Study of the reactivity of palladacycles containing [C(sp2, ferrocene),N,S]- or [C(sp3),N,S]- terdentate ligands with symmetric alkynes

Journal of Organometallic Chemistry 690 (2005) 228–243

www.elsevier.com/locate/jorganchem

Study of the reactivity of palladacycles containing

[C(sp², ferrocene),N,S]^ꢀor [C(sp³),N,S]^ꢀterdentate ligands

with symmetric alkynes

a,

Concepcion Lopez , Sonia Perez , Xavier Solans , Merce Font-Bardıa

a

b

*

´

`

´

a

´

Departament de Quimica Inorganica, Facultat de Quımica, Universitat de Barcelona, Martı i Franques 1-11, 08028-Barcelona, Spain

`

´

`

Departament de Cristal.lograﬁa, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, 08028-Barcelona, Spain

b

Received 21 June 2004; accepted 10 September 2004

Available online 14 October 2004

Abstract

The study of the reactivity of the cyclopalladated complex [Pd{[(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}Cl] (1c) with the

alkynes R¹–C„C–R¹(with R¹= CO₂Me, Ph or Et) is reported.Compound 1c reacts with the equimolar amount of MeO₂C–C„C–

CO₂Me in reﬂuxing CH₂Cl₂to give [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}Cl] (2c), which

arises from the monoinsertion of the alkyne into the r[Pd–C(sp², ferrocene)] bond. However, when the reaction was performed using

Ph–C„C–Ph or Et–C„C–Et no evidence of the insertion of these alkynes into the r[Pd–C(sp², ferrocene)] bond was detected.In

contrast with these results, when 1c was treated with the Tl[BF₄] followed by the removal of the TlCl formed and the subsequent

addition of MeO₂C–C„C–CO₂Me the reaction gave 2c and [Pd{[(MeO₂C–C@C–CO₂Me)₂(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]-

Fe(g⁵-C₅H₅)}][BF₄] (3c); but when the alkyne was R¹–C„C–R¹(with R¹= Ph or Et), the ionic palladacycles [Pd{[(R¹–C@C–

R¹)₂(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}][BF₄] Æ CH₂Cl₂[with R¹= Ph (5c) or Et (6c)] were isolated. In compounds

3c, 5c and 6c, the mode of binding of the butadienyl unit is g³. The reactions of 2c, 3c, 5c and 6c with PPh₃are also reported.

The results obtained from these studies reveal that the r(Pd–S) bond in 2c is more prone to cleave than in 4c–6c. X-ray crystal struc-

tures of 2c, 5c and [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}Cl(PPh₃)] (7c), are also described.

Compound 7c arises from 2c by cleavage of the Pd–S bond and the incorporation of a PPh₃in the coordination sphere of the pal-

ladium. A parallel study focused on the reactions of [Pd{[2-CH₂–4,6-Me₂–C₆H₂]–CH@N–(C₆H₄–2-SMe)}Cl] (1d) (with a

[Csp³,N,S]^ꢀterdentate group) with the three alkynes reveals that the rPd–C(sp², ferrocene)] bond of 1c is more reactive than the

r[Pd–C(sp³)] bond of 1d.

Keywords: Alkyne insertions; Palladacycles; Ferrocene

1. Introduction

Some examples showing the utility of compounds of this

kind in homogeneous catalysis [2a,4], as building blocks

for the synthesis of macromolecules [5], for the determi-

nation of enantiomeric excesses of chiral reagents or

even as chiral recognition agents have been described

[6,7]. Besides that, it is well known that palladacycles

are useful precursors in the synthesis of organic or

organometallic compounds [10–12]. Most of these reac-

tions involve the insertions of small molecules, i.e. alky-

nes, alkenes, CO or isonitriles into the r(Pd–C) bond.

An important area of organometallic chemistry is

that focused on cyclopalladated complexes [1]. Interest

in such compounds has increased exponentially due to

either their physical and/or chemical properties or their

potential applications in a wide variety of areas [2–12].

*

Corresponding author. Tel.: +34934021274; fax: +34934907725.

´

E-mail address: conchi.lopez@qi.ub.es (C. Lopez).

doi:10.1016/j.jorganchem.2004.09.017

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

229

Previous studies on this ﬁeld have shown that the nature

2. Results and discussion

of the ﬁnal product formed by the insertion of alkynes

depends on a wide variety of factors including the nature

of the metallated carbon, the electron-withdrawing/elec-

tron–donor nature of the substituents on the alkyne, the

stoichiometry of the reaction, the remaining ligands

bound to the palladium, etc. [10].

Despite the wide variety of cyclopalladated com-

plexes containing a [C(sp², aryl),N,X]^ꢀor [C(sp³),N,X]^ꢀ

(X = N⁰, S, or O) terdentate group reported so far

[13–15], related derivatives with a r[Pd–C(sp², ferro-

cene)] bond are not so common [16–18]. Most of the

articles published so far refer to compounds [Pd{[(g⁵-

C₅H₃)–CH@N–(CH₂)_n–CH₂–NMe₂]Fe(g⁵-C₅H₅)}Cl]

[with n = 1 (1a) or 2 (1b)] [16] (Chart 1). We have re-

cently reported the syntheses and characterisation of

[Pd{[(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}Cl]

(1c) (Chart 1), which contains a [C(sp², ferrocene),N,S]^ꢀ

terdentate ligand [18].

2.1. Insertion of the alkynes into the r[Pd–C(sp²,

ferrocene)] bond

In a ﬁrst attempt to study the reactivity of 1c with the

alkynes R¹–C„C–R¹(with R¹= CO₂Me, Ph or Et), we

decided to use the most common procedure described in

the literature for mono-, bis- or tris-insertions of alky-

nes, into the r(Pd–C) bond, which consists on the treat-

ment of mono- or dimeric cyclopalladated complexes

with the alkynes (in a alkyne: Pd(II) molar ratio = 1, 2

or 3) in reﬂuxing CH₂Cl₂or CHCl₃[10,12,19].

The treatment of 1c with the equimolar amount of

MeO₂C–C„C–CO₂Me in reﬂuxing CH₂Cl₂for 2 h lead

after work up a deep red solid which was identiﬁed (see

Section 3) as [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–

CH@N–(C₆H₄-2-SMe)]Fe(g⁵-C₅H₅)}Cl] (2c) (Scheme

1) which arises from the insertion of one molecule of

the alkyne into the r[Pd–C(sp², ferrocene)] bond.

However, articles focused on the reactivity of the

r[Pd–C(sp², ferrocene)] bond of palladacycles holding

a [C(sp², ferrocene),N,X]^ꢀterdentate ligand are practi-

cally restricted to reactions of 1a and 1b with the inter-

nal alkynes: R¹–C„C–R¹(with R¹= CO₂Me, Ph or Et)

[19]. In the view of these facts, we were prompted to

study the reactivity of the r[Pd–C(sp², ferrocene)] bond

of 1c and the r[Pd–C(sp³)] bond of [Pd(2-CH₂–4,6-Me₂–

C₆H₂)–CH@N–(C₆H₄–2-SMe)]Cl] (1d) (Chart 1) [14e]

versus the alkynes: R¹–C„C–R¹(with R¹= CO₂Me,

Ph or Et). This type of study could be useful to elucidate

the relative inﬂuence of: (a) the type of metallated car-

bon [C(sp², ferrocene) (in 1c) or C(sp³) (in 1d)], (b) the

substituents on the alkyne (their electron-donor/elec-

tron-withdrawing nature or bulk [20]). The comparison

of the results obtained from these studies and those re-

ported recently for 1a and 1b [19], may also allow to

clarify the relevancy of the electronic properties of the

terminal X group of the [C,N,X]^ꢀ[X = N⁰(in 1a and

1b) or S (in 1c and 1d)] terdentate ligands upon the labil-

ity of the r(Pd–C) bond and the nature of the ﬁnal

product.

The molecular structure of 2c (Fig. 1) consists of dis-

crete molecules of [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-

C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}Cl] sepa-

rated by van der Waals distances. In each molecule,

the palladium(II) is bound to the chlorine, the two

heteroatoms (N and S) of the ligand and the terminal

carbon of the alkene [C(19)] in a highly distorted

square-planar environment [21]. The Pd–N and Pd–

˚

C(19) bond lengths [2.030(8) and 1.985(5) A] do not dif-

fer substantially from those reported for 1c [2.020(3) and

˚

1.978(5) A, respectively] [18], but the Pd–Cl and Pd–S

˚

bond lengths [2.318(5) and 2.390(6) A] are longer than

˚

in 1c [2.2851(14) and 2.3652(11) A]. The N–Pd–S and

Cl–Pd–S bond angles in 2c [82.55(12)ꢁ and 94.23(12)ꢁ,

respectively] are smaller than in 1c [N–Pd–S: 84.72(8)ꢁ

and Cl–Pd–S: 98.83(6)ꢁ] [18]. This may be related to

the larger bulk of the (C,N)^ꢀmoiety of the chelating

group in 2c when compared with that of 1c.

The molecule contains a [5,7,5,6] tetracyclic system

which arises from the fusion of the 1,2-disubstituted pen-

tagonal ring of the ferrocenyl moiety, a seven-membered

H

Me

C

N

n

C

N

SMe

Pd

Cl

NMe₂

SMe

Pd

CH₂

Me

Fe

Cl

Fe

Cl

(1d)

(1c)

n = 1 (1a) or 2 (1b)

Chart 1.

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C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

230

5'

4'

6'

1'

4'

3'

H

1'

H

2'

C

N

C

N

5

2'

1

5

SMe

Pd

α

SMe

4

Pd

Cl

4

2

Cl

2

3

β

R¹

i)

Fe

(1c)

R¹= CO₂Me (2c)

Scheme 1. (i) Equimolar amount of the alkyne in reﬂuxing CH₂Cl₂,

˚

length [1.323(7) A] is a bit larger than those reported for

the free ligand [average value for the two non-equivalent

˚

molecules: 1.268(4) A] or for 1c [1.296(4) A] [18].

