Preparation and structure of a new dipalladium complex with bridging diphenylgermyl ligands. Diverse reactivities of Pd(PCy3)2 and Pt(PCy3)2 toward Ph2GeH2

Article abstract of DOI:10.1021/om050981u

A dinuclear palladium complex having bridging diphenylgermyl ligands, [{Pd(PCy₃)}₂(μ-HGePh₂)₂] (1), was obtained from the reaction of Ph₂GeH₂ with [Pd(PCy ₃)₂]. X-ray

Full text of DOI:10.1021/om050981u

796
Organometallics 2006, 25, 796-798
Preparation and Structure of a New Dipalladium Complex with
Bridging Diphenylgermyl Ligands. Diverse Reactivities of Pd(PCy3)2
and Pt(PCy3)2 toward Ph2GeH2
Makoto Tanabe, Naoko Ishikawa, and Kohtaro Osakada*
Chemical Resources Laboratory (Mail Box R1-3), Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226-8503, Japan
ReceiVed NoVember 15, 2005
Scheme 1
Summary: A dinuclear palladium complex haVing bridging
diphenylgermyl ligands, [{Pd(PCy3)}2(µ-HGePh2)2] (1), was
obtained from the reaction of Ph2GeH2 with [Pd(PCy3)2]. X-ray
crystallographic results and NMR spectra of 1 reVealed
coordination of the Ge ligands to two Pd centers Via a Ge-
H-Pd three-center-two-electron bond and a Ge-Pd σ bond.
The reaction of Ph2GeH2 with [Pt(PCy3)2] produces the
(germyl)hydridoplatinum complexes cis-[Pt(H)(GeHPh2)(PCy3)2]
(cis-3) and trans-[Pt(H)(GeHPh2)(PCy3)2] (trans-3) as the
kinetic and thermodynamic products, respectiVely.
Introduction
Wilking prepared a diplatinum complex having bridging Ge-
HPh2 ligands, [{Pt(PPh3)}2(µ-HGePh2)2], from the reaction of
H2GePh2 with [Pt(PPh3)2(CH2dCH2)].6 The intermediate mono-
nuclear complex cis-[Pt(H)(GeHPh2)(PPh3)2] was isolated at an
early stage of the reaction. Mochida reported that the reaction
of HPh2Ge(SiMe2)nGePh2H (n ) 0-3) with a Pt(0) complex
produced mononuclear Pt(II) complexes with hydride and
germyl ligands as the oxidative addition products, which were
further converted into [{Pt(PPh3)}2(µ-GePh2)2] via intermediate
digermaplatinacycles.7 An analogous dipalladium complex with
bridging organogermyl ligands has no precedent, although
mononuclear complexes with Pd-Ge and PddGe bonds have
been prepared by using R3GeLi, digermylenes, and germylenes
as the source of the Ge ligands.8-13 Herein, we report the
reaction of H2GePh2 with Pd(0) and Pt(0) complexes having
PCy3 ligands and the structure of a new dipalladium complex
bridged by diphenylgermyl ligands.
Reactions of primary (SiH3R) and secondary (SiH2R2) orga-
nosilanes with low-valent late-transition-metal complexes pro-
vide a convenient method for preparation of the dinuclear
complexes with bridging silyl ligands.1 The dinuclear Pd(I) and
Pt(I) complexes formed by this procedure contain a single bond
between the two d9 metal centers, which are bridged by two
organosilyl ligands by three-center-two-electron (M-H-Si)
bonds and M-Si σ bonds.2-5 Scheme 1 depicts a possible
pathway for the formation of these dinuclear complexes. Initial
oxidative addition of a Si-H bond to Pd(0)- and Pt(0)-
phosphine complexes forms mononuclear intermediates with
hydride and silyl ligands, and subsequent dimerization of these
intermediates leads to the dinuclear complexes of Pd(I) and Pt-
(I).
Despite the large number of the Pd and Pt complexes having
bridging organosilyl ligands that have been reported so far, there
have been only a few reports of similar dinuclear complexes
with bridging organogermyl ligands. Recently, Braddock-
Results and Discussion
Treatment of H2GePh2 with [Pd(PCy3)2] at room temperature
for 18 h yields a dinuclear palladium complex with bridging
* To whom correspondence should be addressed. E-mail: kosakada@
res.titech.ac.jp.
