Isomers of chloro(triarylsilyl)hydridorhodium(III) Complexes, mer-RhCl(H)(SiAr3)(PMe3)3. Relevance of their structures to reductive elimination of ClSiAr3

Article abstract of DOI:10.1021/om970846k

RhCl(PMe₃)₃ reacts with HSiPh₃ to give mer-RhCl(H)(SiPh₃)(PMe₃)₃ (1), whose X-ray structure shows octahedral coordination around the Rh(III) center with trans chloro and triphenylsilyl ligands. Reaction of HSi(C₆H₄CF₃-p)₃ with RhCl(PMe₃)₃ gives a mixture of Rh(III) complexes mer-RhCl(H){Si(C₆H₄CF₃-p)₃}(PMe ₃)₃ (2), fac-RhH₂(Si(C₆H₄CF₃-P) ₃}(PMe₃)₃ (3), and cis,mer-RhCl₂(H)(PMe₃)₃ (4) with relative amounts that depend on the specific reaction conditions. X-ray crystallography of 2 shows that the Si(C₆H₄CF_3-P)₃ ligand is cis to both the H and Cl ligands. The differing chemical reactivity of 2 and 1 indicates the importance of the cis-configuration for reductive elimination of HSiAr₃ and ClSiAr₃ from the complexes.

Full text of DOI:10.1021/om970846k

1868
Organometallics 1998, 17, 1868-1872
Isom er s of Ch lor o(tr ia r ylsilyl)h yd r id or h od iu m (III)
Com p lexes, m er -Rh Cl(H)(SiAr 3)(P Me3)3. Releva n ce of
Th eir Str u ctu r es to Red u ctive Elim in a tion of ClSiAr 3
Kohtaro Osakada,* Take-aki Koizumi, Susumu Sarai, and Takakazu Yamamoto*
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226-8503, J apan
Received September 29, 1997
RhCl(PMe3)3 reacts with HSiPh3 to give mer-RhCl(H)(SiPh3)(PMe3)3 (1), whose X-ray
structure shows octahedral coordination around the Rh(III) center with trans chloro and
triphenylsilyl ligands. Reaction of HSi(C6H4CF3-p)3 with RhCl(PMe3)3 gives a mixture of
Rh(III) complexes mer-RhCl(H){Si(C6H4CF3-p)3}(PMe3)3 (2), fac-RhH2{Si(C6H4CF3-p)3}(PMe3)3
(3), and cis,mer-RhCl2(H)(PMe3)3 (4) with relative amounts that depend on the specific
reaction conditions. X-ray crystallography of 2 shows that the Si(C6H4CF3-p)3 ligand is cis
to both the H and Cl ligands. The differing chemical reactivity of 2 and 1 indicates the
importance of the cis-configuration for reductive elimination of HSiAr3 and ClSiAr3 from
the complexes.
Sch em e 1
In tr od u ction
Reductive elimination of chloroalkane or chloroarene
from the RhCl(H)(R)(PR′3)n-type complexes1 is regarded
as a crucial step in Rh complex catalyzed decarbonyla-
tion of acyl chloride to give alkyl or aryl chloride.2 The
reaction is much less common than the C-C bond-
forming reaction from dialkyl transition-metal com-
plexes and is often observed under the high-temperature
conditions. On the other hand, Ir(III) and Pt(IV)
complexes containing the chloro and organosilyl ligands
have been reported to undergo smooth reductive elimi-
nation of chloroorganosilanes at room temperature.3 The
intramolecular coupling of the ligands seems to be
significantly influenced by the coordination geometry.
Recently, we have observed facile formation of chlorot-
riorganosilane from RhCl(H)(SiR3)[P(i-Pr)3]2 containing
a labile pentacoordinated metal center at room temper-
ature.4 On the other hand, mer-RhCl(H)(SiHAr2)-
(PMe3)3, whose chloro and diarylsilyl ligands are at
mutually trans positions of the rigid octahedral coordi-
nation, gives fac-RhH2(SiClAr2)(PMe3)3 as a product of
the thermal reaction, as shown in Scheme 1.5
ium(III) complexes containing the Cl and SiAr3 ligands
at cis or trans coordination sites and their different
reactivity toward reductive-elimination reactions.