The ﬁve-membered chelate ring has an envelope-like

conformation in which the palladium(II) deviates by

˚

ca. 0.9147 A (towards the opposite direction of the iron)

from the plane deﬁned by the atoms N, C(12), C(17) and

S [23].

The phenyl ring is planar [24] and its mean plane

forms angles of 142.0ꢁ and 135.0ꢁ with the imine moiety

and the coordination plane of the molecule, respectively.

The results obtained from the reaction of 1c with

MeO₂C–C„C–CO₂Me are similar to those reported

for 1a and 1b, which also underwent the insertion of

one molecule of MeO₂C–C„C–CO₂Me to give

[Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(CH₂)_n-

(CH₂)–NMe₂]Fe(g⁵-C₅H₅)}Cl] [with n = 1 (2a) or 2 (2b)]

(Chart 2), under identical experimental conditions [19].

In order to elucidate the relative importance of the

nature of the sulphur atom (in 1c) or the amine nitrogen

(in 1a) as well as the backbone holding the two hetero-

atoms [N,N⁰(in 1a) or N,S (in 1c)] upon the structures

of the palladacycles arising from the monoinsertion of

the MeO₂C–C„C–CO₂Me into the r[Pd–C(sp², ferro-

cene)] bond of 1a or 1c, we decided to crystallize

[Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(CH₂)₂–

NMe₂]Fe(g⁵-C₅H₅)}Cl] [19] (2a) (Chart 2) and to solve

Fig. 1. Molecular structure and atom labelling scheme for

[Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵–

C₅H₅)}Cl] (2c). Hydrogen atoms have been omitted for clarity.

˚

[Selected bond lengths (in A) and angles (in ꢁ): Pd–N, 2.030(8); Pd–

S, 2.390(6); Pd–Cl, 2.318(5); Pd–C(19), 1.985(7); C(10)–C(11), 1.452(5);

C(11)–N, 1.323(7); S–C(17), 1.759(6); S–C(18), 1.827(9); C(6)–C(20),

1.483(8); C(19)–C(20), 1.344(6), C(20)–C(21), 1.511(7); C(19)–C(23),

1.482(10); Cl–Pd–S, 94.23(12); S–Pd–N, 82.55(12); N–Pd–C(19),

94.3(2); C(10)–C(11)–N, 123.9(2); C(11)–N–C(12), 117.1(6); C(19)–

Pd–Cl, 90.0(2); C(6)–C(20)–C(19), 125.3(4) and C(20)–C(19)–Pd,

128.4(4)].

palladacycle, a ﬁve-membered chelate ring formed by the

binding of the nitrogen and sulphur to the palladium and

the phenyl ring. The seven-membered palladacycle,

which is formed by the set of atoms: Pd, N, C(6),

C(10), C(11), C(20) and C(19), is not planar. The value

of the torsion angle deﬁned by the atoms C(21)–C(20)–

C(19) and C(23) [ꢀ0.21ꢁ] indicates that the two substitu-

ents on the alkene are in a cis-arrangement. This is

the typical distribution of the substituents found for pal-

ladium(II) compounds arising from the monoinsertion of

alkynes into the r(Pd–C) bond of palladacycles

[11a,b,22].

H

n

C

N

NMe₂

Pd

R¹

Cl

R¹

Fe

The >C@N– functional group is contained in the

seven-membered metallacycle (endocyclic) and forms

an angle of 30.1ꢁ with the C₅H₃ring. The >C@N– bond

n = 1 (2a) or 2 (2b)

Chart 2.

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C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

231

its X-ray crystal structure. The molecular structure of 2a

consists of a 1:1 mixture of: [Pd{[(MeO₂C–C@C–CO_2-

Me)(g⁵-C₅H₃)–CH@N–(CH₂)₂–NMe₂]Fe(g⁵-C₅H₅)}Cl]

(2a) and CH₂Cl₂molecules.

In a ﬁrst attempt to achieve the preparation of the

product arising from the bis(insertion) of the alkyne into

the r[Pd–C(sp², ferrocene)] of 1c, we decided to perform

two diﬀerent experiments, which consisted on: (a) the

reaction of 1c and the alkyne in a 1:2 molar ratio or

(b) the treatment of 2c with the stoichiometric amount

of and MeO₂C–C„C–CO₂Me in reﬂuxing CH₂Cl₂for

varying periods (from 2 h to 3 days). However, in the

two cases only 2c was isolated and no evidence of traces

of any other palladium(II) complex were detected by

NMR. Thus indicating that 2c is not prone to undergo

the insertion of an additional molecule of the alkyne.

When 1c or 1d were treated separately with diphenyl-

acetylene or hex-3-yne [in a alkyne: (1c or 1d) molar ra-

tios = 2 or 1] in reﬂuxing CH₂Cl₂(or CHCl₃) for varying

reaction periods (from 2 h to 2 days), the corresponding

starting materials (1c or 1d) were recovered unchanged

and no evidence of any chemical change was detected

by NMR. These results reveal that 1a, 1b and 1c are

more prone to undergo the insertion of MeO₂C–

C„C–CO₂Me than [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-

C₅H₃)–CH@N–(CH₂)_n–CH₂–NMe₂]Fe(g⁵-C₅H₅)}Cl]

[n = 1 (2a) or 2 (2b)] [19] and 2c (see Scheme 3).

In the heterodimetallic array (Fig. 2) the palla-

dium(II) is bound to the N(1) and N(2) atoms of the

ferrocenyl ligand, a chloride [Cl(1)] and the C(17) car-

bon of the alkene in a distorted square-planar environ-

ment [25]. The N(1)–Pd–N(2) and Cl–Pd–N(2) bond

angles [81.19(17)ꢁ and 93.35(13)ꢁ] are smaller than in

1a [82.59(18)ꢁ and 100.40(14)ꢁ, respectively] [16a].

The molecule has a [5,7,5] tricyclic system formed by

a ﬁve-membered chelate ring, a seven-membered metall-

acycle and the 1,2-disubstituted pentagonal ring of the

ferrocenyl moiety. The ﬁve-membered chelate ring has

an envelope-like conformation in which the C(13) atom

5

˚

deviates ca. 0.463 A [towards the ‘‘Fe(g -C₅H₅)’’ unit]

from the plane deﬁned by the remaining atoms [26].

The seven-membered metallacycle contains the imine

group and the >C@C< double bond. The two substitu-

ents on the alkene moiety are in a cis-arrangement as

reﬂected in the value of the torsion angle C(18)–C(17)–

C(16)–C(20) [2.21ꢁ].

In contrast with the results obtained for 1a, 1b and

1c, when the reaction was performed under identical

experimental conditions using 1d as starting material,

no evidences of any chemical change were detected, even

when the reﬂuxing period was increased up to ﬁve days.

This ﬁnding suggests that in 1d the r(Pd–C) bond is less

reactive than in 1c.

Previous studies based on the insertion of alkynes

into the r[Pd–C(sp², aryl)] bond of cyclopalladated

derivatives have shown that the ﬁrst step of the process

involves the coordination of the alkyne to the palladium

in a cis-arrangement of the metallated carbon atom

[11i]. On this basis, the smaller proclivity of 2a, 2b and

2c to undergo the insertion of one molecule of MeO₂C–

C„C–CO₂Me when compared with that of 1a, 1b and

1c could be related to the diﬀerent lability of the Pd–

Cl bond. To check this hypothesis we decided to eluci-

date whether the removal of the chlorine in 2c, upon

the addition of thallium(I) salts could enhance its reac-

tivity versus MeO₂C–C„C–CO₂Me [27]. With this

aim and as a ﬁrst approach to the problem, 2c was trea-

ted in acetone with a 50% excess of Tl[BF₄] at ca. 20 ꢁC

for 2 h. During this period the precipitation of TlCl was

observed. The subsequent removal of the TlCl and the

excess of Tl[BF₄] (see Section 3) followed by the treat-

ment of the residue with CH₂Cl₂and the equimolar

amount of the alkyne under reﬂux for 2 h lead (after

concentration to dryness of the resulting deep-purple

solution) a solid which was identiﬁed as [Pd{[(MeO₂-

C–C@C–CO₂Me)₂(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]-

Fe(g⁵-C₅H₅)]} [BF₄] (3c) [Scheme 2, step (a)]. Compound

3c arises from the insertion of one molecule of MeO₂C–

C„C–C–O₂Me into the r(Pd–C) bond of 2c, and

contains a g³-butadienyl unit attached to the 1,2-disubsti-

tuted pentagonal ring of the ferrocenyl moiety.

Fig. 2. Molecular structure and atom labeling scheme for com-

pound[Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(CH₂)₂–NMe₂

]Fe(g⁵-C₅H₅)}Cl] Æ CH₂Cl₂(2a). The CH₂Cl₂molecule and the hydro-

˚

gen atoms have been omitted for clarity. [Selected bond lengths (in A)

and angles (in ꢁ): Pd–C(17), 1993(5); Pd–N(1), 2.008(5); Pd–N(2),

2.187(4); Pd–Cl, 2.322(3); N(1)–C(11), 1.277(6); N(1)–C(12), 1.467(6);

N(2)–C(14), 1.475(7); N(2)–C(15), 1.482(7); C(6)–C(16),1.471(7);

C(16)–C(17), 1.345(7); C(16)–C(20), 1.510(7); C(17)–C(18), 1.484(8);

C(17)–Pd–N(1), 94.94(18); N(1)–Pd–N(2), 81.19(17); C(17)–Pd–Cl,

90.69(15); N(2)–Pd–Cl, 93.35(13), C(10)–C(11)–N(1) 126.0(5); C(11)–

N(1)–C(12) 118.9(4); C(6)–C(16)–C(17), 107.6(4) and C(16)–C(17)–Pd,

129.7(4)].