(1) (a) Schubert, U. AdV. Organomet. Chem. 1990, 30, 151-187. (b)
Ogino, H.; Tobita, H. AdV. Organomet. Chem. 1998, 42, 223-290. (c)
Corey, J. Y.; Braddock-Wilking, J. Chem. ReV. 1999, 99, 175-292. (d)
Braunstein, P.; Boag, N. M. Angew. Chem., Int. Ed. 2001, 40, 2427-2433.
(2) Diplatinum complexes: (a) Auburn, M.; Ciriano, M.; Howard, J. A.
K.; Murray, M.; Pugh, N. J.; Spencer, J. L.; Stone, F. G. A.; Woodward, P.
J. Chem. Soc., Dalton Trans. 1980, 659-666. (b) Levchinsky, Y.; Rath,
N. P.; Braddock-Wilking, J. Organometallics 1999, 18, 2583-2586. (c)
Sanow, L. M.; Chai, M.; McConnville, D. B.; Galat, K. J.; Simons, R. S.;
Rinaldi, P. L.; Youngs, W. J.; Tessier, C. A. Organometallics 2000, 19,
192-205. (d) Braddock-Wilking, J.; Corey, J. Y.; Trankler, K. A.; Dill, K.
M.; French, L. M.; Rath. N. P. Organometallics 2004, 23, 4576-4584.
(3) Dipalladium complexes: (a) Kim, Y.-J.; Lee, S.-C.; Park, J.-I.;
Osakada, K.; Choi, J.-C.; Yamamoto, T. Organometallics 1998, 17, 4929-
4931. (b) Kim, Y.-J.; Lee, S.-C.; Park, J.-I.; Osakada, K.; Choi, J.-C.;
Yamamoto, T. Dalton Trans. 2000, 417-421.
(4) Pd-Pt heterobimetallic complexes: (a) Tanabe, M.; Yamada, T.;
Osakada, K. Organometallics 2003, 22, 2190-2192. (b) Yamada, T.;
Tanabe, M.; Osakada, K.; Kim, Y.-J. Organometallics 2004, 23, 4771-
4777.
(5) (a) Sakaki, S.; Yamaguchi, S.; Musashi, Y.; Sugimoto, M. J.
Organomet. Chem. 2001, 635, 173-186. (b) Nakajima, S.; Sumimoto, M.;
Nakao, Y.; Sato, H.; Sakaki, S.; Osakada, K. Organometallics 2005, 24,
4029-4038.
(6) Braddock-Wilking, J.; Corey, J. Y.; White, C.; Xu, H.; Rath, N. P.
Organometallics 2005, 24, 4113-4115.
(7) Usui, Y.; Hosotani, S.; Ogawa, A.; Nanjo, M.; Mochida, K.
Organometallics 2005, 24, 4337-4339.
(8) (a) Brooks, E. H.; Glockling, F. J. Chem. Soc., Chem. Commun. 1965,
510. (b) Crociani, B.; Boschi, T.; Nicolini, M. Inorg. Chim. Acta 1970, 4,
577-580.
(9) (a) Tsumuraya, T.; Ando, W. Organometallics 1989, 8, 2286-2288.
(b) Mochida, K.; Hodota, C.; Yamashita, H.; Tanaka, M. Chem. Lett. 1992,
1635-1638. (c) Komoriya, H.; Kako, M.; Nakadaira, Y.; Mochida, K. J.
Organomet. Chem. 2000, 611, 420-432. (d) Mochida, K. Karube, H.; Nanjo,
M.; Nakadaira, Y. J. Organomet. Chem. 2005, 690, 2967-2974.
(10) Suginome, M.; Oike, H.; Shuff, P. H.; Ito, Y. J. Organomet. Chem.
1996, 521, 405-408.
(11) Lee, C.; Lee, J.; Lee, S. W.; Kang, S. O.; Ko, J. Inorg. Chem. 2002,
41, 3084-3090.
(12) (a) Cygan, Z. T.; Bender, J. E., IV; Litz, K. E.; Kampf, J. W.;
Banaszak Holl, M. M. Organometallics 2002, 21, 5373-5381. (b) Cygan,
Z. T.; Kampf, J. W.; Banaszak Holl, M. M. Inorg. Chem. 2003, 42, 7219-
7226. (c) Cygan, Z. T.; Kampf, J. W.; Banaszak Holl, M. M. Inorg. Chem.
2004, 43, 2057-2063.
(13) Leung, W.-P.; So, C.-W.; Kan, K.-W.; Chan, H.-S.; Mak, T. C. W.
Organometallics 2005, 24, 5033-5037.
