New diruthenium vinyliminium complexes from the insertion of alkynes into bridging aminocarbynes

Journal of Organometallic Chemistry 691 (2006) 2424–2439

www.elsevier.com/locate/jorganchem

New diruthenium vinyliminium complexes from the insertion

of alkynes into bridging aminocarbynes

*

Luigi Busetto, Fabio Marchetti, Stefano Zacchini, Valerio Zanotti

`

Dipartimento di Chimica Fisica ed Inorganica, Universita di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy

Received 19 December 2005; received in revised form 11 January 2006; accepted 11 January 2006

Available online 23 February 2006

Abstract

Primary alkynes R⁰C„CH [R⁰= Me₃Si, Tol, CH₂OH, CO₂Me, (CH₂)₄C„CH, Me] insert into the metal–carbon bond of diruthenium

l-aminocarbynes [Ru₂{l-CN(Me)(R)}(l-CO)(CO)(MeCN)(Cp)₂][SO₃CF₃] [R = 2,6-Me₂C₆H₃(Xyl), 1a; CH₂Ph (Bz), 1b; Me, 1c] to give

the vinyliminium complexes [Ru₂{l-g¹:g³-C(R⁰)@CHC@N(Me)(R)}(l-CO)(CO)(Cp)₂][SO₃CF₃] [R = Xyl, R⁰= Me₃Si, 2a; R = Bz,

R⁰= Me₃Si, 2b; R = Me, R⁰= Me₃Si, 2c; R = Xyl, R⁰= Tol, 3a; R = Bz, R⁰= Tol, 3b; R = Bz, R⁰= CH₂OH, 4; R = Bz, R⁰= CO₂Me,

5a; R = Me, R⁰= CO₂Me, 5b; R = Xyl, R⁰= (CH₂)₄C„CH, 6; R = Xyl, R⁰= Me, 7a; R = Bz, R⁰= Me, 7b; R = Me, R⁰= Me, 7c]. The

related compound [Ru₂{l-g¹:g³-C[C(Me)@CH₂]@CHC@N(Me)(Xyl)}(l-CO)(CO)(Cp)₂][SO₃CF₃], (9) is better prepared by reacting

[Ru₂{l-CN(Me)(Xyl)}(l-CO)(CO)(Cl)(Cp)₂] (8) with AgSO₃CF₃in the presence of HC„CC(Me)@CH₂in CH₂Cl₂at low temperature.

In a similar way, also secondary alkynes can be inserted to give the new complexes [Ru₂{l-g¹:g³-C(R⁰)@C(R⁰)C@N(Me)(R)}(l-

CO)(CO)(Cp)₂][SO₃CF₃] (R = Bz, R⁰= CO₂Me, 11; R = Xyl, R⁰= Et, 12a; R = Bz, R⁰= Et, 12b; R = Xyl, R⁰= Me, 13). The reactions

of 2–7, 9, 11–13 with hydrides (i.e., NaBH₄, NaH) have been also studied, aﬀording l-vinylalkylidene complexes [Ru₂{l-g¹:g³-

C(R⁰)C(R⁰⁰)@C(H)N(Me)(R)}(l-CO)(CO)(Cp)₂] (R = Bz, R⁰= Me₃Si, R⁰⁰= H, 14a; R = Me, R⁰= Me₃Si, R⁰⁰= H, 14b; R = Bz,

R⁰= Tol, R⁰⁰= H, 15; R = Bz, R⁰= R⁰⁰= Et, 16), bis-alkylidene complexes [Ru₂{l-g¹:g²-C(R⁰)C(H)(R⁰⁰)CN(Me)(Xyl)}(l-

CO)(CO)(Cp)₂] (R⁰= Me₃Si, R⁰⁰= H, 17; R⁰= R⁰⁰= Et, 18), acetylide compounds [Ru₂{l-CN(Me)(R)}(l-CO)(CO)(C„CR⁰)(Cp)₂]

(R = Xyl, R⁰= Tol, 19; R = Bz, R⁰= Me₃Si, 20; R = Xyl, R⁰= Me, 21) or the tetranuclear species [Ru₂{l-g¹:g²-C(Me)CCN-

(Me)(Bz)}(l-CO)(CO)(Cp)₂]₂(23) depending on the properties of the hydride and the substituents on the complex. Chromatography

of 21 on alumina results in its conversion into [Ru₂{l-g³:g¹-C[N(Me)(Xyl)]C(H)C@CH₂}(l-CO)(CO)(Cp)₂] (22). The crystal structures

of 2a[CF₃SO₃] Æ 0.5CH₂Cl₂, 12a[CF₃SO₃] and 22 have been determined by X-ray diﬀraction studies.

Keywords: Vinyliminium; Diruthenium complexes; Alkyne insertion; Vinylalkylidene; Hydride addition

1. Introduction

[SO₃CF₃], and represent an interesting example of C–C bond

formation in dinuclear l-carbyne complexes [3]. Studies on

the reactivity of the bridging vinyliminium ligand have evi-

denced its electrophilic character and have shown that

hydride (from NaBH₄) can selectively add to either the C_a

or the C_bof the bridging ligand, depending on the steric

and electronic properties of the ligand substituents (R, R⁰

and R⁰⁰) [4]. Moreover, it has been shown that the C_b-H

hydrogen, when present, is acidic and can be easily removed

upon treatment with NaH. Proton removal generates unsta-

ble intermediate species which aﬀord, upon rearrangement,

mono- and polynuclear iron complexes [5]. In order to

We have recently reported the synthesis of diiron com-

plexes of the type [Fe₂{l-g¹:g³-C_c(R⁰)@C_b(R⁰⁰)C_a@N-

(Me)(R)}(l-CO)(CO)(Cp)₂][SO₃CF₃] [1], which contain a

bridging vinyliminium ligand in an unusual l-g¹:g³coordi-

nation mode [2]. These complexes were obtained by alkyne

insertion into the metal–carbon bond of diiron l-amin-

ocarbynes [Fe₂{l-CN(Me)(R)}(l-CO)(CO)(MeCN)(Cp)₂]-

*

Corresponding author.

E-mail address: valerio.zanotti@unibo.it (V. Zanotti).

doi:10.1016/j.jorganchem.2006.01.020

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

2425

+

extend our investigation and, in particular, with the aim of

understanding the role of the metal in all these reactions,

we report, here, on the synthesis, characterisation and reac-

tivity of new diruthenium vinyliminium complexes.

H

C

R

Me

Ru

R

Me

N

C

N

β

Me

C_α

C_γ

Ru

OC

NCMe

HC CMe

CO

Ru

CH₂Cl₂, 293 K

C

O

C

2. Results and discussion

O

2.1. Insertion of primary and secondary alkynes

1

R = Xyl, 7a; Bz, 7b; Me, 7c

Since alkyne insertion, in dinuclear complexes, usually

requires photolysis or the presence of a labile ligand, as

equivalent of a vacant coordination site, the reactions

have been performed on the acetonitrile complexes [Ru₂-

{l-CN(Me)(R)}(l-CO)(CO)(MeCN)(Cp)₂][SO₃CF₃] [R =

2,6-Me₂C₆H₃(Xyl), 1a; CH₂Ph (Bz), 1b; Me, 1c], whose syn-

thesis is detailed in the experimental part. Complexes 1a–c

react with R⁰C„CH [R⁰= Me₃Si, Tol, CH₂OH, CO₂Me,

(CH₂)₄C„CH] in reﬂuxing THF aﬀording the new vinyli-

minium compounds [Ru₂{l-g¹:g³-C(R⁰)@CHC@N(Me)-

(R)}(l-CO)(CO)(Cp)₂][SO₃CF₃] [R = Xyl, R⁰= Me₃Si, 2a;

R = Bz, R⁰= Me₃Si, 2b; R = Me, R⁰= Me₃Si, 2c; R = Xyl,

R⁰= Tol, 3a; R = Bz, R⁰= Tol, 3b; R = Bz, R⁰= CH₂OH,

4; R = Bz, R⁰= CO₂Me, 5a; R = Me, R⁰= CO₂Me, 5b;

R = Xyl, R⁰= (CH₂)₄C„CH, 6] (Scheme 1).

For the reaction with volatile alkynes diﬀerent

approaches have been adopted. Thus, in the case of propyne,

1 has been reacted overnight at room temperature with a

large excess of the alkyne, whereas the insertion of

HC„CC(Me)@CH₂has been obtained from [Ru₂{l-

CN(Me)(Xyl)}(l-CO)(CO)(Cl)(Cp)₂] (8) and AgSO₃CF₃in

the presence of the alkyne. These procedures led to the for-

mation of the complexes [Ru₂{l-g¹:g³-C(Me)@CHC@

N(Me)(R)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (R = Xyl, 7a; Bz,

7b; Me, 7c), and [Ru₂{l-g¹:g³-C[C(Me)@CH₂]@CHC@

N(Me)(Xyl)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (9) (Scheme 2).

As previously reported for diiron complexes, the inser-

tion of the primary alkynes into the Ru–C bond of the

bridging aminocarbyne is completely regioselective, aﬀord-

+

Me

H

C

Xyl

Me

CH CH₂

N

C

β

Me

C_α

C_γ

Ru

OC

Cl

CO

Ru

AgSO₃CF₃

C

O

C

O

CH₂Cl₂, 223 K

9

8

Scheme 2.

ing the products containing the CH unit in the b-position

[1]. Accordingly, the CH proton in the H spectrum reso-

1

nates at 4.6–6 ppm, as expected for C_bH [1,6]. The ¹³C

NMR spectra of 2–7,9 show two resonances at high fre-

quencies due to the terminal and bridging carbonyls and

distinct resonances for the two inequivalent Cp ligands.

The three carbons of the vinyl iminium ligand resonate in

typical regions, i.e., 216–222 ppm C_a, 53–63 ppm C_band

175–195 ppm C_c. The IR spectra show bands at m(CO)

ca. 1990–2000 and 1815–1825 cm^ꢀ1for the terminal and

bridging carbonyls, respectively, and m(C@N) at 1630–

1680 cm^ꢀ1for the iminium group. A band at 2118 cm^ꢀ1

in the IR spectrum of 6 is attributable to the free C„C

group. It is noteworthy that the carbonyl bands for the

complexes containing the Xyl group on the vinyliminium

ligand (i.e., 2a, 3a, 6, 7a, 9) absorbs at higher frequencies

compared to those of the complexes containing the Bz or

Me groups, whereas the iminium group absorbs at lower

frequencies. This is the consequence of the more acidic

character of the Xyl.

+

The NMR spectra of all complexes 2–7, 9 except 2c, 5b

and 7b, show the presence, in solution, of two isomers in

the ratio 1.1–1.7:1 for the ones containing the Bz group

and 5–10:1 when the Xyl group is present. The two iso-

meric forms are due to the diﬀerent orientation of the sub-

stituents on the iminium group, and can be labelled E and

Z (see Scheme 3) [1]. In perfect agreement, only one species

is present in the case of the symmetrically substituted

vinyliminium complexes 2c, 5b and 7b.

R

Me

Ru

H

C

R

N

C

R'

N

β

Me

OC

C_α

Ru

C_γ

Ru

NCMe

CO

R'C CH

Ru

C

O

C

O

R = Xyl, 1a; Bz, 1b; Me, 1c

R

R'

Xyl SiMe₃

2a

Bz

Me

SiMe₃

Xyl Tol

2b

2c

3a

3b

4

5a

5b

The E and Z isomer can be easily distinguished on the

1

basis of the NMe resonance in the H NMR spectrum.

Bz

Me

Tol

Thus, for the Bz-containing species, the NMe group reso-

nates at 3.4–3.9 ppm for the E isomer and at ca. 3.0–

3.2 ppm for the Z isomer, whereas they resonate at ca.

4.0 (E isomer) and 3.5–3.7 ppm (Z isomer) in the case of

the species with the Xyl group. The analysis of the ¹H

CH₂OH

CO₂Me

Xyl (CH₂)₄CCH 6

Scheme 1.

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L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

+

H

C

H

C

R

Me

R'

N

β

Me

R

C_α

C_γ

Ru

C_γ

Ru

CO

Ru

C

O

Z

E

Scheme 3.

NMR spectra clearly indicates that the E isomer is the pre-

dominant species when the bulky Xyl group is present,

whereas the concentration of the E and Z isomers is similar

in the case of the less bulky Bz substituent. Further support

to these conclusions comes from DPFGSE-NOE [7] and

bidimensional NOESY studies [8]. For instance, the

NOESY spectrum of 2a shows, for the major isomer, cross

peaks between the two Cp ligands, the NMe and one Cp,

C_bH and the Xyl protons, clearly conﬁrming that the two

Cp ligands are in mutual cis position and the NMe group

points towards one Cp ligand (E isomer). Conversely, the

NOESY spectrum shows cross peaks in between the two

Cp ligands and between C_bH and NMe for the minor iso-

mer, which, thus, adopts a cis-Z form. A cis-E structure is

also adopted by 2a in the solid state, as shown by single

crystal X-ray analysis. Thus, the molecular structure of

2a is reported in Fig. 1, whereas the main bond lengths

and bond angles are reported in Table 1. The structure of

2a is equivalent to that previously reported for the analo-

gous diiron complex [Fe₂{l-g¹:g³-C(SiMe₃)@CHC@

N(Me)(Xyl)}(l-CO)(CO)(Cp)₂]⁺(10) and also in this case

it can be discussed with reference to three diﬀerent reso-

Fig. 1. Molecular structure of 2a, with key atoms labelled (all H atoms,

apart from H(14) have been omitted). Displacement ellipsoids are at 30%

probability level. Only the main image of the disordered Cp ligand bound

to Ru(1) is drawn.