The infrared spectrum of 3c showed: a sharp and in-

tense band at 1618 cm^ꢀ1, which is assigned to the

stretching of the >C@N– group, the absorptions due

to the –CO₂functional groups and the characteristic

bands of the [BF₄]^ꢀanion [28]. The molar conductivity

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

232

5'

4'

6'

3'

1'

H

2'

C

N

1

5

1

SMe

2

R¹

4

2

[BF₄]

Pd

α

Pd

4

β

γ

α

3

Cl

3

(a)

R¹

Fe

δ

β

i), ii),iii)

R¹

R¹= CO₂Me (2c)

R¹= CO₂Me (3c)

iii), v)

(4c)

iv), ii)

(b)

5'

6'

4'

H

1'

3'

C

N

2'

5

1

SMe

4

Pd

Cl

2

3

Fe

(1c)

Scheme 2. (i) Tl[BF₄] in acetone (molar ratio Tl(I)/2c = 1.5) at room temperature, (ii) followed by the removal of the TlCl formed and the unreacted

Tl[BF₄] using CH₂Cl₂, followed by the subsequent evaporation to dryness. (iii) Addition of the equimolar amount of the alkyne in reﬂuxing CH₂Cl₂

for 2 h. (iv) Tl[BF₄] in acetone (molar ratio Tl(I)/1c = 1.5) at room temperature. (v) SiO_2ꢀcolumn chromatography (see text).

of

a

10^ꢀ3

M

solution of 3c in acetone [112

(Chart 3) in which the two substituents of the alkene

closest to the ferrocenyl unit are in a trans-arrangement,

while the remaining two CO₂Me groups are in a cis-

disposition.

X^ꢀ1cm²mol^ꢀ1] was consistent with the value expected

for a 1:1 electrolyte [29]. The most relevant features ob-

served in the ¹H NMR spectrum of 3c is the presence of

four singlets at d = 3.71, 3.75, 3.94 and 4.01 ppm. In the

HSQC spectrum these four signals showed cross-peaks

with the resonances at d = 53.0, 53.6, 54.8 and 55.1

ppm observed in the ¹³C{¹H} NMR spectrum. The sig-

nals due to the four types of carbon nuclei of the buta-

dienyl unit {C^a–C^d} appeared at d = 118.9, 134.9, 135.6

and 149.5 ppm and exhibited low intensity. All these

ﬁndings are similar to those reported for [Pd

{[(MeO₂C–C@C–CO₂Me)₂(g⁵-C₅H₃)–CH@N–(CH₂)_n-

(CH₂)–NMe₂]Fe(g⁵-C₅H₅)]}[BF₄] (with n = 1 or 2) [19]

In contrast with the results obtained in the reaction of

2c with MeO₂C–C„C–CO₂Me, when 1c was treated

with a 50% excess of Tl[BF₄], followed by the removal

of the thallium(I) salts, the subsequent concentration

of the ﬁltrate to dryness produced a deep-blue (nearly

black) solid (here in after referred to as 4c). The subse-

quent treatment of a CH₂Cl₂solution of this material

with MeO₂C–C„C–CO₂Me (in a 1c: alkyne molar ratio

1:2) under reﬂux for 1 h, lead to a mixture of two com-

pounds [Scheme 2(b)], which could be isolated by SiO₂

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

233

5'

4'

6'

1'

4'

6'

H

3'

H

1'

C

N

2'

5

1

C

N

1

5

SMe

4

R¹

Pd

Cl

4

2

[BF₄]

Pd

3

2

γ

α

Fe

ii)

3

i)

R¹

4c

Fe

R¹

δ

β

R¹

R¹= Ph (5c) or Et (6c)

(1c)

Scheme 3. (i) Tl[BF₄] in acetone at room temperature for 4 h, followed by ﬁltration and concentration to dryness of the ﬁltrate. (ii) Treatment with

the alkyne (diphenylacetylene or hex-3-yne, in a alkyne: 1c molar ratio = 2) in reﬂuxing CH₂Cl₂for 2 h, followed by SiO₂column chromatography

(see text).

H

C

tical to those of the starting material 1c. The elution

with a CH₂Cl₂:MeOH (100:1) mixture produced the re-

lease of an additional band. The concentration of the

solution gave deep red solids. Their elemental analyses

were consistent with those expected for: [Pd{[(R¹–

C–C@C–R¹)₂(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-

C₅H₅)}[BF₄] Æ CH₂Cl₂[with R¹= Ph (5c), or Et (6c)].

Compounds 5c and 6c arise from the bis(insertion) of

the corresponding alkyne. The FAB⁺mass spectra of

5c and 6c showed a peak at m/z = 796 and 606, respec-

tively, which are consistent with the values expected

for the cationic arrays of these complexes. The infrared

spectra of 5c and 6c showed the typical bands of the

[BF₄]^ꢀanion [28], and a sharp and intense band at

1592 (for 5c) and 1602 (for 6c) cm^ꢀ1, assigned to the

imine group. Molar conductivity measurements of

n

N

R¹

NMe₂

R¹

Pd

Fe

R¹

R¹= CO₂Me

n = 1 (3a) or 2 (3b)

Chart 3.

column chromatography. Elution with CH₂Cl₂, fol-

lowed by concentration to dryness of the band collected

allowed us to isolate the minor component, whose char-

acterization data were identical to those of 2c; while the

subsequent elution with a mixture CH₂Cl₂:MeOH

(100:1) produced the release of an additional deep pur-

ple band, which was collected and concentrated to dry-

ness giving 3c. The molar ratio 3c:2c was 0.5, but when

the reﬂuxing period increased up to 2 h the amount of 2c

recovered decreased [molar ratio 3c:2c ꢁ 9].

10^ꢀ3

M solutions of 5c and 6c [105 and 110

X^ꢀ1cm²mol^ꢀ1, respectively] agreed with the values ex-

pected for 1:1 electrolytes [29].

The X-ray crystal structure of 5c consists of

equimolar amounts of the heterobimetallic cations

[Pd{[(PhC–C@C–Ph)₂(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]-

Fe(g⁵-C₅H₅)}]⁺, [BF₄]^ꢀanions and CH₂Cl₂. In the cat-

ion (Fig. 3), the palladium is bound to the nitrogen

and the sulphur atoms of the ferroceny ligand, to the

terminal carbon of the g³-butadienyl unit [C(21)] and

to the middle point of the segment deﬁned by the atoms

C(18) and C(19) (hereinafter referred to as v) in a

slightly distorted square-planar environment [30]. The

These ﬁndings agree with the results obtained from

the reaction of 2c with MeO₂C–C„C–CO₂Me in the

presence of Tl[BF₄], which also led 3c, and support the

hypothesis that the low lability of the Pd–Cl bond in

2c hinders the insertion of an additional molecule into

the r[Pd–C(sp², alkene)] bond of 2c to give 3c.

More interesting were the results obtained when this

reaction was repeated using diphenylacetylene or hex-

3-yne (molar ratio 1c: alkyne = 0.5) under identical

experimental conditions. In these cases, two diﬀerent

compounds could be isolated by SiO₂-column chroma-

tography. The elution with CH₂Cl₂allowed to isolate

a deep blue solid whose characterisation data was iden-

˚

Pd–N bond distance [2.138(2) A] is larger than that

˚

found for 1c [2.020(9) A] and for 2c [2.030(8) A]. The

˚

Pd–S bond length [2.3011(10) A] falls in the upper range

of the values reported for other palladium(II) thio-

˚

ether derivatives [from 2.24 to 2.31 A] [31] but it is

˚

shorter than in 1c [2.3653(11) A]. This may be attrib-

uted to the diﬀerent inﬂuence of the ligand in a trans-

arrangement [32].

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

234

˚

onal ring of the ferrocenyl unit (2.790 A) suggests the

existence of a CHꢂ ꢂ ꢂp interaction [34]. Besides that, in

the crystal the cationic arrays are associated through

C–Hꢂ ꢂ ꢂp interactions between the C(44)–H(44) bond

of the phenyl ring on the terminal carbon of the g³-buta-

dienyl unit and the aromatic ring deﬁned by the set of

atoms [C(34)–C(39)] of a close cation.

2.2. Attempts to clarify the nature of the intermediate

specie 4c

The results presented in the previous paragraphs re-

veal that reaction of 1c with MeO₂C–C„C–CO₂Me in

the presence of Tl[BF₄] with the alkyne lead to a mixture

of 2c and 3c, while when the reaction was performed un-

der identical experimental conditions but using R¹–

C„C–R¹(R¹= Ph or Et), the ﬁnal products were 5c

or 6c and a nearly invariant amount of the starting

material 1c was also recovered. These ﬁndings are simi-

lar to those obtained for a parallel study using 1a or 1b,

for which the formation of the dimeric compounds:

[Pd₂{[(g⁵-C₅H₃)–CH@N–(CH₂)_n–CH₂–NMe₂]Fe(g⁵-

C₅H₅)}₂Cl(acetone)][BF₄]} [with n = 1 (4a) or 2 (4b) 4b,

4(a)] has been postulated as intermediate species formed

after the treatment of 1a or 1b with Tl[BF₄]. In the view

of these ﬁndings, we were prompted to attempt the char-

acterization of the intermediate specie 4c [35].

Fig. 3. Molecular structure and atom labelling scheme of the cationic

array of [Pd{[(Ph–C@C–Ph)₂(g⁵-C₅H₃)–CH@N–(C₆H₄-2-SMe)]-

Fe(g⁵-C₅H₅)}] [BF₄] Æ CH₂Cl₂(5c). Hydrogen atoms have been omit-

˚

ted for clarity. [Selected bond lengths (in A) and angles (in ꢁ): Pd–N,

2.138(2); Pd–S, 2.3011(10); Pd–C(21), 2.006(3); Pd–C(19), 2.204(3);

Pd–C(18), 2.235(3); Pd–v 2.1049(3); S–C(17), 1.773(3); S–C(46),

1.810(5); C(10)–C(11), 1.426(5); C(11)–N, 1.287(4); C(6)–C(18),

1.489(4); C(18)–C(19), 1.409(4); C(19)–C(20), 1.509(4); C(20)–C(21),

1.330(5); N–Pd–S, 84.17(8); C(21)–Pd–N, 98.2(1), N–Pd–v, 170.9(1);

C(6)–C(10)–C(11), 130.4(3) and C(10)–C(11)–N, 125.7(3)].

