A new series of mono- and dinuclear hydridosilylrhodium(iii) complexes, RhCl(H)(SiAr3)L2 and RhL(SiAr3)H(μ-C1)(μ-H)RhH(SiAr3)L (L = P(i-Pr3)). Preparation by oxidative addition of HSiAr3 and molecular structures of the complexes

Article abstract of DOI:10.1021/om961048h

Reactions of triarylsilanes such as HSiPh₃, HSi(C₆H₄Me-p)₃, HSi(C₆H₄OMe-p)₃, HSi(C₆H₄Cl-p)₃, HSi(C₆H₄F-p)₃, and HSi(C₆H₄CF₃-p)₃ with RhC(H)(SiA₃)L₂ = P(i-Pr)₃) give a series of hydrido(triarylsilyl)rhodium(III) complexes, RhCl(H)(SiAr₃)L₂ (1, Ar = Ph; 2, Ar = C₆H₄Me-p; 3, Ar = C₆H₄OMe-p; 4, Ar = C₆H₄Cl-p; 5, Ar = C₆H₄F-p; 6, Ar = C₆H₄CF₃-p). Tris(phenylethynyl)silane also reacts with the Rh(I) complex to give another oxidative-addition product, RhCl(H)[Si(C≡CPh)₃]L₂ (7). X-ray analyses of 1 and 7 show a distorted-squarepyramidal coordination around the Rh center with the silyl ligand at the apical position. Prolonged reactions of HSiPh₃ and of HSi(C₆H₄OCF₃-p)₃ with RhClL₂ give dinuclear complexes, RhL(SiAr₃)H(μ-Cl)(μ-H)RhH(SiAr₃)L (8, Ar = Ph; 9, Ar = C₆H₄OCF₃-p). X-ray crystallography of 9 shows a molecular structure containing two Rh centers bridged with hydrido and chloro ligands. 1,1,3,3-Tetraisopropyldisiloxane undergoes oxidative addition of the Si - H bonds to RhClL₂ to give a symmetric dinuclear Rh(III) complex with bridging hydrido, chloro, and disiloxanyl ligands, RhL(H)(μ-H)(μ-Cl)[μ-(i-Pr)₂Si - O - Si-(i-Pr)₂]Rh(H)L (10).

Full text of DOI:10.1021/om961048h

Organometallics 1997, 16, 2063-2069
2063
A New Ser ies of Mon o- a n d Din u clea r
Hyd r id osilylr h od iu m (III) Com p lexes, Rh Cl(H)(SiAr 3)L2
a n d Rh L(SiAr 3)H(µ-Cl)(µ-H)Rh H(SiAr 3)L (L ) P (i-P r 3)).
P r ep a r a tion by Oxid a tive Ad d ition of HSiAr 3 a n d
Molecu la r Str u ctu r es of th e Com p lexes
Kohtaro Osakada,* Take-aki Koizumi, and Takakazu Yamamoto*
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226, J apan
Received December 12, 1996X
Reactions of triarylsilanes such as HSiPh3, HSi(C6H4Me-p)3, HSi(C6H4OMe-p)3, HSi(C6H4-
Cl-p)3, HSi(C6H4F-p)3, and HSi(C6H4CF3-p)3 with RhClL2 (L ) P(i-Pr)3) give a series of
hydrido(triarylsilyl)rhodium(III) complexes, RhCl(H)(SiAr3)L2 (1, Ar ) Ph; 2, Ar ) C6H4-
Me-p; 3, Ar ) C6H4OMe-p; 4, Ar ) C6H4Cl-p; 5, Ar ) C6H4F-p; 6, Ar ) C6H4CF3-p). Tris-
(phenylethynyl)silane also reacts with the Rh(I) complex to give another oxidative-addition
product, RhCl(H)[Si(CtCPh)3]L2 (7). X-ray analyses of 1 and 7 show a distorted-square-
pyramidal coordination around the Rh center with the silyl ligand at the apical position.
Prolonged reactions of HSiPh3 and of HSi(C6H4OCF3-p)3 with RhClL2 give dinuclear
complexes, RhL(SiAr3)H(µ-Cl)(µ-H)RhH(SiAr3)L (8, Ar ) Ph; 9, Ar ) C6H4OCF3-p). X-ray
crystallography of 9 shows a molecular structure containing two Rh centers bridged with
hydrido and chloro ligands. 1,1,3,3-Tetraisopropyldisiloxane undergoes oxidative addition
of the SisH bonds to RhClL2 to give a symmetric dinuclear Rh(III) complex with bridging
hydrido, chloro, and disiloxanyl ligands, RhL(H)(µ-H)(µ-Cl)[µ-(i-Pr)2SisOsSi-(i-Pr)2]Rh(H)L
(10).
In tr od u ction
catalyzed synthetic reactions,16-19 including hydrosily-
lation of unsaturated molecules16 and silylformylation
of alkenes and alkynes.17 Recently, a pentacoordinated
hydridosilylrhodium complex, RhCl(H)(SiR3)(DAD) (DAD
) a Salen type diimine ligand), was reported to play an
important role as the intermediate in hydrosilylation
of alkenes catalyzed by RhCl(CO)(DAD).5 Although
hydrosilylation catalyzed by Rh-phosphine complexes
seems to involve similar pentacoordinated silylrhodium-
(III) complexes as the intermediates, there have been
Silylrhodium complexes1-15 have attracted increasing
attention as possible intermediates of Rh-complex-
X Abstract published in Advance ACS Abstracts, April 15, 1997.
(1) (a) Haszeldine, R. N.; Parish, R. V.; Parry, D. J . J . Organomet.
Chem. 1967, 9, P13. (b) Haszeldine, R. N.; Parish, R. V.; Parry, D. J .
J . Chem. Soc. A 1969, 683. (c) Haszeldine, R. N.; Parish, R. V.; Taylor,
R. J . J . Chem. Soc., Dalton Trans. 1974, 2311. (d) Dickers, H. M.;
Haszeldine, R. N.; Malkin, L. S.; Mather, A. P.; Parish, R. V. J . Chem.
Soc., Dalton Trans. 1980, 308.
(2) Oliver, A. J .; Graham, W. A. G. Inorg. Chem. 1971, 10, 1.
(3) Muir, K. W.; Ibers, J . A. Inorg. Chem. 1970, 9, 440.
(4) (a) Fernandez, M.-J .; Maitlis, P. M. J . Chem. Soc., Chem.
