Synthesis and structure of the dinuclear chloro-rhodium π-complexes with vinylsilanes

Article abstract of DOI:10.1016/S0020-1693(03)00049-5

Reaction of the Cramer's complex [{Rh(C₂H₄) ₂(μ-Cl)}₂] with the appropriate vinylsilane molecules yields, by displacement of the ethylene ligands, the complexes [{Rh(η ²-CH₂=CHSiR₃

Full text of DOI:10.1016/S0020-1693(03)00049-5

Inorganica Chimica Acta 350 (2003) 603Á608
/
www.elsevier.com/locate/ica
Synthesis and structure of the dinuclear chloro-rhodium p-complexes
with vinylsilanes
Paulina B lazejewska-Chadyniak, Maciej Kubicki, Hieronim Maciejewski,
˙
Bogdan Marciniec *
Department of Organometallic Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, Poznan´ 60-780, Poland
Received 17 August 2002; accepted 13 December 2002
Dedicated to Professor Pierre Braunstein in recognition of his great contribution to inorganic and organometallic chemistry
Abstract
Reaction of the Cramer’s complex [{Rh(C2H4)2(m-Cl)}2] with the appropriate vinylsilane molecules yields, by displacement of the
ethylene ligands, the complexes [{Rh(h2-CH2Ä
CHSiR3)2(m-Cl)}2] (where R3ꢀMe3 (1), Me2Ph (2), MePh2 (3), Ph3 (4),
/
/
Me2(OSiMe3) (5)). The structures of 1, 2 and 3 complexes have been determined crystalographically. There are the first crystal
structures of dinuclear rhodium(I) complexes with monovinylsilanes. All complexes have been characterised by multinuclear NMR
spectroscopy.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Rhodium(I); Vinylsilane; p-Complexes
1. Introduction
Transition metalÁ
[{Pt(h-CH2Ä
[8,9]. Other platinum complexes containing both divi-
nyltetramethyldisiloxane [10,11] and vinylsilane [12Á15]
/
CHSiMe2)2O}2{m-(h-CH2Ä
/
CHSiMe2)2O}]
/
alkene p-complexes have attracted
/
much attention, largely due to their prominent role in
catalysis and also due to their high lability, as starting
materials for the synthesis of a wide range of new
complexes. A lot of examples of complexes with p-
bonded ligands are known [1] but those containing vinyl
derivatives of organosilicon compounds are uncommon.
The interest in the chemistry of transition metal olefin
complexes containing vinyl derivatives of organosilicon
compounds as p-ligands is fully justified not only by the
particular nature of the bond between vinylsilicon
derivatives and transition metals, but mainly by the
possible application of this kind of complexes to
have also been synthesised. High catalytic activity of
complexes of this kind has stimulated much research
aimed at using other transition metal compounds as
potential catalysts. By analogy to Karstedt’s catalyst,
the complexes of nickel [16] and palladium [17] have
been prepared and a few other phosphineÁ/nickel com-
plexes with vinylsiloxane [17Á20], vinylsilane [20,21] and
/
vinylsilazane [22] have also been analysed.
There are some examples of rhodium p-complexes
with vinylsilicon ligands. Binuclear Rh(I) complexes
with divinylsiloxane [{Rh(h-CH2Ä
(where RꢀMe, Ph) were reported by Lappert group
[23]. Mononuclear Rh complexes of the type
[(acac)Rh(h-CH2ÄCHSiR3)2] or [(acac)Rh{h-(CH2Ä
/
CHSiR2)2O(m-Cl)}2]
/
catalysis of hydrosilylation processes [2Á
platinum compounds used as hydrosilylation catalysts
are Pt(0) complexes containing vinylÁsiloxane ligands
/6]. Among
/
/
CH)2SiR2}] with vinylsilane or divinylsilane were
synthesised by Fitch [24,25] and a few half-sandwich
complexes with divinylsilane, e.g., [(h5-C9H7)Rh{h4-
/
and an example of them is the Karstedt’s catalyst [7]
containing both bridging and chelating divinyl ligands
(CH2Ä
SiR2}] [26] and divinyl-siloxane or -silazane, e.g.,
[Cp*Rh{h-(CH2ÄCHSiMe2)2X}] (where XꢀO, NH)
[27] were also obtained.