Table 1

˚

Selected bond lengths (A) and angles (ꢁ) for complex 2a

Ru(1)–Ru(2)

Ru(1)–C(12)

Ru(2)–C(12)

Ru(2)–C(11)

Ru(1)–C(13)

Ru(2)–C(13)

Ru(1)–C(14)

Ru(1)–C(15)

2.729(47)

2.062(7)

1.996(7)

1.849(8)

2.183(6)

2.080(6)

2.189(7)

1.955(6)

C(11)–O(11)

C(12)–O(12)

C(13)–Si(1)

C(13)–C(14)

C(14)–C(15)

N(1)–C(15)

N(1)–C(19)

N(1)–C(20)

1.144(9)

1.170(8)

1.901(6)

1.404(9)

1.430(9)

1.302(8)

1.456(9)

1.452(9)

˚

nance forms (Scheme 4). The C(13)–C(14) [1.404(9) A]

˚

and C(14)–C(15) [1.430(9) A] interactions appear to be sig-

niﬁcantly diﬀerent, whereas they are almost identical in 10

˚

[1.412(8) and 1.406(8) A, respectively], suggesting an even

greater contribution in 2a for the vinyliminium form (A

in Scheme 4) than the keteniminium form (C). In agree-

˚

Ru(2)–C(13)–C(14)

C(13)–C(14)–C(15)

C(14)–C(15)–Ru(1)

C(14)–C(15)–N(1)

121.5(5)

120.5(6)

78.9(4)

C(15)–N(1)–C(19)

C(15)–N(1)–C(20)

C(19)–N(1)–C(20)

120.6(6)

121.2(5)

117.8(5)

ment, also the N(1)–C(15) interaction in 2a [1.302(8) A]

shows a greater double bond character than in 10

˚

[1.320(7) A]. The Ru(1)–C(13) [2.183(6) A] and Ru(1)–

134.2(6)

˚

C(14) [2.189(7) A] interactions are identical within experi-

mental errors, whereas Ru(1)–C(15) [1.955(6) A] is consid-

˚

erably shorter indicating some double bond character in

agreement with form B.

group (E isomer), whereas NOE is generated between C_bH

and NMe after isomerisation (Z isomer). The peculiar

behaviour of 6 suggests that the presence of functional

groups in the c-position of the ligand can play an important

role in the stereochemistry of these vinyliminium complexes.

In this sense, it is noteworthy that in the case of 9, which

is obtained by insertion of HC„CC(Me)@CH₂into 8 at

low temperature in the presence of AgSO₃CF₃, the Z and

not the E isomer is mainly obtained.

Following the same procedure described above, it is also

possible to insert disubstituted alkynes into 1 (Scheme 5).

Thus, complexes [Ru₂{l-g¹:g³-C(R⁰)@C(R⁰)C@N(Me)(R)}-

(l-CO)(CO)(Cp)₂][SO₃CF₃] (R = Bz, R⁰= CO₂Me, 11;

Ingeneral, interconversion between the E and Z formshas

not been observed for any of the Ru-species described in this

paper neither for the analogous iron complexes previously

reported [1]. The only exception seems to be compound 6,

which is obtained, by insertion of HC„C(CH₂)₄C„CH,

as a E Z mixture (10:1). The E isomer is converted into the

Z form by treatment with an excess of Me₂NH, as clearly

shown by NMR spectroscopy. As expected, the NMe pro-

tons resonate at 3.90 ppm in E-6 and at 3.61 ppm in Z-6.

Moreover, before addition of Me₂NH, irradiation of C_bH

results in the enhancement of the resonances due to the Xyl

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

2427

+

in solution in the case of the Bz-containing complexes 11

and 12b in ratio ca. 2:1, which are attributable to the E

and Z isomers. In agreement with this, the NMe protons

for the E isomer of 11 and 12b resonate at 3.5–3.9 ppm

whereas they resonate at 3.0–3.2 ppm for the Z isomer.

Conversely, both the isomers of 12a and 13 show NMe res-

onances in the ¹H NMR spectra at 3.5–3.7 ppm as expected

for a Z structure in a species containing the Xyl substitu-

ent. Thus, they can be formulated as cis-Z-12a, trans-

Z-12a, cis-Z-13 and trans-Z-13 (see Scheme 6) similarly

to what previously reported for the analogous diiron

complexes [Fe₂{l-g¹:g³-C(R⁰)@C(R⁰)C@N(Me)(Xyl)}(l-

CO)(CO)(Cp)₂][SO₃CF₃] (R⁰= Me, Et) [1].

The cis-Z-isomer seems to be the thermodynamic prod-

uct, whereas the trans-Z-isomer is the kinetic one. Thus,

insertion of 3-hexyne and 2-butyne into 8 at low tempera-

ture in the presence of AgSO₃CF₃results mainly in the for-

mation of trans-Z-12a (trans:cis = 5) and trans-Z-13

(trans:cis = 1.3), respectively; complete isomerisation of

trans-Z-12a and trans-Z-13 into cis-Z-12a and cis-Z-13 is,

then, achieved after heating at reﬂux temperature in THF

for 5 h. The molecular structure of cis-Z-12a is shown in

Fig. 2, whereas the main bond lengths and bond angles

are reported in Table 2. A comparison of the data of cis-

Z-12a (Table 2) and E-2a (Table 1) shows that the observed

diﬀerent geometries (E–Z) and the presence of diﬀerent

groups on the vinyliminium ligand have no eﬀect on all

the listed bond distances.

R

N

R

N

H

C

H

C

R'

Me

C

CO

Ru

C

O

A

+

B

H

C

R

N

R'

C

Me

CO

Ru

C

O

C

Scheme 4.

+

R

R'

R

Me

Ru

R'

N

C

β

Me

C_α

C_γ

Ru

OC

CO

NCMe

R'C CR'

Ru

THF, reflux

C

O

C

O

R = Xyl, 1a; Bz, 1b

R

R'

Bz CO₂Me 11

Xyl Et

Bz Et

12a

12b

2.2. Reactions of the diruthenium vinyliminium complexes

with NaBH₄

Scheme 5.

R = Xyl, R⁰= Et, 12a; R = Bz, R⁰= Et, 12b) have been

obtained by reacting 1a,b in THF with R⁰C„CR⁰

(R⁰= CO₂Me, Et).

As previously mentioned, investigations on the reactiv-

ity of diiron l-vinyliminium complexes have evidenced that

hydride (from NaBH₄) can add selectively to either the C_a

or the C_b. In particular, hydride addition occurs selectively

at the C_aposition, except when the presence of the steri-

cally demanding Xyl group inhibits attack in that position

and directs the addition to the C_b. Addition at the C_agen-

erates neutral complexes which can be appropriately

described as bridging vinylalkylidenes. Conversely, attack

at the C_bproduces bis-alkylidene ligands, anchored to

the Fe–Fe through the C_aand C_c, which assume the nature

of amino carbene and bridging alkylidene, respectively [4].

The analogous compound [Ru₂{l-g¹:g³-C(Me)@

C(Me)C@N(Me)(Xyl)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (13) was

obtained, instead, from [Ru₂{l-CN(Me)(Xyl)}(l-CO)-

(CO)(Cl)(Cp)₂] (8) and AgSO₃CF₃in the presence of the

volatile 2-butyne in CH₂Cl₂at low temperature.

The IR spectra of 11–13, in CH₂Cl₂, show bands in the

typical regions for terminal and bridging carbonyls (1980–

2000 and 1816–1838 cm^ꢀ1, respectively) together with a

band at 1616–1670 cm^ꢀ1attributable to the C@N iminium

group; moreover, an intense band at 1737 cm^ꢀ1is present

in the spectrum of 11, due to CO₂Me. It is noteworthy

the fact that the presence of two strong electron withdraw-

ing CO₂Me groups causes a shift to higher frequencies of

both m(CO) in 11 (i.e., 2004 and 1838 cm^ꢀ1) compared to

12b (i.e., 1986 and 1816 cm^ꢀ1). The NMR spectra of 11–

13 show resonances fully consistent with their nature of

vinyliminium complexes (see Section 4). Their stereochem-

istry requires some further comments. As in the case of

analogous diiron complexes [1], several isomers are

observed due to either the orientation of the N substituents

(E, Z isomers) and the relative position of the Cp ligands

(cis, trans isomers). In particular, two isomers are present

+

R

Me

R

C

Me

R'

N

C

R'

β

N

β

Xyl

C_α

Ru

C_γ

Ru

Xyl

C_α

C_γ

Ru

CO

Ru

C

O

C

O

CO

R = Et, trans-Z-12a

R = Me, trans-Z-13

R = Et, cis-Z-12a

R = Me, cis-Z-13

Scheme 6.

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L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

Fig. 2. Molecular structure of cis-Z-12a, with key atoms labelled (all H atoms have been omitted). Displacement ellipsoids are at 30% probability level.

Only the main image of the disordered Cp ligand bound to Ru(2) is drawn.

Table 2

R

R''

˚

Selected bond lengths (A) and angles (ꢁ) for complex cis-Z-12a

N

H

Me

R'

C

β

Ru(1)–Ru(2)

Ru(1)–C(12)

Ru(2)–C(12)

Ru(2)–C(11)

Ru(1)–C(13)

Ru(2)–C(13)

Ru(1)–C(14)

Ru(1)–C(15)

2.7343(13)

2.052(8)

2.001(9)

1.858(10)

2.165(8)

2.098(8)

2.220(7)

1.962(8)

C(11)–O(11)

C(12)–O(12)

C(13)–C(16)

C(13)–C(14)

C(14)–C(18)

C(14)–C(15)

N(1)–C(15)

N(1)–C(20)

N(1)–C(21)

1.156(11)

1.165(9)

C_α

C_γ

CO

Ru

1.501(11)

1.424(11)

1.518(11)

1.454(11)

1.291(10)

1.479(10)

1.476(10)

C

O

R = Me, Bz

R'

R

R''

+

14a

14b

15

Me₃Si

Tol

Bz

Me

Bz

H

Et

H

C

R

R'

N

β

Ru(2)–C(13)–C(14)

C(13)–C(14)–C(15)

C(14)–C(15)–Ru(1)

C(14)–C(15)–N(1)

122.4(5)

114.5(7)

79.6(5)

C(15)–N(1)–C(20)

C(15)–N(1)–C(21)

C(20)–N(1)–C(21)

121.7(7)

119.9(7)

118.3(6)

Me

C_α

C_γ

Ru

16

Et

Ru

+ NaBH₄

133.1(7)

C

O

Xyl

H

R''

N

R'

Me

C

β

Thus, the reactivity of the diruthenium vinyliminium com-

plexes with NaBH₄has been studied.

C_α

C_γ

CO

R = Xyl

Ru

Addition of NaBH₄to the diruthenium vinyliminium

complexes containing Bz or Me substituents on the iminium

group results in the selective addition of H^ꢀto the C_aaﬀord-

ing new bridging vinylalkylidene species. For instance, 2b,c,

3b and 12b react with NaBH₄in THF to selectively give the

complexes [Ru₂{l-g¹:g³-C(R⁰)C(R⁰⁰)@C(H)N(Me)(R)}(l-

CO)(CO)(Cp)₂] (R = Bz, R⁰= Me₃Si, R⁰⁰= H, 14a;

R = Me, R⁰= Me₃Si, R⁰⁰= H, 14b; R = Bz, R⁰= Tol,

R⁰⁰= H, 15; R = Bz, R⁰= R⁰⁰= Et, 16) (Scheme 7).

C

O

R''

H

R'

17

18

Me₃Si

Et

Scheme 7.

The bridging ligand can be described as a l-vinylalkylid-

ene or, considering also the N(R)(Me) group on C_a, a l-

enaminoalkylidene ligand. Complexes 14–16 have been

characterised spectroscopically. The IR spectra in CH₂Cl₂

show m(CO) at 1930–1950 and 1760–1788 cm^ꢀ1for the ter-

minal and bridging carbonyls, respectively; these bands are

ca. 60 cm^ꢀ1shifted to lower frequencies compared to the

starting cationic complexes, in agreement with the neutral

character of 14–16. The NMR spectra show the presence

in solution of only one isomer for all the complexes studied,

as a result of two factors. First, the hydride addition is not

only regioselective (a-addition) but also stereoselective;

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

2429

in fact the hydride adds trans to the C_b(R⁰⁰) substituent. In

Xyl

Me

H

agreement with this, when R⁰⁰= H, both C_aH and C_bH

N

SiMe₃

Me

C

N

β

SiMe₃

3

C

Xyl

β

appear as doublet with J_HHtypical for a trans geometry.

C_α

C_γ

C_α

C_γ

CO

Ru

CO

Ru

Second, there is free rotation around the C_a–N bond as a

consequence of the lowering of the bond order passing

from the starting vinyliminium ligand to the ﬁnal enam-

inoalkylidene (vinylalkylidene) ligand. In agreement with

this, the two N-bonded methyl groups in 14b give rise to

Ru

C

O

C

O

E-17

Z-17

1

one single resonance in the H NMR spectrum, whereas

Scheme 8.

they are inequivalent in the parent compound 2c.

The l-vinylalkylidene (l-enaminoalkylidene) ligand

shows characteristic resonances in the ¹³C NMR. When

R⁰⁰= H, C_a, C_band C_cresonate at ca. 104, 68 and

160 ppm, respectively; when R⁰⁰= Et, C_ais high ﬁeld

shifted (96 ppm) whereas C_band C_care down ﬁeld shifted

(94 and 180 ppm, respectively). All the other resonances in

the ¹H and ¹³C spectra are fully in agreement with the pro-

posed structure (see Section 4).

a Z conﬁguration of the aminocarbene (Scheme 9). Assign-

ment is based on NMR data which are consistent with the

presence of cis and trans isomers, and by comparison with

the structure of the parent complex 12a, which can exists in

both cis-Z and trans-Z forms.