Commun. 1982, 310. (b) Fernandez, M.-J .; Bailey, P. M.; Bentz, P. O.;
Ricci, J . S.; Koetzle, T. F.; Maitlis, P. M. J . Am. Chem. Soc. 1984, 106,
5458. (c) Ruiz, J .; Mann, B. E.; Spencer, C. M.; Taylor, B. F.; Maitlis,
P. M. J . Chem. Soc., Dalton Trans. 1987, 1963.
(5) Brockmann, M.; Dieck, H.; Klaus, J . J . Organomet. Chem. 1986,
301, 209.
(6) (a) Wang, W.-D.; Hommeltoft, S. I.; Eisenberg, R. Organometal-
lics 1988, 7, 2417. (b) Wang, W.-D.; Eisenberg, R. J . Am. Chem. Soc.
1990, 112, 1833.
(7) Hendriksen, D. E.; Oswald, A. A.; Ansell, G. B.; Leta, S.; Kastrup,
R. V. Organometallics 1989, 8, 1153.
(8) J oslin, F. L.; Stobart, S. R. J . Chem. Soc., Chem. Commun. 1989,
504.
(9) (a) Nagashima, H.; Tatebe, K.; Ishibashi, T.; Sakakibara, J .; Itoh,
K. Organometallics 1989, 8, 2495. (b) Nagashima, H.; Tatebe, K.; Itoh,
K. J . Chem. Soc., Perkin Trans. 1 1989, 1707. (c) Nagashima, H.;
Tatebe, K.; Ishibashi, T.; Nakaoka, A.; Sakakibara, J .; Itoh, K.
Organometallics 1995, 14, 2868.
(10) Thorn, D. L.; Harlow, R. L. Inorg. Chem. 1990, 29, 2017.
(11) Fryzuk, M. D.; Rosenberg, L.; Rettig, S. J . Organometallics
1991, 10, 2537.
(15) Aizenberg, M.; Goikhman, R.; Milstein, D. Organometallics
1996, 15, 1075.
(16) (a) Ojima, I. In Organic Transition-Metal Chemistry; Ishii, Y.,
Tsutsui, M., Eds.; Plenum: New York, 1975; p 255. (b) Speier, J . L. In
Homogeneous Catalysis of Hydrosilation by Transition Metals; Stone,
F. G. A., West, R., Eds.; Advances in Organometallic Chemistry 17;
Academic Press: New York, 1979; p 407. (c) J ardine, F. H. In The
Chemistry of the Metal Carbon Bond: Organometallic Compounds in
Organic Synthesis; Hartley, F. R., Ed.; Wiley: New York, 1987; Vol.
4, p 784. (d) Ojima, I. The Hydrosilylation Reaction. In The Chemistry
of Organic Silicon Compounds; Patai, S.; Rappoport, Z., Eds.; Wiley:
New York, 1989; p 1479. (e) Bergens, S. H.; Noheda, P.; Whelan, J .;
Bosnich, B. J . Am. Chem. Soc. 1992, 114, 2128. (f) Marciniec, B., Ed.
Comprehensive Handbook on Hydrosilylation; Pergamon: Oxford, U.K.,
1992. (g) Marciniec, B.; Gulinski, J . J . Organomet. Chem. 1993, 446,
15.
(17) (a) Matsuda, I.; Ogiso, A.; Sato, S.; Izumi, Y. J . Am. Chem. Soc.
1989, 111, 2332. (b) Matsuda, I.; Ogiso, A.; Sato, S. J . Am. Chem. Soc.
1990, 112, 6120. (c) Matsuda, I.; Sakakibara, J .; Nagashima, H.
Tetrahedron Lett. 1991, 32, 7431. (d) Ojima, I.; Ingallina, P.; Donovan,
R. J .; Clos, N. Organometallics 1991, 10, 38. (e) Ikeda, S.; Chatani,
N.; Kajikawa, Y.; Ohe, K.; Murai, S. J . Org. Chem. 1992, 57, 2. (f)
Wright, M. E.; Cochran, B. B. J . Am. Chem. Soc. 1993, 115, 2059. (g)
Zhou, J .-Q.; Alper, H. Organometallics 1994, 13, 1586.
(12) (a) Osakada, K.; Hataya, K.; Nakamura, Y.; Tanaka, M.;
Yamamoto, T. J . Chem. Soc., Chem. Commun. 1993, 576. (b) Osakada,
K.; Hataya, K.; Yamamoto, T. J . Chem. Soc., Chem. Commun. 1995,
2315. (c) Osakada, K.; Hataya, K.; Yamamoto, T. Inorg. Chim. Acta,
in press.
(13) Hofmann, P.; Meier, C.; Hiller, W.; Heckel, M.; Riede, J .;
Schmidt, M. U. J . Organomet. Chem. 1995, 490, 51.
(14) Marciniec, B.; Krzyzanowski, P. J . Organomet. Chem. 1995,
493, 261.
(18) Suzuki, T.; Mita, I. J . Organomet. Chem. 1991, 414, 311.
(19) (a) Ojima, I.; Inaba, S.; Kogure, T.; Nagai, Y. J . Organomet.
Chem. 1973, 55, C7. (b) Lappert, M. F.; Maskell, R. K. J . Organomet.
Chem. 1984, 264, 217. (c) Corey, J . Y.; Chang, L. S.; Corey, E. R.
Organometallics 1987, 6, 1595. (d) Chang, L. S.; Corey, J . Y. Organo-
metallics 1989, 8, 1885. (e) Baruah, J . B.; Osakada, K.; Yamamoto, T.
J . Mol. Catal. 1995, 101, 17. (f) Baruah, J . B.; Osakada, K.; Yamamoto,
T. Organometallics 1996, 15, 456.
S0276-7333(96)01048-5 CCC: $14.00 © 1997 American Chemical Society

2064 Organometallics, Vol. 16, No. 10, 1997
Osakada et al.
only a few reports on such pentacoordinated silyl-
rhodium complexes with phosphine ligands. RhCl(H)-
(SiCl3)(PPh3)2 with five monodentate ligands around the
Rh center actually has a distorted-octahedral coordina-
tion, whose sixth coordination site is occupied by an
ortho hydrogen of the PPh3 ligand.3 Silylrhodium(I)
complexes with a trigonal-bipyramidal structure have
been obtained by use of a polydentate phosphine ligand
that coordinates to the Rh center in a cagelike fashion.7,8
In the case of silylplatinum and -iridium phosphine
complexes, however, their role in hydrosilylation and
bis-silylation has been well-clarified.20,21
On this basis, we have sought a way to prepare a
series of pentacoordinated hydridosilylrhodium(III) com-
plexes to reveal their molecular structure and chemical
properties and found that the reaction of RhClL2 (L )P-
(i-Pr)3) with HSiAr3 provides such a way. RhClL2 has
been proven to serve as a convenient starting material
of various organorhodium complexes owing to its 14-
electron metal center that undergoes facile oxidative-
addition reactions.22 The sterically bulky P(i-Pr)3 ligand
stabilizes the pentacoordinate hydridosilylrhodium(III)
complexes, while a less bulky PMe3 ligand is known to
give hexacoordinate RhX(H)(SiAr3)(PMe3)3 (X ) Cl,
SAr).12 This paper will present results of reaction of
triarylsilanes with RhClL2 to give pentacoordinated
hydridosilylrhodium(III) complexes, RhCl(H)(SiAr3)L2.