10.1021/om050981u CCC: $33.50 © 2006 American Chemical Society
Publication on Web 12/27/2005

Notes
Organometallics, Vol. 25, No. 3, 2006 797
NMR (1H, 13C{1H}, and 31P{1H}) spectroscopy and elemental
analysis. The 31P{1H} NMR spectrum of trans-3 displays a
singlet with a coupling to 195Pt nuclei (JPPt ) 2650 Hz),
1
indicating that PCy3 ligands occupy trans positions. The H
Figure 1. ORTEP drawing of 1 with ellipsoids drawn at the 30%
probability level. The molecule has a C2 symmetry center at the
midpoint of two Pd centers. Atoms with asterisks are crystallo-
graphically equivalent to those having the same number without
asterisks. Selected distances (Å) and angles (deg): Pd-Pd* )
2.752(1), Pd-P ) 2.308(2), Pd-Ge ) 2.440(1), Pd-Ge* ) 2.415-
(1), Pd-H ) 1.84(7), Ge-H* ) 1.90(7); P-Pd-Ge ) 104.89(6),
P-Pd-Ge* ) 142.65(7), Pd-Ge-Pd* ) 69.05(3), Ge-Pd-Ge*
) 110.95(4), P-Pd-Pd* ) 158.50(6).
NMR spectrum of trans-3 exhibits the signal for the hydride
ligand at δ -4.71 and that for the H bonded to the Ge center at
δ 5.77. The JHPt value of the hydride signal (798 Hz) is much
larger than that of trans-[Pt(H)(SiHPh2)(PCy3)2] (δ -1.3, JHPt
) 666 Hz).14
1
The H NMR spectrum of the reaction mixture after 1.5 h
exhibits signals indicating the formation of trans-3 and cis-[Pt-
(H)(GeHPh2)(PCy3)2] (cis-3) in a 9:91 ratio. The ratio gradually
changes to 96:4 in 48 h, indicating that cis-3 is initially formed
by oxidative addition of H2GePh2 to Pt(0) and is isomerized
into thermodynamically more stable trans-3 during the reaction
2. cis-3 has been characterized by 1H and 31P{1H} NMR spectra
of the reaction mixture in C6D6. The 31P{1H} NMR spectrum
shows two doublets at δ 35.8 and 43.4 with similar coupling
constants (JPPt ) 2505, 2219 Hz). The former signal is assigned
as the PCy3 ligand at the position trans to the H atom on the
basis of comparison with the data for cis-[Pt(H)(SiHPh2)(PCy3)2]
(cis-4) (δ 38.5, JPPt ) 2632 Hz).14 The P-Pt coupling constant
of the latter signal, which is assigned to PCy3 trans to the Ge
atom, is much larger than that of the phosphorus trans to the Si
atom of cis-4 (δ 46.2, JPPt ) 1675 Hz). The 1H NMR spectrum
of cis-3 shows characteristic Ge-H and Pt-H signals at δ 5.45
diphenylgermyl ligands, [{Pd(PCy3)}2(µ-HGePh2)2] (1), as a
light yellow solid in 85% yield, as shown in eq 1. Figure 1
displays the molecular structure of 1 determined by X-ray
crystallography. The molecule has crystallographic C2 symmetry
around the midpoint of the two Pd centers. The distance between
the two Pd centers (2.752(1) Å) suggests the presence of a Pd-
Pd bond, although it is significantly longer than that of [{Pd-
(PCy3)}2(µ-HSiPh2)2] (2) (2.691(1) Å).4a The Pd2Ge2 four-
membered cyclic core is composed of two Pd-H-Ge three-
center-two-electron bonds and two Pd-Ge σ bonds. The final
D map shows the bridging hydrogens involved in the Pd-H-
Ge bond. The Pd-Ge distance involved in the former bonding
(2.440(1) Å) is longer than that in the latter (2.415(1) Å). The
Si analogue 2 contains shorter Pd-Si distances of the Pd-H-
Si three-center-two-electron bond (2.384(2) Å) and of the Pd-
Si σ bond (2.326(2) Å) as compared to the corresponding Pd-
Ge distances of 1, due to the covalent radius of Ge (1.22 Å)
being greater than that of Si (1.17 Å). Ge-H (1.90(7) Å) and
Pd-H (1.84(7) Å) bond distances of 1 are longer compared
with the Si-H (1.63 Å) and Pd-H (1.61 Å) bonds of 2,
respectively.
and -4.48, which are split by 31P-1H and H-1H coupling.