/
CH)2SiMe2}] [25] or [Cp*Rh{h-(CH2Ä
/CH)2-
/
/
* Corresponding author. Fax: ꢁ
/
48-61-8291 508.
E-mail address: marcinb@main.amu.edu.pl (B. Marciniec).
0020-1693/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(03)00049-5

604
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/608
˙
This work was aimed at synthesising and characteris-
ing spectroscopically as well as determining crystal
structures of new dinuclear rhodium(I) complexes hav-
ing h2-vinylsilicon ligands (mono-vinylsilane), using
Cramer’s complex as a starting material. In the hitherto
works, the structures of either mononuclear [26] or
dinuclear [23] complexes with only divinyl silicon
compounds have been reported.
2.3. Synthesis of the complex
[{Rh(CH2Ä
/
CHSiMe2Ph)2(m-Cl)}2] (2)
Complex 2 was prepared in a similar way as 1, except
that CH2ÄCHSiMe2Ph (0.46 ml; 2.52 mmol) was used
instead of CH2ÄCHSiMe3. The orangeÁred oil was
washed with methanol (2ꢂ2 ml). The complex was
obtained with the yield of 70%. OrangeÁred crystals
suitable for X-ray diffraction were obtained from
hexane; m.p. (dec.)ꢀ103 8C.
1H NMR (C6D6, ppm): d 0.31 (s, 12H); 0.49 (s, 12H);
1.37 (bs, 4H3, Ã CH2); 3.23 (d, 4H2, JH2ÃH3
CHÄ 11
Hz, ÃCHÄ 15.3 Hz, ÃCHÄ
CH2); 3.77 (d, 4H1, JH1ÃH3
CH2); 7.27 (m, 12H); 7.63 (m, 8H).
13C NMR (C6D6, ppm): d 0.08, 1.80 (Ã
JCÃRh 15.5 Hz, ÃCHÄCH2), 69.90 (d, JCÃRh
Hz, ÃCHÄCH2); 128.61, 129.69; 134.66, 140.20 (Ã
29Si NMR (INEPT) (C6D6, ppm): d 4.05 (Ã
SiMe2Ph).
/
/
/
/
/
/
/
/
ꢀ
/
2. Experimental
/
/
ꢀ
/
/
/
/
Me); 67.95 (d,
11.9
Ph).
2.1. General methods and chemicals
ꢀ
/
/
/
ꢀ
/
/
/
/
All syntheses and operations were carried out using
standard Schlenk techniques under a carefully deoxyge-
/
1
nated and dried Ar. The H, 13C and 29Si NMR spectra
2.4. Synthesis of the complex
[{Rh(CH2ÄCHSiMePh2)2(m-Cl)}2] (3)
were recorded on Varian Mercury and Varian Gemini
300 VT spectrometers. The reagents were obtained from
the following sources: C6H6 from OBR PR Plock
(Poland), vinyltrimethylsilane, vinyldimethylphenylsi-
lane, vinyltriphenylsilane and vinyldimethyl(trimethylsi-
loxy)silane from ABCR, C5H12, CH3OH and
diethylether from POCh, Gliwice (Poland). All solvents
were distilled in inert atmosphere prior to use.
[{Rh(C2H4)2(m-Cl)}2] [28] and vinyldiphenylmethylsi-
lane [29] were prepared according to the procedures
reported previously.
/
Complex 3 was prepared in a similar way as 1, except
that CH2ÄCHSiMePh2 (0.56 ml; 2.50 mmol) was used
instead of CH2ÄCHSiMe3. The orange oil was washed
with methanol (2ꢂ2 ml) and diethyl ether (2ꢂ2 ml).
The complex was obtained with the yield of 75%.
YellowÁorange crystals suitable for X-ray diffraction
were obtained from pentane; m.p.ꢀ106 8C.