Its infrared spectrum showed the bands due to the

1

[BF₄]^ꢀanion [28] but, its H and ¹³C¹H NMR spectra

were more complex than that initially expected for the

monomeric derivative: [Pd{[(g⁵-C₅H₃)-CH@N–(C₆H₄-

2- SMe)]Fe(g⁵-C₅H₅)}(acetone)][BF₄] which arises from

1c by abstraction of the Cl^ꢀanion and the coordination

of the solvent (acetone). In fact, six diﬀerent singlets due

to the protons and carbon-13 nuclei of the fragments –

CH@N–, –SMe and (g⁵-C₅H₅) (of relative intensities

The cationic array contains a [5,9,5,6] tetracyclic sys-

tem formed by the fusion of the substituted pentagonal

ring, a nine-membered metallacycle, a ﬁve-membered

chelate ring and the phenyl ring.

The >C@N– group is contained in the nine-mem-

bered metallacycle (endocyclic) and the >C@N– bond

1

˚

length [1.287(4) A] is a bit shorter than that found for

1:1:1:1:0.6:0.6) were detected in the H NMR spectrum.

˚

2c [1.323(7) A].

Elemental analyses of 4c were consistent with those

expected for: {[Pd₂{[(g⁵-C₅H₃)-CH@N–(C₆H₄-2-SMe)]-

Fe(g⁵-C₅H₅)}]₂Cl(acetone)][BF₄]}_nand its mass spec-

trum (MALDI-TOF⁺) showed a peak at m/z = 917,

which could be indicative of the presence of the cation:

[Pd{[(g⁵-C₅H₃)–CH@N–(C₆H₄-2-SMe)]Fe(g⁵-C₅H₅)}₂-

Cl(acetone)]⁺. These ﬁndings could suggest that the

intermediate specie 4c could have greater nuclearity.

On the basis of the characterization data available at

this moment [35], we tentatively postulate the formation

of the dimeric cations shown in Fig. 4(b). The higher

complexity of the ¹H and ¹³C NMR spectra of 4c, when

compared with those of 4a and 4b may be attributed to

the presence of the SMe group. The transformation of

1c into 4c involves the abstraction of the Cl^ꢀanion,

the cleavage of the Pd–S bonds of 1c and the formation

of two new Pd–S bonds to achieve the central 10-mem-

bered ring. Consequently, and due to the prochiral nat-

ure of the tioether group in this process, several isomeric

The phenyl rings on the double bond [C(18)–C(19)]

closest to the ferrocenyl unit are cis- to each other while

those on the C(20)–C(21) bond are trans-. This is the

most common distribution of substituents found in re-

lated palladacycles arising from bis(insertion) of alkynes

into the r(Pd–C) bond [11,12].The double bond deﬁned

by the C(18) and C(19) atoms is placed in the opposite

direction of the ‘‘Fe(g⁵-C₅H₅)’’ moiety and these two

carbon atoms are unsymmetrically bound to the palla-

dium(II), as reﬂected in the two Pd–C bond lengths

˚

[Pd–C(18): 2.235(3) A and Pd–C(19): 2.204(3) A].

The ﬁve-membered chelate ring formed by the atoms

Pd,N(1),C(12),C(17) and S has an envelope-like confor-

mation [33] where the palladium(II) deviates by ca.

5

˚

0.304 A {in the opposite direction of the ‘‘Fe(g -

C₅H₅)’’ moiety} from the mean plane.

In each cation the separation between the C(29)–

H(29) bond and the centroid of the substituted pentag-

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

235

H

C

H

Me

Cl

n

S

C

N

NMe₂

Pd

Fe

Cl

Fe

Pd

L

Fe

S

N

C

NMe₂

N

Fe

C

L

Me

H

n

H

(a)

(b)

Fig. 4. Schematic views of the cationic arrays of compounds {[{Pd[{(g⁵-C₅H₃)–CH@N–(CH₂)_n-CH₂–NMe₂}Fe(g⁵-C₅H₅)]}₂Cl(acetone)][BF₄] {n = 1

(4a) or 2 (4b)} (a) and [{Pd[{(g⁵-C₅H₃)–CH@N–(C₆H₄-2- SMe)}Fe(g⁵-C₅H₅)]}₂Cl(acetone)][BF₄] (4c) (b) (L = acetone).

species of 4c could be formed. These isomers may diﬀer

on: (a) the planar chirality of the two metallated frag-

ments, (b) the chirality of the two –SMe groups and even

(c) the relative arrangement of the terminal groups {Cl^ꢀ

and acetone} in the two halves of the molecule.

remaining two at lower energies were due to the –

COO moiety. The bands of the coordinated PPh₃ligand

were also detected [28,36].

The position of the signal due to the protons of the

NMe₂(in 7a) or the SMe (in 7c) groups observed in

1

the H-NMR spectra was very similar to those of the

2.3. Study of the reactivity of the seven- and nine-

membered palladacycles with PPh₃

corresponding free ligands. Thus suggesting that the

r(Pd–NMe₂) (in 2a) or the r(Pd–S) (in 2c) bond cleaved

during the formation of 7a and 7c, respectively. In both

cases the signal due to the imine proton appeared as a

doublet due to phosphorous coupling. ³¹P{¹H} NMR

spectra of 7 showed a singlet at d = 27.8 (for 7a) and

29.5 (for 7c) ppm suggested a cis-arrangement between

the phosphorous atom and the metallated carbon, due

to the so-called transphobia eﬀect [37] and the diﬀer-

ences observed in the positions of the these signals could

be related to the diﬀerent basicity of the imine nitrogen.

The crystal structure of 7c consists of equimolar

amounts of [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@

N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}Cl(PPh₃)] and CH₂Cl₂.

In each one of the dimetallic units (Fig. 5), the palla-

dium(II) is bound to the imine nitrogen of the Schiﬀ

base, a chlorine, the phosphorous of the PPh₃ligand

and the terminal carbon [C(22)] of the alkene in slightly

distorted square-planar environment [38]. The Pd–P

Some authors have reported that palladacycles aris-

ing from the mono- or bis(insertion) of alkynes into

the r(Pd–C) bond are also valuable precursors for the

synthesis of novel organic or organometallic derivatives

[1,10,12]. One of the most common strategies used to

achieve this aim consists of the treatment of the com-

plexes with phosphines (i.e., PPh₃), which promote the

depalladation process of the starting material [11k,11l].

In the view of this, we decided to study the reactivity

of 2a, 2c, 3c, 5c–6c with PPh₃.

The reaction of 2a or 2c with the stoichiometric

amount of PPh₃in CH₂Cl₂produced the cleavage of the

r(Pd–S) bond (of 2c) or the r[Pd–N(amine)] bond (of

2a) and the incorporation of a phosphine ligand in the

coordination sphere of the palladium(II), leading to

[Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(CH₂)₂–

2-NMe₂]Fe(g⁵-C₅H₅)}Cl(PPh₃)] (7a) and [Pd{[(MeO₂C–

C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(CH₂)₂–2-NMe₂]-

Fe(g⁵-C₅-H₅)}Cl(PPh₃)] (7c), respectively (Scheme 4).

When these reactions were performed with 3c, 5c or

6c using the same experimental conditions as for 2c,

no evidence of any chemical change was detected by

NMR. In fact, only the resonance due to the free PPh₃

ligand was observed in the ³¹P{¹H} NMR spectra. Thus

suggesting that 3c, 5c and 6c are less prone to react with

PPh₃than 2c. Compounds 7 were characterized by the

elemental analyses, mass spectrometry, infrared spectra

and mono and two dimensional NMR spectroscopy.

Elemental analyses (Section 3) agreed with those ex-

pected for 7a and 7c. Their IR spectra showed three

bands in the range 1600–1720 cm^ꢀ1, one of them was as-

signed to the stretching of the >C@N– group while the

˚

bond length [2.2579(8) A] falls in the range reported

for related palladium(II) compounds of the type

[Pd(C,N)Cl(PPh₃)], where (C,N) represents a cyclopalla-

dated imine [12g,12j,14b,16,39]. The Pd–N and Pd–Cl(1)

˚

bond distances [2.118(2) and 2.3962(8) A] are slightly

larger than those found for 1c [Pd–N: 2.020(3) and

˚

2.2851(14) A]. The PPh₃ligand and the imine nitrogen

are in a trans-arrangement as reﬂected in the P–Pd–N

bond angle [173.04(8)ꢁ].

Each molecule contains a [5,7,5,6] tetracyclic system

formed by the 1,2-disubstituted pentagonal ring of the

ferrocenyl unit a seven-membered palladacycle which

contains the >C@N– functional group, the ﬁve-mem-

bered chelate ring and the phenyl ring.

The value of the torsion angle: C(20)–C(19)–C(22)–

C(23) is 4.85ꢁ, indicating that the two identical

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

236

5'

4'

5'

4'

6'

1'

3'

1'

2'

H

2'

SMe

C

N

1

5

1

5

SMe

Cl

Pd

β

4

β

α

Cl

2

α

2

3

PPh₃

3

i)

R¹

Fe

R¹= CO₂Me (2c)

R¹= CO₂Me (7c)

H

C

H

NMe₂

N

C

N

5

1

NMe₂

Cl

5

Cl

1

Pd

4

β

α

4

β

2

α

2

i)

PPh₃

3

R¹

Fe

R¹= CO₂Me (2a)

Scheme 4. (i) PPh₃in CH₂Cl₂at room temperature.

R¹= CO₂Me (7a)

substituents (the –CO₂Me groups) on the alkene are in a

cis-disposition.

The aryl ring of the ferrocenyl ligand is planar [40]

and its main plane forms angles of 68.7ꢁ and 117.2ꢁ with

the imine moiety and the coordination plane of the pal-

ladium(II), respectively.