Their transformation into RhL(Ar3Si)H(µ-Cl)(µ-H)RhH-
(SiAr3)L as well as oxidative addition of (i-Pr)2HSiOSiH-
(i-Pr)2 to RhClL2 will also be reported.
F igu r e 1. ORTEP drawing of 1 with 30% thermal el-
lipsoids. Hydrogen atoms other than hydrides are omitted
for simplicity.
Resu lts a n d Discu ssion
Mon on u clea r H yd r id osilylr h od iu m (III) Com -
p lexes. Triarylsilanes such as HSiPh3, HSi(C6H4Me-
p)3, HSi(C6H4OMe-p)3, HSi(C6H4Cl-p)3, HSi(C6H4F-p)3,
and HSi(C6H4CF3-p)3 react smoothly with RhClL2 to
give hydridosilylrhodium(III) complexes 1-6, as shown
in eq 1.
F igu r e 2. ORTEP drawing of 7 with 30% thermal el-
lipsoids. Hydrogen atoms other than hydrides are omitted
for simplicity.
NMR (1H, 31P, and 13C) data of the complexes are
consistent with the pentacoordinated structure. 1H
NMR signals of the hydrido ligands at δ -15.95 to
-16.50 ppm show splitting due to the presence of two
magnetically equivalent P nuclei. Figures 1 and 2
respectively show the molecular structures of 1 and 7
determined by X-ray crystallography. Table 1 sum-
marizes selected bond distances and angles of the
complexes. Both complexes have a distorted-square-
pyramidal coordination around the metal center with
the triorganosilyl ligand at the apical position. This
silyl ligand position and mutually trans position of the
hydrido and chloro ligands suggest a larger trans effect
of the silyl ligand than the hydrido ligand.20h,23 An
analogous square-pyramidal hydridosilyliridium(III) com-
plex, IrCl(H)(SiMeCl2)L2 (L ) P(i-Pr)3), with a Cl-Ir-
Tris(phenylethynyl)silane gives an analogous product,
RhCl(H)[Si(CtCPh)3]L2 (7).
(20) (a) Chatt, J .; Eaborn, C.; Kappor, P. N. J . Organomet. Chem.
1970, 23, 109. (b) Randolph, C. L.; Wrighton, M. S. J . Am. Chem. Soc.
1986, 108, 3366. (c) Lewis, L. N. J . Am. Chem. Soc. 1990, 112, 5998.
(d) Tanaka, M.; Uchimaru, Y.; Lautenschlager, H.-J . Organometallics
1991, 10, 16. (e) Yamashita, H.; Tanaka, M.; Goto, M. Organometallics
1992, 11, 3227. (f) Yamashita, H.; Tanaka, M.; Goto, M. Organome-
tallics 1993, 12, 988. (g) Sakaki, S.; Ieki, M. J . Am. Chem. Soc. 1993,
115, 2373. (h) Ozawa, F.; Hikida, T.; Hayashi, T. J . Am. Chem. Soc.
1994, 116, 2844. (i) Ozawa, F.; Sugawara, M.; Hayashi, T. Organome-
tallics 1994, 13, 3237. (j) Hikida, T.; Onitsuka, K.; Sonogashira, K.;
Hayashi, T.; Ozawa, F. Chem. Lett. 1995, 985.
(21) (a) Hostetler, M. J .; Bergman, R. G. J . Am. Chem. Soc. 1992,
114, 7629. (b) Hostetler, M. J .; Butts, M. D.; Bergman, R. G. Organo-
metallics 1993, 12, 65. (c) Aizenberg, M.; Milstein, D. Angew. Chem.,
Int. Ed. Engl. 1994, 33, 317. (d) Cleary, B. P.; Mehta, R.; Eisenberg,
R. Organometallics 1995, 14, 2297.

Hydridosilylrhodium(III) Complexes
Organometallics, Vol. 16, No. 10, 1997 2065
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) of 1 a n d 7
1
7
Rh-Si
Rh-Cl
Rh-P1
Rh-P2
Rh-H
2.299(2)
2.427(3)
2.383(2)
2.389(2)
1.12
2.229(3)
2.403(3)
2.357(3)
2.382(3)
1.22
Si-Rh-Cl
Si-Rh-P1
Si-Rh-P2
P1-Rh-Cl
P2-Rh-Cl
P1-Rh-P2
Si-Rh-H
P1-Rh-H
P2-Rh-H
Cl-Rh-H
111.09(8)
99.54(7)
100.56(7)
91.66(8)
95.06(8)
154.84(7)
82.5
112.1
56.3
150.8
126.4(1)
98.6(1)
97.0(1)
89.2(1)
89.4(1)
161.5(1)
65.2
87.2
90.5
168.4
F igu r e 3. ORTEP drawing of 9 with 30% thermal el-
lipsoids. Hydrogen atoms and CF3 groups are omitted for
simplicity.
Si angle (106.7°) smaller than the Cl-Rh-Si angles of
1 and 7, has been reported, although the hydrido
position has not been clarified by the X-ray structural
study.24 On the other hand, a hydrido(boryl)iridium-
(III) complex, IrCl(H)(BO2C6H4)L2, reportedly has a
distorted-trigonal-bipyramidal structure with a large
B-Ir-Cl angle (137.5°) around the metal center.25
Con ver sion of th e Hydr idosilylr h odiu m (III) Com -
p lexes in to Din u clea r Com p lexes. Although the
reaction of HSiPh3 with RhClL2 in a 2:1 molar ratio
gives 1 as the sole product for the initial 1 h, a prolonged
reaction for 7 h at room temperature gives a dinuclear
complex, RhL(Ph3Si)H(µ-Cl)(µ-H)RhH(SiPh3)L (8), in
35% isolated yield.
