Synthesis of homo- and heterodinuclear metal complexes with dimethylsilylene bridged unsymmetrical bis(cyclopentadienyl) ligand

Journal of Organometallic Chemistry 634 (2001) 109–121

www.elsevier.com/locate/jorganchem

Synthesis of homo- and heterodinuclear metal complexes with

dimethylsilylene bridged unsymmetrical bis(cyclopentadienyl) ligand

Hiroaki Komatsu, Hiroshi Yamazaki *

Department of Applied Chemistry, Chuo Uni6ersity, Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan

Received 21 March 2001; received in revised form 7 May 2001; accepted 15 May 2001

Abstract

The reaction of the dilithium salt Li₂[Me₂Si(C₅H₄)(C₅Me₄)] (2) of Me₂Si(C₅H₅)(C₅HMe₄) (1) with [MCl(C₈H₁₂)]₂(M=Rh, Ir)

and [RhCl(CO)₂]₂afforded homodinuclear metal complexes [{Me₂Si(h⁵-C₅H₄)(h⁵-C₅Me₄)}{M(C₈H₁₂)}₂] (M=Rh: 3; M=Ir: 4)

and [{Me₂Si(h⁵-C₅H₄)(h⁵-C₅Me₄)}Rh₂(CO)₂(m-CO)] (5), respectively. The reaction of 2 with RhCl(CO)(PPh₃)₂afforded a

mononuclear metal complex [{Me₂Si(C₅HMe₄)(h⁵-C₅H₄)}Rh(CO)PPh₃] (6) leaving the C₅HMe₄moiety intact. Taking advantage

of the difference in reactivity of the two cyclopentadienyl moieties of 2, heterodinuclear complexes were prepared in one pot. Thus,

the reaction of 2 with RhCl(CO)(PPh₃)₂, followed by the treatment with [MCl(C₈H₁₂)]₂(M=Rh, Ir) afforded a homodinuclear

metal complex [Rh(CO)PPh₃{(h⁵-C₅H₄)SiMe₂(h⁵-C₅Me₄)}Rh(C₈H₁₂)] (7) consisting of two rhodium centers with different ligands

and a heterodinuclear metal complex [Rh(CO)(PPh₃){(h⁵-C₅H₄)SiMe₂(h⁵-C₅Me₄)}Ir(C₈H₁₂)] (8). The successive treatment of 2

with [IrCl(C₈H₁₂)]₂and [RhCl(C₈H₁₂)]₂provided heterodinuclear metal complex [Ir(C₈H₁₂){(h⁵-C₅H₄)SiMe₂(h⁵-

C₅Me₄)}Rh(C₈H₁₂)] (9). The reaction of 2 with CoCl(PPh₃)₃and then with PhCꢀCPh gave a mononuclear cobaltacyclopentadiene

complex [{Me₂Si(C₅Me₄H)(h⁵-C₅H₄)}Co(CPhꢁCPhꢂCPhꢁCPh)(PPh₃)] (10). However, successive treatment of 2 with CoCl(PPh₃)₃,

PhCꢀCPh and [MCl(C₈H₁₂)]₂in this order afforded heterodinuclear metal complexes [M(C₈H₁₂){(h⁵-C₅H₄)SiMe₂(h⁵-

C₅Me₄)}Co(h⁴-C₄Ph₄)] (M=Rh: 11; M=Ir: 12) in which the cobalt center was connected to the C₅Me₄moiety. Although the

heating of 10 afforded a tetraphenylcyclobutadiene complex [{Me₂Si(C₅Me₄H)(h⁵-C₅H₄)}Co(h⁴-C₄Ph₄)] (13), in which the cobalt

center was connected to the C₅H₄moiety, simple heating of the reaction mixture of 2, CoCl(PPh₃)₃and PhCꢀCPh resulted in the

formation of a tetraphenylcyclobutadiene complex [{Me₂Si(C₅H₅)(h⁵-C₅Me₄)}Co(h⁴-C₄Ph₄)] (14), in which the cobalt center was

connected to the C₅Me₄moiety. The mechanism of the cobalt transfer was suggested based on the electrophilicity of the formal

trivalent cobaltacyclopentadiene moiety. In the presence of 1,5-cyclooctadiene, the reaction of 2 with CoCl(PPh₃)₃provided a

mononuclear cobalt cyclooctadiene complex [{Me₂Si(C₅Me₄H)(h⁵-C₅H₄)}Co(C₈H₁₂)] (15). The reaction of 15 with n-BuLi

followed by the treatment with [MCl(C₈H₁₂)]₂(M=Rh, Ir) afforded the heterodinuclear metal complexes of [Co(C₈H₁₂){(h⁵-

C₅H₄)SiMe₂(h⁵-C₅Me₄)}M(C₈H₁₂)] (M=Rh: 16; M=Ir: 17). Treatment of 6 with Fe₂(CO)₉at room temperature afforded a

heterodinuclear metal complex [{Me₂Si(C₅HMe₄)(h⁵-C₅H₄)}{Rh(PPh₃)(m-CO)₂Fe(CO)₃}] (18) in which the C₅HMe₄moiety was

kept intact. Treatment of dinuclear metal complex 5 with Fe₂(CO)₉afforded a heterotrinuclear metal complex [{(h⁵-

C₅H₄)SiMe₂(h⁵-C₅Me₄)}{Rh(CO)Rh(m-CO)₂Fe(CO)₃}] (19) having a triangular metal framework. The crystal and molecular

Keywords: Homodinuclear metal complexes; Heterodinuclear metal complexes; Cyclopentadienyl metal complexes

true polynuclear reactions have not been seen fre-

quently, because of the ready fragmentation of the

metal framework. In order to quench cleavage of the

inherently weak metal–metal bonds, bridging ligands

have been used as the support. For this purpose,

bridged bis(h⁵-cyclopentadienyl) ligands such as

[X(C₅H₄)₂] (X=CH₂, Me₂Si, Me₂C, CꢁO, etc.),

1. Introduction

In recent years, considerable attention has been fo-

cused on polynuclear transition-metal complexes be-

cause a multi-metal center may provide reaction

pathways not available to a single metal one. However,

[Me₂C(C₅H₄)(C₉H₆)] and

a

fulvalendiyl ligand

* Corresponding author. Fax: +81-3-38171895.

PII: S0022-328X(01)01022-1

110

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

Table 1

,

Selected bond lengths (A) and bond angles (°) for 3

Bond lengths

Rh1ꢂC1

Rh1ꢂC2

Rh1ꢂC3

Rh1ꢂC4

Rh1ꢂC5

Rh1ꢂC17

Rh1ꢂC18

Rh1ꢂC21

Rh1ꢂC22

C1ꢂSi

2.296(7)

2.261(7)

2.278(7)

2.278(8)

2.212(7)

2.131(8)

2.132(8)

2.110(7)

2.120(9)

1.861(7)

Rh2ꢂC6

Rh2ꢂC7

Rh2ꢂC8

Rh2ꢂC9

Rh2ꢂC10

Rh2ꢂC25

Rh2ꢂC26

Rh2ꢂC29

Rh2ꢂC30

C6ꢂSi

2.276(7)

2.219(7)

2.288(7)

2.281(8)

2.224(8)

2.119(7)

2.139(10)

2.132(9)

1.840(7)

Scheme 1.

[C₅H₄ꢂC₅H₄] have often been employed [1–3]. We have

been interested in the use of bridged unsymmetrical

bis(h⁵-cyclopentadienyl) ligands [Me₂Si(C₅H₄)(C₅Me₄)]

because differences in the steric and electronic effects of

each of the cyclopentadienyl moieties may facilitate

preparation of heterodinuclear metal complexes and

make it possible to insert different reactivity into each

metal center. We report here the synthesis of homo-

and heterodinuclear metal complexes by metathesis re-

action of the dianion of [Me₂Si(C₅H₅)(C₅HMe₄)] with

metal complex halides.

