H, PtCH₃); ¹³C{¹H} NMR 153.1 and 152.9 (2 s, o-C_2pyrand

o-C_6pyr), 136.5 (s, CH), 136.1 (s, p-C_4pyr), 135.0 (s, m-C_3pyr), 125.2

(s, m-C_5pyr), 117.0 (s, CH₂), 70.5 (s, CH₂O), 69.4 (s, OCH₂CH₂),

34.3 (s, CH₂), −6.6 (s, PtCH₃).

trans-PtCl₂[3,5,3′,5′-(NC₅H₃(COO(CH₂)₁₈OCO)₂H₃C₅N)] (trans-

20h). Solutions of trans-19h (0.230 g, 0.20 mmol) in CH₂Cl₂(95 mL)

and of Grubbs’ catalyst (0.0248 g, 0.0301 mmol, 15 mol %) in CH₂Cl₂

(5 mL) were combined in a procedure similar to that for trans-19d

(the resulting solution is 0.002 00 M in trans-19h). After hydro-

genation, an analogous workup gave trans-20h as a light yellow solid

(0.0301 g, 0.0272 mmol, 14% overall). Mp (capillary): 182−184 °C. DSC

(T_i/T_e/T_p/T_c/T_f): 143.5/178.9/187.0/190.3/192.2 °C (endotherm).

trans-PtCl(CH₃)[3-NC₅H₄(CH₂O(CH₂)₈CHCH₂)]₂(trans-24h).

CH₃MgBr (2.94 M in diethyl ether; 1.50 mL, 4.41 mmol) and

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trans-12h (0.9494 g, 1.248 mmol) were combined in a procedure

similar to that for trans-24b. An analogous workup gave trans-24h as a

white waxy solid (0.6175 g, 0.8341 mmol, 67%). NMR (δ, CDCl₃): ¹H

8.89 (m, 2H, o-HC_2pyr), 8.86 (m, 2H, o-HC_6pyr), 7.75 (m, 2H, p-

HC₄₃_pyr), 7.24 (m, 2H, m-HC_5pyr), 5.87−5.74 (ddt, 2H, ³J_HHtrans= 17.0

(0.564 g, 2.58 mmol) in methanol/toluene (1/1 v/v, 4 mL) was

added dropwise over 10 min with stirring. The flask was fitted with a

condenser. The mixture was refluxed (2 h), cooled to room tempera-

ture, and filtered under N₂. The orange solution was aspirated with

CO (1 h). The solvents were removed by oil pump vacuum, and the

residue was chromatographed on a silica column (10 × 2 cm, 4/1 v/v

hexanes/ethyl acetate). An orange band was collected. The solvents

were removed by rotary evaporation and oil pump vacuum. The

residue was dissolved in CH₂Cl₂(ca. 1 mL). The solution was layered

with pentane (20 mL) and kept at −4 °C. After 24 h, the supernatant

was carefully decanted, and the precipitate was dried by oil pump

vacuum to give trans-27a as a light orange solid (0.090 g, 0.149 mmol,

26%). Mp (capillary): 106−108 °C. DSC (T_i/T_e/T_p/T_c/T_f): 79.2/

102.6/106.5/109.1/114.8 °C (endotherm). TGA: onset of mass loss,

3

Hz, J_HHcis= 10.4 Hz, J_HH= 6.6 Hz, CH), 4.94 (m, 4H, CH₂),

4.50 (s, 4H, CH₂O), 3.49 (t, 4H, ³J_HH= 6.6 Hz, OCH₂CH₂), 2.03 (m,

4H, CH₂CHCH₂), 1.62 (m, 4H, OCH₂CH₂), 1.42−1.26 (m, 20H,

CH₂), 0.88 (s, 3H, PtCH₃); ¹³C{¹H} 153.0 and 152.9 (2 s, o-C_2pyrand

o-C_6pyr), 139.4 (s, CH), 136.7 (s, p-C_4pyr), 136.1 (s, m-C_3pyr), 125.1

(s, m-C_5pyr), 114.3 (s, CH₂), 71.5 (s, CH₂O), 69.4 (s, OCH₂CH₂),

34.0, 29.8, 29.6 (2×), 29.3, 29.1, and 26.3 (6 s, 7CH₂), −6.6 (s,

PtCH₃).