Ta ble 2. Selected Bon d Dista n ces a n d An gles
(d eg) of 9 a n d 10
9
10
Rh1-Rh2
Rh1-P1
Rh2-P2
Rh1-H1
Rh2-H1
Rh1-H2
Rh2-H3
Rh1-Cl
Rh2-Cl
Rh1-Si1
Rh2-Si2
2.797(1)
2.320(3)
2.322(3)
1.84
2.777(1)
2.283(3)
2.296(3)
1.64
1.67
1.26
1.77
1.17
2.399(2)
2.403(3)
2.279(3)
2.273(3)
2.439(3)
2.439(3)
2.286(3)
2.295(3)
Rh2-Rh1-Si1
Rh1-Rh2-Si2
Rh2-Rh1-P1
Rh1-Rh2-P2
Cl-Rh1-P1
Cl-Rh2-P2
Cl-Rh1-Si1
Cl-Rh2-Si2
P1-Rh1-H1
P2-Rh2-H1
P1-Rh1-H2
P2-Rh2-H3
100.79(8)
100.19(8)
151.08(7)
149.77(8)
98.77(9)
97.67(10)
128.78(10)
125.8(1)
159
95.78(9)
91.70(8)
152.15(9)
153.35(9)
99.9(1)
101.5(1)
114.8(1)
115.0(1)
166
The NMR (1H, 31P{1H}, and 29Si{1H}) analyses of the
reaction mixture revealed concomitant formation of
RhCl(H)2L2 (23%) and ClSiPh3 (58% based on RhClL2).
Since a similar reaction in a 1:1 ratio for 8 h at room
temperature gives 8 in a much lower yield, formation
of 8 in eq 3 results from reaction of excess HSiPh3
with 1. A similar reaction of HSi(C6H4OCF3-p)3 with
RhClL2 also gives RhL[(C6H4OCF3-p)3Si]H(µ-Cl)(µ-H)-
RhH[Si(C6H4OCF3-p )3]L (9).
166
166
105
98
Figure 3 shows the molecular structure of 9 deter-
mined by X-ray crystallography. The molecule has a
symmetrical structure with two Rh centers. Each metal
center is bonded to chloro, silyl, and phosphine ligands
as well as to a bridging hydrido ligand. The final D map
shows the presence of a bridging hydrido ligand, H1,
unambiguously. Although precise positions of other
hydrido ligands have not been clarified by X-ray crystal-
lography, the 1H NMR data (vide infra) indicate the
presence of the two magnetically equivalent nonbridging
hydrido ligands shown in eq 4. Bond distances and
angles of the complex are summarized in Table 2. P1-
Rh1-H1 and P2-Rh2-H1 (159 and 166°) as well as
Si1-Rh1-Cl and Si2-Rh2-Cl bond angles (128.8 and
125.8°) indicate a distorted-trigonal-bipyramidal coor-
dination around the Rh center.
(22) (a) Garcia Alonso, F. J .; Ho¨hn, A.; Wolf, J .; Otto, H.; Werner,
H. Angew. Chem., Int. Ed. Engl. 1985, 24, 406. (b) Werner, H.; Baum,
M.; Schneider, D.; Windmu¨ller, B. Organometallics 1994, 13, 1089. (c)
Werner, H.; Brekau, U. Z. Naturforsch. 1989, 44B, 1438. (d) Rappert,
T.; Nu¨rnberg, O.; Werner, H. Organometallics 1993, 12, 1359. (e)
Werner, H. J . Organomet. Chem. 1994, 475, 45. (f) Wang, K.; Rosini,
G. P.; Nolan, S. P.; Goldman, A. S. J . Am. Chem. Soc. 1995, 117, 5082.
(23) (a) Chatt, J .; Eaborn, C.; Ibekwe, S. J . Chem. Soc., Chem.
Commun. 1966, 700. (b) Holmes-Smith, R. D.; Stobart, S. R.; Vefghi,
R.; Zaworotko, M. J .; J ochem, K.; Cameron, T. S. J . Chem. Soc., Dalton
Trans. 1987, 969. (c) Ciriano, M.; Green, M.; Howard, J . A. K.; Proud,
J .; Spencer, J . L.; Stone, F. G. A.; Tsipis, C. A. J . Chem. Soc., Dalton
Trans. 1978, 801. (d) Yamashita, H.; Kobayashi, T.; Hayashi, T.;
Tanaka, M. Chem. Lett. 1990, 1447.
The NMR spectra of 8 and 9 are consistent with the
dinuclear structures. Two sets of signals due to the
hydrido ligands are observed in a 1:2 area ratio. The
(24) Yamashita, H.; Kawamoto, A. M.; Tanaka, M.; Goto, M. Chem.
Lett. 1990, 2107.
(25) Westcott, S. A.; Taylor, N. J .; Marder, T. B.; Baker, R. T.; J ones,
N. J .; Calabrese, J . C. J . Chem. Soc., Chem. Commun. 1991, 304.

2066 Organometallics, Vol. 16, No. 10, 1997
Osakada et al.
Sch em e 1. P ossible P a th w a ys for F or m a tion of
Din u clea r Silylr h od iu m Com p lexes
1
F igu r e 4. (a) Observed and (b) simulated H NMR signals
due to nonbridging hydrides of 8. Coupling constants were
determined as follows by comparison of the spectra: 1J (HRh)
2
2
3
) 29 Hz, J (HP) ) 14 Hz, J (HRh) ) 1 Hz, J (HP) ) -1
4
Hz, J (HH) ) 1 Hz.
smaller signal appears as a triplet of triplets (8, -15.78
ppm; 9, -16.12 ppm) and is assigned to the bridging
hydrido ligand. The larger signal due to the non-
bridging hydrido ligands shows a more complicated
pattern (8, -12.16 ppm; 9, -12.62 ppm). Figure 4
shows the signal due to the nonbridging hydrido signal
of 8 as well as that obtained from simulation based on
the assumption of an AA′ part of the AA′MM′XX′ spin
system. The appearance of nonbridging and bridging
hydride signals with splitting due to reasonable coupling
indicates that the complex has the same solution
structure as that by crystallography and that the
hydrido ligands do not show any fluxional behavior on
the NMR time scale.
Deuterium labeling experiments for the reaction
expressed by eq 3 reveal scrambling of hydrogens among
the hydrido ligands, the phosphine ligands, and orga-
nosilanes. Reaction of DSiPh3 with RhClL2 gives a
mixture of partially deuterated 1 and 8. The hydrido
ligand of 1 is 15% deuterated, while both the bridging
and nonbridging hydrido ligands of 8 show the same
20% content of deuterium. The phosphine ligands are
also deuterated, as observed in the 1H and 2H NMR
spectra. A reaction of HSiPh3 with RhClL2 in hexane-
d14 does not introduce deuterium into the products.