Bond angles

C1ꢂSiꢂC6

CpꢂCp* ^a

110.8(3)

85.31

C15ꢂSiꢂC16

109.4(4)

^aDihedral angle between least-squares planes.

complexes [{Me₂Si(h⁵-C₅H₄)(h⁵-C₅Me₄)}{M(C₈H₁₂)}₂]

(M=Rh: 3; M=Ir: 4) (Scheme 1). The ¹H-NMR

spectrum of rhodium complex 3 shows peaks at 3.94

and 2.97 ppm assignable to the oleﬁnic protons of

1,5-cyclooctadiene coordinated to Rh centers. The cor-

responding peaks of (C₈H₁₂)Rh(h⁵-C₅H₅) and

(C₈H₁₂)Rh(h⁵-C₅Me₅) are reported to appear at 3.97

and 2.95 ppm, respectively [5,6]. Therefore, the lower

ﬁeld peak at 3.94 is ascribed to the oleﬁnic protons of

the cyclopentadienylrhodium side and the higher ﬁeld

peak at 2.97 ppm to those of the tetramethylcyclopenta-

dienylrhodium side. In the same way, the peaks at 3.76

and 2.80 ppm in iridium complex 4 are assigned to the

oleﬁnic protons of 1,5-cyclooctadiene coordinated to

the (h⁵-C₅H₄)Ir and (h⁵-C₅Me₄)Ir centers, respectively,

2. Results and discussion

2.1. Synthesis of homodinuclear metal complexes of

rhodium and iridium

Dimethylsilylene-bridged

unsymmetrical

bis(cy-

clopentadiene) [Me₂Si(C₅H₅)(C₅HMe₄)] (1), having a

simple cyclopentadiene moiety and a bulky and elec-

tron-donating tetramethylcyclopentadiene moiety, was

prepared by the literature method [4]. The dilithium

derivative Li₂[Me₂Si(C₅H₄)(C₅Me₄)] (2), prepared in

situ from 1 and n-BuLi, reacted with [MCl(C₈H₁₂)]₂

(M=Rh, Ir) to form dinuclear rhodium and iridium

because

the

mononuclear

iridium

complexes

(C₈H₁₂)Ir(h⁵-C₅H₅) and (C₈H₁₂)Ir(h⁵-C₅Me₅) show the

corresponding peaks at 3.78 and 2.73 ppm, respectively

Fig. 1. ORTEP view of [{Me₂Si(h⁵-C₅H₄)(h⁵-C₅Me₄)}{Rh(C₈H₁₂)}₂] (3).

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

111

[7]. The structure of 3 has been determined unequivo-

cally by single-crystal X-ray diffraction analysis. The

molecular structure is depicted in Fig. 1. Selected bond

distances and angles are listed in Table 1. The two

cyclopentadienyl rings are twisted with each other at a

dihedral angle of 85.31°. No appreciable differences in

the average RhꢂC bond distances between the cy-

which the tetramethylcyclopentadiene moiety (C₅HMe₄)

was kept intact (Scheme 3). The IR spectrum shows

only one strong absorption at 1933 cm⁻¹for the

carbonyl group compared to that at 1942 cm⁻¹in

(h⁵-C₅H₅)Rh(PPh₃)(CO). The ¹H-NMR spectrum

shows a singlet peak at 0.12 ppm for the methyl pro-

tons of dimethylsilyl groups and two singlets at 1.72

and 1.79 ppm for the methyl protons of the non-coordi-

nated tetramethylcyclopentadienyl groups. Two triplets

ascribed to the cyclopentadienyl protons appeared at

4.80 and 5.13 ppm and a broad singlet to the proton of

the uncoordinated tetramethylcyclopentadiene ring at

2.90 ppm, respectively. Failure of the formation of the

expected dinuclear rhodium complex may be caused by

the steric hindrance between the ancillary ligands of the

rhodium halide complex and the tetramethylcyclopenta-

dienyl anion. Previously, Werner prepared related

mononuclear metal complexes from the monoanion of

a bridged bis(cyclopentadiene) and employed them as

the starting material to prepare heterodinuclear metal

complexes through metallation of the remaining cy-

clopentadiene moiety [1]. However, the method requires

several steps for completion. We attempted the synthe-

sis of a dinuclear metal complex in a one-pot manner,

taking advantage of the difference in reactivity of the

two cyclopentadienyl moieties.

clopentadienyl and the tetramethylcyclopentadienyl

5

,

parts are observed (2.265 and 2.258 A in h -C₅R₄Rh

4

,

and 2.123 and 2.127 A in h -codꢂRh).

Complex 2 reacted with [RhCl(CO)₂]₂at room tem-

perature to form the dirhodium complex [{Me₂Si(h⁵-

C₅H₄)(h⁵-C₅Me₄)}Rh₂(CO)₂(m-CO)] (5) bearing

a

RhꢂRh bond and a bridged carbonyl (Scheme 2). The

IR spectrum of 5 shows strong absorptions at 1988,

1952 and 1792 cm⁻¹assignable to the stretching fre-

quencies of the terminal and bridging carbonyls. The

frequencies are lower than those reported for

[Me₂Si(h⁵-C₅H₄)₂Rh₂(CO)₂(m-CO)] (2010, 1975, 1960

and 1800 cm⁻¹in KBr) [8], reﬂecting the existence of a

stronger electron-donating tetramethylcyclopentadienyl

group.

2.2. Synthesis of heterodinuclear metal complexes

Reaction of 2 with two equivalents of RhCl(CO)-

(PPh₃)₂failed to produce a dinuclear rhodium complex

analogous to the known [CH₂(h⁵-C₅H₄)₂{Rh(CO)-

(PPh₃)}₂] [9] but afforded a mononuclear rhodium com-

plex [{Me₂Si(C₅HMe₄)(h⁵-C₅H₄)}Rh(CO)PPh₃] (6) in

Treatment of a solution of 2 in THF with an equimo-

lar amount of RhCl(CO)(PPh₃)₂at room temperature

overnight and then subsequent treatment of the result-

ing solution with [RhCl(C₈H₁₂)]₂at reﬂux for 5 h

afforded a dinuclear rhodium complex [Rh(CO)PPh₃-

{(h⁵-C₅H₄)SiMe₂(h⁵-C₅Me₄)}Rh(C₈H₁₂)] (7) in which

the two rhodium centers carried different ligands

(Scheme 4).

However, similar treatment of the dianion 2 with

RhCl(CO)(PPh₃)₂and [IrCl(C₈H₁₂)]₂failed to give the

corresponding heteronuclear complex and provided 6

together with an iridium phosphine complex IrCl-

(PPh₃)(C₈H₁₂). It is reasonable to assume that the disso-

ciated phosphine from RhCl(CO)(PPh₃)₂in the initial

step reacts with [IrCl(C₈H₁₂)]₂to afford IrCl(PPh₃)-

(C₈H₁₂) of low reactivity. We obtained the intended

heterodinuclear metal complex [Rh(CO)PPh₃{(h⁵-

C₅H₄)SiMe₂(h⁵-C₅Me₄)}Ir(C₈H₁₂)] (8) by using excess

[IrCl(C₈H₁₂)]₂. The ¹H-NMR spectra of 7 and 8, respec-

tively, show peaks at 2.94 and 3.77 ppm for the oleﬁnic

protons of 1,5-cyclooctadiene. In comparison with the

spectra of 3 and 4, those resonances are assignable to

the oleﬁnic protons of 1,5-cyclooctadiene bound to the

tetramethylcyclopentadienyl metal center. Similar treat-

Scheme 2.

Scheme 3.

ment of

2 with [RhCl(C₈H₁₂)]₂and then with

[IrCl(C₈H₁₂)]₂gave a mixture of the desired heterodinu-

clear metal complex and homodinuclear metal complex

3. This may be due to the high reactivity of

[RhCl(C₈H₁₂)]₂toward both cyclopentadieneyl moieties.

We were not successful in separating them by column

Scheme 4.

112

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

PPh₃] (10) in which the C₅HMe₄moiety was kept intact

1

(Scheme 6). The H-NMR spectrum shows a singlet at

0.54 ppm for the six methyl protons of the dimethylsilyl

group, two singlets at 1.67 and 1.79 ppm for the 12

methyl protons of the tetramethylcyclopentadiene

groups, a broad singlet at 2.94 ppm for the one proton

of the tetramethylcyclopentadiene ring and a broad

singlet at 4.61 ppm for the four cyclopentadienyl pro-

tons. The X-ray crystal structure analysis of 10 resulted

in poor resolution but revealed the structure unequivo-

cally. We attempted the synthesis of a heterodinuclear

complex containing cobalt and rhodium in a one-pot

manner through the anion of 10 as the intermediate.