trans-PtCl(CH₃)[3,3′-(NC₅H₄(CH₂O(CH₂)₁₀OCH₂)H₄C₅N)]

(trans-25d). CH₃MgBr (2.94 M in diethyl ether; 0.33 mL, 0.97

mmol) and trans-13d (0.2038 m, 0.3274 mmol) were combined in a

procedure similar to that for trans-24b. An analogous workup gave

trans-25d as a white solid (0.1273 g, 0.2114 mmol, 65%). NMR (δ,

CDCl₃): ¹H 9.06 (m, 2H, o-HC_2pyr), 8.94 (m, 2H, o-HC_6pyr), 7.51 (m,

2H, p-HC_4pyr), 7.19 (m, 2H, m-HC_5pyr), 4.52 (s, 4H, CH₂O), 3.55 (t,

3

114.7 °C. NMR (δ, CDCl₃): ¹H 7.81 (t, 2H, J_HH= 7.8 Hz,

3

p-HC_4pyr), 7.59 (d, 4H, J_HH= 7.8 Hz, m-HC_3,5pyr), 6.08 (ddt, 4H,

3

³J_HHtrans= 17.2 Hz, J_HHcis= 10.6 Hz, J_HH= 5.4 Hz, CH), 5.76 (d,

4

4H, J_RhH= 15.0 Hz, 4CHH′O), 5.64 (d, 4H, J_RhH= 15.0 Hz,

3

2

4CHH′O), 5.46 (dd, 4H, J_HHtrans= 17.2 Hz, J_HH= 1.6 Hz, 

3

2

CH_EH_Z), 5.33 (dd, 4H, J_HHcis= 10.4 Hz, J_HH= 1.5 Hz, CH_EH_Z),

4.29 (dt, 8H, ³J_HH= 5.5 Hz, ⁴J_HH= 1.4 Hz, OCH₂); ¹³C{¹H} 183.6 (d,

¹J_RhC= 70.3 Hz, CO), 162.2 (s, o-C_2,6pyr), 138.0 (s, p-C_4pyr), 134.1 (s,

CH), 121.5 (s, m-C_3pyr), 117.7 (s, CH₂), 73.4 and 72.1 (2 s,

CH₂OCH₂). IR (cm⁻¹, powder film): 3088 (w), 3015 (w), 2860 (m),

2837 (w), 1945 (s, ν_CO), 1610 (m), 1583 (w), 1471 (m), 1332 (m),

1239 (w), 1116 (s), 1007 (s), 988 (m), 787 (s). MS:⁴¹576 ([27a −

CO]⁺, 40%), 569 ([27a − Cl]⁺, 20%), 321 ([27a − 4a − 2Cl]⁺,

100%), 220 ([4a + H]⁺, 30%).

3

4H, J_HH= 5.5 Hz, OCH₂CH₂), 1.64 (m, 4H, OCH₂CH₂), 1.54 (m,

4H, CH₂), 1.39 (m, 8H, CH₂), 0.93 (s, 3H, PtCH₃); ¹³C{¹H} 153.6

and 152.7 (2 s, o-C_2pyrand o-C_6pyr), 136.7 (s, p-C_4pyr), 135.2 (s, m-

C_3pyr), 124.5 (s, m-C_5pyr), 71.2 (s, CH₂O), 69.8 (s, OCH₂CH₂), 30.2,

29.9, 29.6, 26.7 (4 s, 4CH₂), −6.4 (s, PtCH₃).

trans-PtCl(CH₃)[3,3′-(NC₅H₄(CH₂O(CH₂)₁₈OCH₂)H₄C₅N)]

(trans-25h). CH₃MgBr (2.94 M in ether; 0.28 mL, 0.82 mmol) and

trans-13h (0.2034 g, 0.2768 mmol) were combined in a procedure

similar to that for trans-24b. An analogous workup gave trans-25h as

an off-white solid (0.0815 g, 0.114 mmol, 41%). NMR (δ, CDCl₃): ¹H

8.97 (m, 2H, o-HC_2pyr), 8.91 (m, 2H, o-HC_6pyr), 7.68 (m, 2H, p-

HC_4pyr), 7.22 (m, 2H, m-HC_5pyr), 4.50 (s, 4H, CH₂O), 3.50 (t, 4H,

³J_HH= 6.4 Hz, OCH₂CH₂), 1.63 (m, 4H, OCH₂CH₂), 1.40−1.22 (m,

Crystallography. A. trans-11b. A saturated CH₂Cl₂solution

was layered with ethyl acetate. After one day, the yellow plates

were taken to a Bruker APEX2 X-ray diffractometer for data

collection as outlined in Table S1 (Supporting Information).