Similar H-D exchange between trialkylphosphine and
hydrido ligands has been reported in the photoreaction
of hydridoruthenium complexes.26 An equimolar reac-
tion of 1 and DSiPh3 gives HSiPh3 and 8, the latter of
which contains 32% deuterated bridging and nonbridg-
ing hydrido ligands. The equal deuterium content in
the bridging and nonbridging hydrido ligands is at-
tributed to rapid exchange of the hydrogen between 1
and HSiPh3 (or DSiPh3) prior to formation of 8 or to
the exchange between bridging and nonbridging hydrido
ligands in 8.
In the first step (i), the mononuclear complex (A)
undergoes reductive elimination of ClSiAr3 to generate
RhHL2 (B). A new complex (C) may be formed by the
reaction expressed in (ii) and the bimetallic complex by
coupling of A and C as shown in (iii). An alternative
route involves a direct coupling of A and B accompanied
by phosphine liberation (iii′). The intermediate unsym-
metrical dinuclear complex D in this pathway further
undergoes oxidative addition of HSiAr3 to give the
dinuclear complex (cf. iv). In relation to the reaction
expressed in (i), reductive elimination of chloroorga-
nosilanes from transition-metal complexes with chloro
and triorganosilyl ligands has been reported with a
Pt(II) complex.27
Reactions of HSi(C6H4Cl-p)3, HSi(C6H4F-p)3, and
HSi(C6H4CF3-p)3 with RhClL2 in a 2:1 ratio for several
hours at room temperature give the corresponding
mononuclear complexes 4-7. They are converted into
the dinuclear complexes to only a small extent even in
the prolonged reactions. The difference in the reactivity
of the mononuclear complexes depending on the kind
of HSiAr3 is accounted for by high stability of the Rh-
Si bond, with the Ar groups having electron-withdraw-
ing ability, which prevent the previously discussed
reductive elimination of ClSiAr3 under the conditions.
A Din u clea r Rh Com p lex w ith a Br id gin g Disi-
loxa n yl Liga n d . It is reported that 1,1,3,3-tetrameth-
yldisiloxane, Me2HSiOSiHMe2, oxidatively adds to Pt(0)
and Ir(I) PPh3 complexes to give the respective Pt(II)
and Ir(III) complexes with a chelating disiloxanyl ligand
(Chart 1a).28,29 Contact of Pt(SiMe2dSiMe2)(dppe) (dppe
) 1,2-bis(diphenylphosphino)ethane), having an η2-
P r ocess for t h e F or m a t ion of t h e Din u clea r
Com p lex. Scheme 1 depicts possible reaction pathways
for formation of the dinuclear complexes.
(27) (a) Chalk, A. J . J . Chem. Soc., Chem. Commun. 1969, 1207. (b)
Chalk, A. J .; Harrod, J . F. J . Am. Chem. Soc. 1965, 87, 16.
(28) Eaborn, C.; Metham, T. N.; Pidcock, A. J . Organomet. Chem.
1973, 54, C3.
(29) (a) Greene, J .; Curtis, M. D. J . Am. Chem. Soc. 1977, 99, 5176.
(b) Curtis, M. D.; Greene, J .; Butler, W. M. J . Organomet. Chem. 1979,
164, 371.
(26) (a) Chaudret, B. J . Organomet. Chem. 1984, 268, C33. (b)
Kletzin, V. H.; Werner, H. Angew. Chem., Int. Ed. Engl. 1983, 22, 873.
(c) Suzuki, H.; Lee, D. H.; Oshima, N. Moro-oka, Y. Organometallics
1987, 6, 1569.

Hydridosilylrhodium(III) Complexes
Organometallics, Vol. 16, No. 10, 1997 2067
Ch a r t 1. P ossible Coor d in a tion Mod es of th e
Disiloxa n yl Liga n d
disilene ligand, with oxygen results in formation of
Pt(SiMe2OSiMe2)(dppe), whose crystallographic study
disclosed a short contact between two Si atoms as shown
in Chart 1b.30 A bimetallic complex, {OsCl(CO)(PPh3)2-
Si(OH)2}2O, with a bridging disiloxanyl ligand (Chart
1c) was prepared by hydrolysis of Si-Cl bonds of Os-
(SiCl3)Cl(CO)(PPh3)2.31 This versatility in coordination
of the -SiX2-O-SiX2- group is partially due to the
flexibility of the Si-O-Si bond angle.
1,1,3,3-Tetraisopropyldisiloxane reacts with RhClL2
in a 2:1 ratio to give a mixture of RhL(H)(µ-H)[µ-(i-Pr)2-
Si-O-Si(i-Pr)2]Rh(H)L (10) and RhClH2L2 in a 60:40
molar ratio. Complex 10 is isolated by fractional
crystallization of the products.
F igu r e 5. ORTEP drawing of 10 with 30% thermal
ellipsoids. Hydrogen atoms other than hydrides are omitted
for simplicity.
suggests a potential utility as the Si-containing sup-
porting ligand for dinuclear complexes.
Con clu sion
The triarylsilanes HSiAr3 and HSi(CtCPh)3 undergo
oxidative addition to RhClL2 to give a new series of
pentacoordinate hydridosilylrhodium(III) complexes.
The complexes with SiPh3 and Si(C6H4OCF3-p)3 ligands
further react to result in the formation of a new type of
dinuclear silylrhodium complex. The reaction of 1,1,3,3-
tetraalkyldisiloxane also successfully gives a new di-
nuclear Rh complex with a bridging disiloxanyl ligand.
This ligand, having a stable Si-O bond and flexible Si-
O-Si bond angle, seems to serve as a bridging ligand
to stabilize various bimetallic frameworks of transition-
metal complexes similarly to dppm that is suited for the
bridging ligand of bimetallic Pd and Pt complexes.
Figure 5 shows a molecular structure of 10 deter-
mined by X-ray crystallography. The molecule contains
bridging chloro, hydrido, and disiloxanyl ligands. Non-
bridging hydrido ligands occupy syn positions of the Rh2-
Si2O five-membered ring, while complex 9 has two silyl
ligands at mutually anti positions with respect to the
plane, including two Rh and bridging chloro and hydrido
atoms. The distance between the Si atoms (3.08 Å) is
large enough to exclude a direct Si-Si interaction
suggested by the structural study of a Pt complex, Pt-
(SiMe2OSiMe2)(dppe) (Si-Si ) 2.54 Å).30 The Si-O-
Si bond angle of 10 (138.9°) is within the range of the
angle of linear and cyclic siloxanes (130-180°).32
Coordination of the disiloxanyl ligand of 10 forms an
Rh2Si2O five-membered-ring system stabilized by bridg-
ing coordination of hydrido and chloro ligands. It differs
from that of a bimetallic complex, {OsCl(CO)(PPh3)2Si-
(OH)2}2O, whose two Os centers are apart from each
other due to an anti orientation of Os(1) and Si(2) (and
Os(2) and Si(1)) in the Os(1)-Si(1)-O-Si(2)-Os(2)
bonding. This new type of coordination of the disiloxa-
nyl group containing a thermally stable Si-O bond
Exp er im en ta l Section
Gen er a l Con sid er a tion s, Mea su r em en ts, a n d Ma ter i-
a ls. Manipulation of the complexes was carried out under
nitrogen or argon using the standard Schlenk technique.