1
Reaction 2 is contrasted with the reaction of H2GePh2 with
[Pt(PPh3)2(CH2dCH2)], which affords a dinuclear Pt complex
with bridging GeHPh2 ligands via the intermediate mononuclear
complex cis-[Pt(H)(GeHPh2)(PPh3)2].6 Dissociation of a PPh3
ligand from the mononuclear intermediate or its cis geometry
may induce its dimerization accompanied by intermolecular
reductive elimination of the two hydride ligands. cis-3 is
isomerized into the thermodynamically more stable isomer with
a trans structure but does not dimerize, due to dissociation of
the PCy3 ligand being more difficult than that of PPh3.
We have reported the preparation of the germyl-bridged
dinuclear palladium complex 1 and the mononuclear (germyl)-
hydridoplatinum complex 3 from the oxidative addition reaction
of Ge-H bonds to the zerovalent complexes [M(PCy3)2] (M )
Pd, Pt). The former reaction probably involves a mononuclear
Pd(II) complex formulated as [Pd(H)(GePh2H)(PCy3)2], although
the intermediate was neither isolated nor characterized because
of its facile conversion into the dinuclear Pd(I) complex.
The 1H NMR spectrum of 1 exhibits an apparent triplet at δ
0.42. This signal is assigned to the hydrogen involved in Pd-
H-Ge bonding and shows splitting due to virtual coupling with
two phosphorus nuclei. The peak position is almost the same
as that for the diplatinum complex with bridging diphenylgermyl
and PPh3 ligands, [{Pt(PPh3)}2(µ-HGePh2)2] (δ 0.43),6 while it
appears at a much higher field position than the Pd-H-Si
hydrogen of 2 (δ 2.07). The 31P{1H} NMR spectrum of 1
contains a single signal at δ 52.8, while the PCy3 ligand of the
dipalladium complex 2 with SiHPh2 ligands shows the signal
at δ 45.1.
Experimental Section
General Procedures. All manipulations of the complexes were
carried out using standard Schlenk techniques under an argon or a
nitrogen atmosphere. Hexane and toluene were distilled from
sodium benzophenone ketyl and stored under nitrogen. H, 13C-
1
{1H}, and 31P{1H} NMR spectra were recorded on a Varian
Mercury 300 spectrometer. The peak position of the 31P{1H} NMR
The reaction of H2GePh2 with [Pt(PCy3)2] at room temper-
ature for 72 h forms a mononuclear (germyl)hydridoplatinum
complex, trans-[Pt(H)(GeHPh2)(PCy3)2] (trans-3), as shown in
eq 2. trans-3 was isolated in 87% yield and characterized by
(14) Chan, D.; Duckett, S. B.; Heath, S. L.; Khazal, I. G.; Perutz, R. N.;
Sabo-Etienne, S.; Timmins, P. L. Organometallics 2004, 23, 5744-5756.

798 Organometallics, Vol. 25, No. 3, 2006
Notes
Table 1. Crystallographic Data and Details of Refinement
of 1
spectrum was referenced to external 85% H3PO4. Diphenylgermane
was obtained from Gelest and used as received. IR absorption
spectra were recorded with a Shimadzu FT/IR-8100 spectrometer.
Elemental analyses were carried out with a Yanaco MT-5 CHN
autocorder.
formula
formula wt
color
cryst size/mm
cryst syst
space group
a/Å
C60H88P2Pd2Ge2
1229.28
yellow
0.20 × 0.38 × 0.42
monoclinic
P21/c (No. 14)
10.272(10)
14.025(14)
20.255(19)
93.092(12)
2914(5)
Preparation of [Pd(PCy3)2]. The reported preparation method15
was modified. To a toluene solution (7 mL) of [Pd(Me)2(tmeda)]
(tmeda ) N,N,N′,N′-tetramethylethylenediamine) (0.748 g, 2.96
mmol) was added twice the molar amount of PCy3 (1.66 g, 5.92
mmol). The reaction mixture was stirred for 1 h at room temper-
ature. The solvent was removed under reduced pressure to yield a
white solid. The solid was washed twice with 4 mL portions of
b/Å
c/Å
â/deg
V/Å3
Z
2
D
calcd/g cm-3
1.401
1
hexane and dried in vacuo to give [Pd(PCy3)2] (1.50 g, 76%). H
F(000)
1268.00
µ/cm-1
17.189
NMR (300 MHz, C6D6, room temperature): δ 2.20 (d, 12H, JHP
)
12 Hz), 1.81-1.65 (m, 36H), 1.29 (m, 18H). 13C{1H} NMR (75
MHz, C6D6, room temperature): δ 34.6 (PCH), 32.3 (PCHCH2),
27.9 (PCHCH2CH2), 27.0 (PCHCH2CH2CH2). 31P{1H} NMR (121
MHz, C6D6, room temperature): δ 39.7.