For the four structures presented here, bond lengths

and angles of the ‘‘(g⁵-C₅H₅)Fe(g⁵-C₅H₃)’’ fragment

are consistent with those found for most ferrocene deriv-

atives [41], and the two pentagonal rings are planar [42]

and nearly parallel [tilt angle: 1.1ꢁ (for 2a), 4.2ꢁ (for 2c),

7.9ꢁ (for 5c) and 3.5ꢁ (for 7c)] and they deviate by ca:

3.5ꢁ (in 2a), 10.4ꢁ (in 2c), 29.7ꢁ (in 5c) and 7.15ꢁ (in 7c)

from the ideal eclipsed conformation. In all cases the sep-

aration between the two metal atoms [5.1553, 5.1189,

Fig. 5. Molecular structure and atom labelling scheme for

[Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe

(g⁵-C₅H₅)}Cl(PPh₃)] Æ CH₂Cl₂(7c). The CH₂Cl₂molecule and the

hydrogen atoms have been omitted for clarity. [Selected bond lengths

˚

4.5033 and 4.9774 A for 2a, 2c, 5c and 7c, respectively]

are clearly greater than the sum of the van der Waals radii

[43] of these atoms, thus suggesting the absence of any

direct interaction between the Fe and the Pd.

˚

(in A) and angles (in ꢁ): Pd–N, 2.118(2); Pd–P, 2.2579(8); Pd–Cl(1),

2.3962(8); Pd–C(22), 1.999(3); C(10)–C(11) 1.439(4); C(11)–N,

1.280(4); S–C(17), 1.764(5); S–C(18), 1.717(9); C(9)–C(19), 1.471(4);

C(19)–C(20), 1.510(4); C(19)–C(22), 1.348(4); C(22)–Pd–N, 88.13(11);

P–Pd–C(22), 92.05(9); N–Pd–Cl, 90.18(7); P–Pd–Cl(1), 89.30(3); N–

C(12)–C(17), 119.4(3); N–C(11)–C(10), 123.2(3); C(11)–C(10)–C(9),

128.3(3); C(10)–C(9)–C(19), 127.7(3); C(9)–C(19)–C(22), 123.7(3);

C(19)–C(22)–Pd, 120.7(2) and C(17)–S–C(18), 104.2(4)]

2.4. Conclusions

The results presented here reveal that despite the dif-

ferent nature and hardness of the terminal X group

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

237

[X = N⁰(in 1a and 1b) or S in 1c] in a trans-arrangement

to the metallated carbon of palladacycles with a [C(sp²,

ferrocene),N,X]^ꢀgroup, the reactivity of 1a, 1b and 1c

with R¹–C„C–R¹(R¹= CO₂Me, Ph or Et) is alike.

In contrast with these ﬁndings the results obtained

for [Pd{[(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}-

Cl] (1c) and [Pd{(2-CH₂–4,6-Me₂–C₆H₂)–CH@N–

(C₆H₄–2-SMe)}Cl] (1d) [14e], with a mer-[C,N,S]^ꢀlig-

and, indicated that 1c is more prone to undergo the

insertion of the alkynes than 1d. The diﬀerences ob-

served in the reactivity of 1c and 1d may be ascribed

to the diﬀerent lability of the Pd–Cl bond and/or the

nature of the metallated carbon [a C(sp², ferrocene) in

1c or a C(sp³) in 1d]. The comparison of selected struc-

tural data for 1c and 1d (Table 1) [14e,18] shows that the

Pd–Cl and Pd–C bond lengths in 1d are larger than in

1c, and on this basis one would expect a greater lability

of these bonds in 1d. However, the experimental work

revealed that under identical experimental conditions

1c underwent the insertion of MeO₂C–C„C–CO₂Me,

while 1d was recovered unchanged. In the view of these

facts, other more subtle factors, such as the free space

available for the approach of the alkyne to the palla-

dium(II) may also play a crucial role in these reactions.

As can be easily seen in Table 1, the S–Pd–Cl and C–Pd–

Cl bond angles for 1c are greater than for 1d, thus indi-

cating that the environment of the palladium(II) is more

constrained in 1d than in 1c, and consequently, the ap-

proach of the bulky MeO₂C–C„C–CO₂Me, is expected

to be more diﬃcult in 1d than in 1c.

reactions of their derivatives arising from the mono-

or bis(insertion) of the three alkynes under study may

produce diﬀerent organic or organometallic compounds.

Studies on this area are currently on the way.

3. Experimental

3.1. Materials and methods

The alkynes: R¹–C„C–R¹(with R¹= CO₂Me, Ph or

Et), PPh₃and K[PF₆] were obtained from commercial

sources and used as received. Compounds 1a, 1c, 1d

and 2a were prepared as described previously

[16,18,19]. The solvents were dried and distilled before

use [44]. Some of the preparations described below re-

quire the use of the Highly hazardous materials Tl[BF₄]

which should be handled with Caution. Tl[BF₄] was syn-

thesized as reported before [45].

Elemental analyses (C, H, N and S) were carried out

`

at the Serveis de Recursos Cientiﬁcs i Tecnics (Univ. Ro-

vira i Virgili, Tarragona). Mass spectra MALDI-TOF⁺

for (4c) and FAB⁺for the remaining compounds were

performed at the Servei dꢀEspectrometria de Masses

(Univ. Barcelona) with a VOYAGER-DE-RP and

VG-Quatro instruments, respectively using 2-hydroxy-

benzoic acid [(DHB), for MALDI-TOF⁺and 3-nitro-

benzylalcohol [(NBA), for FAB⁺] as matrix. Molar

conductivity measurements of 10^ꢀ3M solutions of the

compounds in acetone were determined at 20 ꢁC with

a CRISON microMC2200 conductivity-meter. Infrared

spectra were obtained with a Nicolet 400FTIR instru-

On the other hand, and since it is well known that

palladacycles arising from the insertion of alkynes into

the r(Pd–C) bond are valuable precursors for the syn-

thesis of organic or organometallic products [10–12],

the new compounds presented in this work appear to

be excellent candidates to be studied in this ﬁeld. Despite

the similar reactivity of 1a, 1b and 1c versus the alkynes

R¹–C„C–R¹(R¹= CO₂Me, Et or Ph), depalladation

1

ment using KBr pellets. Routine H NMR spectra and

¹³C{¹H} spectra were obtained with a Gemini 200

MHz, a Bruker 250-DXR or a Mercury 400 MHz

1

instruments. High resolution H NMR spectra and the

1

two dimensional [¹H H NOESY and COSY and H

¹³C heteronuclear single quantum coherence (HSQC)

and the heteronuclear multiple bond coherence

(HMBC)] NMR experiments were recorded with either

a Varian VRX-500 or with a Bruker Advance DMX

500 instruments at 20 ꢁC. Except were quoted, the sol-

vent used for the NMR studies was CDCl₃(99.8%)

and SiMe₄was used as internal reference. ³¹P{¹H} spec-

tra of 7a and 7c were obtained with a Bruker 250-DXR

instrument in CDCl₃(99.9%) and using trimethylphos-

phite as reference [d³¹P{P(OMe)₃} = 140.17 ppm].

Table 1

˚

Selected bond lengths (in A) and bond angles (in ꢁ) around the

palladium(II)

in

[Pd{[(g⁵–C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-

C₅H₅)}Cl] (1c) and [Pd(2-CH₂–4,6-Me₂–C₆H₂)–CH@N–(C₆H₄–2-

SMe)]Cl] (1d)

1c^a

1d^b

Pd–Cl

Pd–C^c

Pd–S

2.2851(14)

1.978(5)

2.313(3)

2.041(4)

2.409(3)

2.026(4)

92.52(14)

94.44(10)

80.04(12)

87.47(15)

2.3653(11)

2.020(3)

Pd–N

3.2. Preparation of the compounds

C–Pd–Cl

Cl–Pd–S

S–Pd–N

N–Pd–C

a

95.52(15)

98.83(6)

84.72(8)

3.2.1. [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)-CH@

N–(C₆H₄–2SMe)]Fe(g⁵-C₅H₅)}Cl] (2c)

81.38(16)

Complex 1c (150 mg, 3.14 · 10^ꢀ4mol) was dissolved

in 20 mL of CH₂Cl₂, then 40 lL (3.12 · 10^ꢀ4mol) of

MeO₂C–C„C–CO₂Me were added. The resulting reac-

tion mixture was reﬂuxed for 2 h and ﬁltered out. The

Data from Ref. [18].

b

c

Data from Ref. [14e].

In 1c, the metallated carbon atoms is a C(sp², ferrocene), while in

1d it is a C(sp³) atom.

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

238

undissolved materials were discarded and the ﬁltrate was

concentrated to ca. 10 mL on a rotary evaporator. The

to dryness on a rotary evaporator. The residue was trea-

ted with ca. 20 mL of CH₂Cl₂and stirred at room tem-

perature for 15 min and then ﬁltered out. The

undissolved materials were discarded. Then 18 lL

(1.64 · 10^ꢀ4mol) of MeO₂C–C„C–CO₂Me were added

dropwise to the ﬁltrate and the reaction mixture was

then reﬂuxed for 2 h. Then, the solution was ﬁltered

out and the ﬁltrate was concentrated to dryness on a ro-

tary evaporator. The isolated solid was puriﬁed by SiO₂-

column chromatography using a CH₂Cl₂/MeOH (100:1)

mixture as eluant (yield: 47 mg, 71.2%).

dark solution was passed through

a

short (2

cm · 2.5 cm) SiO₂column chromatography using a

CH₂Cl₂:MeOH (100:0.2 mixture) as eluant. The deep

red band eluted was collected and concentrated to dry-

ness on a rotary evaporator. The solid formed was dried

in vacuum for 2 days (yield: 161 mg, 82.8%). Character-

isation data: Anal. (%) Calc. for C₂₄H₂₂ClFeNO₄PdS

(found): C, 46.63 (46.49); H, 3.59(3.41); N, 2.27 (2.23)

and S, 5.19 (5.27). MS (FAB⁺): m/z = 619 [M ꢀ Cl]⁺.