Resu lts a n d Discu ssion
RhCl(PMe3)3 reacts with HSiPh3 to give the oxidative-
addition product mer-RhCl(H)(SiPh3)(PMe3)3 (1) in 21%
yield6 after recrystallization from a toluene-pentane
mixture, as shown in eq 1. X-ray crystallography of 1
Initial formation of ClSiHAr2 and ensuing oxidative
addition of its Si-H bond to the resulting RhH(PMe3)3
would account for generation of the (chlorodiaryl)silyl-
rhodium(III) complex. In this paper, we report the pre-
paration and structure of the chloro(triarylsilyl)rhod-
established the structure shown in Figure 1. The
molecule has a slightly distorted octahedral coordination
around the Rh center that is bonded to three meridional
PMe3 ligands and to chloro and triphenylsilyl ligands
at mutually trans positions. Table 1 summarizes se-
lected bond distances and angles of the molecule. The
Rh-Si bond distance (2.346(2) Å) is shorter than that
found in the structurally analogous complexes mer-Rh-
(SAr)H(SiPh3)(PMe3)3 (2.38 Å),7 indicating a smaller
trans influence of the chloro ligand.
(1) (a) Stille, J . K.; Regan, M. T. J . Am. Chem. Soc. 1974, 96, 1508.
(b) Stille, J . K.; Fries, R. W. Ibid. 1974, 96, 1514. (c) Stille, J . K.; Huang,
F.; Regan, M. T. Ibid. 1974, 96, 1518. (d) Lau, K. S. Y.; Huang, B. F.;
Baenziger, N.; Stille, J . K. Ibid. 1977, 99, 5664. (e) Kampmeier, J . A.;
Rodehorst, R. M.; Philip, J . B. J r. Ibid. 1981, 103, 1847.
(2) (a) Tsuji, J . Organic Synthesis via Metal Carbonyls; J ohn
Wiley: New York, 1977; Vol. 2, p 633. (b) Doughty, D. H.; Pignolet, L.
H. Homogeneous Catalysis with Metal Phosphine Complexes; Pignolet,
L. H., Ed.; Plenum Press: New York, 1982; p 343.
(5) Osakada, K.; Sarai, S.; Koizumi, T.; Yamamoto, T. Organome-
tallics 1997, 16, 3973.
(3) (a) Chalk A. J .; Harrod, J . F. J . Am. Chem. Soc. 1965, 87, 16. (b)
Chalk, A. J . J . Chem. Soc., Chem. Commun. 1969, 1207.
(4) (a) Osakada, K.; Koizumi, T.; Yamamoto, T. Bull. Chem. Soc.
J pn. 1997, 70, 189. (b) Osakada, K.; Koizumi, T.; Yamamoto, T.
Organometallics 1997, 16, 2063.
(6) The low isolated yield of 1 is due to a rapid and reversible
equilibrium between the complex and Rh(I) complexes resulting from
reductive elimination of HSiPh3 from 1 in the solution. See, ref 9 also.
(7) Osakada, K.; Hataya, K.; Yamamoto, T. Inorg. Chim. Acta 1997,
259, 203.