2.3. Reactions of the diruthenium vinyliminium complexes

with NaH

The replacement of the Bz or Me substituents on the imin-

ium group with the bulkier Xyl substituent results in the

complete change of the regiochemistry of the reaction. As

expected, the Xyl substituent acts as protecting group with

respect to the iminium carbon and directs the attack on the

adjacent less hindered C_b. Thus, addition of NaBH₄in

THF to 2a and 12a results in the formation of the bis-alky-

lidene complexes [Ru₂{l-g¹:g²-C(R⁰)C(H)(R⁰⁰)CN(Me)-

(Xyl)}(l-CO)(CO)(Cp)₂] (R⁰= Me₃Si, R⁰⁰= H, 17; R⁰=

R⁰⁰= Et, 18). Compounds 17–18 display the usual m(CO)

band pattern consisting in two absorptions attributable to

the terminal and bridging CO (e.g., 1918 and 1747 cm^ꢀ1

for 17). Moreover, a band at ca. 1510 cm^ꢀ1is present, indi-

cating a partial double bond character of the C_a–N bond,

in agreement with the presence of an aminocarbene group

Bridging vinyliminium complexes derived from the

insertion of primary alkynes display a C_b-H hydrogen,

which, in the case of the diiron complexes, is slightly acidic

and can be removed by treatment with NaH. This reaction

has allowed the synthesis of diﬀerent products (i.e., mono-,

di- and tetra-nuclear iron complexes) depending on the nat-

ure of the substituents in the parent vinyliminium ligand

[5]. By analogy, the deprotonation of the diruthenium com-

plexes 3a, 2b and 7a occurs by treatment of with NaH. The

reaction is accompanied by deinsertion of the alkyne,

resulting in the formation of [Ru₂{l-CN(Me)(R)}(l-

CO)(CO)(C„CR⁰)(Cp)₂] (R = Xyl, R⁰= Tol, 19; R = Bz,

R⁰= Me₃Si, 20; R = Xyl, R⁰= Me, 21), which contain a

terminal acetylide and a bridging aminocarbyne ligand

(Scheme 10). The IR spectra show terminal and bridging

m(CO) at ca. 1966 and 1795 cm^ꢀ1, respectively, together

with two absorptions at 1515–1547 and 2022–2094 cm^ꢀ1

attributable to m(C@N) and m(C„C), respectively. The

bridging aminocarbyne carbon resonates in the ¹³C spectra

in the typical low ﬁeld region (ca. 310 ppm), whereas the

two C„C carbons resonate at 94–112 ppm. Two isomers

are present in solution, as usually observed in diruthenium

and diiron complexes of the type [M₂{l-CN(Me)(R)}(l-

CO)(CO)(L)(Cp)₂] (L = acyl, CN, Cl, Br, N₃) [9] with

R ¼ Me. These are due to the diﬀerent orientation that

the substituents R and Me can adopt with respect to the

inequivalent M atoms and because of the hindered rotation

1

in the ligand. The main features of the H NMR spectra

are the presence of two distinct resonances for the two

inequivalent Cp ligands at 4.9–5.2 ppm, whereas the protons

on C_bresonate at 3–4 ppm; when two protonsare attached to

C_b, a typical geminal ²J_HHis observed. In the ¹³C NMR spec-

tra the bis-alkylidene ligand shows resonances at 250–

258 ppm (C_a), 70–84 ppm (C_b) and 130–160 ppm (C_c).

Moreover, the NMR spectra of 17 and 18 show the presence

in solution of two isomeric species. In the case of 17, where

two hydrogens are present on C_b, they correspond to the E

and Z forms, due to the diﬀerent orientations of the Xyl

and Me groups on the aminocarbene nitrogen and hindered

rotation around the C_a–N bond (Scheme 8), as clearly indi-

cated by the NMR data. The parent complex 2a was also

present in solution as a mixture of the E and Z forms, in

nearly the same proportion (ca. 10:1); this indicates that

the hydride addition occurs without altering the relative

arrangement of the N-substituents.

Me

H

Et

H

Et

Me

N

Et

C

Xyl

β

C

β

Et

N

The results described show that the reactions of the diru-

thenium vinyliminium complexes well parallel those of the

corresponding diiron compounds. A slight diﬀerence con-

sist in the higher tendency, for the diruthenium complexes,

to adopt a trans geometry for the Cp ligands. Indeed, in the

case of 18, the cis and trans isomers are observed, both with

C_α

C_γ

Xyl

C_γ

C_α

CO

Ru

C

O

C

O

CO

Scheme 9.

2430

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

+

Xyl

N

H

C

Xyl

Me

Ru

R

Me

Ru

H

C

R

Me

R'

N

C

N

C

R'

N

C

β

C

OC

Me

C_α

OC

R

H

C_γ

Ru

CO

C

CO

NaH

Ru

Al₂O₃

C

O

C

O

C

O

C

CH₂Cl₂

O

21

22

R

R'

Xyl Tol

Bz SiMe₃2b

Xyl Me

7a

R'

3a

Xyl Tol

Bz SiMe₃20

Xyl Me

21

19

Scheme 12.

Scheme 10.

around the aminocarbyne C–N bond (E and Z isomers,

Scheme 11). For steric reasons, the Z isomer, in which

the bulkier Xyl group points far from the acetylide,

predominates.

The behaviour of 3a and 2b is identical to that of the cor-

responding diiron counterparts, resulting in the formation of

the r-alkynyl products. By contrast, compound 7a and its

diiron analogue [Fe₂{l-g¹:g³-C(Me)@C(H)C@N(Me)-

(Xyl)}(l-CO)(CO)(Cp)₂]⁺, follow diﬀerent reaction routes;

indeed, treatment of the diiron complex with NaH was

reported to give fragmentation of the Fe–Fe bond, yielding

the mono-metallic species [Fe(Cp)(CO){CN(Me)(Xyl)-

CHC(Me)C(O)}] [5].

Column chromatography on Al₂O₃of 21, using CH₂Cl₂

as eluent, results in its isomerisation to give the l-g¹:g³-

buta-1,3-diene-1,3-diyl complex [Ru₂{l-g³:g¹-C[N(Me)(X-

yl)]C(H)C@CH₂}(l-CO)(CO)(Cp)₂] (22) (Scheme 12). The

formation of 22 requires the coupling between the terminal

–C„CMe acetylide ligand and the bridging aminocarbyne

followed by 1,3-hydrogen migration.

The molecular structure of 22 (Fig. 3 and Table 3) shows

that the molecule maintains the cis-[Ru₂(l-CO)(CO)(Cp)₂]

core present in the parent compound 21. The bridging

C[N(Me)(Xyl)]C(H)C@CH₂ligand is r-bonded to Ru(2)

3

˚

Fig. 3. Molecular structure of 22, with key atoms labelled (all H atoms,

apart from H(14), H(16A) and H(16B), have been omitted). Displacement

ellipsoids are at 30% probability level. Only the main image of the

disordered Cp ligands bound to Ru(1) and Ru(2) are drawn.

[Ru(2)–C(13) 2.108(4) A] and g -coordinated to Ru(1) in

˚

an allyl like fashion [Ru(1)–C(13) 2.217(3) A; Ru(1)–

˚

C(14) 2.164(3) A; Ru(1)–C(15) 2.064(4) A]. In agreement

˚

with this, the C(13)–C(14) [1.424(5) A] and C(14)–C(15)

[1.415(5) A] distances are almost identical and display a

partial p-character. Conversely, C(15)–C(16) [1.317(5) A]

˚

is essentially a double bond and, therefore, the ligand can

be considered a 1,2,3-g³butadienyl in which one of the

substituent on the terminal carbon C(13) has been replaced

by a second metal atom, Ru(2). All the bonding parameters

Table 3

˚

Selected bond lengths (A) and angles (ꢁ) for complex 22

Ru(1)–Ru(2)

Ru(1)–C(12)

Ru(2)–C(12)

Ru(2)–C(11)

Ru(1)–C(13)

Ru(2)–C(13)

Ru(1)–C(14)

Ru(1)–C(15)

2.7251(7)

1.962(4)

2.076(4)

1.853(4)

2.217(3)

2.108(4)

2.164(3)

2.064(4)

C(11)–O(11)

C(12)–O(12)

C(13)–N(1)

N(1)–C(17)

N(1)–C(18)

C(13)–C(14)

C(14)–C(15)

C(15)–C(16)

1.137(5)

1.177(5)

1.383(4)

1.446(5)

1.442(5)

1.424(5)

1.415(5)

1.317(5)

R

Me

Ru

Me

Ru

R

R'

N

C

N

C

OC

C

Ru

Ru(2)–C(13)–C(14)

C(13)–C(14)–C(15)

C(14)–C(15)–C(16)

C(14)–C(15)–Ru(1)

C(16)–C(15)–Ru(1)

119.3(2)

Ru(2)–C(13)–N(1)

C(14)–C(13)–N(1)

C(13)–N(1)–C(17)

C(13)–N(1)–C(18)

C(17)–N(1)–C(18)

124.9(3)

C

O

C

O

120.6(3)

141.5(4)

74.3(2)

115.1(3)

122.9(3)

121.0(3)

116.1(3)

Z-isomer

E-isomer

144.1(3)

Scheme 11.

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

2431

products. These results are not obvious because related

complexes, containing the M₂(CO)₂(Cp)₂frame, show dis-

tinct behaviours for iron and ruthenium. As an example

the diiron bridging methylidyne complex [Fe₂(l-CH)-

(l-CO)(CO)₂(Cp)₂]⁺investigated by Casey, has not a

ruthenium counterpart [12]. Likewise, the large variety of

reactions described by Knox on diruthenium complexes

[6,13] has been only limitedly reproduced by the corre-

sponding iron complexes [14]. On the other hand, diiron

and diruthenium bridging amino carbyne complexes [M₂-

{l-CN(R)(Me)}(l-CO)(CO)₂(Cp)₂]⁺have shown a very

similar reactivity towards the addition of nucleophiles [15].

Our ﬁndings on the chemistry of the diruthenium vinyli-

minium complexes, together with those previously reported

on the diiron compounds [4,5], evidence the electrophilic

character of the vinyliminium ligand.

O

C

Bz

Ru

+

N

CO

C_α

N

H

C

Bz

Me

C_γ

Me

N

Me

β

C

β

Me

C_α

C_γ

Ru

CO

Me

Bz

C

β

Me

Ru

NaH

Ru

C_α

C_γ

C

CO

O

Ru

C

O

7b

23

Scheme 13.

relative to the coordination to Ru(1) perfectly resemble

the ones previously reported for other 1,2,3-g³butadi-

enyl complexes [10]. Finally, the C(13)–N(1) distance

[1.383(4) A] and the almost perfect sp hybridisation of

N(1) [sum angle 360.0(5)ꢁ] suggest the presence of some

p-interaction between the nitrogen and the ligand.

The addition of hydride on the vinyliminium ligand is of

general character and is inﬂuenced by the steric demand

and electronic properties of the substituents at the iminium

nitrogen rather than by the nature of the metal atoms.

However, some diﬀerences have been found, like the

higher presence of trans isomers in the diruthenium com-

plexes. In addition, fragmentation of the M–M bond, was

observed for some of the diiron vinyliminum complexes,

but not in the corresponding diruthenium species. This sug-

gests a greater stability for the diruthenium complexes, but

is not be considered a conclusive evidence because of the

limited number of compounds examined so far.

2

˚

The bridging l-g³:g¹-C[N(Me)(Xyl)]C(H)C@CH₂ligand

is characterised by four diﬀerent resonances in the ¹³C NMR

spectrum at 187.6 (C_c), 48.7 (C_b), 165.7 (C_a) and 103.4

(@CH₂) ppm; moreover, the ¹H NMR spectrum shows a sin-

glet at 3.72 ppm for C_bH and two broad resonances at 5.22

and 4.92 ppm due to the methylidene group @CH₂.

Finally, the reaction of 7b with NaH results in the

formation of the tetranuclear complex [Ru₂{l-g¹:g²-

C(Me)CCN(Me)(Bz)}(l-CO)(CO)(Cp)₂]₂(23) in moderate

yields (56%) (Scheme 13). Again, the reaction parallels that

described for the diiron counterpart and the spectroscopic

properties of 23 closely resemble those of the correspond-

ing tetra-iron species [Fe₂{l-g¹:g²-C(Me)CCN(Me)₂}(l-

CO)(CO)(Cp)₂]₂[5]. The mechanism of this intriguing

dimerisation reaction remains unclear: one possibility is

that C_b-H proton removal is accompanied by a change in

the bridging ligand, which might assume the bis-alkylidene

coordination mode. This would generate an uncoordinated

C_bcarbon, displaying carbene character, which should

dimerise. Similar dimerisations have been reported for

the deprotonated forms of some alkoxy- and amino-car-

bene complexes, which undergo oxidative coupling to give

bridging bis-carbene complexes in an overall sequence

described as ‘‘dehydrodimerisation’’ [11].