1H NMR (C6D6, ppm): d 0.32 (s, 6H); 0.95 (s, 6H);
1.36 (dd, 4H3, JH2ÃH3
11.1 Hz, JH1ÃH3 14.9 Hz, Ã
11.1 Hz, ÃCHÄCH2);
14.9 Hz, ÃCHÄCH2); 7.55 (m,
/
/
/
/
/
/
ꢀ
/
ꢀ
/
/
CHÄ
/
CH2); 3.21 (d, 4H2, JH2ÃH3
ꢀ
/
/
/
3.57 (d, 4H1, JH1ÃH3
ꢀ
/
/
/
2.2. Synthesis of the complex
24H); 7.97 (m, 16H).
13C NMR (C6D6, ppm): d ꢃ
[{Rh(CH2Ä
/
CHSiMe3)2(m-Cl)}2] (1)
/
1.81 (Ã
/
Me); 65.22 (d,
12.1
Ph).
9.43
JCÃRh
ꢀ
CHÄ
/
14.1 Hz, Ã
/
CHÄ
/
CH2), 70.44 (d, JCÃRh
ꢀ
/
A 3 ml portion of CH2Ä/CHSiMe3 (0.02 mol) was
Hz, Ã
/
/
CH2); 128.23, 129.32, 135.28, 135.53 (Ã
/
added to a vigorously stirred solution of 0.2 g
[{Rh(C2H4)2(m-Cl)}2] (0.51 mmol) in dried and deox-
idised diethyl ether (7 ml), placed in a Schlenk’s flask in
Ar atmosphere. The reaction was carried out for 3 h at
room temperature (r.t.). After that time, the mixture was
filtered off by a cannula system. From the filtrate,
diethyl ether and the excess of vinyltrimethylsilane were
evaporated leaving orange solid. The complex was
obtained with the yield of 80%. Orange crystals suitable
for X-ray diffraction were obtained from diethyl ether;
29Si NMR (INEPT) (C6D6, ppm):
SiMePh2).
d
ꢃ
/
(Ã
/
2.5. Synthesis of the complex
[{Rh(CH2ÄCHSiPh3)2(m-Cl)}2] (4)
/
Complex 4 was prepared in a similar way as 1, except
that CH2ÄCHSiMePh3 (0.64 g; 2.24 mmol) was used
instead of CH2ÄCHSiMe3. The red oil was washed with
methanol (3ꢂ2 ml). The complex in the form of a redÁ
orange solid was obtained with the yield of 75%. m.p.ꢀ
177 8C.
1H NMR (C6D6, ppm): d 3.18 (d, 4H, JH1ÃH3
Hz, ÃCHÄCH2); 4.12 (dd, 4H, JH2ÃH3 11.7 Hz,
JH1ÃH3 15.3 Hz, ÃCHÄCH2); 4.57 (d, 4H, JH2ÃH3
11.9 Hz, ÃCHÄCH2); 7.70 (m, 36H); 8.07 (m, 24H).
13C NMR (C6D6, ppm): d 58.93 (bs, Ã
CHÄCH2),
71.00 (d, JCÃRh 12.1 Hz, ÃCHÄCH2), 130.18, 130.35,
135.17, 135.77 (Ph).
/
/
/
/
melting point (decomposition) m.p. (dec.)ꢀ
1H NMR (C6D6, ppm): d 0.45 (s, 36H, Ã
SiMe3); 0.97
(dd, 4H3, JH2ÃH3
11.3 Hz, JH1ÃH3 15.4 Hz, ÃCHÄ
CH2); 3.25 (d, 4H2, JH2ÃH3
11.3 Hz, ÃCHÄCH2); 3.77
(d, 4H1, JH1ÃH3
15.4 Hz, ÃCHÄCH2).
13C NMR (C6D6, ppm): d 0.12 (Ã
JCÃRh 14.7 Hz, ÃCHÄCH2), 68.92 (d, JCÃRh
Hz, ÃCHÄCH2).
29Si NMR (INEPT) (C6D6, ppm): d 0.14 (Ã
/
140 8C.