S0276-7333(97)00846-7 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 04/09/1998

Chloro(triarylsilyl)hydridorhodium(III) Complexes
Organometallics, Vol. 17, No. 9, 1998 1869
formula RhCl(H)(SiPh3)(PMe3)3, despite the apparently
facile reductive elimination of HSiPh3 and its reoxida-
tive addition, indicates that 1 has a greater thermody-
namic stability. The oxidative-addition reactions of
oxirane, HCl, and thiol to RhCl(PMe3)3 formed com-
plexes containing the hydrido trans to PMe3 as the
thermodynamic products.10 A theoretical study of the
oxidative addition of HSiR3 to RhCl(PH3)2 also suggests
a higher stability of the product containing Cl and silyl
ligands at trans sites.11
HSi(C6H4CF3-p)3 reacts with RhCl(PMe3)3 to produce
Rh(III) complexes with different structures from 1. The
product contains a mixture of Rh(III) complexes, mer-
RhCl(H){Si(C6H4CF3-p)3}(PMe3)3 (2), fac-RhH2{Si(C6H4-
CF3-p)3}(PMe3)3 (3), and cis,mer-RhCl2(H)(PMe3)3 (4), as
shown in eq 2. Concomitant formation of ClSi(C6H4-
F igu r e 1. ORTEP drawing of mer-RhCl(H)(SiPh3)(PMe3)3
(1) at the 30% ellipsoidal level. The crystal contains
solvated toluene molecules. The molecule has a crystal-
lographic mirror plane containing the Rh, Cl, and Si atoms
as well as the P atom at a trans position to the hydrido.
Atoms with asterisks are crystallographically equivalent
to those with the same number without an asterisk. The
hydrogen atoms, except for the hydrido and atoms in the
solvent molecule, are omitted for simplicity.
CF3-p)3 and several uncharacterized Rh complexes in
small amounts is also noted.12
The product ratio, obtained from relative 1H NMR
peak area ratios, depends on the initial molar ratio of
HSi(C6H4CF3-p)3 and RhCl(PMe3)3. An equimolar reac-
tion of HSi(C6H4CF3-p)3 and RhCl(PMe3)3 for 8 h gives
2 (20%) and 3 (33%) accompanied by recovery of RhCl-
(PMe3)3 (>25%). The reaction in a 2:1 molar ratio for a
short period (15 min) results in formation of 2 (20%), 3
(24%), and 4 (8%). Increasing the ratio of HSi(C6H4-
CF3-p)3 and RhCl(PMe3)3 to 3:1 changes the yields of
complexes 2, 3, and 4 to 11%, 78%, and 12%, respec-
tively. The three Rh(III) products were isolated by
fractional crystallization and characterized by means
of X-ray crystallography as well as NMR spectroscopy.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) of 1, 2, a n d 3
1
2
3
Rh-Cl
2.543(2)
2.394(2)
2.333(2)
2.463(7)
2.387(8)
2.327(4)
Rh-P1
2.325(4)
2.326(4)
2.346(4)
2.338(4)
Rh-P2
Rh-P3
Rh-Si
2.346(2)
94.72(7)
82.52(4)
93.00(4)
164.29(7)
2.377(8)
94.4(3)
83.4(1)
92.4(1)
166.3(3)
Cl-Rh-P1
Cl-Rh-P2
P1-Rh-P2
P2-Rh-P2*
P1-Rh-P3
P2-Rh-P3
Si-Rh-Cl
Si-Rh-P1
Si-Rh-P2
Si-Rh-P3
100.2(1)
96.4(1)
99.8(1)
161.19(7)
104.09(7)
96.30(4)
109.8(2)
155.7(3)
90.5(2)
(9) The results of the temperature-dependent NMR measurement
of 1 are as follows. The 1H and 31P{1H} NMR spectra of a toluene-d8
solution of the complex at -70 °C show the signals of 1 only. The 31P-
{1H} NMR spectrum at -30 °C shows a decrease in the amount of 1,
which is accompanied by the generation of a multitude of signals
inclucing those due to RhCl(PMe3)3 (δ -1.13 and -12.47). At 25 °C,
the 31P{1H} NMR spectrum shows the peaks due to 1 (δ -13.04 and
-28.35) and a broad signal (ν1/2 ) ca. 200 Hz) at δ -10. The latter
signal is assigned to the Rh(I) complexes which undergo structural
change on the NMR time scale, because Rh(III) complexes with PMe3
ligands do not undergo such fluxional behavior in the NMR spectra at
room temperature. The 1H NMR spectrum at 25 °C shows a single
broad peak at δ 1.19 assigned to the PMe3 hydrogens of the Rh(I)
complexes in addition to signals due to 1 and HSiPh3. The fluxional
behavior among the Rh(I) complexes may be attributed to reversible
coordination of the SiH group of HSiPh3 and its liberation.