Cell parameters were obtained from 36 frames using a 0.5° scan

and refined with 17 016 reflections. Integrated intensity

information for each reflection was obtained by reduction of

the data frames with the program suite APEX2.⁴⁶Lorentz,

polarization, and absorption corrections⁴⁷were applied. The

space group was determined from systematic reflection

conditions and statistical tests. The structure was solved by

direct methods using SHELXTL (SHELXS).⁴⁸Non-hydrogen

atoms were refined with anisotropic thermal param-

eters. The hydrogen atoms were placed in idealized positions.

The parameters were refined by weighted least-squares refine-

ment on F²to convergence.⁴⁸

B. trans-13d. A saturated CH₂Cl₂solution was layered with ethyl

acetate. After 1 day, the yellow plates were analyzed as described for

trans-11b (cell parameters from 36 frames using a 0.5° scan; refined

with 24 911 reflections). The structure was solved and refined as for

trans-11b. Two independent molecules were found in the unit cell.

Both exhibited disordered methylene groups (two in one molecule,

80:20 occupancies; six in the other, (70−50):(30−50) occupancies),

which were treated by restraining the bond lengths and angles to

idealized values. In the final stages of refinement, additional electron

density not associated with either molecule was observed and

tentatively assigned to a disordered CH₂Cl₂molecule (occupancy ca.

50%). After many attempts to model the disorder, the electron density

contribution was extracted with the program PLATON/SQUEEZE.⁴⁹

C. trans-13h. A saturated CH₂Cl₂solution was layered with ethyl

acetate. After 1 day, yellow plates of the solvate trans-13h·CH₂Cl₂

were analyzed as described for trans-11b (cell parameters from 36

frames using a 0.5° scan; refined with 14 813 reflections). The

structure was solved and refined as for trans-11b.

28H, CH₂), 0.91 (s, 3H, PtCH₃); ¹³C{¹H} 153.3 and 153.2 (2 s,

o-C_2pyrand o-C_6pyr), 136.6 (s, p-C_4pyr), 136.2 (s, m-C_3pyr), 125.0 (s,

m-C_5pyr), 71.3 (s, CH₂O), 69.7 (s, OCH₂CH₂), 29.6, 29.45, 29.44,

29.41, 29.38, 29.37, 29.25, 26.1 (8 s, 8CH₂), −6.5 (PtCH₃).

trans-Pt(Cl)(CCPh)[3,5-NC₅H₃(COO(CH₂)₃CHCH₂)₂]₂

(trans-26c). A round-bottom flask was charged with trans-19c (0.124

g, 0.142 mmol), CuI (0.0027 g, 0.014 mmol), and CH₂Cl₂/i-Pr₂NH

(10/1 v/v, 12 mL) with stirring. Then PhCCH (0.0207 g, 0.199

mmol) in CH₂Cl₂/i-Pr₂NH (2 mL) was added dropwise over 5 min.