Reaction of 2 with CoCl(PPh₃)₃and PhCꢀCPh in

THF for 8 h at room temperature and then with

[RhCl(C₈H₁₂)]₂overnight afforded a reddish-brown

crystalline compound. The IR and NMR spectra as

well as the elemental analysis suggested the formation

of a heterodinuclear complex of the formula [{(h⁵-

C₅H₄)Me₂Si(h⁵-C₅Me₄)}Rh(C₈H₁₂)Co(h⁴-C₄Ph₄)] (11),

where the expected cobaltacyclopentadiene structure

was transformed into the h⁴-cyclobutadienecobalt

structure. Similarly, the iridium analog [(h⁵-

Scheme 5.

Scheme 6.

chromatography or recrystallization. The treatment of

2 with [IrCl(C₈H₁₂)]₂and then with [RhCl(C₈H₁₂)]₂

afforded the heterodinuclear complex [Ir(C₈H₁₂){(h⁵-

C₅H₄)SiMe₂(h⁵-C₅Me₄)}Rh(C₈H₁₂)] (9) in a good yield

(Scheme 5).

It is well established that the reaction of CoCl(PPh₃)₃

with alkali metal cyclopentadienide provides bis(t-

riphenylphosphine)(h⁵-cyclopentadienyl)cobalt and that

subsequent treatment of the complex with PhCꢀCPh

affords (triphenylphosphine)(h⁵-cyclopentadienyl)tetra-

phenylcobaltacyclopentadiene [10]. However, the prepa-

ration of the corresponding bis-phosphine cobalt com-

plex of the bulky C₅Me₅ligand was not successful for

steric reasons. In accord with these facts, the treatment

of 2 with CoCl(PPh₃)₃in the presence of PhCꢀCPh

afforded only the mononuclear cobalt complex

[{Me₂Si(C₅HMe₄)(h⁵- C₅H₄)}Co(CPhꢁCPhꢂCPhꢁCPh)-

C₅H₄)Me₂Si(h⁵-C₅Me₄)}Co(h⁴-C₄Ph₄)Ir(C₈H₁₂)]

(12)

was prepared. The structures of 11 and 12 have been

determined by single-crystal X-ray diffraction analysis.

The molecular structures are depicted in Figs. 2 and 3.

Selected bond distances and angles are listed in Tables

2 and 3. Originally, we considered structure A for these

complexes, but unexpectedly, the X-ray crystallographic

analysis revealed structure B, suggesting the involve-

ment of an intraligand cobalt metal transfer reaction.

Simple heating of mononuclear complex 10 at toluene

reﬂux gave the (h⁵-cyclopentadienyl)cobalt(h⁴-cyclobu-

Fig. 2. ORTEP view of [Rh(C₈H₁₂){(h⁵-C₅H₄)Me₂Si(h⁵-C₅Me₄)}Co(h⁴-C₄Ph₄)] (11).

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

113

Fig. 3. ORTEP view of [Ir(C₈H₁₂){(h⁵-C₅H₄)Me₂Si(h⁵-C₅Me₄)}Co(h⁴-C₄Ph₄)] (12).

Table 2

tadiene)

complex

[Co(h⁴-C₄Ph₄){(h⁵-C₅H₄)Me₂Si-

,

Selected bond lengths (A) and bond angles (°) for 11

(C₅Me₄H)}] (13). However, when 2 was heated with

CoCl(PPh₃)₃and PhCꢀCPh in THF or kept at ambient

temperature for several days, [{(C₅H₅)Me₂Si(h⁵-

C₅Me₄)}Co(h⁴-C₄Ph₄)] (14) was obtained after hydroly-

sis, which had the same composition as 13 but a

Bond lengths

RhꢂC1

RhꢂC2

RhꢂC3

RhꢂC4

RhꢂC5

CoꢂC6

CoꢂC7

CoꢂC8

CoꢂC9

CoꢂC10

2.287(4)

2.257(4)

2.276(5)

2.250(5)

2.191(4)

2.092(3)

2.075(3)

2.098(4)

2.084(4)

2.066(4)

RhꢂC17

RhꢂC18

RhꢂC21

RhꢂC22

2.116(4)

2.099(4)

2.089(5)

2.111(5)

1

different structure. The H-NMR spectrum of 13 shows

peaks at 4.63 and 4.70 ppm assignable to the protons of

the h⁵-cyclopentadienyl ring; however, the spectrum of

14 shows no corresponding peaks but exhibits peaks at

6.20 and 6.50 ppm, which are assignable to the oleﬁnic

protons of the cyclopentadiene ring. The peaks ascrib-

able to the aliphatic proton of the cyclopentadiene rings

appear at 2.73 ppm in 13 and 3.42 ppm in 14. The

corresponding peak of 6 appeared at 2.90 ppm. Based

on the NMR data, we deduced that the h⁴-tetraphenyl-

cyclobutadiene cobalt moiety was connected to the

cyclopentadienyl site in 13 and to the tetramethylcy-

clopentadienyl site in 14 (Schemes 7 and 8).

CoꢂC25

CoꢂC26

CoꢂC27

CoꢂC28

1.993(3)

2.000(3)

1.997(3)

1.996(3)

Bond angle

CpꢂCp* ^a

92.05

^aDihedral angle between least-squares planes.

Table 3

,

Selected bond lengths (A) and bond angles (°) for 12

Bond lengths

IrꢂC1

IrꢂC2

IrꢂC3

IrꢂC4

2.266(3)

2.270(4)

2.292(4)

2.254(4)

2.190(4)

2.088(3)

2.080(3)

2.093(3)

2.086(3)

2.064(3)

IrꢂC17

IrꢂC18

IrꢂC21

IrꢂC22

2.115(4)

2.080(4)

2.109(4)

2.114(4)

IrꢂC5

CoꢂC6

CoꢂC7

CoꢂC8

CoꢂC9

CoꢂC10

CoꢂC25

CoꢂC26

CoꢂC27

CoꢂC28

1.993(3)

2.003(3)

2.004(3)

2.000(3)

We suggest the mechanism of the intraligand cobalt

transfer from cyclopentadienyl to tetramethylcyclopen-

tadienyl groups as shown in Scheme 9. The driving

force of the cobalt transfer may arise from the formal

trivalent state of cobalt in the cobaltacyclopentadiene

Bond angle

structure, which prefers

a more electron-rich te-

CpꢂCp* ^a

91.74

tramethylcyclopentadienyl site. The transformation

may be assisted by the presence of [MCl(C₈H₁₂)]₂(M=

^aDihedral angle between least-squares planes.

114

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

Scheme 7.

Scheme 10.

The dilithium anion 2 reacted with CoCl(PPh₃)₃in

the presence of 1,5-cyclooctadiene to yield mononuclear

complex [(C₅Me₄H)Me₂Si{(h⁵-C₅H₄)Co(C₈H₁₂)}] (15),

in which the tetramethylcyclopentadiene moiety was left

intact (Scheme 10). The ¹H-NMR spectrum of 15 shows

a singlet at 0.89 ppm for the methyl protons of the

dimethylsilyl group and two singlets at 1.79 and 2.73

ppm for the methyl protons of the tetramethylcyclopen-

tadiene group. A broad singlet at 2.94 ppm for the

aliphatic proton of the tetramethylcyclopentadiene ring

has the same value as that in 10. The treatment of

mononuclear complex 15 with n-BuLi in THF solution

at room temperature and then with [MCl(C₈H₁₂)]₂

(M=Rh, Ir) afforded heterodinuclear metal cycloocta-

diene complexes [Co(C₈H₁₂){(h⁵-C₅H₄)SiMe₂(h⁵-C₅-

Me₄)}M(C₈H₁₂)] (M=Rh: 16, M=Ir: 17) (Scheme 10).