(10) (a) Milstein, D. Acc. Chem. Res. 1984, 17, 221 and references
therein. (b) Sacco, A.; Ugo, R.; Moles, A. J . Chem. Soc. A 1966, 1670.
(c) Henderson, R. A. J . Chem. Soc., Dalton Trans. 1985, 2067. (d)
Osakada, K.; Hataya, K.; Yamamoto, T. Inorg. Chem. 1993, 32, 2360.
(e) Osakada, K.; Hataya, K.; Yamamoto, T. Organometallics 1993, 12,
3358.
103.2(1)
145.6(1)
102.2(1)
1
The H NMR spectrum of 1 in benzene-d6 shows not
only the peaks of 1 but those of the SiH and phenyl
hydrogens of HSiPh3 that are liberated from 1 through
1
reductive elimination in solution. The H NMR signal
of the hydrido ligand at δ -9.49 has a large coupling
constant (161 Hz) between the H and trans-P nuclei.
The 31P{1H} NMR spectrum contains a doublet of
doublets and a doublet of triplets in ca. 2:1 peak area
ratio similar to mer-RhCl(H)(SiHAr2)(PMe3)3 and mer-
1
Rh(SAr)(H)(SiAr3)(PMe3)3.7,8 The H NMR spectrum of
1 at 25 °C in toluene-d8 shows a SiH hydrogen peak (δ
5.70) whose relative intensity decreases on cooling the
solution and is almost negligible at -70 °C. The
temperature-dependent NMR spectra suggest that com-
plex 1 is in a reversible equilibrium with a mixture of
HSiPh3 and Rh(I) complexes formed through reductive
elimination of HSiPh3. The data indicate that complex
1 is favored at lower temperatures.9 Preferential for-
mation of 1 among several possible isomers with the
(11) Koga, N.; Morokuma, K. J . Am. Chem. Soc. 1993, 115, 6883.
See also: J ime´nez-Catano, R.; Hall, M. B. Organometallics 1996, 15,
1889.
(12) Formation of ClSi(C6H4CF3-p)3 was confirmed by comparison
of the 29Si{1H} NMR spectrum of the reaction mixture with that of
the authentic sample. The presence of an isomer of mer-RhCl(H)[Si-
(C6H4CF3-p)3](PMe3)3, having the Cl and Si(C6H4CF3-p)3 ligands at
mutually trans positions similar to 1, in the reaction product cannot
be excluded because the 1H NMR spectrum of the crude product shows
hydrido peaks due to several uncharacterized Rh(III) complexes also.
Isolation and further characterization of these minor products were
unsuccessful.
(8) Osakada, K.; Hataya, K.; Yamamoto, T. J . Chem. Soc., Chem.
Commun. 1995, 2315.

1870 Organometallics, Vol. 17, No. 9, 1998
Osakada et al.
F igu r e 2. ORTEP drawing of mer-RhCl(H){Si(C6H4CF3-
p)3}(PMe3)3 (2) at the 50% ellipsoidal level. The crystal
contains solvated hexane molecules. Atoms with asterisks
are crystallographically equivalent to those with the same
number without an asterisk. The hydrogen atoms and
atoms in the solvent molecule are omitted for simplicity.
F igu r e 3. ORTEP drawing of fac-Rh(H)2{Si(C6H4CF3-p)3}-
(PMe3)3 (3) at the 30% ellipsoidal level. The crystal contains
solvated hexane molecules. The hydrogen atoms, except for
hydrido ligands and atoms in the solvent molecule, are
omitted for simplicity. One of the two disordered positions
of F7-F9 are shown.