4. Experimental details

4.1. General

All reactions were carried out routinely under nitrogen

using standard Schlenk techniques. Solvents were distilled

immediately before use under nitrogen from appropriate

drying agents. Infrared spectra were recorded on a Per-

kin–Elmer Spectrum 2000 FT-IR spectrophotometer and

elemental analyses were performed on a ThermoQuest

Flash 1112 Series EA Instrument. ESI MS spectra were

recorded on a Waters Micromass ZQ 4000 with samples

dissolved in CH₃CN. All NMR measurements were per-

formed on Varian Gemini 300, Varian Mercury Plus 400

and Varian Inova 600 instruments. The chemical shifts

for ¹H and ¹³C were referenced to internal TMS. The spec-

tra were fully assigned via DEPT experiments and H,¹³C

1

correlation measured using gs-HSQC and gs-HMBC

1

experiments [16]; H,¹H correlations were determined by

3. Conclusions

gs-COSY experiments [17]. When two isomers were pres-

ent, in some cases it has not been possible to assign all

the resonances to the minor isomer, especially when it

was present in very low concentration. Monodimensional

NOE measurements were recorded using the DPFGSE-

NOE sequence [7], whereas bidimensional measurements

were recorded using a NOESY sequence modiﬁed with

homospoil gradients [8]. All chemicals were used as

received from Aldrich Co., except [Ru₂{l-CN(Me)(R)}(l-

The data reported in this paper demonstrate the possibil-

ity of extending the preparation of bridging vinyliminium

ligands, previously reported for diiron complexes, to diru-

thenium compounds. Thus, alkyne insertion into the metal

carbyne bond is of general character and is not inﬂuenced

by the nature of the metal (Fe or Ru). Moreover, our studies

show a near complete analogy between the two cases,

regarding both the reactivity and stereochemistry of the

2432

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

CO)(CO)₂(Cp)₂][SO₃CF₃] (R = Xyl, Bz, Me) [14a] and

[Ru₂{l-CN(Me)₂}(l-CO)(CO)(MeCN)(Cp)₂][SO₃CF₃], 1c

[9b], which were prepared by published methods.

42.89; H, 4.26; N, 1.68. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1

)

1

2000vs, 1823s (CO), 1628ms (C@N). H NMR (CDCl₃,

293 K) Isomer E: d 7.24–6.93 (m, 3H, Xyl), 5.69, 5.53 (s,

10H, Cp), 5.02 (s, 1H, C_b-H), 4.00 (s, 3H, N-Me), 2.18,

1.92 (s, 3H, Me₂C₆H₃), 0.29 (s, 1H, Me₃Si); Isomer Z: d

7.24–6.93 (m, 3H, Xyl), 5.96 (s, 1H, C_b-H), 5.59, 5.42 (s,

10H, Cp), 3.67 (s, 3H, N-Me), 2.41, 2.03 (s, 3H, Me₂C₆H₃),

0.45 (s, 1H, Me₃Si). Isomer ratio E/Z = 10. ¹³C NMR

(CDCl₃, 293 K) Isomer E: d 231.5 (l-CO), 221.1 (C_a-N),

197.6 (CO), 188.1 (C_c), 144.3 (C-ipso Xyl), 132.0, 131.5

(C-Me Xyl), 129.7, 129.5, 129.4 (CH Xyl), 91.3, 88.7

(Cp), 63.1 (C_b), 47.4 (N-Me), 17.9, 17.8 (Me₂C₆H₃), 2.2

(Me₃Si); Isomer Z: d 231.5 (l-CO), 220.7 (C_a-N), 197.4

(CO), 188.0 (C_c), 144.1–128.3 (arom), 90.0, 88.2 (Cp),

63.4 (C_b), 50.9 (N-Me), 19.6, 19.3 (Me₂C₆H₃), 2.5 (Me₃Si).

2b: Yield: 61.4 mg (80%). Anal. Calc. for C₂₇H₃₀-

F₃NO₅Ru₂SSi: C, 42.24; H. 3.94, N, 1.82. Found: C,

4.2. Synthesis of [Ru₂{l-CN(Me)(R)}(l-CO)(CO)-

(MeCN)(Cp)₂][SO₃CF₃] (R = Xyl, 1a; Bz, 1b)

Me₃NO (44.0 mg, 0.587 mmol) was added to a solution

of [Ru₂{l-CN(Me)(R)}(l-CO)(CO)₂(Cp)₂][SO₃CF₃] (0.351

mmol) in CH₃CN (10 mL). After stirring at room temper-

ature for 1 h, the solvent was removed in vacuo and the res-

idue washed with petroleum ether (2 · 5 mL), dissolved in

CH₂Cl₂(5 mL) and ﬁltered through a celite pad. Removal

of the solvent under reduced pressure from the ﬁltrated

aﬀorded the ﬁnal product as a yellow-orange powder.

1a: Yield: 208.8 mg (82%). Anal. Calc. for C₂₅H₂₅-

F₃N₂O₅Ru₂S: C, 41.43; H, 3.48; N, 3.87. Found: C,

41.12; H, 3.55; N, 3.69. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1

)

41.98; H, 4.05, N, 1.76. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1

)

1

1982vs, 1820s (CO), 1530m (C@N). H NMR (CD₂Cl₂,

293 K) Isomer a: d 7.31–7.21 (m, 3H, arom), 5.35, 4.94

(s, 10H, Cp), 4.28 (s, 3H, NMe), 2.39, 2.19 (s, 6H,

C₆H₃Me₂), 2.21 (s, 3H, MeCN); Isomer b: d 7.31–7.21

(m, 3H, arom), 5.52, 4.71 (s, 10H, Cp), 4.18 (s, 3H,

NMe), 2.29, 2.16 (s, 6H, C₆H₃Me₂), 2.15 (s, 3H, MeCN).

a/b = 8.5. ¹³C{¹H} NMR (CD₂Cl₂, 293 K) Isomer a: d

310.8 (l-C), 235.2 (l-CO), 200.1 (CO), 147.8 (C-ipso

Xyl), 132.7, 132.0 (C-Me Xyl), 129.7, 128.8, 128.6 (CH

Xyl), 118.7 (C„N), 89.6, 88.1 (Cp), 53.3 (N-Me), 18.3,

17.2 (C₆H₃Me₂), 3.7 (MeCN); Isomer b: d 310.6 (l-C),

236.1 (l-CO), 199.8 (CO), 147.7 (C-ipso Xyl), 132.8,

132.1 (C-Me Xyl), 129.7, 128.9, 128.7 (CH Xyl), 90.5,

87.4 (Cp), 54.6 (N-Me), 18.5, 17.3 (C₆H₃Me₂), 3.8

(MeCN).

1988vs, 1818s (CO), 1669ms (C@N). H NMR (CDCl₃,

293 K) Isomer E: d 7.50–7.20 (m, 5H, Ph), 5.61, 5.40 (s,

10H, Cp), 4.93 (s, 1H, C_b-H), 4.84, 4.71 (d AB,

²J_HH= 14 Hz, 2H, CH₂Ph), 3.62 (s, 3H, N-Me), 0.34 (s,

9H, SiMe₃); Isomer Z: d 7.50–7.20 (m, 5H, Ph), 5.64,

5.42 (s, 10H, Cp), 5.70, 5.26 (d, ²J_HH= 7 Hz, 2H, CH₂Ph),

5.19 (s, 1H, C_b-H), 3.21 (s, 3H, N-Me), 0.44 (s, 9H, SiMe₃).

Isomer ratio E/Z = 1.1. ¹³C NMR (CDCl₃, 293 K) Isomer

E: d 230.4 (l-CO), 216.7 (C_a-N), 198.1 (CO), 184.8 (C_c),

127.5–132.5 (arom), 88.4, 90.9 (Cp), 66.6 (CH₂Ph), 62.8

(C_b), 44.4 (N-Me), 2.5 (SiMe₃); Isomer Z: d 230.4 (l-

CO), 216.1 (C_a-N), 197.6 (CO), 183.4 (C_c), 127.5–132.5

(Ph), 84.4, 90.9 (Cp), 66.6 (CH₂Ph), 62.2 (C_b), 47.4 (N-

Me), 2.3 (SiMe₃).

2c: Yield: 53.3 mg (77%). Anal. Calc. for C₂₁H₂₆-

F₃NO₅Ru₂SSi: C, 36.46; H. 3.79, N, 2.02. Found: C,

1b: Yield: 227.0 mg (91%). Anal. Calc. for C₂₄H₂₃-

F₃N₂O₅Ru₂S: C, 40.56; H, 3.26; N, 3.94. Found: C,

36.81; H, 3.50, N, 2.26. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1

)

40.89; H, 3.04; N, 373. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1

)

1988vs, 1815s (CO), 1682ms (C@N). H NMR (CDCl₃,

293 K): d 5.53, 5.32 (s, 10H, Cp), 5.42 (s, 1H, C_b-H),

3.63, 3.36 (s, 3H, N-Me), 0.34 (s, 1H, Me₃Si). ¹³C NMR

(CDCl₃, 293 K): d 230.2 (l-CO), 216.5 (C_a-N), 197.6

(CO), 183.1 (C_c), 90.7, 88.1 (Cp), 62.2 (C_b), 50.4, 45.7

(N-Me), 2.3 (Me₃Si).

1

1982vs, 1817s (CO), 1588w, 1574m, 1550m (C@N). ¹H

NMR (CD₂Cl₂, 293 K) Isomer a: d 7.50–7.20 (m, 5H,

arom), 5.56 (s, 2H, CH₂Ph), 5.40, 5.29 (s, 10H, Cp), 3.94

(s, 3H, NMe), 2.16 (s, 3H, MeCN); Isomer b: d 7.50–7.20

(m, 5H, arom), 5.77 (s, 2H, CH₂Ph), 5.56, 5.21 (s, 10H,

Cp), 3.89 (s, 3H, NMe), 2.06 (s, 3H, MeCN). a/b = 1.5.

3a: Yield: 60.0 mg (75%). Anal. Calc. for C₃₂H₃₀-

F₃NO₅Ru₂S: C, 48.01; H. 3.78, N, 1.75. Found: C, 47.87;

H, 3.92, N, 1.63. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 2002vs,

1827s (CO), 1629ms (C@N). ¹H NMR (CDCl₃, 293 K) Iso-

mer E: d 7.37–7.03 (m, 7H, arom), 5.68, 5.42 (s, 10H, Cp),

4.67 (s, 1H, C_b-H), 4.01 (s, 3H, N-Me), 2.36, 2.15, 1.97 (s,

9H, p-MeC₆H₄+ Me₂C₆H₃); Isomer Z: d 7.37–7.03 (m,

7H, arom), 5.41, 5.18 (s, 10H, Cp), 5.09 (s, 1H, C_b-H),

3.70 (s, 3H, N-Me), 2.38, 2.31, 2.07 (s, 9H, p-MeC₆H₄+

Me₂C₆H₃). Isomer ratio E/Z = 5. ¹³C NMR (CDCl₃,

293 K) Isomer E: d 228.0 (l-CO), 220.8 (C_a-N), 197.6

(CO), 190.9 (C_c), 151.5–126.6 (arom), 93.6, 89.3 (Cp), 62.0

(C_b), 47.1 (N-Me), 21.0 (p-MeC₆H₄), 17.9, 17.5 (Me₂C₆H₃);

Isomer Z: d 228.3 (l-CO), 221.1 (C_a-N), 198.2 (CO), 189.8

(C_c), 151.5–126.6 (arom), 93.8, 89.3 (Cp), 62.0 (C_b), 50.8 (N-

Me), 21.1 (p-MeC₆H₄), 18.0, 17.6 (Me₂C₆H₃).

4.3. Synthesis of [Ru₂{l-g¹:g³-C(R⁰)@CHC@N(Me)(R)}-

(l-CO)(CO)(Cp)₂][SO₃CF₃] (R = Xyl, R⁰= Me₃Si, 2a;

R = Bz, R⁰= Me₃Si, 2b; R = Me, R⁰= Me₃Si, 2c; R = Xyl,

R⁰= Tol, 3a; R = Bz, R⁰= Tol, 3b)

A solution of 1a–c (0.100 mmol) and the appropriate

alkyne R⁰C„CH (0.300 mmol; R⁰= Me₃Si, Tol) in THF

(12 mL) was reﬂuxed for 1 h aﬀording an orange solution.

Hence, the solvent was removed under reduced pressure

and the residue dissolved in CH₂Cl₂(5 mL) and chromato-

graphed through a Al₂O₃column. The ﬁnal product was

obtained as an orange fraction using CH₃CN as eluent.

2a: Yield: 56.3 mg (72%). Anal. Calc. for C₂₈H₃₂-

F₃NO₅Ru₂SSi: C, 43.01; H, 4.13; N, 1.79. Found: C,

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

2433

3b: Yield: 58.9 mg (75%). Anal. Calc. for C₃₁H₂₈-

F₃NO₅Ru₂S: C, 47.39; H, 3.59, N, 1.78. Found: C, 46.97;

H, 3.44, N, 1.67. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1990vs,

1820s (CO), 1666ms (C@N). ¹H NMR (CDCl₃, 293 K) Iso-

mer E: d 7.42–7.11 (m, 9H, Ph + Tol), 5.50, 5.31 (s, 10H,

Ph), 5.79 (s, 1H, C_b-H), 5.56, 5.48 (s, 10H, Cp), 5.22,

5.18 (d AB, J_HH= 15.4 Hz, 2H, CH₂Ph), 3.94 (s, 3H,

2

CO₂Me), 3.21 (s, 3H, N-Me); Isomer E: d 7.39–7.18 (m,

5H, Ph), 5.61 (s, 1H, C_b-H), 5.54, 5.47 (s, 10H, Cp), 4.91,

2

4.65 (d, J_HH= 14.0 Hz, 2H, CH₂Ph), 3.98, (s, 3H,

2

Cp), 4.94 (s, 1H, C_b-H), 4.86, 4.72 (d AB, J_HH= 14.2 Hz,

+CO₂Me), 3.52 (s, 3H, N-Me). Isomer ratio Z/E = 1.7.