IR: 1716 and 1699 (COO); 1602(>C@N–) cm^ꢀ1. K_M

Characterisation data for 3c: Anal. (%) Calc. for

C₃₀H₂₈BF₄FeNO₈PdS (found): C, 44.39 (44.60); H,

3.48 (3.62); N, 1.73 (1.85) and S, 3.95 (4.04). MS

(FAB⁺): m/z = 724 {M ꢀ [BF₄]^ꢀ}⁺. IR: 1732 [br.

(COO)] and 1618 (>C@N–) cm^ꢀ1K_M(in acetone) = 112

1

(in acetone) = 12 X^ꢀ1cm²mol^ꢀ1. H NMR data (500

MHz) [46]: d = 8.23 [s, 1H, –CH@N-]; 4.75 [t, 1H, H³,

J = 2.4]; 4.81 [t, 1H, H⁴, J = 2.4]; 5.59 [d, 1H, H⁵,

J = 2.4]; 4.31 [s, 5H, C₅H₅]; 2.85 [s, 3H, SMe], 7.70 [d,

3

4

1H, H , J = 7.5]; 7.42 [t, 1H, H , J = 7.5]; 7.40 [t, 1H,

X^ꢀ1cm²mol^{ꢀ1 1}H NMR data (500 MHz) [46]:

.

0

5

6

H , J = 7.5]; 7.53 [d, 1H, H , J = 7.5]; 5.12 [s, 2H,

CH₂Cl₂]; 3.78 [s, 3H, OMe] and 2.73 [s, 3H, OMe].

¹³C{¹H} NMR data (100.58 MHz) [46]: d = 165.2

[>C@N–]; 78.4 [C¹]; 73.1 [C²]; 77.1 [C³]; 74.6 [C⁴]; 77.3

d = 8.72[s, 1H, –CH@N–]; 4.60 [s, 1H, H³]; 4.93 [s,

0

1H, H⁴], 5.60 [s, 1H, H⁵]; 4.36 [s, 5H, C₅H₅]; 7.49[dd,

3

4

1H, H , J = 7.5, J = 1.0]; 7.23 [td,1H, H , J = 7.5,

0

4

J = 1.0]; 7.23 [td, 1H, H , J = 7.5, J = 1.0]; 7.40 [td,

0

5

1

2

5

6

0

[C ]; 71.0 [C₅H₅]; 22.9 [–SMe]; 155.2 [C ]; 130.5 [C ];

1H, H , J = 7.5, J = 1.0]; 7.64 [dd, 1H, H , J = 7.5,

J = 1.0]; 3.71, 3.75, 3.94 and 4.01 [4s, 12H, 4-

OMe].¹³C{¹H} NMR data (100.58 MHz) [46]:

d = 167.4 [–CH@N–]; 89.2 [C¹]; 87.5 [C²]; 75.0 [C³];

3

4

5

6

0

120.4 [C ]; 130.6 [C ]; 129.5 [C ]; 131.1 [C ]; 51.8

[OMe]; 51.7 [OMe]; 171.8 and 172.7 [COO] and 130.2

and 146.2 [C^aand C^b, respectively].

4

5

1

0

74.8 [C ]; 76.2 [C ]; 72.1 [C₅H₅]; 152.8 [C ]; 122.5

3.2.2. [Pd{[(MeO₂–C@C–CO₂Me)₂(g⁵-C₅H₃)–CH@N–

(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}] [BF₄] (3c)

This complex can be prepared using two diﬀerent

procedures which diﬀer in the nature of the starting

material 1c or 2c.

[C ]; 121.4 [C ]; 128.3 [C ]; 131.4 [C ]; 135.6 [C ];

53.0, 53.6, 54.9 and 55.1[4 OMe];158.8, 163.9, 166.6

and 168.2 [4-COO] and 118.9, 134.9, 135.6 and 149.5

[C^a, C^b, C^dand C^c].

2

3

4

5

6

0

Method a. Compound 1c (150 mg, 3.14 · 10^ꢀ4mol)

was dissolved in 20 mL of acetone, then 137 mg

(4.7 · 10^ꢀ4mol) of Tl[BF₄] were added. The reaction

mixture was stirred at ca. 20 ꢁC for 4 h and then ﬁltered

out to remove the TlCl formed. The ﬁltrate was concen-

trated to dryness on a rotary evaporator and the deep

blue residue was dissolved in 20 mL of CH₂Cl₂. Then

80 lL (7.28 · 10^ꢀ4mol) of MeO₂C–C„C–CO₂Me were

added dropwise at room temperature. Once the addition

had ﬁnished, the reaction mixture was reﬂuxed for 2 h.

After this period it was ﬁltered out and concentrated

to dryness on a rotary evaporator. The gummy residue

was dissolved in 10 mL of CH₂Cl₂and passed through

a short SiO₂column chromatography (2.5 cm · 3.0

cm). The elution with CH₂Cl₂produced a deep red band

which was concentrated to dryness giving 2c (11 mg).

Once this band was collected a CH₂Cl₂/MeOH (100: 1)

mixture was used, and the band released lead, after work

up, 3c, which was dried in vacuum for 2 days (yield: 137

mg).

3.2.3. [Pd{[(R¹–C@C–R¹)₂(g⁵-C₅H₃)–CH@N–(C₆H₄–

2-SMe)]Fe(g⁵-C₅H₅)}][BF₄] Æ CH₂Cl₂[with R¹= Ph

(5c), Et (6c)]

To a solution containing 150 mg (3.14 · 10^ꢀ4mol) of

1c and 20 mL of acetone an excess ofTl[BF₄] (137 mg,

4.7 · 10^ꢀ4mol) was added. The reaction mixture was

stirred at ca. 20 ꢁC for 4 h. After the removal of the TlCl

formed by ﬁltration, the ﬁltrate was concentrated to dry-

ness on a rotary evaporator. The residue was treated with

20 mL of CH₂Cl₂and ﬁltered out to remove the excess of

Tl[BF₄] and then 6.8 · 10^ꢀ4mol of the corresponding al-

kyne: R¹–C„C–R¹(R¹= Et or Ph) were added slowly to

the deep-blue (nearly black) ﬁltrate. Once the addition

had ﬁnished, the reaction mixture was reﬂuxed for 2 h.

After this period the resulting deep purple solution was

ﬁltered out and passed through a short SiO₂-column

chromatography (2.5 cm · 3.0 cm). Elution with CH₂Cl₂

produced the release of a deep-blue band which lead after

concentration to dryness to small amounts of 1c [49mg

(for R¹= Ph) and 52 mg (for R¹= Et)]. The desired com-

plexes 5c or 6c were isolated after the subsequent elution

with a CH₂Cl₂:MeOH (100:1) mixture and concentration

to dryness of the collected red bands. Yields: 98 mg (for

5c) and 79mg (for 6c). Characterisation data for 5c:

Anal. (%) Calc. for C₄₅H₃₆BF₄FeNPdS Æ CH₂Cl₂(found):

Method b. A 100 mg amount of 2c (1.62 · 10^ꢀ4mol)

was dissolved in 20 mL of acetone, then Tl[BF₄] (71 mg,

12.4 · 10^ꢀ4mol) was added. The reaction mixture was

stirred at ca. 20 ꢁC for 4 h and then ﬁltered out to re-

move the TlCl formed. The ﬁltrate was concentrated

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

239

C, 58.27(58.32); H, 3.95(4.11); N, 1.45(1.51) and S,

3.31(3.51). MS (FAB⁺): m/z = 796 {M ꢀ {[BF₄]^ꢀand

CH₂Cl₂}]⁺. IR: 1592 (>C@N–) cm^ꢀ1. K_M(in ace-

3.2.5. Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@

N–(CH₂)₂–NMe₂]Fe(g⁵-C₅H₅)}Cl(PPh₃)] (7a)

This complex was prepared according to the proce-

dure described above for 7c but using the stoichiometric

amount of [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–

CH@N–(CH₂)₂–NMe₂]Fe(g⁵-C₅H₅)}Cl] (2a) as starting

material. Yield: 41 mg, 81%. Characterisation data.

Anal. (%) Calc. for: C₃₉H₄₀N₂O₄FePdPCl (found): C,

56.48 (56.60); H, 4.86 (5.05) and N, 3.80 (3.68). MS

(FAB⁺): m/z = 793 [M ꢀ Cl]⁺. IR: 1716 and 1699

(COO); 1602 (>C@N–) cm^ꢀ1. K_M(in acetone) = 9

1

tone) = 105 X^ꢀ1cm²mol^ꢀ1. H NMR data (500 MHz)

[46]: d = 9.25 [s, 1H, –CH@N–]; 5.18 [t, 1H, H³,

J = 2.5]; 5.06 [t, 1H, H⁴, J = 2.5]; 5.30 [d, 1H, H⁵,

J = 2.5]; 3.82 [s, 5H, C₅H₅]; 2.25 [s, 3H, SMe]; 6.96 [d,

3

0

1H, H ]; 5.12 [s, 2H, CH₂Cl₂]; 7.17–8.20 [br. m., 23H,

4

5

6

0

H , H , H and 20 protons of the phenyl ring of the

R¹group]. ¹³C{¹H} NMR data (100.58 MHz) [46,47]:

d = 164.0 [>C@N–]; 88.1 [C¹]; 71.6 [C²]; 77.5 [C³]; 74.8

[C⁴]; 75.7 [C⁵]; 73.0 [C₅H₅]; 26.2 [-SMe],and 146.1,

136.2, 132.4 and 120.1 [C^a, C^b, C^d, C^c, respectively].