Complex 2 was obtained in a hexane-solvated form by
repeated recrystallization of the product of the equimo-
lar reaction. The coordination geometry around the Rh
center of the complex shown in Figure 2 can be
rationalized as a distorted octahedron having the tri-
arylsilyl and chloro ligands at mutually cis positions and
three PMe3 ligands at meridional coordination sites; the
hydrido ligand that should occupy the remaining site
trans to the chloro ligand was not located in the final
difference-Fourier map. Significantly distorted coordi-
nation with P1-Rh-Si (155.7(3)°) and Si-Rh-Cl (109.8-
(2)°) bond angles suggests severe steric congestion
between triarylsilyl and PMe3 or Cl ligands. The
difference of the Rh-Si bond distances of 1 (2.346(2) Å)
and 2 (2.377(8) Å) can be attributed to a smaller trans
influence of the Cl than the PMe3 ligand.13 Dissolution
of analytically pure crystals of 2 in benzene-d6 produces
a mixture containing 2, 3, 4, and uncharacterized
Sch em e 2
Ch a r t 1
1
complexes. The H NMR signal at δ -12.96 due to the
hydrido ligand of 2 does not contain a P-H coupling
constant larger than 100 Hz, indicating a structure with
the three PMe3 ligands all cis to the hydrido ligand.
Recrystallization of the product in the 3:1 reaction of
HSi(C6H4CF3-p)3 and RhCl(PMe3)3 led to preferential
crystallization of 4. Complex 3 is obtained from recrys-
tallization of the product after removal of 4 and char-
acterized by X-ray crystallography, as shown in Figure
3. The PMe3 ligands occupy three facial coordination
sites of a highly distorted octahedron. The presence of
two equivalent hydrido ligands was indicated by the 1H
NMR spectrum, which shows the hydrido peak at δ
-10.47 with a similar coupling pattern to fac-RhH2-
(SiClPh2)(PMe3)3.5 X-ray crystallography and NMR
data of 4 show a structure having two chloro ligands at
mutually cis positions and three PMe3 ligands at me-
ridional coordination sites (Supporting Information).
Scheme 2 depicts a plausible pathway of the reaction
of HSi(C6H4CF3-p)3 and RhCl(PMe3)3 to give 2 and 3.
Initial oxidative addition of HSi(C6H4CF3-p)3 to the Rh-
(I) complex gives 2, which undergoes coupling of the
chloro and triarylsilyl ligands to afford RhH(PMe3)3. The
resulting hydridorhodium(I) complex reacts with the
HSi(C6H4CF3-p)3 contained in the reaction mixture to
afford 3. The above mechanism is consistent with the
results that complex 1, having trans Cl and SiPh3
ligands, is not converted into other Rh(III) complexes
in the solution containing HSiPh3 at room temperature.
As described above, the Rh(III) complexes formulated
as RhCl(H)(SiAr3)(PMe3)3 undergo reductive elimination
of HSiAr3 and/or ClSiAr3 depending on the coordination
geometry. Oxidative addition of triarylsilane to RhCl-
(PMe3)3 could provide two isomeric Rh(III) complexes
A and B having three meridional PMe3 ligands, as
shown in Chart 1.
(13) Elongation of Rh-Si bond is not due to the presence of the CF3
group on the phenyl group because the substituent on the aryl group,
X, of RhCl(H){SiH(C6H4X-p)2}(PMe3)3 has been reported to influence
the Rh-Si bond distance to a negligible extent. See, ref 5.
The complex with structure A undergoes reductive
elimination of HSiAr3 followed by its rapid reoxidative

Chloro(triarylsilyl)hydridorhodium(III) Complexes
Organometallics, Vol. 17, No. 9, 1998 1871
Ta ble 2. Cr ysta l Da ta a n d Deta ils of th e Str u ctu r e
Refin em en t of 1, 2, a n d 3
90 Hz). The signal due to the meta and para hydrogens of
the phenyl group is overlapped with the signals due to HSiPh3.