¹³C NMR (CDCl₃, 293 K) Isomer Z: d 228.7 (l-CO),

214.4 (C_a-N), 196.3 (CO), 175.6 (C_c), 165.9 (CO₂Me),

134.4–122.7 (CH Ph), 92.0, 89.7 (Cp), 63.0 (CH₂Ph), 58.8

(C_b), 52.9 (CO₂Me), 45.1 (NMe); Isomer E: d 227.2 (l-

CO), 214.4 (C_a-N), 196.6 (CO), 175.6 (C_c), 165.2 (CO₂Me),

134.4–122.7 (CH Ph), 92.0, 89.7 (Cp), 67.4 (CH₂Ph), 58.5

(C_b), 52.5 (CO₂Me), 43.7 (NMe).

2H, CH₂Ph), 3.62 (s, 3H, N-Me), 2.37 (s, 3H, p-MeC₆H₄);

Isomer Z: d 7.42–7.11 (m, 9H, Ph + Tol), 5.52, 5.34 (s,

2

10H, Cp), 5.29 (s, 1H, C_b-H), 5.24 (d, J_HH= 14.1 Hz,

1H, CH₂Ph. Second doublet hidden by Cp), 3.22 (s, 3H,

N-Me), 2.38 (s, 3H, p-MeC₆H₄). Isomer ratio E/Z = 1.3.

¹³C NMR (CDCl₃, 293 K) Isomer E: d 230.0 (l-CO),

216.3 (C_a-N), 197.8 (CO), 187.2 (C_c), 151.5, 137.0 (C-ipso

Ph + Tol), 132.0 (C-Me Tol), 129.8–128.8 (CH Ph + Tol),

127.2 (p-CH Ph), 93.2, 89.2 (Cp), 66.7 (CH₂Ph), 59.8

(C_b), 44.3 (N-Me), 21.0 (p-MeC₆H₄); Isomer Z: d 231.6

(l-CO), 216.5 (C_a-N), 197.5 (CO), 188.3 (C_c), 151.5,

137.0 (C-ipso Ph + Tol), 131.4 (C-Me Tol), 129.8–128.8

(CH Ph + Tol), 127.3 (p-CH Ph), 93.2, 89.3 (Cp), 62.8

(CH₂Ph), 60.0 (C_b), 47.2 (N-Me), 21.0 (p-MeC₆H₄).

5b: Yield: 57.6 mg (85%). Anal. Calc. for C₂₀H₂₀-

F₃NO₇Ru₂S: C, 35.45; H, 2.98, N, 2.07. Found: C, 35.16;

H, 3.12, N, 2.29. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1996vs,

1

1828s (CO), 1735s (CO₂Me). H NMR (CDCl₃, 293 K): d

5.49 (s, 1H, C_b-H), 5.41, 5.34 (s, 10H, Cp), 3.83 (s, 3H,

CO₂Me), 3.53, 3.30 (s, 6H, NMe₂). ¹³C NMR (CDCl₃,

293 K): d 227.8 (l-CO), 214.6 (C_a-N), 196.7 (CO), 175.8

(C_c), 167.7 (CO₂Me), 92.1, 89.8 (Cp), 58.7 (C_b), 53.1

(CO₂Me), 50.8, 46.2 (NMe₂).

4.4. Synthesis of [Ru₂{l-g¹:g³-C(R⁰)@CHC@N(Me)-

(R)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (R = Bz, R⁰= CH₂OH,

4; R = Bz, R⁰= CO₂Me, 5a; R = Me, R⁰= CO₂Me, 5b)

4.5. Synthesis of [Ru₂{l-g¹:g³-C[(CH₂)₄CCH]@CHC@

N(Me)(Xyl)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (6)

A solution of 1 (0.100 mmol) and the appropriate alkyne

R⁰C„CH (0.300 mmol; R⁰= CH₂OH, CO₂Me) in THF

(12 mL) was reﬂuxed for 1 h aﬀording an orange-red solu-

tion. After removal of the solvent in vacuo, the residue was

washed with petroleum ether (3 · 5 mL) and Et₂O

(3 · 5 mL), dissolved in CH₂Cl₂(5 mL), ﬁltered through

celite and dried in vacuo aﬀording the ﬁnal product as an

orange-red powder.

A solution of 1a (88.1 mg, 0.121 mmol) and HC„

C(CH₂)₄C„CH (02 mL, 1.35 mmol) in THF (1 mL) was

reﬂuxed for 1 h aﬀording an orange solution. Hence, the

solvent was removed under reduced pressure and the resi-

due dissolved in CH₂Cl₂(5 mL) and chromatographed

through a Al₂O₃column. The ﬁnal product was obtained

as an orange fraction using CH₃CN as eluent. Yield:

71.7 mg (75%). Anal. Calc. for C₃₁H₃₂F₃NO₅Ru₂S: C,

47.14; H, 4.08, N, 1.77. Found: C, 47.49; H, 3.74, N,

1.95. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 2118w (C„C),

2000vs, 1823s (CO), 1631m, 1588w (C@N). ¹H NMR

(CDCl₃, 293 K) Isomer E: d 7.33–6.95 (m, 3H, arom),

5.66, 5.48 (s, 10H, Cp), 4.64 (s, 1H, C_b-H), 3.90 (s, 3H,

N-Me), 3.64, 3.27 (m, 2H, C(1)H₂), 2.34 (m, 2H,

C(3)H₂), 2.17, 1.87 (s, 6H, Me₂C₆H₃), 1.92 (t

⁴J_HH= 2.7 Hz, 1H, C„CH), 1.90, 1.57 (m, 2H, C(2)H₂),

1.4–1.7 (m, 2H, C(4)H₂); Isomer Z: d 7.40–7.10 (m, 3H,

arom), 5.74 (s, 1H, C_b-H), 5.62, 5.08 (s, 10H, Cp), 3.61 (s,

3H, N-Me), 3.70, 3.60 (m, 2H, C(1)H₂), 2.40, 2.03 (s, 6H,

Me₂C₆H₃), 2.30 (m, 2H, C(3)H₂), 2.10, 1.90 (m, 2H,

4: Yield: 54.4 mg (75%). Anal. Calc. for C₂₅H₂₄-

F₃NO₆Ru₂S: C, 41.37; H, 3.33, N, 1.93. Found: C, 41.56;

H, 3.12, N, 2.09. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1989vs,

1816s (CO), 1667ms (C@N). ¹H NMR (CDCl₃, 293 K) Iso-

mer Z: d 7.39–7.13 (m, 5H, Ph), 5.97 (s, 1H, C_b-H), 5.62,

5.46 (m, 2H, CH₂OH), 5.59, 5.35 (s, 10H, Cp), 5.14, 5.03

2

(d AB, J_HH= 13.9 Hz, 2H, CH₂Ph), 3.16 (s, 3H, N-Me),

0.85 (br, 1H, OH); Isomer E: d 7.39–7.13 (m, 5H, Ph),

6.00 (s, 1H, C_b-H), 5.64, 5.42 (m, 2H, CH₂OH), 5.59,

2

5.37 (s, 10H, Cp), 4.85, 4.44 (d, J_HH= 14.3 Hz, 2H,

CH₂Ph), 3.42 (s, 3H, N-Me), 0.85 (br, 1H, OH); Isomer

ratio Z/E = 1.2. ¹³C NMR (CDCl₃, 293 K) Isomer Z: d

231.7 (l-CO), 218.0 (C_a-N), 197.3 (CO), 191.6 (C_c), 131.9

(C-ipso Ph), 129.3–128.4 (CH arom), 91.0, 88.6 (Cp), 74.8

(CH₂OH), 62.8 (CH₂Ph), 53.8 (C_b), 47.1 (N-Me); Isomer

E: d 230.6 (l-CO), 218.4 (C_a-N), 197.5 (CO), 191.5 (C_c),

131.5 (C-ipso Ph), 129.3–128.4 (CH arom), 91.0, 88.6

(Cp), 74.8 (CH₂OH), 67.8 (CH₂Ph), 53.6 (C_b), 43.1 (N-

Me). ESI MS: ES+ m/z 578.

4

C(2)H₂), 2.03 (t, J_HH= 2.6 Hz, 1H, C„CH), 1.50 (m,

2H, C(4)H₂); Isomer ratio E/Z = 10. ¹³C NMR (CDCl₃,

293 K) Isomer E: d 229.5 (l-CO), 222.4 (C_a-N), 197.8

(CO), 196.6 (C_c), 144.1 (C-ipso Xyl), 132.0, 131.2 (C-Me

Xyl), 129.8–128.8 (CH Xyl), 92.2, 88.9 (Cp), 84.2 (C„CH),

69.0 (C„CH), 59.4 (C_b), 55.1 (C(1)H₂), 47.0 (N-Me), 34.4

(C(2)H₂), 27.8 (C(4)H₂), 18.2 (C(3)H₂), 17.9, 17.4

(Me₂C₆H₃); Isomer Z: d 228.7 (l-CO), 221.7 (C_a-N),

198.6 (CO), 195.9 (C_c), 141.4 (C-ipso Xyl), 134.3, 133.2

(C-Me Xyl), 129.7, 129.5, 128.8 (CH Xyl), 92.2, 92.1

(Cp), 84.6 (C„CH), 68.8 (C„CH), 60.2 (C_b), 54.5

5a: Yield: 57.3 mg (76%). Anal. Calc. for C₂₆H₂₄-

F₃NO₇Ru₂S: C, 41.44; H, 3.21, N, 1.86. Found: C, 41.17;

H, 3.34, N, 1.92. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1997vs,

1

1827s (CO), 1728s, 1714sh (CO₂Me), 1671ms (C@N). H

NMR (CDCl₃, 293 K) Isomer Z: d 7.39–7.18 (m, 5H,

2434

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

(C(1)H₂), 50.7 (N-Me), 34.4 (C(2)H₂), 27.8 (C(4)H₂), 18.2

(C(3)H₂), 17.9, 17.7 (Me₂C₆H₃). ESI MS: ES+ m/z 642.

reduced pressure and the residue dissolved in CH₂Cl₂

and chromatographed through Al₂O₃; the product was

obtained as an orange fraction using THF as eluent. Yield:

34.7 mg (76%). Anal. Calc. for C₂₂H₂₂ClNORu₂: C, 46.36;

H, 3.89; N, 2.46. Found: C, 46.58; H, 3.72; N, 2.38. IR

(CH₂Cl₂, 293 K): m (cm^ꢀ1) 1970vs, 1797s (CO), 1509ms

4.6. Synthesis of [Ru₂{l-g¹:g³-C(Me)@CHC@N(Me)-

(R)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (R = Xyl, 7a; Bz, 7b;

Me, 7c)

1

(C@N). H NMR (CD₂Cl₂, 293 K): d 7.24–7.16 (m, 3H,

A solution of 1 (0.304 mmol) in CH₂Cl₂(15 mL) was sat-

urated with MeC„CH and stirred overnight at room

temperature. Hence, the resulting solution was chromato-

graphed through a Al₂O₃column. The ﬁnal product was

obtained as a yellow-orange fraction using MeOH as eluent.

7a: Yield: 169.4 mg (77%). Anal. Calc. for C₂₆H₂₆-

F₃NO₅Ru₂S: C, 43.15; H, 3.62, N, 1.94. Found: C, 42.98;

H, 3.86, N, 2.08. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1998vs,

arom), 5.16, 4.81 (s, 10H, Cp), 4.28 (s, 3H, NMe), 2.29,

2.14 (s, 6H, C₆H₃Me₂).

4.8. Synthesis of [Ru₂{l-g¹:g³C(C(Me)@CH₂)@CHC@

N(Me)(Xyl)}(l-CO)(CO)(Cp)₂] [SO₃CF₃] (9)

AgSO₃CF₃(25.0 mg, 0.097 mmol) was added to a

solution containing 8 (34.1 mg, 0.060 mmol) and HC„

CC(Me)@CH₂(0.4 mL, 4.21 mmol) in CH₂Cl₂(5 mL) at

ꢀ50 ꢁC. After stirring at room temperature for 1 h, the

mixture was ﬁltered through Al₂O₃using CH₃CN in

order to remove AgCl. Hence, the solvent was removed

in vacuo and the residue dissolved in CH₂Cl₂(5 mL) and

chromatographed through an Al₂O₃column. The ﬁnal

product was obtained as a bright orange fraction using

CH₃CN as eluent. Yield: 31.4 mg (71%). Anal. Calc. for

C₂₇H₂₈F₃NO₅Ru₂S: C, 43.96; H, 3.83, N, 1.90. Found:

1

1824s (CO), 1628ms (C@N). H NMR (CDCl₃, 293 K): d

7.07–6.87 (m, 3H, arom), 5.60, 5.39 (s, 10H, Cp), 4.57 (s,

1H, C_b-H), 3.82 (s, 3H, N-Me), 3.32 (s, 3H, C_c-Me),

2.10, 1.79 (s, 6H, Me₂C₆H₃). ¹³C NMR (CDCl₃, 293 K):

d 229.4 (l-CO), 222.5 (C_a-N), 198.0 (CO), 190.7 (C_c),

144.3 (C-ipso Xyl), 132.2, 131.4 (C-Me Xyl), 129.8, 129.5

(CH Xyl), 92.6, 89.0 (Cp), 60.8 (C_b), 47.2 (N-Me), 43.2

(C_c-Me), 18.7, 17.6 (Me₂C₆H₃).