/
/
ꢀ
/
ꢀ
/
/
/
ꢀ15.3
/
ꢀ
/
/
/
/
/
ꢀ
/
ꢀ
/
/
/
ꢀ
/
/
/
ꢀ
/
/Me); 68.66 (d,
/
/
ꢀ
/
/
/
ꢀ
/
12.3
/
/
/
/
ꢀ
/
/
/
/SiMe3).

P. B lazejewska-Chadyniak et al. / Inorganica Chimica Acta 350 (2003) 603Á
/608
605
˙
29Si NMR (INEPT) (C6D6, ppm): d ꢃ
/
13.90 (Ã
/
SiPh3).
separate runs (782 frames) in order to cover the
symmetry-independent part of the reciprocal space.
The v-scan was used with the step of 0.758, two
reference frames were measured after every 50 frames,
and they showed no systematic changes neither in the
peak positions nor in their intensities. The unit-cell
parameters were determined by the least-square treat-
ment of the setting angles of 1220 (1), 12 351 (2), and
1581 (3) highest-intensity reflections, chosen from the
whole experiment. The Lorentz and polarisation correc-
tions were applied [31], and then the reflections were
merged and corrected for absorption with Sortav
[32].The structures were solved by direct methods with
SHELXS-97 program [33], and refined with the full-
matrix least-squares by SHELXL-97 [34]. Non-hydrogen
atoms were refined anisotropically; the positions of
hydrogen atoms were generated geometrically and they
were refined as a ‘riding model’ with their Uiso para-
meters set at 1.2 times Ueq of the appropriate carrier
atom.
2.6. Synthesis of the complex
[{Rh(CH2Ä
/
CHSiMe2(OSiMe3))2(m-Cl)}2] (5)
Complex 5 was prepared in a similar manner as 1,
except that CH2ÄCHSiMe2(OSiMe3) (0.54 ml; 2.44
mmol) was used instead of CH2ÄCHSiMe3. The dark
red oil was washed with pentane (2ꢂ2 ml). The
complex as a orangeÁbrown solid was obtained with
the yield of 70%. m.p.ꢀ97 8C.
1H NMR (INEPT) (C6D6, ppm): d 0.21 (s, 36H,
CH3); 0.52 (s, 12H, ÃCH3); 0.89 (s, 12H, ÃCH3); 1.16
(dd, 4H, JH2ÃH3 11.5 Hz, JH1ÃH3 15.4 Hz, ÃCHÄ
CH2); 3.40 (d, 4H2, JH2ÃH3
11.3 Hz, ÃCHÄCH2);
3.81 (d, 4H1, JH1ÃH3
15.4 Hz, ÃCHÄCH2).
13C NMR (C6D6, ppm): d 2.34 (Ã
OSiMe3); 3.22
SiMe2Ã); 68.46 (d, JCÃRh 14.4 Hz, ÃCHÄCH2);
68.94 (d, JCÃRh 11.9 Hz, ÃCHÄCH2).
29Si NMR (INEPT) (C6D6, ppm): d 2.36 (d,
SiMe2Ã), 7.96 (ÃOSiMe3).
/
/
/
/
/
Ã
/
/
/
ꢀ
/
ꢀ
/
/
/
ꢀ
/
/
/
ꢀ
/
/
/
/
(Ã
/
/
ꢀ
/
/
/
ꢀ
/
/
/
A summary of crystal data, data collection and
refinement is given in Table 1.