For 6c: Anal. (%) Calc. for C₃₀H₃₆BF₄FeNPdS Æ CH₂Cl₂

(found): C, 47.94 (48.05); H, 4.93 (5.03); N, 1.80 (2.02)

and S, 4.13 (4.38). MS (FAB⁺): m/z = 606 [M ꢀ [BF₄]^ꢀ

and CH₂Cl₂]⁺. IR: 1602 (>C@N–) cm^ꢀ1. K_M(in ace-

tone) = 110X^ꢀ1cm²mol^ꢀ1}.]⁺. ¹H NMR data (500

MHz) [46]: d = 9.28 [s, 1H, –CH@N–]; 4.63 [t, 1H, H³,

J = 2.4]; 4.89 [t, 1H, H⁴, J = 2.4]; 5.40 [d, 1H, H⁵,

J = 2.4]; 4.43 [s, 5H, C₅H₅], 2.76 [s, 3H, SMe]; 7.61 [d,

X^ꢀ1cm²mol^ꢀ1

.

¹H NMR data (500 MHz) [46]:

4

d = 8.20 [d, 1H, –CH@N–, J_(P–H)= 10.6]; 4.52 [t, 1H,

H³, J = 2.6]; 4.79 [t, 1H, H⁴, J = 2.6]; 4.89 [d, 1H, H⁵,

J = 2.6]; 4.19 [s, 5H, C₅H₅], 2.28 [s, 6H, NMe₂]; 4.58

and 3.50 [br.m, 2H, @N–CH₂–], 3.05 and 2.58 [br.m,

2H, –CH₂–N–]; 3.64 [s, 3H, OMe] and 3.22 [s, 3H,

OMe]. ³¹P{¹H} NMR data: d = 27.8 ppm.

3.3. Crystallography

3

4

0

1H, H , J = 7.5]; 7.64 [t, 1H, H , J = 7.5]; 7.32 [t, 1H,

A prismatic crystal of 2a, 2c, 5c or 7c (sizes in Table 2)

was selected an mounted on a ENRAF-CAD diﬀractom-

eter (for 2a) or on a MAR345 diﬀractometer (for 2c, 5c

and 7c). For 2a, unit cell parameters were determined

from automatic centering of 25 reﬂections in the range

12ꢁ 6 H 6 21ꢁ and reﬁned by full matrix-least.squares

method. For 2c, 5c and 7c, unit-cell parameters were

determined from 27,781 reﬂections (for 2c), 27,215 (for

5c) and 34,465 (for 7c) (in the range 3ꢁ < H < 31ꢁ) and re-

ﬁned by least-squares method. Intensities were collected

with graphite monochromatized Mo K_aradiation. The

number of reﬂections measured was: 16,228 (in the range

2.35ꢁ 6 H 6 30.04ꢁ) for 2a, 75,647 (in the range 2.45ꢁ 6

H 6 31.60ꢁ) for 2c, 27,215 (in the range 2.89ꢁ 6

H 6 31.51ꢁ) for 5c and 46,268 (in the range

1.67ꢁ 6 H 6 31.63ꢁ) for 7c; of which 7379 (for 2a),

2295 (for 2c), 9506 (for 5c) and 13,070 (for 7c) were

non-equivalent by symmetry [R_int(on I) = 0.041 (for

2a), 0.053 (for 2c), 0.019 (for 5c) and 0.038 (for 7a)].

The number of reﬂections assumed as observed applying

the condition I > 2r(I) was 3827 (for 2a), 2107 (for 2c),

9506 (for 5c), 11979 (for 7c). Lorentz-polarization cor-

rections were made but absorption corrections were not.

The structure was solved by direct methods using

SHELXS computer program [48] and reﬁned by full-ma-

trix least-squares method with the ^SHELX97computer

program [49] using 2295 (for 2a), 7379 (for 2c), 10,092

(for 5c) or 13070 (for 7c) reﬂections (very negative inten-

5

6

0

H , J = 7.5]; 8.32 [d, 1H, H , J = 7.5]; 2.06, 2.46, 2.30

and 2.06 [4m, 8H, –CH₂–(Et)];0.88, 0.94,1.18, 1.42 [4t,

12H, CH₃(Et)] and 5.12 [s, 2H, CH₂Cl₂]. ¹³C{¹H}

NMR data (100.58 MHz) [46]: d = 166.2. [>C@N–];

87.9 [C¹]; 78.4 [C²]; 74.7 [C³]; 74.5 [C⁴]; 75.9 [C⁵]; 71.9

1

2

3

0

[C₅H₅]; 22.4 [–SMe]; 150.4 [C ]; 132.4 [C ]; 120.1 [C ];

4

5

6

0

128.1 [C ]; 131.2 [C ], 135.3 [C ]; 25.8, 26.0, 28.6,

34.5 [–CH₂(Et)]; 12.6, 15.2, 15.3 and 16.9 [CH₃(Et)]

and 99.1, 117.5, 143.0 and 143.2 [C^a, C^b, C^d, C^c,

respectively].

3.2.4. [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@

N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}Cl(PPh₃)] Æ CH₂Cl₂

(7c)

To a solution formed by 40 mg (6.5 · 10^ꢀ5mol) of 2c

and 10 mL of CH₂Cl₂, PPh₃(17 mg, 6.5 · 10^ꢀ5mol) was

added. The reaction mixture was stirred at ca. 20 ꢁC for

30 min. After this period, the solution was ﬁltered out

and slow evaporation of the solvent gave orange crystals

suitable for X-ray diﬀraction, which were collected and

air-dried. Yield: 54 mg, 86%. Characterisation data.

Anal. (%) Calc. for: C₄₂H₃₇ClFeNO₄PPdS Æ CH₂Cl₂

(found): C, 53.50 (53.62); H, 4.07 (4.12); N, 1.45 (1.40)

and S, 3.32 (3.40). MS (FAB⁺): m/z = 844 [M ꢀ Cl]⁺.

IR: 1717 and 1698 (COO); 1617 (>C@N–) cm^ꢀ1. K_M

1

(in acetone) = 15 X^ꢀ1cm²mol^ꢀ1. H NMR data (500

4

MHz) [46]: d = 7.90 [d, 1H, –CH@N–, J_(P–H)= 8.2];

3.90 [t, 1H, H³, J = 2.6 Hz]; 4.65 [t, 1H, H⁴,

J = 2.6Hz]; 4.90 [d, 1H, H⁵, J = 2.6 Hz]; 4.29 [s, 5H,

sities were not assumed). The function minimized was

P

wiF_o|²ꢀ |F_c|²|², where w = [r²(I) + 0.0684P²]^ꢀ1(for

2a), w = [r²(I) + 0.0619P²+ 0.5401P]^ꢀ1(for 2c), w =

[r²(I) + 0.0460P)²+ 7.2802P]^ꢀ1(for 5c) and w =

[r²(I) + 0.0643P)²+ 4.8020P]^ꢀ1(for 7c) and P =

(|F_o|²+ 2|F_c|²)/3; f, f⁰and f⁰⁰were taken from the litera-

ture [50].

3

0

C₅H₅]; 2.39 [s, 3H, –SMe]; 6.62 [dd, 1H, H , J = 7.5,

J = 1.0]; 5.12 [s, 2H, CH₂Cl₂]; 7.32–7.85 [br.m, 18H,

4

5

6

0

H , H , H and protons of the PPh₃ligand]; 3.72 [s,

3H, OMe] and 3.17 [s, 3H, OMe]. ³¹P{¹H} NMR data:

d = 29.5 ppm.

´

C. Lopez et al. / Journal of Organometallic Chemistry 690 (2005) 228–243

240

Table 2

Crystallographic data and details of the reﬁnement of the cystal structures of [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(C₆H₄–2-SMe)]Fe(g⁵-

C₅H₅)}Cl] (2c), [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(CH₂)₂–NMe₂]Fe(g⁵-C₅H₅)}Cl]CH₂Cl₂(2a), [Pd{[(Ph–C–C@C–Ph)₂(g⁵-C₅H₃)–

CH@N–(C₆H₄–2-SMe)]Fe(g⁵-C₅H₅)}][BF₄] Æ CH₂Cl₂(5c), [Pd{[(MeO₂C–C@C–CO₂Me)(g⁵-C₅H₃)–CH@N–(C₆H₄-2-SMe)]Fe(g⁵-C₅H₅)}Cl (PPh₃)] Æ

CH₂Cl₂(7c)

2c

2a

5c

7c

Empirical formula

Formula weight

T (K)

C₂₄H₂₂ClFeNO₄PdS C₂₁H₂₅ClFeN₂O₄Pd Æ CH₂Cl₂C₄₆H₃₆BF₄FeNPdS Æ CH₂Cl₂C₄₂H₃₇ClFeNO₄PPdS Æ CH₂Cl₂

618.19

293(2)

652.06

293(2)

968.81

293(2)

965.38

293(2)

˚

k (A)

0.71073

Monoclinic

0.1 · 0.1 · 0.2

0.71069

Monoclinic

0.1 · 0.1 · 0.2

0.71073

Monoclinic

0.1 · 0.1 · 0.2

0.71073

Monoclinic

0.1 · 0.1 0.2

Crystal system

Crystal dimensions

(mm · mm · mm)

Space group

P2₁/c

P2₁/n

˚

a (A)

20.31(6)

9.10(2)

12.82(3)

90.0

17.405(3)

8.657(11)

22.830(3)

90.0

9.2480(10)

11.5140(10)

39.7400(10)

90.0

19.8620(10)

10.5330(10)

20.7080(10)

90.0

˚

b (A)

˚

c (A)

a (ꢁ)

b (ꢁ)

c (ꢁ)

Z

92.90(8)

90.0

130.743(10)

90.0

92.040(10)

90.0

106.270(10)

90.0

4

3

˚

V (A )

2366(10)

1.735

1.606

2006(3)

1.662

1.584

4228.9(6)

1.522

0.996

4158.7(5)

1.542

1.106

D (mg · m^ꢀ3

)

l (mm^ꢀ1

F(000)

)

1240

2.45 to 31.60

1312

2.35 to 30.04

1960

2.89 to 31.51

1960

1.67 to 31.63

H Range for data

collection (ꢁ)

Number of reﬂections

75647

16228

16219

46268

collected

Number of unique

reﬂections [R(int)]

Number of data

Number of parameters

Goodness-of-ﬁt on F²

2295 [0.0534]

7379 [0.0417]

10,092 [0.0196]

13,070 [0.0382]

2295

292

7379

306

10,092

597

1.092

13,070

577

1.241

1.065

0.978

Final R indices [I > r(I)] R₁= 0.0322

wR₂= 0.0878

R₁= 0.0603

wR₂= 0.1209

R₁= 0.1490

wR₂= 0.1506

0.566 and ꢀ0.537

R₁= 0.0537

wR₂= 0.1280

R₁= 0.0575

wR₂= 0.1309

0.859 and ꢀ0.744

R₁= 0.0592

wR₂= 0.1498

R₁= 0.0664

wR₂= 0.1540

0.769 and ꢀ0.744

R indices (all data)

R₁= 0.0363

wR₂= 0.0911

0.226 and ꢀ0.345

Largest diﬀerence peak

ꢀ3

˚

and hole (e A

)

Standard deviation parameters are given in parenthesis.