7b: Yield: 175.0 mg (81%). Anal. Calc. for C₂₅H₂₅-

F₃NO₅Ru₂S: C, 42.25; H, 3.55, N, 1.97. Found: C, 42.61;

H, 3.74, N, 1.48. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1): 1988vs

C, 44.03; H, 3.77, N, 1.99. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1

)

2002vs, 1828s (CO), 1627ms, 1588w (C@N). ¹H NMR

(CDCl₃, 293 K) Isomer Z: d 7.36–6.95 (m, 3H, Xyl), 5.47,

5.10 (s, 10H, Cp), 5.02 (br, 1H, C_b-H), 4.85 (br, 2H,

CH₂@), 3.61 (s, 3H, N-Me), 2.38, 2.28, 2.00 s, (9H,

Me₂C₆H₃+ C(Me)@CH₂). ¹³C NMR (CDCl₃, 293 K)

Isomer Z: d 227.3 (l-CO), 221.4 (C_a-N), 198.2 (CO),

194.6 (C_c), 156.9 (C-ipso Xyl), 134.0, 133.2 (C-Me Xyl),

129.7–128.9 (CH Xyl), 123.0 (C(Me)@CH₂), 111.4

(C(Me)@CH₂), 93.8, 89.1 (Cp), 60.6 (C_b), 47.1 (N-Me),

26.9 (C(Me)@CH₂), 18.0, 17.8 (Me₂C₆H₃).

1

(CO), 1817s (l-CO), 1666mw, 1606m (C@N). H NMR

(CDCl₃, 293 K): Isomer E: d 7.33–7.09 (m, 5H, Ph), 5.28,

2

4.42 (d, J_HH= 14.3 Hz, 2H, CH₂Ph), 5.53, 5.27 (s, 10H,

Cp), 5.22 (s, 1H, C_b-H), 3.41 (s, 3H, C_c-Me), 3.36 (s, 3H,

N-Me); Isomer Z: d 7.33–7.09 (m, 5H, Ph), 5.84, 4.71 (d,

²J_HH= 14.6 Hz, 2H, CH₂Ph), 5.54, 5.26 (s, 10H, Cp),

5.12 (s, 1H, C_b-H), 3.43 (s, 3H, C_c-Me), 3.04 (s, 3H, N-

Me). Isomer ratio E/Z = 1.2. ¹³C NMR (CDCl₃, 293 K)

Isomer E:d 230.9 (l-CO), 217.9 (C_a-N), 198.2 (CO), 187.6

(C_c), 131.8 (C-ipso Ph), 129.5–127.4 (CH Ph), 92.3, 88.9

(Cp), 67.7 (CH₂Ph), 59.3 (C_b), 43.5 (N-Me), 42.3 (C_c-

Me); Isomer Z: d 232.3 (l-CO), 218.1 (C_a-N), 197.9

(CO), 187.9 (C_c), 132.3 (C-ipso Ph), 129.5–127.4 (CH

Ph), 92.3, 89.0 (Cp), 67.6 (CH₂Ph), 59.6 (C_b), 47.2

(NMe), 42.4 (C_c-Me).

4.9. Synthesis of [Ru₂{l-g¹:g³C(CO₂Me)@C(CO₂Me)C@

N(Me)(Bz)}(l-CO)(CO)(Cp)₂] [SO₃CF₃] (11)

A solution of 1b (0.085 mmol) and MeO₂CC„CCO₂Me

(0.100 mL, 0.708 mmol) in THF (12 mL) was reﬂuxed for

1 h. After removal of the solvent in vacuo, the residue

was washed with petroleum ether (3 · 5 mL) and Et₂O

(3 · 5 mL), dissolved in CH₂Cl₂(5 mL), ﬁltered through

celite and dried in vacuo aﬀording the ﬁnal product as an

yellow-orange powder. Yield: 58.6 mg (86%). Anal. Calc.

for C₂₈H₂₆F₃NO₉Ru₂S: C, 41.43; H, 3.23, N, 1.73. Found:

7c: Yield: 169.5 mg (88%). Anal. Calc. for C₁₉H₂₀-

F₃NO₅Ru₂S: C, 36.02; H, 3.18, N, 2.21. Found: C, 35.87;

H, 3.49, N, 2.05. IR (in CH₂Cl₂, 293 K) m (cm^ꢀ1): 1987vs

1

(CO), 1817s (l-CO), 1680ms (C@N). H NMR (CDCl₃,

298 K): d 5.49, 5.26 (s, 10H, Cp), 5.08 (s, 1H, C_b-H),

3.52, 3.27 (s, 6H, NMe₂), 3.40 (s, 3H, C_c-Me), ¹³C NMR

(CDCl₃, 298 K): d 231.3 (l-CO), 217.4 (C_a-N), 197.9

(CO), 186.6 (C_c), 92.1, 88.8 (Cp), 59.2 (C_b), 50.4, 46.0

(NMe₂), 42.2 (C_c-Me).

C, 41.22; H, 3.12, N, 1.89. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1

)

2004vs (CO), 1838s (l-CO), 1737vs, 1726sh (COOMe),

1670ms (C@N). ¹H NMR (CDCl₃, 293 K) Isomer E: d

7.50–7.20 (m, 5H, Ph), 5.62, 5.51 (s, 10H, Cp), 5.10 (d,

²J_HH= 15.9 Hz, 1H, CH₂Ph. Second doublet hidden by

Cp), 4.01, 3.88 (s, 9H, N-Me + CO₂Me); Isomer Z: d

7.50–7.20 (m, 5H, Ph), 5.59, 5.57 (s, 10H, Cp), 5.04, 4.48

4.7. Synthesis of [Ru₂{l-CN(Me)(Xyl)}(l-CO)(CO)-

(Cl)(Cp)₂] (8)

2

A solution containing 1a (58.1 mg, 0.080 mmol) and

(Et₄N)(Cl) (90.2 mg, 0.532 mmol) in THF (10 mL) was

reﬂuxed for 1 h. Then, the solvent was removed under

(d, J_HH= 14.1 Hz, 2H, CH₂Ph), 4.00, 3.88 (s, 6H,

CO₂Me), 3.23 (s, 3H, N-Me). Isomer ratio E/Z = 2.2. ¹³C

NMR (CDCl₃, 293 K) Isomer E: d 225.4 (l-CO), 212.0

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

2435

(C_a-N), 196.0 (CO), 175.0 (C_c), 170.6, 166.2 (CO₂Me),

131.7 (C-ipso Ph), 129.5, 129.3, 128.6 (CH Ph), 93.2, 91.1

(Cp), 63.5 (CH₂Ph), 58.9 (C_b), 53.9, 53.1 (CO₂Me), 47.7

(NMe); Isomer Z: d 224.7 (l-CO), 212.6 (C_a-N), 196.5

(CO), 175.0 (C_c), 169.9, 165.1 (CO₂Me), 130.8 (C-ipso

Ph), 129.5, 129.0, 128.6 (CH Ph), 93.1, 91.3 (Cp), 67.7

(CH₂Ph), 59.6 (C_b), 53.8, 52.9 (CO₂Me), 44.2 (N-Me).

(l-CO), 219.8 (C_a-N), 198.9 (CO), 191.3 (C_c), 131.2 (C-ipso

Ph), 129.4–128.3 (CH arom), 92.2, 89.0 (Cp), 78.8 (C_b),

65.6 (CH₂Ph), 43.5 (N-Me), 43.0 (c-CH₂CH₃), 23.0 (b-

CH₂CH₃), 20.0, 15.9 (CH₂CH₃); Isomer Z: d 232.7 (l-

CO), 218.2 (C_a-N), 198.3 (CO), 191.0 (C_c), 132.2 (C-ipso

Ph), 129.4–128.3 (CH arom), 92.4, 88.8 (Cp), 79.1 (C_b),

63.0 (CH₂Ph), 45.1 (N-Me), 43.0 (c-CH₂CH₃), 22.1 (b-

CH₂CH₃), 19.1, 15.2 (CH₂CH₃).

4.10. Synthesis of [Ru₂{l-g¹:g³C(Et)@C(Et)C@N(Me)-

(R)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (R = Xyl, 12a; R =

Bz, 12b)

4.11. Synthesis of [Ru₂{l-g¹:g³C(Me)@C(Me)C@

N(Me)(Xyl)}(l-CO)(CO)(Cp)₂][SO₃CF₃] (13)

A solution of 1a,b (0.100 mmol) and EtC„CEt (0.100

mL, 0.868 mmol) in THF (10 mL) was reﬂuxed for 1 h

aﬀording an orange solution. Hence, the solvent was

removed under reduced pressure and the residue dissolved

in CH₂Cl₂(5 mL) and chromatographed through a Al₂O₃

column. The ﬁnal product was obtained as an orange frac-

tion using CH₃CN as eluent.

AgSO₃CF₃(25.0 mg, 0.097 mmol) was added to a solu-

tion containing 8 (34.1 mg, 0.060 mmol) and MeC„CMe

(0.6 mL, 7.67 mmol) in CH₂Cl₂(5 mL) at ꢀ50 ꢁC. After

stirring at room temperature for 3 h, the mixture was ﬁl-

tered through Al₂O₃using CH₃CN in order to remove

AgCl. Hence, the solvent was removed in vacuo and the

residue dissolved in CH₂Cl₂(5 mL) and chromatographed

through an Al₂O₃column. The ﬁnal product was obtained

as a bright orange fraction using CH₃CN as eluent. Yield:

28.3 mg (64%). Found: C, 44.12; H, 3.67, N, 2.01.

C₂₇H₂₈F₃NO₅Ru₂S requires: C, 43.97; H,. 3.83%, N,

1.90%. Colour: orange. IR (in DCM, 293 K) m (cm^ꢀ1) Iso-

mer cis: 1984vs (CO), 1825s (l-CO), 1617ms, 1588m

(C@N); Isomer trans: 1988vs (CO), 1831s (l-CO),

12a: Yield: 55.1 mg (72%). Anal. Calc. for C₂₉H₃₂-

F₃NO₅Ru₂S: C, 45.49; H, 4.21, N, 1.83. Found: C, 45.32;

H, 4.38, N, 1.7. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1984vs,

1925s (CO), 1616m, 1587w (C@N). ¹H NMR (CDCl₃,

293 K) Isomer cis: d 7.40–7.12 (m, 3H, arom), 5.64, 5.08

(s, 10H, Cp), 3.55 (s, 3H, N-Me), 3.88–3.51, 2.77–2.12

(m, 4H, c-CH₂CH₃+ b-CH₂CH₃), 2.41, 2.04 (s, 6H,

3

1

Me₂C₆H₃), 1.54 (t, J_HH= 7.4 Hz, 3H, c-CH₂CH₃), 1.35

1613ms, 1587m (C@N). H NMR (CDCl₃, 293 K) Isomer

3

(t, J_HH= 7.7 Hz, 3H, b-CH₂CH₃); Isomer trans: d 7.40–

cis: 7.64–7.08 (m, 3H, arom), 5.65, 5.06 (s, 10H, Cp),

3.58, 3.52 (s, 6H, N-Me + c-CH₃), 2.39, 2.04 (s, 6H,

Me₂C₆H₃), 2.16 (s, 3H, b-CH₃); Isomer trans: 7.32–6.92

(m, 3H, arom), 5.24, 4.78 (s, 10H, Cp), 3.65, 3.46 (s, 6H,

N-Me + c-CH₃), 2.29, 1.97 (s, 6H, Me₂C₆H₃), 2.17 (3H,

b-CH₃). Isomer ratio trans/cis = 1.3. ¹³C NMR (CDCl₃,

293 K) Isomer cis: 228.7 (l-CO), 222.3 (C_a-N), 199.2

(CO), 184.5 (C_c), 141.2 (C-ipso Xyl), 133.9, 133.8 (C-Me

Xyl), 130.2–129.1 (CH Xyl), 93.1, 89.6 (Cp), 74.8 (C_b),

48.7 (N-Me), 38.5 (c-CH₃), 18.3, 18.2, 17.7 (b-

CH₃+ Me₂C₆H₃); Isomer trans: 227.3 (l-CO), 219.32

(C_a–N), 1995.1 (CO), 179.3 (C_c), 142.3 (C-ipso Xyl),

133.8, 132.9 (C-Me Xyl), 130.2–129.1 (CH Xyl), 91.4,

89.8 (Cp), 80.6 (C_b), 48.5 (N-Me), 38.5 (c-CH₃), 18.2,

18.1, 18.0 (b-CH₃+ Me₂C₆H₃).

7.12 (m, 3H, arom), 5.30, 4.87 (s, 10H, Cp), 3.72 (s, 3H,

N-Me), 3.88–3.51, 2.77–2.12 (m, 4H, c-CH₂CH₃+ b-

3

CH₂CH₃), 1.46 (t, J_HH= 7.4 Hz, 3H, c-CH₂CH₃), 1.35

3

(t, J_HH= 7.7 Hz, 3H, b-CH₂CH₃); Isomer ratio cis/

trans = 2.5. ¹³C NMR (CDCl₃, 293 K) Isomer cis: d 228.2

(l-CO), 221.9 (C_a-N), 199.4 (CO), 193.7 (C_c), 140.9–

122.9 (arom), 92.5, 89.2 (Cp), 79.0 (C_b), 49.0 (N-Me),

42.6 (c-CH₂CH₃), 24.2 (b-CH₂CH₃), 20.6, 16.4 (c-

CH₂CH₃+ b-CH₂CH₃), 18.3, 18.2 (Me₂C₆H₃); Isomer

trans: 226.8 (l-CO), 218.5 (C_a-N), 199.4 (CO), 194.8 (C_c),

140.9–122.9 (arom), 91.1, 89.9 (Cp), 79.0 (C_b), 49.2 (N-

Me), 41.9 (c-CH₂CH₃), 25.9 (b-CH₂CH₃), 20.7, 15.6 (c-

CH₂CH₃+ b-CH₂CH₃), 18.2, 18.0 (Me₂C₆H₃).