Ã
/
/
/
2.7. X-ray structure determination for 1, 2 and 3
The diffraction data obtained for reddish-brown,
plate-shaped crystals, sealed in glass capillaries, were
collected on a KUMA KM4CCD diffractometer [30] at
3. Results and discussion
Each of the binuclear Rh(I) complexes, [{Rh(h2-
r.t. (1 and 3) and at 110 K (2), using graphite-
CH2Ä
/
CHSiR3)2(m-Cl)}2] (R3ꢀ
/
Me3 (1), Me2Ph (2),
˚
0.71073 A). In
each case, the data collection was performed in six
monochromated Mo Ka radiation (lꢀ
/
MePh2 (3), Ph3 (4) or Me2(OSiMe3) (5)), was synthesised
by displacement of the four ethylene ligands from
Table 1
Crystal data
Compound
1
2
3
Formula
Rh2Cl2C20H48Si4
677.66
monoclinic
2/c
Rh2Cl2C40H56Si4
925.93
triclinic
Rh2Cl2C20H48Si4
Formula weight
Crystal system
Space group
triclinic
P
/
1
P/1
˚
a (A)
21.221(4)
8.073(2)
20.658(4)
90
15.0649(7)
18.1114(8)
18.1575(7)
106.648(4)
90.297(3)
111.478(4)
4383.1(3)
4
13.710(3)
14.158(3)
16.910(3)
106.61(3)
113.52(3)
90.25(3)
2587.7
2
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
116.68(3)
90
3
˚
V (A )
Z
3162.3(12)
4
1.423
dx (Mg mꢃ3
)
1.403
1.010
1904
1.365
0.79
1208
m (mmꢃ1
F(000)
)
1.371
1392
Crystal size (mm)
u Range for data collection (8)
Reflections collected
0.1ꢂ
/
0.15ꢂ
25
/
0.3
0.1ꢂ
/
0.2ꢂ
24
/
0.3
0.07ꢂ
/
0.1ꢂ0.3
/
2.15Á
/
3.02Á
/
3.0Á24
/
9847
2772
31 564
13 677
0.0558
0.1365
1.24
14 543
6221
Independent reflections
R [I ꢀ/2s(I)]
0.0579
0.1228
1.27
0.0566
0.0755
1.04
wR2 [I ꢀ/2s(I)]
S
ꢃ3
˚
Drmax/Drmin (e A
)
1.74 and ꢃ
/
0.75
1.30 and ꢃ
/
1.68
0.37 and ꢃ0.32
/

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/608
˙
Scheme 1.
[{Rh(h2-C2H4)2(m-Cl)}2] by the appropriate vinylsilane
(see Scheme 1).
The structures of 1, 2 and 3 complexes have been
determined crystalographically. All complexes have
been characterised by multinuclear NMR spectroscopy.
Fig. 3. ORTEP view of the complex 3 (33% probability ellipsoids).
Labels of carbon atoms are omitted for clarity.
The molecular structures of complexes 1, 2A, and 3
with the atom numbering scheme are depicted in Figs.
1Á3, respectively.
/
Selected geometrical parameters are listed in Table 2.
Complex 1 occupies the special position of the space
group C2/c, on a twofold axis that runs by the middle
and is perpendicular to the RhÁ Á ÁRh and ClÁ Á ÁCl lines.
Compound 2 crystallises with two symmetry-indepen-
dent molecules in the asymmetric part of the unit cell
(hereinafter referred to as 2A and 2B, respectively).
In all three complexes the coordination of rhodium is
square-planar (the mid-points of the double bonds are
regarded as the coordination sites). This is evident from
the inspection of bond angles as well as from the least-
square plane calculations: the maximum deviation of the
rhodium atom from the plane defined by four coordina-
Fig. 1. ORTEP view of the complex 1, showing the labelling scheme
(33% probability ellipsoids).
Fig. 2. ORTEP view of the complex 2, showing the labelling scheme (33% probability ellipsoids).

P. B lazejewska-Chadyniak et al. / Inorganica Chimica Acta 350 (2003) 603Á
/608
607
˙
Table 2
Selected bond lengths and bond angles (X1, X2, X3, X4 denote the
C32
close to 0 and 91208. The differences in the mutual
orientation of the central ring and the phenyl ring planes
are probably due to the steric requirements.