The flask was fitted with a condenser. The solution was refluxed

(3 days) and cooled to room temperature. The solvents were removed

by rotary evaporation and oil pump vacuum. The residue was

chromatographed on a silica column (25 × 2 cm, gradient elution, 8/2

to 0/10 v/v hexanes/ethyl acetate). The solvents were removed from

the product-containing fractions by rotary evaporation and oil pump

vacuum. The residue was dissolved in CH₂Cl₂(ca. 1 mL) and carefully

layered with hexanes (20 mL). The sample was kept at −4 °C. After

24 h, the supernatant was decanted and the precipitate dried by oil

pump vacuum to give trans-26c as a pale yellow solid (0.0245 g, 0.0261

1

4

mmol, 18%). NMR (δ, CDCl₃): H 9.96 (d, 4H, J_HH= 1.9 Hz, o-

4

HC_2,6pyr), 9.01 (t, 2H, J_HH= 1.9 Hz, p-HC_4pyr), 7.24−7.13 (m, 5H,

Ph), 5.85 (ddt, 4H, J_HHtrans= 17.1 Hz, J_HHcis= 10.3 Hz, J_HH= 6.7

3

2

Hz, CH), 5.08 (dd, 4H, J_HHtrans= 17.1 Hz, J_HH= 1.9 Hz, 

3

2

CH_EH_Z), 5.02 (dd, 4H, J_HHcis= 10.3 Hz, J_HH= 1.9 Hz, CH_EH_Z),

3

4.43 (t, 8H, J_HH= 6.6 Hz, OCH₂), 2.25−2.20 (m, 8H, CH₂), 1.94−

1.87 (m, 8H, CH₂); ¹³C{¹H} 162.7 (s, CO), 158.6 (s, o-C_2,6pyr), 140.1

(s, p-C_4pyr), 137.7 (s, CH), 132.1 (s, o-C_Ph), 128.9 (s, C_3,5pyr), 128.3

(s, p-C_Ph), 127.2 (s, m-C_Ph), 126.5 (s, i-C_Ph), 115.7 (s, CH₂), 94.0

and 85.0 (2 s, CC), 66.4 (s, OCH₂), 30.4 (s, CH₂), 28.1 (s, CH₂). IR

(cm⁻¹, powder film): 3076 (w), 2961 (w), 2907 (w), 2351 (m), 2131

(m, ν_C≡C), 1725 (s), 1640 (m), 1598 (m), 1444 (m), 1305 (s), 1262

(s), 1239 (s), 1112 (s), 984 (s), 911 (s), 741 (s). MS:⁴¹938 (26c⁺,

100%)

D. trans-17a. A concentrated CH₂Cl₂solution was layered

with hexanes. After 7 days, the yellow blocks were taken directly

to a Nonius KappaCCD area detector for data collection as outlined

in Table S2 (Supporting Information). Cell parameters were

obtained from 10 frames using a 10° scan and refined with 1788

reflections. Lorentz, polarization, and absorption corrections⁵⁰were

applied. The space group was determined from systematic absences

and subsequent least-squares refinement. The structure was solved by

trans-Rh(Cl)(CO)[2,6-NC₅H₃(CH₂OCH₂CHCH₂)₂]₂(trans-27a).

A Schlenk flask was charged with [RhCl(coe)₂]₂(0.430 g, 0.599

mmol) and methanol/toluene (1/1 v/v, 22 mL). A solution of 4a

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Article

direct methods. The parameters were refined with all data by full-

matrix least squares on F²using SHELXL-97.⁵¹Non-hydrogen atoms

were refined with anisotropic thermal parameters. The hydrogen

atoms were fixed in idealized positions using a riding model. The

complex exhibited a 2-fold symmetry axis containing the N−Pt−N

vector and an orthogonal mirror plane containing the Cl−Pt−Cl

vector. The data indicated some disorder at C3, but this could not be

resolved. Scattering factors were taken from the literature.⁵²

E. trans-18a. A concentrated CHCl₃solution was layered with

hexanes. After 3 days, the pale yellow blocks were analyzed as

described for trans-17a (cell parameters from 10 frames using a 10°

scan; refined with 2487 reflections). The structure was solved and

refined as for trans-17a. The structure exhibited an inversion center at

platinum.

F. trans-18b. A concentrated CHCl₃solution was layered with

hexanes. The sample was kept at −4 °C. After 3 days, the yellow

needles were analyzed as described for trans-17a (cell para-

meters from 10 frames using a 10° scan; refined with 2898 reflections).

The structure was solved and refined as for trans-17a. Three atoms

were disordered, which were refined to an 81:19 occupancy ratio (C7/

C8/O9 and C7′/C8′/O9′). The structure exhibited an inversion center

at platinum.