The ¹H-NMR spectra of 16 and 17 are similar. In

comparison with the spectrum of 15, the resonance of

the methyl protons of the dimethylsilyl group shifted to

a lower ﬁeld (0.46 (15), 0.89 (16) and 0.85 (17) ppm),

and the resonances of the methyl protons for te-

tramethylcyclopentadienyl shifted to an upper ﬁeld

(1.79, 2.73 (15), 1.43, 1.87 (16) and 1.54, 1.90 (17) ppm).

Scheme 8.

Rh, Ir) behaving as a phosphine sponge. Initial product

of the reaction of 2 with CoCl(PPh₃)₃and PhCꢀCPh

may be a cobaltacyclopentadiene complex (10%) in

which the cobalt moiety is connected to the sterically

less bulky cyclopentadienyl group and stabilized by the

coordination of PPh₃. Dissociation of PPh₃from 10%

gives an equilibrium mixture of cobaltacyclopentadi-

enes in which the cobalt moiety is connected to the

cyclopentadienyl and the tetramethylcyclopentadienyl

groups, respectively (C and D). D cannot be stabilized

by PPh₃for steric reason and gradually changes to the

corresponding cobalt cyclobutadiene complex (14%). The

reaction of either C or 14% with [MCl(C₈H₁₂)]₂may

produce 11 and 12.

Scheme 9.

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

115

,

FeꢂC(35) (1.901(9) A) and FeꢂC(36) (1.922(9) A). Also,

the angles of RhꢂC(35)ꢂO(1) (127.9(7)°) and Rhꢂ

C(36)ꢂO(2) (133.2(7)°) are smaller than those of

2.3. Synthesis of heteronuclear metal complexes

containing rhodium and iron

FeꢂC(35)ꢂO(1)

(149.9(8)°)

and

FeꢂC(36)ꢂO(2)

The reaction of 6 with Fe₂(CO)₉at room temperature

afforded a heterodinuclear complex containing both

rhodium and iron, [{Me₂Si(C₅HMe₄)(h⁵-C₅H₄)}{Rh-

(PPh₃)(m-CO)₂Fe(CO)₃}] (18), in which the C₅HMe₄

moiety was left intact (Scheme 11). (h⁵-C₅Me₅)Rh(CO)₂

is reported to react with Fe₂(CO)₉to form the dinuclear

complex [Fe(CO)₃(m-CO)₂Rh(CO)(h⁵-C₅Me₅)] [11]. The

IR spectrum of 18 shows strong absorptions at 2021,

1955, 1945, 1811 and 1782 cm⁻¹in KBr and 2030,

1961, 1806 and 1777 cm⁻¹in CHCl₃, assignable to

terminal and bridging CO ligands. Lower frequencies

than those of [Fe(CO)₃(m-CO)₂Rh(CO)(h⁵-C₅Me₅)]

(2053, 2017, 1979, 1961, 1835 and 1825 cm⁻¹) are

ascribed to the replacement of one CO by one

triphenylphosphine ligand. Complex 18 has been char-

acterized by X-ray analysis. The selected bond distances

and angles are tabulated in Table 4. The molecular

structure is depicted in Fig. 4. The C₅Me₄H moiety was

kept intact and the sp³carbon bearing a hydrogen atom

was connected to the silicon atom. The FeꢂRh bond

(145.3(8)°). The bridging carbonyls are semi-bridging to

the Rh center, because the Rh core has a high electron

density.

Dinuclear rhodium complex 5 reacted with Fe₂(CO)₉

at room temperature to form heterotrinuclear complex

[{(h⁵-C₅H₄)SiMe₂(h⁵- C₅Me₄)}{Rh(CO)Rh(m - CO)₂-Fe-

(CO)₃}] (19) (Scheme 12). The IR spectra showed CO

stretching absorptions at 2027, 1977, 1967, 1832 and

1784 cm⁻¹in KBr and 2043, 1990, 1826 and 1775

cm⁻¹in CHCl₃. Compared with the IR spectra of

[(h⁵-C₅Me₅)₂Rh₂Fe(CO)₆] which has a face-capped car-

bonyl (2051, 2019, 1993, 1971, 1953, 1837, 1801 and

1690 cm⁻¹in hexane) [11] and those of [(h⁵-

C₅H₅)₂Rh₂Fe(CO)₆] which has no such face-capped car-

bonyl (2054, 2002, 1989, 1980, 1839 and 1792 cm⁻¹

)

[13], the structure of 19 is estimated to consist of two

bridging carbonyls and four terminal carbonyls. An

unequivocal structure of 19 was obtained by X ray

crystallographic analysis (Fig. 5). Selected bond dis-

tances and angles are listed in Table 5. The RhꢂRh

,

length (2.612(2) A) is slightly greater than that found in

,

bond length of 2.6600(5) A is slightly greater than the

a similar complex [(h⁵-C₅H₅)(PⁱPr₃)Rh(m-CꢁCH₂)(m-

,

lengths of 2.648(3) and 2.650(1) A found in the tetranu-

,

CO)Fe(CO)₃] (2.604(1) A) [12]. The metal-bridging car-

clear complex (h⁵-C₅H₅)₂Rh₂Fe₂(CO)₈[13] and the din-

uclear complex [CH₂(h⁵-C₅H₄)Rh₂(CO)₂(m-CO)] [12],

respectively. The Rh(2)ꢂFe bond length (2.5922(9)) is

,

bonyl bond distances of RhꢂC(35) (2.103(8) A) and

,

RhꢂC(36) (2.090(9) A) are longer than those of

,

shorter than the Rh(1)ꢂFe bond length (2.6960(8) A), in

accord with the location of the two bridging carbonyls

between the Rh(2) and the Fe metal centers. It is

reasonable to ﬁnd a bridging carbonyl on the Rh(2)

center bearing an electron-rich ancillary ligand because

a bridging carbonyl draws more electrons than does a

terminal one.

Scheme 11.

3. Experimental

Table 4

,

Selected bond lengths (A) and bond angles (°) for 18

Bond lengths

RhꢂFe

RhꢂC1

RhꢂC2

RhꢂC3

RhꢂC4

RhꢂC5

RhꢂP

Bond angles

C1ꢂSiꢂC6

RhꢂC35ꢂFe

RhꢂC35ꢂO1

RhꢂC36ꢂO2

CpꢂCp* ^a

3.1. General procedures

2.612(2)

2.325(8)

2.245(8)

2.251(9)

2.278(9)

2.233(9)

2.312(3)

RhꢂC35

RhꢂC36

FeꢂC35

FeꢂC36

FeꢂC39

C1ꢂSi

2.103(8)

2.090(9)

1.901(9)

1.922(9)

1.79(1)

All reactions were carried out under an atmosphere

of N₂by Schlenk tube techniques. The starting materi-

als Me₂Si(C₅H₅)(C₅HMe₄) (1) [4], Fe₂(CO)₉[14],

CoCl(PPh₃)₃[15], [RhCl(C₈H₁₂)]₂[16], [RhCl(CO)₂]₂

[17], trans-RhCl(CO)(PPh₃)₂[18] and [IrCl(C₈H₁₂)]₂[19]

were prepared according to the literature procedures.

THF was distilled over sodium benzophenone ketyl

under N₂.

1.865(9)

1.913(9)

C6ꢂSi

104.1(4)

81.2(3)

127.9(7)

133.2(7)

29.6

RhꢂC36ꢂFe

FeꢂC35ꢂO1

FeꢂC36ꢂO2

81.3(3)

149.9(8)

145.3(8)

¹H-NMR spectra were recorded on a JOEL JNM-

GSX400 spectrometer. IR spectra were recorded on

JASCO A-202 and Shimadzu FTIR-8100M. Elemental

^aDihedral angle between least-squares planes.

116

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

Fig. 4. ORTEP view of [{Me₂Si(C₅HMe₄)(h⁵-C₅H₄)}{Rh(PPh₃)(m-CO)₂Fe(CO)₃}] (18).

3.3. [{Me₂Si(p⁵-C₅H₄)(p⁵-C₅Me₄)}{Ir₂(C₈H₁₂)₂}] (4)

analyses were done with a Yanaco CHN CORDER

MT-5.