The coordination of two olefins to the each rhodium
atom frequently results in the formation of a mixture of
isomers in which the substituent can either face towards
or away from the rhodium atom being placed on the
same or the opposite side as the substituent at the
second olefin [24,26]. The NMR data of dimeric
/
mid-points of the double CÄ
/
C bonds: C11Ã
/
C12, C21Ã
/
C22, C31Ã
/
and C41Ã/C42, respectively)
1
2A
2B
3
Bond lengths
Rh1Ã
Rh1Ã
Rh1Ã
Rh1Ã
Rh2Ã
Rh2Ã
Rh2Ã
Rh2Ã
C11Ã
C21Ã
C31Ã
C41Ã
C12Ã
C22Ã
C32Ã
C42Ã
ŽSiÃ
ŽSiÃ
/
X1
X2
Cl1
Cl2
X3
X4
Cl1
Cl2
2.000(10) 2.022(8)
2.026(7)
2.022(7)
2.394(2)
2.389(2)
2.013(7)
2.030(7)
2.378(2)
2.400(2)
2.025(10)
2.041(10)
2.392(3)
2.385(3)
2.028(10)
2.037(10)
2.391(3)
2.378(3)
/
2.019(8)
2.387(2)
2.364(2)
2.014(7)
2.385(2)
2.398(2)
2.009(7)
2.034(7)
2.389(2)
2.392(2)
/
/
rhodiumÁvinylsilane complexes, recrystallised from the
/
/
respective solvents (diethyl ether (1), hexane (2) or
pentane (3)) indicated the presence of a single isomer.
The vinylic carbon and proton resonances (in the 13C
NMR and 1H NMR, respectively) of all complexes
appear in much higher field than those of the free ligand.
Three vinyl resonances observed in the 1H NMR spectra
/
/
/
/
C12
C22
C32
C42
Si1
1.383(9)
1.398(10) 1.400(10) 1.395(11)
/
1.405(11) 1.387(11) 1.396(10) 1.395(11)
1.397(11) 1.412(10) 1.391(11)
/
/
1.401(11) 1.383(10) 1.371(12)
are assigned to (Ä
/
CHÃ
/
), (Ä
/
CH2-trans) or (Ä/CH2-cis) on
/
1.844(7)
1.868(7)
1.855(8)
1.870(8)
1.886(7)
1.866(7)
1.855
1.864(7)
1.876(7)
1.875(7)
1.880(8)
1.859
1.882(11)
1.829(11)
1.862(10)
1.837(10)
1.850
the basis of the coupling constant data, which is
illustrated by the following structure.
/
Si2
/
Si3
/
Si4
/
C3sp

1.848
3.360
/
Car
1.882
3.590
1.884
3.460
1.861
3.441
Rh1Á Á ÁRh2
Bond angles
X1Ã
X1Ã
X1Ã
X2Ã
X2Ã
Cl1Ã
Cl1Ã
Rh1Ã
Rh1Ã
X3ÃRh2Ã
X3ÃRh2Ã
X3ÃRh2Ã
X4ÃRh2Ã
X4ÃRh2Ã
C11ÃC12Ã
C21ÃC22Ã
C31ÃC32Ã
C41ÃC42Ã
Cl1ÃRh1Ã
Rh1ÃCl1Ã
Roof angle
/
Rh1Ã
Rh1Ã
Rh1Ã
Rh1Ã
Rh1Ã
Rh1Ã
Rh2Ã
Cl1Ã
Cl2Ã
/
X2
92.6(3)
92.8(2)
92.0(3)
91.6(2)
92.1(3)
93.5(2)
174.3(3
92.5(4)
91.8(3)
173.9(3)
The resonance in the high field is assigned to the
‘inner’ protons (H2 and H3) and that in the low field to
the ‘outer’ (H1) ones [37]. This assignment is supported
/
/
Cl1
Cl2
Cl1
Cl2
/
/
174.5(3)
173.9(3)
92.8(3)
173.0(2)
175.6(3)
94.9(3)
/
/
173.4(2) 175.7(3)
93.1(2) 93.1(3)
/
/
by JH1ÃH3 and JH2ÃH3 which are 14.9Á
/
15.4 and 11.0Á
/
/
/
Cl2
81.83(7)
81.62(7)
81.65(7)
97.50(7)
97.10(7)
92.2(3)
81.50(7) 82.61(11)
81.62(6) 82.77(11)
92.94(6) 92.01(11)
92.52(7) 92.53(11)
11.9 Hz, respectively (in all synthesised complexes), for
the trans and cis coupling constants. In all complexes,
due to steric effects, the silyl groups lie in face off to
rhodium atom and opposite to another silyl group from
second molecule of vinylsilane. The signals for the vinyl
carbons in the 13C NMR spectra were split into two
doublets corresponding to the methine and methylene