RhClL2, triarylsilanes, and tris(phenylethynyl)silane were
prepared according to the literature method.33,34 DSiPh3 was
prepared by LiAlD4 reduction of ClSiPh3. 1,1,3,3-Tetraisopro-
pylsiloxane was prepared by reaction of HSiCl3 with i-PrMgBr
followed by passage through a short silica gel column. NMR
spectra (1H, 13C, 31P, and 29Si) were recorded on a J EOL EX-
400 spectrometer. Simulation of the NMR spectrum of 8 was
carried out by using a program system, gNMR.35 Elemental
analyses were carried out with a Yanagimoto type MT-2 CHN
autocorder.
P r ep a r a tion of 1-6. To RhClL2 (230 mg, 0.49 mmol)
dispersed in pentane (5 mL) was added HSiPh3 (260 mg, 0.98
mmol) at room temperature. The reaction mixture soon turned
from purple to yellow-orange. A yellow solid began to be
separated from the solution. After it was stirred for 1 h, the
reaction mixture was cooled to -30 °C for 12 h to complete
separation of the solid product, which was collected by filtra-
tion, washed with a minimum amount of pentane, and dried
in vacuo to give 1 (200 mg, 58%). Anal. Calcd for C36H58ClP2-
RhSi: C, 60.1; H, 8.1. Found: C, 59.9; H, 8.0. 1H NMR (400
(30) Pham, E. K.; West, R. Organometallics 1990, 9, 1517.
(31) Rickard, C. E. F.; Roper, W. R.; Salter, D. M.; Wright, L. J . J .
Am. Chem. Soc. 1992, 114, 9682.
(32) (a) Gildewell, C.; Liles, D. C. J . Chem. Soc., Chem. Commun.
1977, 632. (b) Morosin, B.; Harrah, L. A. Acta Crystallogr. 1981, B37,
579. (c) Shklover, V. E.; Dubchak, I. L.; Struchkov, Y. T.; Mileshkevich,
V. P.; Nikolaev, G. A.; Tsyganov, Y. V. J . Struct. Chem. 1981, 22, 225.
(d) Dubchak, I. L.; Shklovar, V. E.; Struchkov, Y. T. J . Struct. Chem.
1983, 24, 756. (e) Ovchinnikov, Y. E.; Shklover, V. E.; Struchkov, Y.
T.; Remizova, A. A.; Lavrukhin, B. D.; Astapova, T. V.; Zhdanov, A. A.
Z. Anorg. Allg. Chem. 1985, 524, 75. (f) Ovchinnikov, Y. EÄ .; Shklover,
V. E.; Struchkov, Y. T.; Lavrukhin, B. D.; Astapova, T. V.; Zhdanov,
A. A. J . Struct. Chem. (Engl. Transl.) 1986, 27, 120.
(33) Werner, H.; Wolf, J .; Ho¨hn, A. J . Organomet. Chem. 1985, 287,
395.
(34) (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.
(35) gNMR version 3.6; Cherewell Scientific Publishing Ltd., Oxford,
U.K., 1996.

2068 Organometallics, Vol. 16, No. 10, 1997
Ta ble 3. Cr ysta llogr a p h ic Da ta a n d Deta ils of Refin em en t of 1, 7, 9, a n d 10
Osakada et al.
1
7
9
10
chem formula
fw
C36H58ClP2SiRh
719.25
C42H58ClP2SiRh
791.31
C65H81ClF18O6P2Si2Rh2
C30H73ClOP2Si2Rh2
809.29
cryst syst
space group
a, Å
monoclinic
P21/c (No. 14)
11.899(5)
monoclinic
P21/c (No. 14)
9.935(5)
triclinic
P1h (No. 2)
15.208(4)
orthorhombic
P212121 (No. 19)
13.132(3)
b, Å
15.750(7)
20.84(1)
18.671(5)
23.460(8)
c, Å
20.48(1)
20.27(1)
13.804(5)
13.028(3)
R, deg
â, deg
γ, deg
V, Å3
92.50(3)
92.78(3)
103.66(2)
3798
93.31(4)
91.70(4)
3832
4194
4013
Z
4
9.14
1520
1.247
4
5.93
1664
1.253
2
6.32
1692
1.451
4
µ, cm-1
F(000)
10.47
1704
1.339
F
calcd, g cm-3
cryst size, mm
2θ range, deg
scan rate, deg min-1
hkl
0.2 × 0.2 × 0.2
0.4 × 0.6 × 0.6
0.2 × 0.4 × 0.4
0.2 × 0.4 × 0.4
3.0-55.0
3.0-55.0
3.0-55.0
3.0-55.0
8
8
8
8
0 e h e 12, 0 e k e 17,
0e h e 12, 0 e k e 25,
0 e h e 19, -23 e k e 23,
0 e h e 16, 0 e k e 30,
0 e l e 16
5124
3734
343
-22 e l e 20
-25 e l e 23
-16 e l e 17
no. of unique rflns
no. of rflns used (I g 3σ(I))
no. of variables
R(Fo)a
8639
3201
410
0.047
9887
3641
424
0.061
17416
7659
865
0.070
0.048
0.036
Rw(Fo)a
0.054
0.052
0.071
a
2
2
R ) Σ||Fo| - |Fc||/Σ|Fo|, Rw ) [Σw|Fo - Fc| /Σw|Fo| ]1/2; weighting scheme [{σ(Fo)}2]-1
.
MHz in C6D6 at 25 °C): δ -16.20 (dt, 1H, Rh-H, J (HRh) )
21 Hz, J (HP) ) 13 Hz), 1.11 (dt, 18H, CHCH3, J ) 7 and 6
Hz), 1.19 (dt, 18H, CHCH3, J ) 7 and 6 Hz), 1.88 (m, 6H, PCH),
7.10-7.20 (m, 9H, C6H5 (meta and para)), 8.25 (d, 6H, C6H5
(ortho), J ) 7 Hz). 31P{1H} NMR (160 MHz in C6D6 at 25 °C):
37.14 ppm (d, J (RhP) ) 114 Hz).