The number of hydrogen atoms located from a diﬀer-

ence synthesis was 2 (for 2a), 13 (for 5c) and 18 (for 7c)

and they were reﬁned with an overall isotropic tempera-

ture factor. The number of hydrogen atoms computed

and reﬁned using an isotropic temperature factor equal

to 1.2 times the equivalent temperature factor of the

atom linked to it was: 25 (for 2a), all (for 2c), 23 (for

5c) and 19 (for 7c). The ﬁnal R(on F) factor were

0.060 (2a), 0.032 (2c), 0.057 (5c) and 0.059 (7c), wR

(on F²) = 0.120 (2a), 0.088 (2c), 0.130 (5c) and 0.250

(7c) and the goodness-of-ﬁt was: 0.978, 1.065, 1.091

and 1.241 for 2a, 2c, 5c and 7c, respectively.

236374, 236375, 236376 and 236377. Copies of this

information can be obtained from The Director, CCDC,

12 Union Road, Cambridge CB2-1EZ, UK (fax: +44-

1233-336033; e-mail: deposit@ccdc.ac.uk or www.ccdc.

cam.ac.uk).

Acknowledgements

This work was supported by the Ministerio de Cien-

´

cia y Tecnologıa of Spain, the Generalitat de Catalunya

(Grant Nos. BQU2003-00906 and SRG-2001-00054,

respectively) and FEDER funds.

4. Supplementary materials

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ZO = 4.0984 [deviations from the plane are as follows: S,

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C(12) and C(17) is (ꢀ0.7708)XO + (0.6098)YO + (0.1844)ZO =

3.7447 [deviations from the plane: S, ꢀ0.0004; N, 0.005; C812,

˚

ꢀ0.1562; N, 0.1831; Cl, 0.1491 and C(19), ꢀ0.1759 A].

˚

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CH@N–]; 4.43, 4.64, 4.51, 4.55, 4.62 and 4.57 [6s, C₅H₅]; 3.82, 3.70,

4.25, 4.01, 4.07 and 3.96 [s, H³]; 4.66, 4.50, 4.40, 4.60, 4.75 and 4.73

[s, H⁴], 5.30, 5.22, 4.80, 5.04, 5.18 and 5.08 [H⁵]; 2.94, 2.76, 2.92,

[23] The least-squares equation of the plane deﬁned by the atoms S, N,

C(12) and C(17) is (ꢀ0.4567)XO + (0.6038)YO + (0.6534)

ZO = 4.6201 [deviations from the plane: S, 0.010; N, ꢀ0.012;

˚

C(12), 0.023 and C(17), ꢀ0.021 A].

[24] The least-squares equation of the plane deﬁned by the set of atoms

[C(12),C(13),C(14), C(15), C(16) and C(17) is: (ꢀ0.4982)XO +

(0.5839)YO + (0.6418)ZO = 4.3757 [deviations from the plane:

C(12), ꢀ0.020;C(13), 0.010;C(14), 0.018; C(15), ꢀ0.038; C(16),

2.75, 3.23 and 2.70 [SMe]; 7.45, 7.66, 7.70, 7.35, 7.53 and 7.80 [d,

6

0.027 and C(17), 0.002 A].

H ]. ¹³C{¹H} NMR selected data in acetone-d₆( in ppm):

0

˚

[25] In 2a, the least-squares equation of the plane deﬁned by the

atoms: Cl, N(1), N(2) and C(17) is (0.2494)XO + (ꢀ0.01617)YO +

(0.9663)ZO = 3.5431 [deviations from the plane: Cl, 0.064; N(1),

d = 177.5, 172.2,177.1,172.2,175.4 and 170.4 [–CH@N]; 71.4, 72.2,

71.6, 72.0, 71.7 and 72.3 [C₅H₅]; 26.8, 27.1, 26.9, 27.6, 27.2 and 27.4

[SMe]. The {¹H ¹H} NOESY spectrum of 4c in acetone-d₆at 20 ꢁC

revealed the existence of interchanges in solution.

˚

0.075; N(2), 0.068 and C(17), ꢀ0.067 A].

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ZO=3.9175 [deviations from the plane: Pd, ꢀ0.162; N(1), 0.244;

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N and C(22) is (0.0526)XO + (0.9795)YO +

(ꢀ0.1943)ZO=0.7271 [deviations from the plane: P, ꢀ0.037; Cl,

˚

0.036; N, ꢀ0.004 and C(22), 0.7171 A].

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YO + (0.2343)ZO = ꢀ2.6384 [deviations from the plane: S,

˚

ꢀ0.276; N, 0.235, C(21), 0.283 and v, 0.241 A].

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˚

A]. In 7c: (0.5466)XO + (0.1077)YO + (0.8304)ZO = 16.3418 and

´ ´ ´

(m) A. Fernandez, D. Vazquez-Garcıa, J.J. Fernandez, M.

´

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Lopez-Torres, A. Suarez, S. Castro-Juız, J.M. Vila, Eur. J. Inorg.

´

(0.5126)XO + (0.1556)YO + (ꢀ0.8444)ZO = 12.914

[deviations

from these planes C(1), ꢀ0.004; C(2), 0.002; C(3), 0.0016; C(4),

ꢀ0.003; C(5), 0.004; C(6), 0.007; C(7), ꢀ0.010; C(8), 0.010; C(9),

Chem. (2002) 2389.

[40] The least-squares equation of the plane deﬁned by the set of atoms

[C(12)–C(17)] is (0.7081)XO + (ꢀ0.3878)YO + (0.5904)ZO =

10.87 [deviations from the plane: C(12), ꢀ0.025; C(13), 0.016;

˚

ꢀ0.005 and C(10), 0.001 A. C(3), 0.0016; C(4), ꢀ0.003; C(5),

0.004; C(6), 0.007; C(7), ꢀ0.010; C(8), 0.010; C(9), ꢀ0.005 and

˚

C(10), 0.001 A].

C(14), 0.08; C(15), ꢀ0.023; C(16), 0.014 and C(17), 0.010 A].

[41] T.H.Allen,O.Kennard,Chem.Deigns.Automat.News8(1993)146.

[42] The least-squares equations of the planes deﬁned by the sets of

atoms [C(1)–C(5) and [C(6)–C(19)] are: In 2c: (0.7985)XO +

(0.4571)YO + (ꢀ0.3979) = 8.3013 and (0.7548)XO + (0.4517)

YO + (ꢀ0.4538)ZO = 4.5359 [deviations from these planes C(1),

ꢀ0.010; C(2), 0.002; C(3), 0.006; C(4), ꢀ0.012; C(5), 0.014; C(6),

[43] (a) J. Bondi, J. Phys. Chem. 64 (1964) 441;

(b) A.I. Kitaigorodskii, Molecular Crystals and Molecules,

Academic Press, London, UK, 1973.

[44] C. Kowala, J. Swan, Aust. J. Chem. 19 (1966) 547.

[45] D.D. Perrin, W.L.F.. Armarego, Puriﬁcation of Laboratory

Chemicals, third ed., Pergamon Press, London, UK, 1998.

[46] Labelling of the atoms corresponds to those shown in Schemes 1–4.

[47] Selected data.

˚

ꢀ0.005; C(7), 0.006; C(8), ꢀ0.005; C(9), 0.002 and C(10), 0.002 A].

In 2a: (0.6793)XO + (0.3515)YO + (ꢀ0.6442)ZO = 3.2385 and

(0.0.6739)XO + (0.3387)YO + (ꢀ0.6566) = ꢀ0.1627

[deviations

from these planes C(1), ꢀ0.051; C(2), 0.024; C(3), 0.012; C(4),

ꢀ0.005; C(5), 0.006; C(6), ꢀ0.009; C(7), 0.012; C(8), ꢀ0.010; C(9),

[48] G.M. Sheldrick, ^SHELXSA Computer Program for Determination

of Crystal Structure, University of Go¨ttingen, Go¨ttingen, Ger-

many, 1997.

˚

0.004 and C(10), 0.003 A]. In 5c: (ꢀ0.7327)XO +

[49] G.M. Sheldrick, ^SHELX97. A Computer Program for Determina-

tion of Crystal Structure, University of Go¨ttingen, Go¨ttingen,

Germany, 1997.

(0.6322)YO + (0.2519) = 7.9790 and (ꢀ0.6970)XO + (0.7033)

YO + (0.1402) = 4.0938 [deviations from these planes C(1),

0.006; C(2), ꢀ0.006; C(3), 0.003; C(4), 0.002; C(5), ꢀ0.005; C(6),

ꢀ0.002; C(7), 0.007; C(8), ꢀ0.009; C(9), 0.008 and C(10), ꢀ0.004

[50] International Tables of X-Ray Crystallography, vol. 4, Kynoch

Press, Birmingham, UK, 1974, pp. 99–100, 149.

Article Doi

Study of the reactivity of palladacycles containing [C(sp2, ferrocene),N,S]- or [C(sp3),N,S]- terdentate ligands with symmetric alkynes

DOI: 10.1016/j.jorganchem.2004.09.017

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Full text of DOI:10.1016/j.jorganchem.2004.09.017

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