The dilithium salt, prepared from 1 (0.26 g, 1.07

mmol) and n-BuLi (1.53 M, 1.4 ml, 2.14 mmol) in

THF, was treated with [IrCl(C₈H₁₂)]₂(0.86 g, 1.28

mmol) and heated at reﬂux for 8 h. After the solvent

was removed, the residue was dissolved in a small

amount of C₆H₆and chromatographed on alumina.

The pale yellow eluate by hexane was concentrated and

kept under refrigeration to give white crystals of 4, 0.20

g (0.24 mmol, 22%); m.p. 172 °C. Anal. Found: C,

45.75; H, 5.65. Calc. for C₃₂H₄₆SiIr₂: C, 45.58; H,

3.2. [{Me₂Si(p⁵-C₅H₄)(p⁵-C₅Me₄)}{Rh₂(C₈H₁₂)₂}] (3)

A solution of 1 (0.24 g, 0.98 mmol) in THF was

treated with n-BuLi (1.63 M, 1.4 ml, 2.14 mmol) in

hexane at 0 °C, and the resulting solution was stirred

overnight at room temperature (r.t.). A solution of

[RhCl(C₈H₁₂)]₂(0.51 g, 1.03 mmol) in THF was added

to the above reaction mixture and heated at reﬂux for 5

h. After the reaction mixture was evaporated and dis-

solved in C₆H₆, the solution was hydrolyzed with a

saturated aqueous solution of NH₄Cl, and the organic

layer was separated and dried over Na₂SO₄. After

concentration, the residue was chromatographed on

alumina. The yellow eluate by hexane was concentrated

and kept under refrigeration to give yellow crystals of

3, 0.23 g (0.35 mmol, 36%); m.p. 168 °C. Anal. Found:

C, 56.92; H, 6.72. Calc. for C₃₂H₄₆SiRh₂: C, 57.83; H,

1

5.50%. H-NMR (CDCl₃): l 0.59 (s, 6H, SiMe₂), 1.57

(s, 6H, C₅Me₄), 1.91 (s, 6H, C₅Me₄), 1.80 (m, 8H,

C₈H₁₂), 2.05 (m, 8H, C₈H₁₂), 2.80 (m, 4H, C₈H₁₂), 3.76

1

6.98%. H-NMR (CDCl₃): l 0.67 (s, 6H, SiMe₂), 1.44

(s, 6H, C₅Me₄), 1.88 (s, 6H, C₅Me₄), 1.91 (m, 8H,

C₈H₁₂), 2.19 (m, 8H, C₈H₁₂), 2.97 (m, 4H, C₈H₁₂), 3.94

(m, 4H, C₈H₁₂), 4.80 (s, 2H, C₅H₄), 5.43 (s, 2H, C₅H₄).

Scheme 12.

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

117

mmol) overnight. After the solution was evaporated,

the residue was dissolved in a small amount of C₆H₆

and chromatographed on alumina. The black eluate by

hexane–C₆H₆(1:2) was evaporated, and the residue

was crystallized from hexane to give black crystals of 5,

0.08 g (0.15 mmol, 10%). Anal. Found: C, 42.94; H,

4.19. Calc. for C₁₉H₂₂O₃SiRh₂: C, 42.87; H, 4.17%.

¹H-NMR (CDCl₃): l 0.55 (s, 6H, SiMe₂), 1.96 (s, 6H,

C₅Me₄), 2.15 (s, 6H, C₅Me₄), 5.36 (s, 2H, C₅H₄), 6.03

(s, 2H, C₅H₄). IR (nujol, cm⁻¹): w_CO1988, 1952, 1792.

3.5. [{Me₂Si(C₅HMe₄)(p⁵-C₅H₄)}Rh(CO)PPh₃] (6)

The dilithium salt, prepared from 1 (1.27 g, 5.21

mmol) and n-BuLi (1.65 M, 4.8 ml, 7.92 mmol) in

THF, was treated with RhCl(CO)(PPh₃)₂(3.45 g, 5.00

mmol) at reﬂux for 6 h. The reaction mixture was

removed and dissolved in C₆H₆, and the solution was

hydrolyzed with a saturated aqueous solution of

NH₄Cl. The organic layer was separated and dried over

Na₂SO₄. After concentration, the solution was chro-

matographed on alumina. The red eluate by hexane was

evaporated, and the residue was crystallized from hex-

ane to give orange crystals of 6, 1.89 g (2.81 mmol,

56%); m.p. 108 °C. Anal. Found: C, 65.17; H, 6.09.

Fig. 5. ORTEP view of [Rh(CO){(h⁵-C₅H₄)SiMe₂(h⁵-C₅Me₄)}{Rh(m-

CO)₂Fe(CO)₃}] (19).

1

Calc. for C₃₅H₃₈OPSiRh: C, 65.03; H, 6.02%. H-NMR

Table 5

(CDCl₃): l 0.12 (s, 6H, SiMe₂), 1.72 (s, 6H, C₅Me₄),

1.79 (s, 6H, C₅Me₄), 2.90 (br, 1H, Me₄C₅H), 4.81 (s,

2H, C₅H₄), 5.13 (s, 2H, C₅H₄), 7.32–7.58 (m, 15H,

PꢂPh₃). IR (KBr, cm⁻¹): w_CO1933.

,

Selected bond lengths (A) and bond angles (°) for 19

Bond lengths

Rh1ꢂRh2

Rh2ꢂFe1

Rh1ꢂC1

Rh1ꢂC2

Rh1ꢂC3

Rh1ꢂC4

Rh1ꢂC5

Rh1ꢂC17

Rh2ꢂC19

FeꢂC19

C1ꢂSi

2.6600(5)

2.5922(9)

2.277(4)

2.216(5)

2.245(5)

2.282(5)

2.238(5)

1.823(6)

2.018(4)

1.951(5)

1.876(5)

Rh1ꢂFe1

2.6960(8)

Rh2ꢂC6

Rh2ꢂC7

Rh2ꢂC8

Rh2ꢂC9

Rh2ꢂC10

Rh2ꢂC18

2.229(4)

2.284(4)

2.273(4)

2.269(4)

2.225(4)

1.940(5)

2.101(5)

3.6. [Rh(CO)PPh₃{(p⁵-C₅H₄)SiMe₂(p⁵-C₅Me₄)}-

Rh(C₈H₁₂)] (7)

The dilithium salt, prepared from 1 (0.12 g, 0.49

mmol) and n-BuLi (1.63 M, 0.8 ml, 1.30 mmol) in

THF, was treated with RhCl(CO)(PPh₃)₂(0.36 g, 0.52

mmol) in C₆H₆at r.t. for 1 day. The solution of

[RhCl(C₈H₁₂)]₂(0.12 g, 0.24 mmol) in C₆H₆was then

added to the mixture and heated at reﬂux for 5 h. The

reaction mixture was hydrolyzed with a saturated

aqueous solution of NH₄Cl. The organic layer was

separated and dried over Na₂SO₄. After concentration

of the solution, the residue was chromatographed on

alumina. The yellow eluate by hexane–C₆H₆(1:1) was

evaporated to dryness, and the residue was crystallized

from hexane to give orange crystals of 7, 0.09 g (0.11

mmol, 23%); m.p. 145 °C. Anal. Found: C, 61.49; H,

6.11. Calc. for C₄₃H₄₉OPSiRh₂: C, 61.00; H, 5.83%. IR

C6ꢂSi

1.880(4)

Bond angles

Rh1ꢂFeꢂRh2

Rh2ꢂRh1ꢂFe

FeꢂC18ꢂRh2

Rh2ꢂC18ꢂO2

FeꢂC18ꢂO2

CpꢂCp* ^a

60.36(2)

57.88(2)

79.7(2)

144.0(4)

136.3(4)

79.84

Rh1ꢂRh2ꢂFe

C1ꢂSiꢂC6

FeꢂC19ꢂRh2

Rh2ꢂC19ꢂO3

FeꢂC19ꢂO3

61.75(2)

108.6(2)

81.5(2)

134.9(4)

143.6(4)

^aDihedral angle between least-squares planes.

(m, 4H, C₈H₁₂), 4.80 (t, 2H, J=1.7 Hz, C₅H₄), 5.46 (t,

2H, J=1.7 Hz, C₅H₄).