G. trans-20e. A concentrated CHCl₃solution was layered with

hexanes. The sample was kept at −20 °C. After 7 days, the light yellow

blocks of the solvate trans-20e·2CHCl₃were analyzed as described for

trans-17a (cell parameters from 10 frames using a 10° scan; refined

with 10 662 reflections). The structure was solved and refined as for

trans-17a. Several sets of atoms were disordered, which were refined to

66:34 (C44/C44′), 65:35 (C53/C53′), and 73:27 (C65/C65′)

occupancy ratios. Large atomic displacement factors for C46−C52

indicated additional disorder, which could not be resolved.

H. trans-16. A concentrated CHCl₃solution of trans-16 was layered

with hexanes. After 7 days, the yellow blocks were analyzed as

described for trans-17a (cell parameters from 10 frames using a 10°

scan; refined with 2337 reflections). The structure was solved and

refined as for trans-17a. The structure exhibited an inversion center at

palladium.

(2) Khuong, T.-A. V.; Nunez, J. E.; Godinez, C. E.; Garcia-Garibay,

M. A. Acc. Chem. Res. 2006, 39, 413.

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̈

opus/volltexte/2008/1125/). (b) Zeits, P. D. Doctoral dissertation,

Texas A&M University, 2011. This thesis will become available on the

web in August of 2013 (http://library.tamu.edu/about/collections/

theses-dissertations); prior to that date copies are available from the

corresponding author.

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J. Org. Chem. 2002, 478.

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(19) Dijkstra, H. P.; Chuchuryukin, A.; Suijkerbuijk, B. M. J. M.; van

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(20) Chuchuryukin, A. V.; Chase, P. A.; Dijkstra, H. P.; Suijkerbuijk,

B. M. J. M.; Mills, A. M.; Spek, A. L.; van Klink, G. P. M.; van Koten,

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ASSOCIATED CONTENT

* Supporting Information

Text giving details of the reactions with Grubbs’ second-

generation catalyst and tables of crystallographic data and CIF

files for the complexes in Table 1. This material is available free

of charge via the Internet at http://pubs.acs.org.

■

S

AUTHOR INFORMATION

Corresponding Author

*Tel: 979-845-1399. E-mail: gladysz@mail.chem.tamu.edu.

■

Author Contributions

^§Both co-workers contributed equally to the experimental work.

(21) Lanfranchi, M.; Nobile, C. F.; Pellinghelli, M. A.; Vasapollo, G.;

Sacco, A. J. Organomet. Chem. 1986, 312, 249.

(22) Tamao, K.; Kodama, S.; Nakajima, I.; Kumada, M. Tetrahedron

1982, 38, 3347.

Notes

The authors declare no competing financial interest.

(23) (a) Tagat, J. R.; McCombie, S. W.; Barton, B. E.; Jackson, J.;

Shortail, J. Bioorg. Med. Chem. Lett. 1995, 5, 2143. (b) Jacquemard, U.;

ACKNOWLEDGMENTS

■

We thank the U.S. National Science Foundation (No. CHE-

0719267), the Deutsche Forschungsgemeinschaft (DFG, GL

300/9-1), and Johnson Matthey PMC (precious metal loans)

for support.

Routier, S.; Dias, N.; Lansiaux, A.; Goossens, J.-F.; Bailly, C.; Mer

́

our,

J.-Y. Eur. J. Med. Chem. 2005, 40, 1087.

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Chem. 1996, 74, 2121. (b) Tessier, C.; Rochon, F. D. Inorg. Chim. Acta

1999, 295, 25.

(25) Silverstein, R. M.; Bassler, G. C.; Morrill, T. Spectrometric

Identification of Organic Compounds, 5th ed.; Wiley: New York, 1991;

pp 239−241.

DEDICATION

■

This article is dedicated with admiration and affection to the

memory of our Texas neighbor, Professor F. G. A. Stone.

(26) (a) Colamarino, P.; Orioli, P. L. J. Chem. Soc., Dalton Trans.

1975, 1656. (b) Tessier, C.; Rochon, F. D. Inorg. Chim. Acta 1999,

295, 25.

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2876

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dx.doi.org/10.1021/om201145x | Organometallics 2012, 31, 2854−2877

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Gyroscope-like platinum and palladium complexes with trans-spanning bis(pyridine) ligands

DOI: 10.1021/om201145x

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