/
/
Cl2
/
/
Rh2
Rh2
90.04(6)
/
/
/
/X4
92.3(3)
93.5(4)
/
/
Cl1
Cl2
Cl1
Cl2
175.5(2)
94.2(2)
91.8(2)
174.5(2) 174.7(3)
92.9(2)
93.2(2)
/
/
92.1(3)
91.6(3)
/
/
/
/
172.8(2)
126.9(6)
127.9(7)
128.9(6)
130.0(6)
174.5(2) 174.4(3)
127.4(6) 128.0(8)
126.0(6) 126.8(9)
127.8(6) 128.6(8)
125.7(6) 128.3(9)
carbons, and testified to the 13CÃ
14 and 12 Hz, respectively). The coupling constants
J(13CÃ103Rh) are similar to those observed for other
/
103Rh coupling (about
/
/
Si1
Si2
Si3
Si4
129.4(5)
127.8(6)
/
/
/
/
/
/
/
rhodium p-complexes containing vinylsilanes as ligands
[24,26]. The presence of only two doublets assigned the
olefinic carbons in 13C NMR spectra and three vinyl
resonance in the 1H NMR spectra, along with the results
of structural analysis confirm the co-ordination of 4
equiv. of vinylsilane ligands and indicated one dominant
rhodium species.
In accordance to the Cramer’s observation, rho-
dium(I) complexes of alkenes carrying electronegative
substituents are more stable than those of comparable
unsubstituted alkenes [36]. It means that the kind of
substituent at silicon in vinylsilane also influences the
stability of complexes with vinylsilicon ligands. Repla-
cement of methyl groups (complex 1) by phenyl groups
/
/
Cl2Ã
Rh2Ã
/
Rh2
Cl2
ꢃ30.01(9)
/
ꢃ
/
11.03(8)
ꢃ
/
25.08(7) 23.78(10)
/
/
/
ꢃ
/
11.08(8)
ꢃ
145.8
/
25.21(7) 23.70(10)
147.6
138.8
165.5
˚
tion sites is 0.048 A (Rh2 in molecule 2A). The CÄ
/C
bonds are approximately perpendicular to these planes.
Central four-membered rings RhÃClÃRhÃCl have
flattened roof shape; the roof angles (defined as the
dihedral angle between two ClÃRhÃCl planes) are in the
range 138.88 (1)Á165.58 (2A). These angles, of course,
/
/
/
/
/
/
correlate with the intramolecular RhÁ Á ÁRh distances (cf.
Table 2).
The bond lengths are well within the typical ranges,
which were observed for similar complexes, i.e. [{Rh(h2-
(complex 2Á4) increases electron-withdrawing behaviour
/
of alkene substituent, observed in NMR spectra. De-
pending on the number of phenyl groups replacing
CH2Ä
[35]. The conformations around Si atoms are very
similar; CÄCÃSiÃC torsion angles are in each molecule
/
CHSiR2)2O(m-Cl)}2] [23] or [{Rh(COD)(m-Cl)}2]
/
/
/
methyl groups in complexes 1Á4, the resonance of the
/

608
P. B lazejewska-Chadyniak et al. / Inorganica Chimica Acta 350 (2003) 603Á
/608
˙
[6] M.A. Brook, Silicon in Organic, Organometallic and Polymer
Chemistry, Wiley, New York, 2000.
[7] B.D. Karstedt, US Patent 3775452 (1973).
carbon atom attached to silicon is shifted to a higher
field (d 13C changes from 68.66 ppm in 1 to 58.93 ppm
in 4). Similar shifts were observed by Fitch et al. for
[8] G. Chandra, P.Y. Lo, P.B. Hitchcock, M.F. Lappert, Organo-
metallics 6 (1987) 191.
complexes of the type [(acac)Rh(CH2Ä
/
CHSiMen-
[9] P.B. Hitchcock, M.F. Lappert, N.J.W. Warhurst, Angew. Chem.,
Int. Ed. Engl. 30 (1991) 438.