1

3.4. [{Me₂Si(p⁵-C₅H₄)(p⁵-C₅Me₄)}Rh₂(CO)₂(v-CO)] (5)

(nujol, cm⁻¹): w_CO1952. H-NMR (CDCl₃): l 0.56 (s,

6H, SiMe₂), 1.41 (s, 6H, C₅Me₄), 1.87 (s, 6H, C₅Me₄),

4.95 (s, 2H, C₅H₄), 5.17 (s, 2H, C₅H₄), 1.92 (m, 4H,

C₈H₁₂), 2.15 (m, 4H, C₈H₁₂), 2.94 (m, 4H, C₈H₁₂),

7.37–7.61 (m, 15H, PꢂPh₃).

The dilithium salt, prepared from 1 (0.37 g, 1.52

mmol) and n-BuLi (1.66 M, 2.1 ml, 3.49 mmol) in

THF, was treated with [RhCl(CO)₂]₂(0.60 g, 1.54

118

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

3.7. [Rh(CO)PPh₃{(p⁵-C₅H₄)SiMe₂(p⁵-C₅Me₄)}-

Ir(C₈H₁₂)] (8)

tion of the solvent, the solution was chromatographed

on alumina. The reddish-brown eluate by C₆H₆–hexane

(3:1) was evaporated to dryness, and the residue was

crystallized from hexane–CH₂Cl₂to give reddish-

brown crystals of 10, 0.37 g (0.56 mmol, 31%); m.p.

128 °C. Anal. Found: C, 78.43; H, 6.42. Calc. for

The dilithium salt, prepared from 1 (0.22 g, 0.90

mmol) and n-BuLi (1.53 M, 1.2 ml, 1.84 mmol) in

THF, was treated with a solution of RhCl(CO)(PPh₃)₂

(0.90 g, 1.30 mmol) at reﬂux for 4 h. [IrCl(C₈H₁₂)]₂

(0.90 g, 2.68 mmol) was added to the reaction mixture

and heated at reﬂux for 8 h. After the solvent was

removed, the residue was dissolved in a small amount

of C₆H₆and chromatographed on alumina. The dark

yellow eluate by hexane–C₆H₆(3:1) was evaporated

and crystallized from hexane–C₆H₆to give orange crys-

tals of 8, 0.31 g (0.33 mmol, 37%); m.p. 243 °C. Anal.

Found: C, 55.50; H, 5.39. Calc. for C₄₃H₄₉OPSiIrRh:

1

C₆₂H₅₈PSiCo·1/3CH₂Cl₂: C, 78.86; H, 6.23%. H-NMR

(CDCl₃): l 0.54 (s, 6H, SiMe₂), 1.67 (s, 6H, C₅Me₄),

1.79 (s, 6H, C₅Me₄), 2.94 (br, 1H, Me₄C₅H), 4.61 (s,

4H, C₅H₄), 6.33–6.83 (m, 20H, C₄ꢂPh₄), 7.19, 7.33 (br,

15H, PPh₃).

3.10. [Rh(C₈H₁₂){(p⁵-C₅H₄)SiMe₂(p⁵-C₅Me₄)}Co-

(p⁴-C₄Ph₄)] (11)

C, 55.18; H, 5.28%. IR (KBr, cm⁻¹): w_CO1953. H-

The dilithium salt, prepared from 1 (0.24 g, 1.00

mmol) and n-BuLi (1.59 M, 1.3 ml, 2.1 mmol), was

treated with CoCl(PPh₃)₃(0.90 g, 1.02 mmol) and

PhCꢀCPh (0.78 g, 4.38 mmol) for 8 h. [RhCl(C₈H₁₂)]₂

(0.25 g, 0.51 mmol) was then added to the mixture. The

reaction mixture was stirred overnight. The solvent was

removed and the residue was dissolved in C₆H₆. The

solution was hydrolyzed with a saturated solution of

NH₄Cl, and the organic layer was separated and dried

over Na₂SO₄. After concentration, the solution was

chromatographed on alumina. The brown eluate by

hexane–C₆H₆(2:1) was evaporated, and the residue

was crystallized from hexane–C₆H₆to give reddish-

brown crystals of 11, 0.15 g (0.17 mmol, 18%); m.p.

238 °C. Anal. Found: C, 71.50; H, 6.40. Calc. for

1

NMR (CDCl₃): l 0.52 (s, 6H, SiMe₂), 1.53 (s, 6H,

C₅Me₄), 1.90 (s, 6H, C₅Me₄), 4.92 (s, 2H, C₅H₄), 5.17

(s, 2H, C₅H₄), 1.80 (d, 4H, C₈H₁₂), 2.02 (m, 4H, C₈H₁₂),

2.76 (br, 4H, C₈H₁₂), 7.37 (m, 9H, PPh₃), 7.58 (m, 6H,

PPh₃).

3.8. [Ir(C₈H₁₂){(p⁵-C₅H₄)SiMe₂(p⁵-C₅Me₄)}Rh(C₈H₁₂)]

(9)

The dilithium salt, prepared from 1 (0.15 g, 0.61

mmol) and n-BuLi (1.69 M, 0.7 ml, 1.18 mmol) in

THF, was treated with [IrCl(C₈H₁₂)]₂(0.20 g, 0.30

mmol) in C₆H₅Me for 5 h. [RhCl(C₈H₁₂)]₂(0.12 g, 0.24

mmol) was added to the resulting mixture and stirred

overnight. After the reaction mixture was removed and

dissolved in C₆H₆, the solution was hydrolyzed with a

saturated aqueous solution of NH₄Cl, and the organic

layer was separated and dried over Na₂SO₄. After

concentration, the residue was chromatographed on

alumina. The pale yellow eluate by hexane was concen-

trated and kept in a refrigerator to give yellow crystals

of 9, 0.20 g (0.27 mmol, 56%); m.p. 175 °C. Anal.

Found: C, 50.55; H, 6.07. Calc. for C₃₂H₄₆SiIrRh: C,

50.98; H, 6.15%. ¹H-NMR (CDCl₃): l 0.62 (s, 6H,

SiMe₂), 1.46 (s, 6H, C₅Me₄), 1.89 (s, 6H, C₅Me₄), 4.82

(s, 2H, C₅H₄), 5.46 (s, 2H, C₅H₄), 1.79 (m, 4H, C₈H₁₂),

1.92 (m, 4H, C₈H₁₂), 2.18 (m, 4H, C₈H₁₂), 2.05 (m, 4H,

C₈H₁₂), 2.97 (m, 4H, C₈H₁₂), 3.77 (m, 4H, C₈H₁₂).

1

C₅₂H₅₄SiCoRh: C, 71.88; H, 6.26%. H-NMR (CDCl₃):

l 0.26 (s, 6H, SiMe₂), 1.36 (s, 6H, C₅Me₄), 1.60 (s, 6H,

C₅Me₄), 4.50 (s, 2H, C₅H₄), 5.35 (s, 2H, C₅H₄), 1.85 (m,

4H, C₈H₁₂), 2.11 (m, 4H, C₈H₁₂), 3.82 (m, 4H, C₈H₁₂),

7.19–7.37 (m, 20H, C₄-Ph₄).