8.05 (d, 6H, SiC6H4 (ortho), J ) 9 Hz). 31P{1H} NMR (in C6D6
at 25 °C): 37.39 ppm (d, J (RhP) ) 110 Hz).
P r ep a r a tion of 7. To RhClL2 (190 mg, 0.42 mmol) dis-
persed in pentane (3 mL) was added HSi(CtCPh)3 (170 mg,
0.51 mmol) at room temperature. After the mixture was
stirred for 12 h at room temperature, the solvent was removed
under reduced pressure to leave a brown solid which was
recrystallized from toluene-pentane, giving 7 as yellow crys-
tals (64%). Anal. Calcd for C42H58ClP2RhSi‚0.5C7H8: C, 65.6;
H, 7.4. Found: C, 64.9; H,7.1. 1H NMR (in C6D6 at 25 °C): δ
-16.50 (dt, 1H, Rh-H, J (HRh) ) 21 Hz, J (HP) ) 12 Hz), 1.40
(dt, 18H, CHCH3, J ) 7 and 6 Hz), 1.53 (dt, 18H, CHCH3, J )
7 and 6 Hz), 3.15 (m, 6H, PCH), 6.92 (m, 9H, C6H5 (meta and
para)), 7.49 (m, 6H, C6H5 (ortho)). 31P{1H} NMR (in C6D6 at
25 °C): 43.71 ppm (d, J (RhP) ) 114 Hz).
Complexes 2-6 were prepared analogously. 2 (containing
0.5 mol of C6H14): yield 91%. Anal. Calcd for C42H71ClP2-
RhSi: C, 62.7; H, 8.9. Found: C, 62.5; H, 8.4. 1H NMR (in
C6D6 at 25 °C): δ -16.22 (dt, 1H, Rh-H, J (HRh) ) 22 Hz,
J (HP) ) 13 Hz), 1.15 (dt, 18H, CHCH3, J ) 7 and 6 Hz), 1.24
(dt, 18H, CHCH3, J ) 7 and 6 Hz), 1.96 (m, 6H, PCH), 2.10 (s,
3H, CH3), 7.04 (d, 6H, SiC6H4 (meta), J ) 8 Hz), 8.20 (d, 6H,
SiC6H4 (ortho), J ) 8 Hz). 31P{1H} NMR (in C6D6 at 25 °C):
37.37 ppm (d, J (RhP) ) 117 Hz). 3: yield 99%. Anal. Calcd
for C39H64ClO3P2RhSi: C, 57.9; H, 8.0. Found: C, 58.4; H,
7.6. 1H NMR (in C6D6 at 25 °C): δ -16.17 (dt, 1H, Rh-H,
J (HRh) ) 22 Hz, J (HP) ) 13 Hz), 1.15 (dt, 18H, CHCH3, J )
7 and 6 Hz), 1.26 (dt, 18H, CHCH3, J ) 7 and 6 Hz), 1.95 (m,
6H, PCH), 3.32 (s, 3H, OCH3), 6.84 (d, 6H, SiC6H4 (meta), J )
7 Hz), 8.21 (d, 6H, SiC6H4 (ortho), J ) 7 Hz). 31P{1H} NMR
(in C6D6 at 25 °C): 37.15 ppm (d, J (RhP) ) 117 Hz). 4: yield
89%. Anal. Calcd for C36H55Cl4P2RhSi: C, 52.6; H, 6.7.
Found: C, 52.8; H, 6.6. 1H NMR (in C6D6 at 25 °C): δ -16.15
(dt, 1H, Rh-H, J (HRh) ) 21 Hz, J (HP) ) 13 Hz), 0.97 (dt,
18H, CHCH3, J ) 7 and 6 Hz), 1.10 (dt, 18H, CHCH3, J ) 7
and 6 Hz), 1.75 (m, 6H, PCH), 7.16 (d, 6H, SiC6H4 (meta), J )
8 Hz), 7.92 (d, 6H, SiC6H4Cl (ortho), J ) 8 Hz). 31P{1H} NMR
(in C6D6 at 25 °C): 37.97 ppm (d, J (RhP) ) 110 Hz). 5: yield,
83%. Anal. Calcd for C36H55ClF3P2RhSi: C, 55.9; H, 7.2.
Found: C, 56.2; H, 6.9. 1H NMR (in C6D6 at 25 °C): δ -16.16
(dt, 1, Rh-H, J (HRh) ) 21 Hz, J (HP) ) 13 Hz), 1.01 (dt, 18H,
CHCH3, J ) 7 and 6 Hz), 1.13 (dt, 18H, CHCH3, J ) 7 and 6
Hz), 1.78 (m, 6H, PCH), 6.86 (dd, 6H, SiC6H4F (ortho), J ) 9
and 1 Hz), 8.00 (dd, 6H, SiC6H4F (meta), J ) 9 and 2 Hz).
31P{1H} NMR (in C6D6 at 25 °C): 37.71 ppm (d, J (RhP) ) 117
Hz). 6: yield, 39%. Anal. Calcd for C39H55ClF9P2RhSi: C,
50.7; H, 6.0. Found: C, 49.9; H, 6.0. Insufficient agreement
of elemental analysis of 6 and 7 with the calculated value is
partially due to contamination of RhCl(H)L2 formed during
recrystallization. 1H NMR (in C6D6 at 25 °C): δ -15.95 (dt,
1H, Rh-H, J (HRh) ) 19 Hz, J (HP) ) 13 Hz), 0.89 (dt, 18H,
CHCH3, J ) 7 and 6 Hz), 1.07 (dt, 18H, CHCH3, J ) 7 and 6
Hz), 1.59 (m, 6H, PCH), 7.38 (d, 6H, SiC6H4 (meta), J ) 9 Hz),
P r ep a r a tion of 8. To a pentane (10 mL) solution of RhClL2
(290 mg, 0.63 mmol) was added HSiPh3 (580 mg, 1.3 mmol)
at room temperature. The purple solution was soon turned
into yellow and then into brown. Stirring for 1 h caused initial
separation of a yellow solid which, on further stirring, under-
went dissolution accompanied by separation of a new yellow-
orange solid from the solution. After it was stirred for 8 h at
room temperature, the resulting solid product was collected
by filtration and recrystallized from toluene-pentane to give
8 as orange crystals (35%). Anal. Calcd for C54H75ClP2Rh2-
Si2: C, 59.9; H, 7.0. Found: C, 59.7; H, 6.8. 1H NMR (in C6D6
at 25 °C): δ -15.78 (m, 2H, Rh-H, coupling constants
obtained from simulation of the spectrum: 1J (HRh) ) 29 Hz,
2
3
4
2J (HP) ) 14 Hz, J (HRh) ) 1 Hz, J (HP) ) -1 Hz, J (HH) )
1 Hz), -12.16 (tt, 1H, Rh-H-Rh, J (HRh) ) 60 Hz, J (HP) )
24 Hz), 0.7-1.2 (br, 36H, CH3), 1.65 (m 6H, J ) 7 Hz), 7.15-
7.25 (m, 18H, C6H5 (meta and para)), 7.88 (d, 12H, C6H5
(ortho), J ) 6 Hz). 31P{1H} NMR (in C6D6 at 25 °C): 53.26
ppm (AA′ part of an AA′XX′ pattern, coupling constants
obtained from simulation of the spectrum: J (PP) ) 5 Hz,
1J (RhP) ) 141 Hz, 2J (RhP) ) 5 Hz, J (RhRh) ) 49 Hz).