Note. If the mixture of cis- and trans-12a is further

reﬂuxed for ca. 5 h, pure cis-12a is obtained.

Note. If the mixture of cis- and trans-13 is reﬂuxed for

ca. 5 h in THF, pure cis-13 is obtained.

12b: Yield: 58.6 mg (78%). Anal. Calc. for C₂₈H₃₀-

F₃NO₅Ru₂S: C, 44.73; H, 4.02, N, 1.86. Found: C, 44.12;

H, 3.87, N, 2.01. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1986vs,

1816s (CO), 1653ms (C@N). ¹H NMR (CDCl₃, 293 K) Iso-

mer E: d 7.40–7.11 (m, 5H, Ph), 5.58, 5.38 (s, 10H, Cp),

4.12. Synthesis of [Ru₂{l-g¹:g³C(R⁰)C(R⁰⁰)@C(H)N-

(Me)(R)}(l-CO)(CO)(Cp)₂] (R = Bz, R⁰= Me₃Si,

R⁰⁰= H, 14a; R = Me, R⁰= Me₃Si, R⁰⁰= H, 14b; R = Bz,

R⁰= Tol, R⁰⁰= H, 15; R = Bz, R⁰= R⁰⁰= Et, 16)

2

4.80, 4.41 (d, J_HH= 14.6 Hz, 2H, CH₂Ph), 3.58 (m, 2H,

c-CH₂CH₃), 3.46 (s, 3H, N-Me), 2.28 (m, 2H, b-CH₂CH₃),

3

1.44 (t, 3H, J_HH= 7.4 Hz, c-CH₂CH₃), 1.06 (t, J_HH

=

NaBH₄(9.00 mg, 0.237 mmol) was added to a solution

of 2b,c, 3b or 12b (0.100 mmol), respectively, in THF

(10 mL). After stirring 30 min at room temperature,

MeOH (5 mL) was added and the solution further stirred

for 15 min in order to destroy unreacted NaBH₄. The

resulting suspension was ﬁltered through a Al₂O₃pad

and the solvent removed in vacuum from the ﬁltrated.

7.6 Hz, 3H, b-CH₂CH₃); Isomer Z: d 7.40–7.11 (m, 5H,

Ph), 5.60, 5.36 (s, 10H, Cp), 5.34, 4.90 (d, J_HH= 14.3 Hz,

2H, CH₂Ph), 3.58 (m, 2H, c-CH₂CH₃), 3.00 s, (3H, N-Me),

2

3

2.28 (m, 2H, b-CH₂CH₃), 1.16 (t, 3H, J_HH= 7.4 Hz, c-

CH₂CH₃), 0.92 (t, ³J_HH= 7.6 Hz, 3H, b-CH₂CH₃); Isomer

ratio E/Z = 2. ¹³C NMR (CDCl₃, 293 K) Isomer E: d 231.7

2436

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

The residue was, then, dissolved in CH₂Cl₂(5 mL) and

chromatographed through Al₂O₃. The product was

obtained as an orange fraction using CH₂Cl₂eluent.

14a: Yield: 47.1 mg (76%). Anal. Calc. for C₂₆H₃₁-

NO₂Ru₂Si: C, 50.39; H, 5.04, N, 2.26. Found: C, 50.04;

H, 5.12, N, 2.56. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1928vs,

in CH₂Cl₂(5 mL) and ﬁltered through Al₂O₃, aﬀording a

yellow-orange solution, from which the product was

obtained after chromatography through a Al₂O₃column

using CH₂Cl₂as eluent.

17: Yield: 48.9 mg (77%). Anal. Calc. for C₂₇H₃₄NO₂-

Ru₂Si: C, 51.09; H, 5.40, N, 2.21. Found: C, 51.16; H, 5.30;

N, 2.33. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1918vs, 1747s (CO),

1515m (C@N). ¹H NMR (CDCl₃, 293 K) Isomer E: d

7.26–6.98 (m, 3H, arom), 5.21, 5.06 (s, 10H, Cp), 4.05,

1

1760s (CO). H NMR (CDCl₃, 293 K): d 7.45–7.21 (m,

3

5H, Ph), 5.20, 5.01 (s, 10H, Cp), 4.38 (d, J_HH= 8.79 Hz,

2

1H, C_b-H), 3.81, 3.53 (d, J_HH= 14.28 Hz, 2H, CH₂Ph),

3

2

2.75 (d, J_HH= 8.79 Hz, 1H, C_a-H), 2.14 (s, 3H, NMe),

3.68 (d, J_HH= 20.4 Hz, 2H, C_bH₂), 3.70 (s, 3H, N-Me),

0.29 (s, 9H, SiMe₃). ¹³C{¹H} (CDCl₃, 293 K): d 254.4 (l-

CO), 205.9 (CO), 156.6 (l-Cc), 137.5 (C-ipso arom),

128.7, 128.3, 127.2 (CH arom), 105.2 (C_a-H), 87.6, 81.4

(Cp), 69.2 (C_b-H), 61.2 (CH₂Ph), 37.8 (NMe), 2.8 (SiMe₃).

14b: Yield: 34.4 mg (67%). Anal. Calc. for C₂₀H₂₇-

NO₂Ru₂Si: C, 44.19; H, 5.01, N, 2.58. Found: C, 44.34;

H, 5.15, N, 2.38. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1948vs,

1784s (CO). ¹H NMR (CDCl₃, 293 K): d 5.26, 5.02 (s,

2.02 (s, 6H, Me₂C₆H₃), 0.18 (s, 9H, SiMe₃); Isomer Z: d

7.26–6.98 (m, 3H, arom), 5.17, 5.01 (s, 10H, Cp), 4.16,

3.76 (d, J_HH= 20.4 Hz, 2H, C_bH₂), 3.72 (s, 3H, N-Me),

2

2.08 (s, 6H, Me₂C₆H₃), 0.20 (s, 9H, SiMe₃). Isomer ratio

E/Z = 13. ¹³C{¹H} (in CDCl₃, 293 K) Isomer E: d 252.7

(l-CO), 247.2 (C_a), 206.3 (CO), 142.3 (C-ipso Xyl), 135.1,

132.7, 131.7 (l-Cc + C-Me Xyl), 128.9, 128.3, 128.0 (CH

Xyl), 87.2, 85.6 (Cp), 69.6 (C_bH₂), 47.5 (NMe), 17.5, 17.2

(Me₂C₆H₃), 2.4 (SiMe₃); Isomer Z: d 87.5, 85.4 (Cp), 70.8

(C_bH₂), 47.5 (NMe), 18.0, 17.9 (Me₂C₆H₃), 2.2 (SiMe₃).

18: Yield: 43.9 mg (71%). Anal. Calc. for C₂₈H₃₃-

NO₂Ru₂: C, 54.44; H, 5.38, N, 2.27. Found: C, 54.28; H,

5.45; N, 2.18. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1905vs,

1757s (CO), 1508m (C@N). ¹H NMR (CDCl₃, 293 K) Iso-

mer cis-Z: d 7.29–6.93 (m, 3H, arom), 5.14, 4.59 (s, 10H,

3

10H, Cp), 4.30 (d, J_HH= 8.6 Hz, 1H, C_b-H), 2.19 (s, 6H,

3

NMe₂), 2.53 (d, J_HH= 8.6 Hz, 1H, C_a-H).

15: Yield: 56.8 mg (89%). Anal. Calc. for C₃₀H₂₉-

NO₂Ru₂: C, 56.50; H, 4.58, N, 2.20. Found: C, 56.97; H,

4.12, N, 2.77. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1931vs,

1

1760s (CO). H NMR (CDCl₃, 293 K): d 7.08–7.40 (m,

3

9H, Ph + Tol), 5.09, 4.94 (s, 10H, Cp), 4.25 (d, J_HH

=

2

3

8.8 Hz, 1H, C_b-H), 3.82, 3.59 (d, J_HH= 14.3 Hz, 2H,

CH₂Ph), 2.82 (d, J_HH= 8.8 Hz, 1H, C_a-H), 2.36, 2.15

Cp), 3.65, 3.26 (dq, J_HH= 13.0 Hz, J_HH= 7.3 Hz, 2H,

c-CH₂CH₃), 3.20 (m, 1H, C_bH), 3.16 (s, 3H, N-Me),

2.27, 2.24 (s, 6H, Me₂C₆H₃), 1.50, 1.30 (m, 2H, b-

3

(6H, s, NMe + p-MeC₄H₆). ¹³C{¹H} (CDCl₃, 293 K): d

245.4 (l-CO), 205.5 (CO), 161.9 (l-C_c), 155.2, 137.4,

134.2 (C-ipso Ph + Tol), 129.0, 128.6, 128.3, 128.0, 127.2

(CH Ph + Tol), 102.1 (C_a-H), 89.8, 83.0 (Cp), 67.20 (C_b-

H), 61.3 (CH₂Ph), 37.5 (NMe), 21.0 (MeC₄H₆).

3

CH₂CH₃), 1.40 (t, J_HH= 7.3 Hz, 3H, c-CH₂CH₃), 1.25

(³J_HH= 7.6 Hz, 3H, b-CH₂CH₃); Isomer trans-Z: d 7.29–

6.93 (m, 3H, arom), 5.23, 4.93 (s, 10H, Cp), 3.80, 3.30

(m, 2H, c-CH₂CH₃), 3.40 (m, 1H, C_bH), 2.94 (s, 3H, N-

Me), 2.30, 2.26 (s, 6H, Me₂C₆H₃), 2.40, 1.90 (m, 2H, b-

16: Yield: 53.1 mg (88%). Anal. Calc. for C₂₇H₃₁-

NO₂Ru₂: C, 53.71; H, 5.17, N, 2.32. Found: C, 53.15; H,

5.32, N, 2.06. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 1938vs,

3

CH₂CH₃), 1.45 (t, J_HH= 7.1 Hz, 3H, c-CH₂CH₃), 0.73

(³J_HH= 7.5 Hz, 3H, b-CH₂CH₃). Isomer ratio cis-Z/

trans-Z = 5. ¹³C{¹H} (in CDCl₃, 293 K) Isomer cis-Z: d

257.6 (C_a), 251.4 (l-CO), 207.3 (CO), 160.5 (l-C_c), 146.1

(C-ipso Xyl), 134.7, 133.4 (C-Me Xyl), 129.5, 127.90

127.6 (CH Xyl), 89.4, 86.5 (Cp), 82.1 (C_bH), 46.4, 26.1

(b + c-CH₂CH₃) 41.0 (NMe), 19.2, 18.2, 17.8, 14.5

(Me₂C₆H₃+ b + c-CH₂CH₃); Isomer trans-Z: d 256.7

(C_a), 251.6 (l-CO), 206.2 (CO), 160.1 (l-C_c), 146.1 (C-ipso

Xyl), 136.3, 136.1 (C-Me Xyl), 130–127 (CH Xyl), 89.1,

85.0 (Cp), 84.4 (C_bH), 44.9, 24.1 (b + c-CH₂CH₃) 40.4

(NMe), 21.3, 20.2, 19.8, 14.0 (Me₂C₆H₃+ b + c-CH₂CH₃).

1

1787s (CO). H NMR (CDCl₃, 293 K): d 7.62–7.10 (m,

2

5H, Ph), 5.14, 4.75 (s, 10H, Cp), 3.96, 3.48 (d, J_HH

=

2

14.1 Hz, 2H, CH₂Ph), 3.74, 3.20 (dq, J_HH= 13.0 Hz,

³J_HH= 7.4 Hz, 2H, a-CH₂CH₃), 2.48, 2.29 (dq,

²J_HH= 13.6 Hz, J_HH= 7.5 Hz, 2H, b-CH₂CH₃), 2.15 (s,

3

3H, NMe), 1.37 (t, J_HH= 7.3 Hz, 3H, a-CH₂CH₃), 1.16

3

(t, J_HH= 7.5 Hz, 3H, b-CH₂CH₃), 0.92 (s, 1H, C_a-H).

¹³C{¹H} (CDCl₃, 293 K): d 246.4 (l-CO), 205.8 (CO),

179.5 (l-C_c), 139.9 (C-ipso Ph), 130.9, 128.8, 128.3,

128.2, 126.6 (CH Ph), 96.1 (C_a-H), 94.4 (C_b-Et), 89.2,

85.5 (Cp), 65.9 (CH₂Ph), 44.5 (NMe), 43.2, 23.9 (CH₂CH₃),

21.4, 16.3 (CH₂CH₃).

4.14. Synthesis of [Ru₂{l-CN(Me)(R)}(l-CO)(CO)-

(CCR⁰)(Cp)₂] (R = Xyl, R⁰= Tol, 19; R = Bz, R⁰=

Me₃Si, 20; R = Xyl, R⁰= Me, 21)

4.13. Synthesis of [Ru₂{l-g¹:g²-C(R⁰)C(H)(R⁰⁰)CN(Me)-

(Xyl)}(l-CO)(CO)(Cp)₂] (R⁰= Me₃Si, R⁰⁰= H, 17;

R⁰= R⁰⁰= Et, 18)

NaH (10.0 mg, 0.417 mmol) was added to a solution of

3a, 2b and 7 (0.100 mmol), respectively, in THF (10 mL).

After stirring 30 min at room temperature, MeOH (5 mL)

was added and the solution further stirred for 15 min in

order to eliminate unreacted NaH. The resulting suspen-

sion was ﬁltered through a celite pad and the solvent

removed in vacuum from the ﬁltrated. The residue was,

NaBH₄(12.0 mg, 0.316 mmol) was added to a solution

of 2a or 12b (0.100 mmol) in THF (6 mL) and stirred at

room temperature for 2 h. Hence, MeOH (0.4 mL) was

added and the solution further stirred for 20 min. The sol-

vent was then removed in vacuo and the residue dissolved

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

2437

then, washed with petroleum ether (3 · 15 mL) and dried in

vacuum aﬀording the ﬁnal product as an orange powder.