3.11. [Ir(C₈H₁₂){(p⁵-C₅H₄)SiMe₂(p⁵-C₅Me₄)}Co-

(p⁴-C₄Ph₄)] (12)

The dilithium salt, prepared from 1 (0.30 g, 1.23

mmol) and n-BuLi (1.53 M, 1.6 ml, 2.45 mmol) in

THF, was treated with CoCl(PPh₃)₃(1.08 g, 1.23 mmol)

and PhCꢀCPh (0.55 g, 3.09 mmol) overnight. After the

solvent was removed, the residue was washed with dry

hexane several times to remove excess PPh₃and again

dissolved in THF. [IrCl(C₈H₁₂)]₂(1.01 g, 1.50 mmol)

was added to the reaction solution and heated at reﬂux

for 8 h. The solvent was evaporated, and the residue

was dissolved in a small amount of C₆H₆and chro-

matographed on alumina. The yellow eluate by hex-

ane–C₆H₆(7:1) was evaporated and crystallized from

hexane–C₆H₆to give reddish-brown crystals of 12, 0.17

g (0.18 mmol, 15%); m.p. 243 °C. Anal. Found: C,

65.46; H, 5.80. Calc. for C₅₂H₅₄SiCoIr: C, 65.18; H,

3.9. [{Me₂Si(C₅Me₄H)(p⁵-C₅H₄)}Co(CPhꢁCPhꢂ

CPhꢁCPh)PPh₃] (10)

The dilithium salt, prepared from 1 (0.44 g, 1.80

mmol) and n-BuLi (1.63 M, 2.5 ml, 4.07 mmol) in

THF, was treated with CoCl(PPh₃)₃(1.94 g, 2.20 mmol)

and PhCꢀCPh (1.21 g, 6.80 mmol) for 4 h. The reaction

mixture was evaporated to dryness and dissolved in

C₆H₆. The solution was hydrolyzed with a saturated

aqueous solution of NH₄Cl. The organic layer was

separated and dried over Na₂SO₄. After the concentra-

1

5.68%. H-NMR (CDCl₃): l 0.23 (s, 6H, SiMe₂), 1.37

(s, 6H, C₅Me₄), 1.60 (s, 6H, C₅Me₄), 4.51 (t, 2H, J=1.7

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

119

Hz, C₅H₄), 5.36 (s, 2H, J=1.8 Hz, C₅H₄), 1.73 (m, 4H,

C₈H₁₂), 1.98 (m, 4H, C₈H₁₂), 3.65 (m, 4H, C₈H₁₂), 7.21

(m, 12H, C₄ꢂPh₄), 7.36 (m, 8H, C₄ꢂPh).

tals of 15, 0.22 g (0.54 mmol, 38%); m.p. 82 °C. Anal.

Found: C, 70.87; H, 9.16. Calc. for C₂₄H₃₅SiCo: C,

70.21; H, 8.59%. ¹H-NMR (CDCl₃): l 0.46 (s, 6H,

SiMe₂), 1.57 (pseudo-q, 4H, C₈H₁₂), 1.73 (s, 6H,

C₅Me₄), 1.79 (s, 6H, C₅Me₄), 2.37 (br, 4H, C₈H₁₂), 2.94

(br, 1H, C₅Me₄H), 3.39 (br, 4H, C₈H₁₂), 3.50 (s, 2H,

C₅H₄), 5.13 (s, 2H, C₅H₄).

3.12. [{Me₂Si(C₅Me₄H)(p⁵-C₅H₄)}Co(p⁴-C₄Ph₄)] (13)

A solution of 10 (0.80 g, 0.92 mmol) in C₆H₅Me was

heated at 80 °C for 18 h. After concentration of the

solution, the residue was chromatographed on alumina.

The yellow eluate by hexane was evaporated to dryness.

The residue was crystallized from hexane to give yellow

orange crystals of 13, 0.20 g (0.30 mmol, 33%); m.p.

150 °C. Anal. Found: C, 80.42; H, 6.76. Calc. for

3.15. [(C₈H₁₂)Rh{(p⁵-C₅Me₄)Me₂Si(p⁵-C₅H₄)Co-

(C₈H₁₂)] (16)

Complex 15 (0.17 g, 0.41 mmol) was treated with

n-BuLi (1.54 M, 0.27 ml, 0.42 mmol) in THF

overnight. The reaction solution was reacted with

[RhCl(C₈H₁₂)]₂(0.13 g, 0.53 mmol) at reﬂux for 5 h.

After the solvent was removed and the residue was

dissolved in C₆H₆, the solution was hydrolyzed with a

saturated aqueous solution of NH₄Cl, and the organic

layer was dried over Na₂SO₄. After concentration of

the solution, the residue was chromatographed on alu-

mina. The yellow–orange eluate by hexane was evapo-

rated to dryness, and the residue was crystallized from

hexane to give yellow–orange crystals of 16, 0.18 g

(0.29 mmol, 71%); m.p. 183 °C. Anal. Found: C, 61.09;

H, 7.62. Calc. for C₃₂H₄₆SiCoRh: C, 61.93; H, 7.47%.

¹H-NMR (CDCl₃): l 0.89 (s, 6H, SiMe₂), 1.43 (s, 6H,

C₅Me₄), 1.87 (s, 6H, C₅Me₄), 1.60 (d, 4H, C₈H₁₂) 1.93

(d, 4H, C₈H₁₂), 2.19 (m, 4H, C₈H₁₂), 2.42 (m, 4H,

C₈H₁₂), 2.96 (br, 4H, C₈H₁₂), 3.47 (br, 4H, C₈H₁₂), 3.69

(t, 2H, J=1.9 Hz, C₅H₄), 5.17 (t, 2H, J=1.7 Hz,

C₅H₄).

1

C₄₄H₄₃CoSi: C, 80.21; H, 6.58%. H-NMR (CDCl₃): l

0.31 (s, 6H, SiMe₂), 1.62 (s, 6H, C₅Me₄), 1.65 (s, 6H,

C₅Me₄), 2.73 (br, 1H, C₅Me₄ꢂH), 4.63 (t, 2H, J=1.7

Hz, C₅H₄), 4.70 (t, 2H, J=1.8 Hz, C₅H₄), 7.17–7.23

(m, 12H, C₄Ph₄), 7.44–7.46 (m, 8H, C₄Ph₄).

3.13. [{Me₂Si(C₅H₅)(p⁵-C₅Me₄)}Co(p⁴-C₄Ph₄)] (14)

The dilithium salt, prepared from 1 (0.29 g, 1.19

mmol) and n-BuLi (1.54 M, 1.6 ml, 2.46 mmol), was

treated with CoCl(PPh₃)₃(1.05 g, 1.19 mmol) and

PhCꢀCPh (0.74 g, 4.16 mmol) in THF for 2 days at r.t.

The solution was hydrolyzed with a saturated aqueous

solution of NH₄Cl, and the organic layer was dried

over Na₂SO₄. The solution was concentrated and chro-

matographed on alumina. The ﬁrst yellow band was

eluted by hexane and a second reddish-brown band

eluted by C₆H₆–hexane (1:2). The yellow elute was

evacuated to dryness and crystallized from hexane to

give yellow orange crystals of 14, 0.12 g (0.18 mmol,

15%). From the reddish-brown elute reddish-brown

crystals of 10 were obtained, 0.17 g (0.18 mmol, 15%);

m.p. 180 °C. Anal. Found: C, 80.27; H, 6.70. Calc. for

3.16. [(C₈H₁₂)Ir{(p⁵-C₅Me₄)Me₂Si(p⁵-C₅H₄)Co(C₈H₁₂)]

(17)

1

C₄₄H₄₃CoSi: C, 80.21; H, 6.58%. H-NMR (CDCl₃): l

0.22 (s, 6H, SiMe₂), 1.44 (s, 6H, C₅Me₄), 1.65 (s, 6H,

C₅Me₄), 3.42 (br, 1H, C₅H₄ꢂH), 6.20 (s, 2H, C₅H₄),

6.50 (s, 2H, C₅H₄), 7.20 (m, 12H, C₄Ph₄), 7.35 (m, 8H,

C₄Ph₄).

Complex 15 (0.20 g, 0.49 mmol) was treated with

n-BuLi (1.54 M, 0.32 ml, 0.49 mmol) in THF

overnight. The reaction solution was treated with

[IrCl(C₈H₁₂)]₂(0.17 g, 0.51 mmol) at reﬂux for 5 h. The

solvent was evaporated and the residue was dissolved in

C₆H₆. The solution was hydrolyzed with a saturated

aqueous solution of NH₄Cl, and the organic layer was

dried over Na₂SO₄. After concentration of the solution,

the residue was chromatographed on alumina. The

orange eluate by hexane was evaporated to dryness,

and the residue was crystallized from hexane to give

orange crystals of 17, 0.14 g (0.20 mmol, 41%); m.p.