31P{1H} NMR (C6D6, 160 MHz): δ -13.04 (dd, J (PP) ) 31 Hz,
J (PRh) ) 102 Hz), -28.35 (dt, J (PP) ) 31 Hz, J (PRh) ) 94
Hz).
compound
formula
mol wt
cryst syst
space group
a (Å)
1‚C7H8
2‚C6H14
3‚0.5C6H14
C34H51ClP3RhSi C36H54ClF9P3RhSi C33H48F9P3RhSi
719.14
orthorhombic
Pnma (No. 62) Pnma (No. 62)
23.746(9)
14.641(6)
10.483(2)
917.18
orthorhombic
839.64
monoclinic
P21/n (No. 14)
13.387(7)
21.547(9)
14.162(10)
100.74(4)
4013
4
6.27
1724
1.390
Rea ction s of HSi(C6H4CF 3-p)3 w ith Rh Cl(P Me3)3. (a )
1:1 a n d 2:1 Rea ction s. To a pentane (3 mL) dispersion of
RhCl(PMe3)3 (157 mg, 0.43 mmol) was added HSi(C6H4CF3-
p)3 (198 mg, 0.43 mmol) in one portion at room temperature.
The orange solid dispersed in, and the solvent gradually turned
colorless upon stirring. After 8 h, the resulting pale yellow
solid was collected by filtration, washed with a minimum
amount of pentane, and dried in vacuo (359 mg). The1H
and 31P{1H} NMR spectra of the solid product showed the
presence of 2 (20%) and 3 (33%) in addition to several
uncharacterized products and unreacted RhCl(PMe3)3 (>25%).
Recrystallization from a toluene-hexane mixture gave 2 in a
hexane-solvated form as colorless crystals (12%). Anal. Calcd
for C36H54ClF9P3RhSi: C, 47.14; H, 5.93, Cl, 3.86; F, 18.64.
Found: C, 47.15; H, 5.86; Cl, 3.73; F, 18.27. 1H NMR (400
MHz, C6D6): δ -17.29 (ddt, 1H, RhH, J (RhH) ) 21 Hz, J (HP)
) 18, 18, and 15 Hz), 1.13 (d, 9H, P(CH3)3, J (HP) ) 6 Hz),
1.30 (triplet due to virtual coupling, 18H, P(CH3)3), 7.40 (d,
6H, C6H4(meta), J ) 9 Hz), 7.69 (d, 6H, C6H4(ortho), J ) 7
Hz).
12.121(4)
20.461(7)
17.684(7)
b (Å)
c (Å)
â (deg)
V (Å3)
3644
4
7.27
1504
1.311
4385
4
6.39
1888
1.390
Z
µ (cm-1
F(000)
)
Dcalcd (g cm-3
)
cryst size (mm 0.3 × 0.4 × 0.4 0.3 × 0.5 × 0.5
0.4 × 0.5 × 0.6
× mm × mm)
2θ range (deg) 5.0-55.0
5.0-50.0
3057
5.0-55.0
9454
no. of unique
reflns
5354
no. of reflns
used
2166
1459
3635
no. of variables 205
258
0.070
0.072
415
0.077
0.078
R
0.049
0.039
Rw
a
Weighting scheme: [σ(Fo)2]-1
.
addition. Structure B has the Cl, H, and SiAr3 ligands
at the coordination sites which are suited for direct
reductive elimination of both HSiAr3 and ClSiAr3.
Liberation of ClSiAr3 from 2 with structure B seems to
occur through an intramolecular pathway, while com-
plex 1 with structure A does not undergo direct coupling
of the ligands at mutually trans positions. The present
study shows that the structure of the product of the
oxidative addition of an Si-H bond in HSiAr3 depends
on the substituent on the aryl group.