no. of unique rflns
6075 (Rint ) 0.040)
no. of obsd rflns (I > 2.00σ(I))
no. of variables
R1 (I > 2.00σ(I))
wR2 (all data)
2843
345
0.0762
0.2150
GOF
0.991
Preparation of [Pt(Ph)2(PCy3)2]. To a toluene solution (7 mL)
of [Pt(Ph)2(cod)]16 (1.01 mg, 2.20 mmol) was added PCy3 (1.50 g,
5.35 mmol) at room temperature. Stirring the solution for 1 h at
that temperature caused separation of a white solid, which was
collected through filtration, washed three times with 4 mL portions
of hexane, and dried in vacuo to yield [Pt(Ph)2(PCy3)2] (1.79 g,
2
and PCHCH2CH2CH2), -4.71 (t, 1H, PtH, JHP ) 13 Hz, JHPt
)
798 Hz). 13C{1H} NMR (75 MHz, C6D6, room temperature): δ
150.9 (s, C6H5 ipso, JCPt ) 43 Hz), 137.8 (s, C6H5 ortho, JCPt
2
3
)
11 Hz), 127.3 (s, C6H5 meta), 126.4 (s, C6H5 para), 37.6 (apparent
triplet, PCH, JCP ) 14 Hz, JCPt ) 28 Hz), 30.8 (apparent triplet,
PCHCH2, JCP ) 14 Hz), 27.6 (apparent triplet, PCHCH2CH2, JCP
) 5.5 Hz), 26.9 (s, PCHCH2CH2CH2). 31P{1H} NMR (121 MHz,
C6D6, room temperature): δ 39.2 (JPPt ) 2650 Hz). IR (KBr, cm-1):
ν 1970, 1918.
1
90%). H NMR (300 MHz, C6D6, room temperature): δ 7.69 (m,
4H, C6H5 ortho, JHPt ) 58 Hz), 7.06 (t, 4H, C6H5 meta, JHH ) 7
Hz), 6.81 (t, 2H, C6H5 para, JHH ) 7 Hz), 2.21 (m, 18H, PCy3),
1.50-1.80 (m, 30H, PCy3), 1.18 (br, 18H, PCy3).
Characterization of cis-[Pt(H)(GeHPh2)(PCy3)2] (cis-3). An
NMR tube containing a C6D6 (600 µL) solution of cis-[Pt(Ph)2-
(PCy3)2] (17 mg, 0.018 mmol) was heated to produce [Pt(PCy3)2]
as described above. Addition of Ph2GeH2 (3.4 µL, 0.018 mmol) to
the solution afforded a cis-(germyl)hydridoplatinum complex (cis-
3), which isomerized into trans-3 over time. cis-3 was characterized
Preparation of [{Pd(PCy3)}2(µ-HGePh2)2] (1). To a toluene
(5 mL) solution of [Pd(PCy3)2] (90.1 mg, 0.14 mmol) was added
an equimolar amount of Ph2GeH2 (30 µL, 0.16 mmol), and the
mixture was stirred at room temperature for 18 h. The solvent was
removed under reduced pressure to yield a light yellow solid, which
was washed five times with 2 mL portions of hexane and dried in
vacuo to give 1 as a yellow solid (71 mg, 85%). Anal. Calcd for
C60H88Ge2P2Pd2: C, 58.62; H, 7.22. Found: C, 58.39; H, 7.10. 1H
NMR (300 MHz, C6D6, room temperature): δ 8.07 (d, 8H, C6H5
ortho, JHH ) 7 Hz), 7.33 (t, 8H, C6H5 meta, JHH ) 7 Hz), 7.18 (t,
4H, C6H5 para, JHH ) 7 Hz), 1.90-1.70 (m, 18H, C6H11), 1.58-
1.50 (m, 18H, C6H11), 1.38-1.25 (m, 12H, C6H11), 1.05-0.81 (m,
18H, C6H11), 0.42 (apparent triplet, 2H, GeH, JHP ) 5.3 Hz). 13C-
{1H} NMR (75 MHz, CD2Cl2, room temperature): δ 150.1 (s, C6H5
ipso), 135.6 (s, C6H5 ortho), 127.8 (s, C6H5 para), 127.5 (s, C6H5
meta), 36.9 (apparent triplet, PCH, JCP ) 7.8 Hz), 30.8 (s,
PCHCH2), 27.7 (apparent triplet, PCHCH2CH2, JCP ) 5.5 Hz), 26.5
(s, PCHCH2CH2CH2). 31P{1H} NMR (121 MHz, C6D6, room
temperature): δ 52.8.