199 °C Anal. Found: C, 54.03; H, 6.78. Calc. for

C₃₂H₄₆CoIrSi: C, 54.14; H, 6.53%. ¹H-NMR (CDCl₃): l

0.85 (s, 6H, SiMe₂), 1.54 (s, 6H, C₅Me₄), 1.60 (pseudo-

q, 4H, C₈H₁₂), 1.84 (pseudo-q, 4H, C₈H₁₂), 1.90 (s, 6H,

C₅Me₄), 2.06 (m, 4H, C₈H₁₂), 2.41 (m, 4H, C₈H₁₂), 2.79

(br, 4H, C₈H₁₂), 3.46 (br, 4H, C₈H₁₂), 3.67 (t, 2H,

J=2.0 Hz, C₅H₄), 5.18 (t, 2H, J=2.0 Hz, C₅H₄).

3.14. [(C₅Me₄H)Me₂Si(p⁵-C₅H₄)Co(C₈H₁₂)] (15)

The dilithium salt, prepared from 1 (0.35 g, 1.43

mmol) and n-BuLi (1.54 M, 1.9 ml, 2.93 mmol) in

THF, was reacted with CoCl(PPh₃)₃(2.54 g, 2.89

mmol) and 1,5-C₈H₁₂(6 ml, 6.80 mmol) overnight. The

reaction mixture was evacuated to dryness and the

residue was dissolved in C₆H₆. The solution was hy-

drolyzed with a saturated aqueous solution of NH₄Cl,

and the organic layer was dried over Na₂SO₄. After

concentration, the resulting solution was chro-

matographed on alumina. The yellow–orange eluate by

hexane was evacuated to dryness and the residue was

crystallized from pentane–MeCN to yield orange crys-

120

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

3.17. [{Me₂Si(C₅HMe₄)(p⁵-C₅H₄)}-

{Rh(PPh₃)(v-CO)₂Fe(CO)₃}] (18)

eluted by hexane–C₆H₆(3:1) was evacuated, and the

residue was crystallized from hexane–C₆H₆to give

green crystals of 19, 0.05 g (0.07 mmol, 47%); m.p.

159 °C. Anal. Found: C, 39.16; H, 3.32. Calc. for

C₂₂H₂₂O₆SiFeRh₂: C, 39.31; H, 3.30%. ¹H-NMR

(CDCl₃): l 0.57 (s, 6H, SiMe₂), 1.80 (s, 6H, C₅Me₄),

1.83 (s, 6H, C₅Me₄), 4.89 (t, 2H, J=1.9 Hz, C₅H₄),

5.65 (m, 2H, C₅H₄). IR (KBr, cm⁻¹): w_CO2027, 1977,

1967, 1832, 1784. IR (CHCl₃, cm⁻¹): w_CO2043, 1990,

1826, 1775.

A suspension of 6 (0.53 g, 0.83 mmol) and Fe₂(CO)₉

(0.41 g, 1.13 mmol) in hexane was stirred at r.t.

overnight. The resulting purple solution was evacuated

to dryness. The residue was dissolved in a small amount

of C₆H₆and chromatographed on alumina. The purple

eluate by hexane–C₆H₆(3:1) was evacuated to dryness,

and the residue was crystallized from CH₂Cl₂–hexane

to give purple crystals of 18, 0.51 g (0.63 mmol, 76%);

m.p. 140 °C. Anal. Found: C, 57.59; H, 4.85. Calc. for

C₃₉H₃₈O₅PSiFeRh: C, 58.22; H, 4.76%. ¹H-NMR

(CDCl₃): l 0.47 (s, 6H, SiMe₂), 1.59 (s, 6H, C₅Me₄),

1.75 (s, 6H, C₅Me₄), 2.83 (br, 1H, C₅Me₄H), 4.97 (s,

2H, C₅H₄), 5.19 (s, 2H, C₅H₄), 7.36–7.44 (m, 15H,

PPh₃). IR (KBr, cm⁻¹): w_CO2021, 1955, 1945, 1811,

1782. IR (CHCl₃, cm⁻¹): w_CO2030, 1961, 1806, 1777.

3.19. X-ray diffraction studies

Single crystals suitable for X-ray analysis were

mounted on a glass ﬁber, and all measurements were

made on a Rigaku AFC7S diffractometer with graphite

,

monochromatized Mo–K_aradiation (u=0.71069 A).

Cell constants and orientation matrixes were deter-

mined by a least-squares reﬁnement of 25 centered

reﬂections with 39.16B2qB39.81° for 3, 25.07B2qB

29.49° for 11, 38.90B2qB39.84° for 12, 20.23B2qB

23.52° for 18, 27.91B2qB36.42° for 19. The data

collection was performed at r.t. using the ꢀ–2q scan

technique. Details of crystal and data collection

parameters are summarized in Table 6. The structure

solution and reﬁnements were carried out sing the

TEXSAN program package. The positions of the non-hy-

drogen atoms were determined by Patterson methods

3.18. [{(p⁵-C₅H₄)SiMe₂(p⁵-C₅Me₄)}-

{Rh(CO)Rh(v-CO)₂ꢂFe(CO)₃}] (19)

To a solution of 5 (0.08 g, 0.15 mmol) in Et₂O was

added Fe₂(CO)₉(0.25 g, 0.69 mmol) and stirred

overnight at r.t. The color of the mixture turned deep

green. After the solvent was evaporated to dryness, the

residue was dissolved in a small amount of C₆H₆and

chromatographed on alumina. The green fraction

Table 6

Crystal data and structure reﬁnement parameters for complexes 3, 11, 12, 18 and 19

Complex

3

11

12

18

19

Empirical formula

Formula weight

Crystal system

Space group

C₃₂H₄₆SiRh₂

664.61

Monoclinic

C2

C₅₂H₅₄SiCoRh

868.92

Triclinic

C₅₂H₅₄SiCoIr

958.24

Triclinic

C₃₉H₃₈O₅PsiFeRh C₂₂H₂₂O₆SiFeRh₂

804.54

672.16

Triclinic

Monoclinic

P2₁/n

(

P1

Unit cell dimensions

,

a (A)

19.829(1)

12.670(1)

15.938(1)

13.096(5)

14.112(8)

12.390(7)

101.88(7)

105.77(4)

97.69(4)

2112(2)

13.096(4)

14.108(5)

12.385(3)

101.85(3)

105.86(2)

97.61(3)

2110(1)

13.163(3)

13.216(3)

11.034(3)

90.98(2)

100.29(2)

73.24(2)

1807.1(8)

2

9.261(2)

27.462(2)

9.822(2)

,

b (A)

,

c (A)

h (°)

i (°)

k (°)

V (A )

133.566(2)

103.78(1)

3

,

2901.3(4)

4

1.521

2426.3(6)

4

1.840

Z

2

D_calc(g cm⁻³

)

1.366

1.508

1.478

Crystal dimensions (mm)

0.40×0.30

0.15×0.13×0.30

0.38×0.20×0.35

0.08×0.04×0.30

0.12×0.12×0.20

×0.40

11.95

ꢀ–2q

55

v, Mo–K_a(cm⁻¹

Scan type

2q_max(°)

)

8.46

ꢀ–2q

55

36.15

ꢀ–2q

55

9.76

ꢀ–2q

50

20.15

ꢀ–2q

55

Reﬂections collected

Unique reﬂections

Reﬂections observed [I\3.00|(I)]

Number of parameters

Goodness-of-ﬁt

R

3591

3491

3117

314

2.35

0.030

0.027

10 110

9688

6144

496

1.57

0.039

0.034

10 099

9675

7866

496

1.80

0.030

0.027

6672

6367

3488

433

1.66

0.058

0.043

6036

5701

3866

289

1.19

0.032

0.033

R_w

H. Komatsu, H. Yamazaki / Journal of Organometallic Chemistry 634 (2001) 109–121

121

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Organomet. Chem. 584 (1999) 329;

(

DIRDIF PATTY). All non-hydrogen atoms were reﬁned

anisotropically by full-matrix least-squares techniques.

All hydrogen atoms were placed at calculated positions.

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4. Supplementary material

Crystallographic date for the structural analysis have

been deposited with the Cambridge Crystallographic

Data Centre, CCDC nos. 160435–160439 for com-

pounds 3, 11, 12, 18 and C₅H₄, respectively. Copies of

this information may be obtained free of charge from

The Director, CCDC, 12 Union Road, Cambridge CB2

1EZ, UK (Fax: +44-1223-336033; e-mail: deposit@

ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).

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