19: Yield: 39.6 mg (61%). Anal. Calc. for C₃₁H₂₉-

NO₂Ru₂: C, 57.31; H, 4.50, N, 2.16. Found: C, 57.22; H,

4.62, N, 2.09. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 2094s

(C„C), 1966vs, 1795s (CO), 1516ms (C@N). ¹H NMR

(CDCl₃, 293 K): d 7.22–7.11 (m, 3H, Xyl), 6.97, 6.83 (d

(C-ipso Xyl), 136.2, 135.9 (C-Me Xyl), 129.7, 128.5, 126.7

(CH Me₂C₆H₃), 103.4 (CH₂), 87.8, 85.0 (Cp), 48.7 (C_b),

45.9 (N-Me), 20.2, 18.9 (Me₂C₆H₃).

4.16. Synthesis of [Ru₂{l-g¹:g²-C(Me)CCN(Bz)(Me)}-

(l-CO)(CO)(Cp)₂]₂(23)

3

AB, J_HH= 7.9, 4H, p-C₆H₄Me), 5.30, 4.81 (s, 10H, Cp),

NaH (125.1 mg, 5.21 mmol) was added to a solution of

7b (352.2 mg, 0.496 mmol) in THF (20 mL). The resulting

suspension was stirred at room temperature for 40 min

and, then, ﬁltered through a Al₂O₃pad. After removal of

the solvent from the ﬁltrated, the residue was chromato-

graphed through Al₂O₃; the ﬁnal product was obtained

as a green fraction using CH₂Cl₂/THF (3:1) as eluent.

Yield: 147.1 mg (53%). Anal. Calc. for C₄₈H₄₆N₂O₄Ru₄:

C, 51.51; H, 4.14, N, 2.50. Found: C, 51.89; H, 3.85, N,

2.15. IR (in CH₂Cl₂, 293 K) m (cm^ꢀ1): 1918vs (CO),

4.07 (s, 3H, N-Me), 2.37, 2.24, 2.19 (s, 9H, Me₂C₆H₃+ p-

C₆H₄Me). ¹³C{¹H} (CDCl₃, 293 K): d 310.1 (l-C), 235.2

(l-CO), 201.9 (CO), 148.0 (C-ipso Xyl), 133.8, 133.1,

132.8 (C-Me Xyl + Tol), 130.8–127.8 (CH Xyl + Tol),

107.2, 98.5 (C„C), 89.0, 87.7 (Cp), 50.8 (NMe), 21.2 (p-

C₆H₄Me), 18.3, 17.4 (Me₂C₆H₃).

20: Yield: 42.0 mg (68%). Anal. Calc. for C₂₆H₂₉NO₂-

Ru₂Si: C, 50.55; H, 4.73, N, 2.27. Found: C, 51.05; H, 4.89,

N, 2.42. IR (CH₂Cl₂, 293 K): m (cm^ꢀ1) 2022s (C„C),

1

1969vs, 1798s (CO), 1547ms (C@N). H NMR (CDCl₃,

1738vs (CO), 1540m (CN). H NMR (CDCl₃, 293 K): d

293 K) Isomer a: d 7.30–7.50 (m, 5H, Ph), 5.49, 5.34 (d,

²J_HH= 14.8 Hz, 2H, CH₂Ph), 5.23, 5.16 (s, 10H, Cp),

3.73 (s, 3H, N-Me), ꢀ0.07 (s, 9H, SiMe₃); Isomer b: d

7.66–7.00 (m, 5H, Ph), 5.25, 4.86 (s, 10H, Cp), 5.04, 4.69

2

(d, J_HH= 14.8 Hz, 2H, CH₂Ph), 3.37 (s, 3H, C_c-Me),

2.35 (s, 6H, N-Me). ¹³C{¹H} (CDCl₃, 293 K): d 251.3 (l-

CO), 231.3 (C_a-N), 204.6 (CO), 157.5 (C_c), 134.8 (C-ipso

Ph), 129.6, 129.0, 128.5 (CH Ph), 89.0, 87.8 (Cp), 66.1

(CH₂), 64.9 (C_b), 46.5 (C_c-Me), 38.6 (N-Me).

2

7.30–7.50 (m, 5H, Ph), 5.95, 5.55 (d, J_HH= 15.4 Hz, 2H,

CH₂Ph), 5.25, 5.10 (s, 10H, Cp), 3.67 (s, 3H, N-Me),

ꢀ0.05 (s, 9H, SiMe₃). Isomer ratio a/b = 1.7. ¹³C{¹H}

(CDCl₃, 293 K) Isomer a: d 308.9 (l-C), 239.8 (l-CO),

201.5 (CO), 134.9 (C-ipso Ph), 129.1, 128.2, 127.0 (CH

Ph), 111.7, 94.1 (C„C), 89.1, 87.8 (Cp), 69.4 (CH₂Ph),

47.5 (NMe), 1.6 (SiMe₃); Isomer b: d 307.2 (l-C), 235.5

(l-CO), 201.4 (CO), 135.5 (C-ipso Ph), 129.1, 128.0,

127.3 (CH Ph), 111.9, 94.4 (C„C), 90.0, 87.9 (Cp), 68.3

(CH₂Ph), 49.4 (NMe), 1.5 (SiMe₃).

4.17. X-ray structural determinations

Compounds 2a[CF₃SO₃] Æ 0.5CH₂Cl₂and 12a[CF₃SO₃]

were crystallised from CH₂Cl₂/Et₂O, whereas compound

22 was crystallised from CH₂Cl₂/pentane. Crystal data were

collected at room temperature on a Bruker AXS SMART

2000 CCD diﬀractometer using Mo Ka radiation. Intensity

data were measured over full diﬀraction spheres using 0.3ꢁ

wide x scans, crystal-to-detector distance 5.2 cm. Cell

dimensions and orientation matrixes were initially deter-

mined from least-squares reﬁnements on reﬂections mea-

sured in 3 sets of 20 exposures collected in three diﬀerent

x regions and eventually reﬁned against all reﬂections.

The software ^SMART[18] was used for collecting frames of

data, indexing reﬂections and determinations of lattice

parameters. The collected frames were then processed for

integration by the software ^SAINTand empirical absorption

corrections were applied with ^SADABS[19]. The structure was

solved by direct methods and reﬁned by full-matrix least-

squares based on all data using F²[20]. Crystal data are

listed in Table 4. Non-H atoms were reﬁned anisotropically,

unless otherwise stated. H-atoms were placed in calculated

positions, except positions of H(14) in 2a[CF₃SO₃] Æ

0.5CH₂Cl₂and H(14), H(16A), H(16B) in 22 which were

located in the Fourier map and reﬁned isotropically with

thermal parameter 20% greater than that of the attached

21: Yield: 39.0 mg (68%). Anal. Calc. for C₂₅H₂₅-

NO₂Ru₂: C, 53.35; H, 4.39; N, 2.44. Found: C, 57.22; H,

4.62, N, 2.09. IR (in DCM, 293 K) m (cm^ꢀ1): 2123w

1

(C„C), 1962vs (CO), 1792s (l-CO), 1516ms (C@N). H

NMR (CDCl₃, 293 K): d 7.11 (m, 3H, Xyl), 5.18, 4.74 (s,

10H, Cp), 3.99 (s, 3H, N-Me), 2.32, 2.23 (s, 6H, Me₂C₆H₃),

1.65 (s, 3H, Me). ¹³C{¹H} (CDCl₃, 293 K): d 310.7 (l-C),

236.4 (l-CO), 202.8 (CO), 148.3 (C-ipso Xyl), 133.9,

133.2 (C-Me Xyl), 129.9, 128.3, 128.1 (CH Xyl), 99.4,

84.6 (C„C), 88.8, 87.9 (Cp), 51.0 (NMe), 18.5, 17.2

(Me₂C₆H₃), 6.3 (Me).

4.15. Synthesis of [Ru₂{l-g³:g¹-C[N(Me)(Xyl)]C(H)C@

CH₂}(l-CO)(CO)(Cp₂)] (22)

Complex 21 (100.0 mg, 0.174 mmol) was dissolved in

CH₂Cl₂(5 mL) and transferred on top of a Al₂O₃column.

Product 22 was obtained as an orange fraction using

CH₂Cl₂as eluent. Yield: 54.2 mg (54%). Anal. Calc. for

C₂₅H₂₅NO₂Ru₂: C, 52.35; H, 4.39, N, 2.44. Found: C,

52.68; H, 4.11, N, 2.15. IR (in CH₂Cl₂293 K) m (cm^ꢀ1):

carbon. One Cp ligand, the CF₃SO^ꢀanion and the CH₂Cl₂

3

1

1953vs (CO), 1769s (l-CO). H NMR (CDCl₃, 293 K): d

molecule in 2a[CF₃SO₃] Æ 0.5CH₂Cl₂, one Cp ligand in

12a[CF₃SO₃] and the two Cp ligands in 22 are disordered.

Disordered atomic positions were split and reﬁned isotrop-

ically using similar distance and similar U restraints and one

occupancy parameter per disordered group.

7.14–7.08 (m, 3H, Xyl), 5.22, 4.92 (br, 2H, CH₂), 5.48,

5.06 (s, 10H, Cp), 3.72 (s, 1H, C_b-H), 3.27 (s, 3H, N-Me),

2.67, 2.56 (s, 6H, Me₂C₆H₃). ¹³C{¹H} (CDCl₃, 298 K): d

243.0 (l-CO), 203.1 (CO), 187.6 (C_c), 165.7 (C_a), 149.6

2438

L. Busetto et al. / Journal of Organometallic Chemistry 691 (2006) 2424–2439

Table 4

Crystal data and experimental details for 2a[CF₃SO₃] Æ 0.5CH₂Cl₂, 12a[CF₃SO₃] and 22

Complex

Formula

F_w

2a[CF₃SO₃] Æ 0.5CH₂Cl₂

C_28.5H₃₃ClF₃NO₅Ru₂SSi

824.30

12a[CF₃SO₃]

C₂₉H₃₂F₃NO₅Ru₂S

765.76

22

C₂₅H₂₅NO₂Ru₂

573.60

T (K)

k, A

Crystal system

293(2)

0.71073

293(2)

0.71073

Triclinic

293(2)

˚

0.71073

Monoclinic

P2₁/n

8.7520(18)

15.631(3)

16.007(3)

90

91.42(3)

90

2189.1(8)

4

Monoclinic

P2₁/c

10.839(2)

17.836(4)

17.527(4)

90

103.76(3)

90

3290.9(11)

4

ꢀ

Space group

P1

˚

a (A)

8.2832(17)

12.695(3)

15.101(3)

105.87(3)

102.36(3)

90.72(3)

1487.8(5)

2

˚

b (A)

˚

c (A)

a (ꢁ)

b (ꢁ)

c (ꢁ)

3

˚

Cell volume (A )

Z

D_c(g cm^ꢀ3

)

1.664

1.153

1652

1.709

1.143

768

1.740

1.401

1144

l (mm^ꢀ1

F(000)

)

Crystal size (mm)

h Limits (ꢁ)

Reﬂections collected

Independent reﬂections [R_int

Data/restraints/parameters

Goodness on ﬁt on F²

R₁(I > 2r(I))

0.26 · 0.21 · 0.14

1.65–25.03

28655

5810 [0.0637]

5810/100/391

1.042

0.33 · 0.25 · 0.13

1.44–25.03

13197

5241 [0.0696]

5241/38/371

0.987

0.23 · 0.16 · 0.12

1.82–27.10

23022

4824 [0.0562]

4824/127/275

1.027

]

0.0527

0.0584

0.0357

wR₂(all data)

Largest diﬀ. peak and hole (e A

0.1500

0.809/ꢀ0.946

0.1614

1.154/ꢀ0.826

0.0932

0.786/ꢀ0.537

ꢀ3

˚

)

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Acknowledgements

`

We thank the Ministero dell’Universita e della Ricerca

Scientiﬁca e Tecnologica (MIUR) (project: ‘‘New strategies

for the control of reactions: interactions of molecular frag-

ments with metallic sites in unconventional species’’) and

the University of Bologna (‘‘Funds for Selected Research

Topics’’) for ﬁnancial support.

Appendix A. Supplementary material

[3] C.P. Casey, L.K. Woo, P.J. Fagan, R.E. Palermo, B.R. Adams,

Organometallics 6 (1987) 447.

[4] (a) V.G. Albano, L. Busetto, F. Marchetti, M. Monari, S. Zacchini,

V. Zanotti, Organometallics 23 (2004) 3348;

(b) V.G. Albano, L. Busetto, F. Marchetti, M. Monari, S. Zacchini,

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[5] L. Busetto, F. Marchetti, S. Zacchini, V. Zanotti, Organometallics 24

(2005) 2297.

Crystallographic data for the structural analyses have

been deposited with the Cambridge Crystallographic

Data Centre, CCDC Nos. 292588 for 2a[CF₃SO₃] Æ

0.5CH₂Cl₂, 292589 for 22, 292590 for 12a[CF₃SO₃]. Cop-

ies of this information can be obtained free of charge

from the Director, CCDC, 12 Union Road, Cambridge,

CB2 1EZ, UK (fax: +44 1233 336033; e-mail: deposit@

ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk). Supple-

mentary data associated with this article can be found,

in the online version, at doi:10.1016/j.jorganchem.2006.

01.020.

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New diruthenium vinyliminium complexes from the insertion of alkynes into bridging aminocarbynes

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