1
from the H and 31P{1H} NMR spectra of the reaction mixture
collected a few minutes after addition. The cis/trans ratio for
complex 3 was determined from the integration of the ortho position
1
1
of GePh2H in H NMR spectra. H NMR (300 MHz, C6D6, room
temperature): δ 8.15 (d, C6H5 ortho, JHH ) 7 Hz), 7.5-7.1 (C6H5
meta and para of GePh2H, overlapped with biphenyl’s proton), 5.45
3
3
(ddd, GeH, JHH ) 5.4 Hz, JHP ) 8.4 Hz (cis), 24.3 Hz (trans)),
3
2
1.9-0.3 (PCy3 region), -4.48 (ddd, PtH, JHH ) 5.4 Hz, JHP
)
22 Hz (cis), 149 Hz (trans), JHPt ) 762 Hz). 31P{1H} NMR (121
2
MHz, C6D6, room temperature): δ 35.8 (P trans to H, JPP ) 11
Hz, JPPt ) 2505 Hz), 43.4 (P trans to Ge, JPP ) 11 Hz, JPPt
2
)
2219 Hz).
X-ray Crystallography. A crystal of 1 suitable for X-ray
diffraction study was mounted on a glass capillary. Data for 1 were
collected at -160 °C on a Rigaku Saturn CCD diffractometer
equipped with monochromated Mo KR radiation (λ ) 0.710 73
Å). Calculations were carried out by using the program package
Crystal Structure version 3.7 for Windows. A full-matrix least-
squares refinement was used for the non-hydrogen atoms with
anisotropic thermal parameters. Hydrogen atoms, except for the
GeH hydrogens of 1, were located by assuming ideal geometry
and were included in the structure calculations without further
refinement of the parameters. Crystallographic data and details of
refinement are summarized in Table 1.
Preparation of trans-[Pt(H)(GeHPh2)(PCy3)2] (trans-3). Ph2-
GeH2 (62 µL, 0.33 mmol) was added to the toluene (7 mL) solution
of [Pt(PCy3)2], which was prepared via reductive elimination of
cis-[Pt(Ph)2(PCy3)2] (302 mg, 0.33 mmol) at 60 °C for 1 h. The
reaction mixture was stirred at room temperature for 72 h. The
solution was filtered to remove a small mount of an impurity. The
solvent was removed under reduced pressure. The residual material
was washed twice with 3 mL portions of hexane and dried in vacuo
to give trans-3 as a white solid (283 mg, 87%). Anal. Calcd for
1
C48H78GeP2Pt: C, 58.54; H, 7.98. Found: C, 58.84; H, 8.09. H
NMR (300 MHz, C6D6, room temperature): δ 8.07 (d, 4H, C6H5
ortho, JHH ) 7 Hz), 7.31 (t, 4H, C6H5 meta, JHH ) 7 Hz), 7.19 (t,
2H, C6H5 para, JHH ) 7 Hz, overlapped with solvent), 5.77 (br,
Acknowledgment. This work was supported by Grants-in-
Aid for Scientific Research from the Ministry of Education,
Culture, Sports, Science and Technology of Japan.
2
1H, GeH, JHPt ) 60 Hz), 2.28 (br, 6H, PCH), 2.05 (d, 12H,
PCHCH2, JHP ) 12 Hz), 1.69 (br, 12H, PCHCH2CH2) 1.61 (br,
18H, PCHCH2 and PCHCH2CH2CH2), 1.16 (br, 18H, PCHCH2CH2
Supporting Information Available: Crystallographic data for
1 as a CIF file. This material is available free of charge via the
Internet at http://pubs.acs.org.
(15) Otsuka, S.; Yoshida, T.; Matsumoto, M.; Nakatsu, K. J. Am. Chem.
Soc. 1976, 98, 5850-5858.
(16) Shekhar, S.; Hartwig, J. F. J. Am. Chem. Soc. 2004, 126, 13016-
13027.
OM050981U