Formation of RhCl(H)2L2 (23%) and ClSiPh3 (58% based on
RhClL2) was observed in the NMR spectrum of the reaction
mixture.
P r ep a r a tion of 9. To RhClL2 (200 mg, 0.41 mmol) dis-
persed in pentane (2 mL) was added HSi(C6H4OCF3-p)3 (410
mg, 0.83 mmol) at room temperature. The purple solution was
soon turned into yellow and then into brown. Stirring the
reaction mixture for 5 h at room temperature followed by
cooling the system at -20 °C caused separation of orange

Hydridosilylrhodium(III) Complexes
Organometallics, Vol. 16, No. 10, 1997 2069
microcrystals, which were collected by filtration and dried in
vacuo (260 mg). Recrystallization of the product from toluene-
pentane gave 9. Anal. Calcd for C60H69ClF18O6P2Si2Rh2: C,
45.4; H, 4.4. Found: C, 46.1; H, 5.0. 1H NMR (in C6D6 at 25
°C): δ -16.12 (m, 2H, Rh-H), -12.62 (tt, 1H, Rh-H-Rh,
J (HRh) ) 57 Hz, J (HP) ) 25 Hz), 0.60-1.00 (broad peak, 36H,
P-CH-CH3), 1.49 (m, 6H, P-CH), 7.01 (d, 12H, SiC6H4 (meta),
J ) 9 Hz), 7.53 (d, 12H, SiC6H4 (ortho), J ) 9 Hz). 31P{1H}
NMR (in C6D6 at 25 °C): 54.30 ppm (AA′ part of an AA′XX′
pattern; J (PP) ) 2 Hz, 1J (RhP) ) 139 Hz, 2J (RhP) ) 5 Hz,
and J (RhRh) ) 44 Hz).
P r ep a r a tion of 10. To a pentane (5 mL) dispersion of
RhClL2 (200 mg, 0.44 mmol) was added 1,1,3,3-tetraisopro-
pylsiloxane (140 mg, 0.57 mmol) at room temperature. The
purple solution soon turned yellow-brown. Stirring the reac-
tion mixture for 12 h and removing the solvent under reduced
pressure left a brown paste. The product was washed with a
minimum amount of acetone and recrystallized from acetone
to give 10 as yellow crystals (47 mg, 26%). Anal. Calcd for
Cr ysta l Str u ctu r e Deter m in a tion . Crystals of 1, 7, and
9 suitable for crystallography were obtained by recrystalliza-
tion from toluene-pentane mixtures, while recrystallization
of 10 was carried out from acetone. Crystals were mounted
in glass capillary tubes 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. Empirical absorption correction (ψ
scan method) of the collected data was applied. Table 3
summarizes crystal data and details of data refinement.
Calculations were carried out by using the program package
teXsan on a VAX-II computer. Atomic scattering factors were
taken from the literature.36 A full-matrix least-squares refine-
ment was used for non-hydrogen atoms with anisotropic
thermal parameters. Positions of hydrido ligands were de-
termined by the difference Fourier technique, while the other
hydrogens were located by assuming ideal positions. Positions
of nonbridging hydrido ligands of 9 were not determined
unambiguously, due to insufficient convergence of the struc-
tural calculations. These hydrogens were included in the
structure calculation without further refinement of the pa-
rameters.
C
30H73ClOSi2P2Rh: C, 44.5; H, 9.1. Found: C, 44.0; H, 9.4.
1H NMR (in C6D6 at 25 °C): δ -14.67 (m, 2H, Rh-H), -12.90
(tt, 1H, Rh-H-Rh, J (HRh) ) 56 Hz, J (HP) ) 28 Hz), 1.12
(dd, 18 H, P-CH-CH3, J (PH) ) 13 Hz, J (HH) ) 7 Hz), 1.35
(septet, 1H, Si-CH, J (HH) ) 7 Hz), 1.37 (septet, 1H, Si-CH,
J (HH) ) 7 Hz), 1.45 (d, 6H, Si-CH-CH3, J (HH) ) 7 Hz), 1.51
(d, 6H, Si-CH-CH3, J (HH) ) 7 Hz), 2.11 (doublet of septets,
2H, P-CH, J (PH) ) 7 Hz, J (HH) ) 7 Hz). 13C{1H} NMR (100
MHz in C6D6 at 25 °C): δ 20.23 (P-CH-CH3), 20.38 and 20.91
(Si-CH-CH3), 22.4 (Si-CH), 25.84 (a filled-in doublet due to
virtual coupling, P-CH). 31P{1H} NMR (in C6D6 at 25 °C):
57.65 ppm (AA′ part of an AA′XX′ pattern; J (PP) ) 1 Hz,
1J (RhP) ) 145 Hz, 2J (RhP) ) 3 Hz, and J (RhRh) ) 45 Hz).
The low isolated yield of 10 in the above reaction is due to low
Ack n ow led gm en t. This work was financially sup-
ported by a Grant-in-Aid for Scientific Research from
the Ministry of Education, Science, Sports, and Culture,
J apan. T.K. gratefully acknowledges the Research
Fellowship of the J apan Society for the Promotion of
Science for Young Scientists for a Scholarship.
1
yield in the recrystallization procedure. The H and 31P{1H}
NMR spectra of the reaction mixture before purification
indicate formation of 10 and RhCl(H)2L2 in a 60:40 molar ratio.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data for complexes 1, 7, 9, and 10 (43 pages). Ordering
information is given on any current masthead page.
(36) International Tables for X-ray Crystallography; Kynoch: Bir-
mingham, U.K., 1974; Vol. IV.
OM961048H