Although the isolated crystalline 2 gave satisfactory el-
emental analyses and X-ray diffraction data, dissolution of the
crystals in benzene-d6 caused an immediate change into a
mixture of 2, 3, 4, and other uncharacterized Rh(III) com-
plexes. The above NMR data of 2 was obtained from the
mixture. The partial conversion of 2 into other Rh complexes
in solution is significantly retarded by addition of HSi(C6H4-
CF3-p)3.
Similar reaction in a 2:1 molar ratio for 15 min at room
temperature gave a mixture of 2 (20%), 3 (24%), and 4 (8%) in
addition to several uncharacterized complexes.
Exp er im en ta l Section
(b) 3:1 Rea ction . To a THF (3 mL) solution of RhCl(PMe3)3
(186 mg, 0.51 mmol) was added HSi(C6H4CF3-p)3 (708 mg, 1.5
mmol) at room temperature. Stirring the solution caused a
color change from orange to colorless. After 8 h, the solvent
was evaporated to dryness. Addition of pentane (10 mL) to
the resulting viscous product caused separation of a colorless
Gen er a l, Mea su r em en ts, a n d Ma ter ia ls. Manipulations
of the metal complexes were carried out under nitrogen or
argon using standard Schlenk techniques. RhCl(PMe3)3 and
HSi(C6H4CF3-p)3 were prepared according to the literature
methods.14 Other chemicals were used as received from
commercial suppliers. IR and NMR spectra (1H and 31P) were
recorded on a J ASCO810 spectrophotometer and on a J EOL
EX-400 spectrometer, respectively. Peak positions of the
31P{1H} NMR spectra were referenced to external 85% H3PO4.
Elemental analyses were carried out on a Yanaco MT-5 CHN
autocorder and on a Yanaco YS-10 by ion chromatography.
Rea ction of HSiP h 3 w ith Rh Cl(P Me3)3. To a pentane
(3 mL) dispersion of RhCl(PMe3)3 (151 mg, 0.41 mmol) was
added HSiPh3 (107 mg, 0.41 mmol) at room temperature to
lead to dissolution of the complex. The solution changed color
from orange to colorless, which was accompanied by a gradual
deposition of a colorless solid. After 8 h, the separated solid
product was collected by filtration and dried in vacuo.
Recrystallization from a toluene-pentane mixture gave 1
as a toluene-solvated form (61 mg, 21%). Anal. Calcd for
1
solid (357 mg). The H NMR spectrum indicated the presence
of 2 (11%), 3 (78%), and 4 (12%).
Recrystallization of the product from a THF-pentane mix-
1
ture caused preferential separation of 4 as crystals (11%). H
NMR (400 MHz, C6D6): δ -17.20 (ddt, 1H, RhH, J (HRh) ) 21
Hz, J (HP) ) 18 and 15 Hz), 0.95 (d, 9H, P(CH3)3, J (HP) ) 10
Hz), 1.40 (triplet due to virtual coupling, 18H, P(CH3)3). 31P-
{1H} NMR (160 MHz in C6D6): δ -6.75 (dd, J (PP) ) 31 Hz,
J (PRh) ) 94 Hz), 6.57 (dt, J (PP) ) 31 Hz, J (PRh) ) 133 Hz).
The filtrate of the above recrystallization was evaporated
to dryness. Addition of pentane to the resulting yellow paste
led to the separation of 3 as a colorless solid. Anal. Calcd for
C
30H41F9P3RhSi: C, 45.24; H, 5.19. Found: C, 45.74; H, 5.80.