(OEt)3ꢃn] ( where nꢀ
/
0Á3) [24]. The distance between
/
two doublets (in 13C NMR spectra) increases along with
the number of phenyl groups, from 0.26 ppm (1) to
[10] L.N. Lewis, J. Stein, R.E. Colborn, Y. Gao, J. Dong, J.
Organomet. Chem. 521 (1996) 221.
1
12.07 ppm (4). The H NMR and 13C NMR spectra of
[11] J. Stein, L.L. Lewis, Y. Gao, R.A. Scott, J. Am. Chem. Soc. 121
(1999) 3693.
complex 5 containing vinyldimethyl(trimethylsiloxy)si-
lane are very similar to those obtained for complex 1,
[12] L.N. Lewis, R.E. Colborn, H. Grade, G.L. Bryant, Jr., C.A.
Sumpter, R.A. Scott, Organometallics 14 (1995) 2202.
[13] J.W. Fitch, K.C. Chan, J.A. Froelich, J. Organomet. Chem. 160
(1978) 477.
which suggests that the nature of CH2Ä
/CHSiMe3 and
CH2ÄCHSiMe2(OSiMe3) is similar.
/
[14] J.W. Fitch, M. Brown, N.H. Hall, P.P. Mebe, K.A. Owens, M.R.
Roesch, J. Organomet. Chem. 244 (1983) 201.
[15] E.M. Haschke, J.W. Fitch, J. Organomet. Chem. 57 (1973) C93.
[16] H. Maciejewski, B. Marciniec, I. Kownacki, J. Organomet. Chem.
597 (2000) 175.
4. Supplementary materials
Additional crystallographic data have been deposited
with the Cambridge Crystallographic Data Centre as
supplementary publication CCDC Nos. 188002 (1),
188003 (2) and 188004 (3). Copies of the data may be
obtained free of charge on application to The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
[17] J. Krause, G. Cestaric, K.J. Haack, K. Seevogel, W. Storm, K.R.
Porschke, J. Am. Chem. Soc. 121 (1999) 9807.
¨
[18] P.B. Hitchcock, M.F. Lappert, C. MacBeath, F.P.E. Scott,
N.J.W. Warhurst, J. Organomet. Chem. 528 (1997) 185.
[19] P.B. Hitchcock, M.F. Lappert, H. Maciejewski, J. Organomet.
Chem. 605 (2000) 221.
[20] P.B. Hitchcock, M.F. Lappert, C. MacBeath, F.P.E. Scott,
N.J.W. Warhurst, J. Organomet. Chem. 534 (1997) 139.
[21] L.S. Isaeva, T.A. Peganowa, P.V. Petrovski, J. Organomet. Chem.
248 (1983) 357.
(fax: ꢁ44-1223-336-033, e-mail: deposit@ccdc.cam.ac.
/
uk or www: http://www.ccdc.cam.ac.uk).
[22] H. Maciejewski, M. Kubicki, B. Marciniec, A. Sydor, Polyhedron
21 (2002) 1261.
[23] C.J. Cardin, P.B. Hitchcock, M.F. Lappert, C. MacBeath, N.J.
Warhurst, J. Organomet. Chem. 584 (1999) 366.
[24] J.W. Fitch, W.T. Osterloch, J. Organomet. Chem. 213 (1981) 493.
[25] J.W. Fitch, D. Westmoreland, J. Organomet. Chem. 268 (1984)
269.
Acknowledgements
Financial support of our work by the State Commit-
tee for Scientific Research, Poland, project number
K026/T09/2001 is gratefully acknowledged.
[26] C.P. Lenges, P.S. White, M. Brookhart, J. Am. Chem. Soc. 121
(1999) 4385.
[27] S.S.D. Brown, S.N. Heaton, M.H. Moore, R.N. Perutz, G.
Wilson, Organometallics 15 (1996) 1392.
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