1H NMR (400 MHz, C6D6): δ -10.47 (m, 2H, RhH, J (HP) )
116 Hz), 0.65 (d, 27H, P(CH3)3, J (HP) ) 7 Hz), 7.45 (d, 6H,
C6H4(meta)), 7.78 (d, 6H, C6H4(ortho)). 31P{1H} NMR (160
MHz, C6D6): δ -19.77 (dd, J (PP) ) 23 Hz, J (PRh) ) 98 Hz),
-25.07 (dt, J (PP) ) 23 Hz, J (PRh) ) 90 Hz). Further
recrystallization from a toluene-hexane mixture afforded
single crystals of 3‚0.5 C6H14, which was characterized by X-ray
crystallography.
C
34H51ClP3RhSi: C, 56.79; H, 7.15; Cl, 4.93. Found: C, 56.72;
H, 7.07; Cl, 4.89. IR (cm-1, KBr): 1930 (ν(Rh-H)).
The 1H NMR spectrum at 25 °C showed the presence of 1
and HSiPh3 in a 48:52 molar ratio. 1H NMR (C6D6, 400
MHz): δ -9.49 (ddt, 1H, RhH, J (RhH) ) 13 Hz, J (HPtrans) )
161 Hz, J (HPcis) ) 18 Hz), 0.96 (d, 9H, P(CH3)3, J (PH) ) 7
Hz), 1.23 (apparent triplet due to virtual coupling, 18H,
P(CH3)3), 7.90 (d, 6H, C6H5(ortho), J (HH) ) 7 Hz, J (HSi) )
Cr ystal Str u ctu r e Deter m in ation . Crystals were mounted
in a glass capillary tube under argon. The unit cell parameters
were obtained by least-squares refinement of 2θ values of 25
reflections with 25° e 2θ e 35°. Intensities were collected on
a Rigaku AFC-5R automated four-cycle diffractometer by using
graphite-monochromated Mo KR radiation (λ ) 0.710 69 Å)
and the ω-2θ method. An empirical absorption correction (ψ
scan method) of the collected data was applied. Crystal data
(14) (a) Price, F. P. J . Am. Chem. Soc. 1947, 69, 2600. (b) Benkeser,
R. A.; Foster, D. J . J . Am. Chem. Soc. 1952, 74, 5314. (c) Steward, O.
W.; Pierce, O. R. J . Am. Chem. Soc. 1961, 83, 1916. (d) J ones, R. A.;
Real, F. M.; Wilkinson, G. J . Chem. Soc., Dalton Trans. 1980, 511. (e)
Price, R. T.; Anderson, R. A.; Muetterties, E. L. J . Organomet. Chem.
1989, 376, 407.

1872 Organometallics, Vol. 17, No. 9, 1998
Osakada et al.
and details of the structure refinement are summarized in
Table 2. Calculations were carried out by using the teXsan
program package on a VAX-II computer. Atomic scattering
factors were taken from the literature.15 A full-matrix least-
squares refinement was used for the non-hydrogen atoms with
anisotropic thermal parameters. Hydrogen atoms except for
the RhH hydrogen were located by assuming ideal positions
(d ) 0.95 Å) and were included in the structure calculation
without further refinement of the parameters. The positions
of the RhH hydrogen of 1 and 3 were determined with the
difference Fourier technique and included in the calculation
with isotropic thermal factors (1) or without further refinement
of the parameters (3). The RhH hydrogen of 2 was not located
due to insufficient convergence of the structural calculation.
A CF3 group in a molecule of 3 has three F atoms (F7-F9) at
two disordered positions with 50% probability. The corre-
sponding C and F atoms and the C atoms of the solvent in 3
were refined isotropically.
Ack n ow led gm en t. This work was financially sup-
ported by Grants-in-Aid for Scientific Research from the
Ministry of Education, Science, Sports, and Culture,
J apan.
Su p p or tin g In for m a tion Ava ila ble: Tables of positional
parameters, thermal parameters, and bond distances and
angles of 1, 2, and 3 and the results of crystallography of 4
(26 pages). Ordering information is given on any current
masthead page.
(15) International Tables for X-ray Crystallography; Kynoch: Bir-
mingham, England, 1974; Vol. IV.
OM970846K