Synthesis of novel metal-germavinylidene complexes from bisgermavinylidene

Article abstract of DOI:10.1021/om0503085

The bisgermavinylidene [(Me₃SiN=PPh₂) ₂C=Ge→Ge=C(PPh₂=NSiMe₃)₂] (1) has been used as the source of unstable germavinylidene for the synthesis of a series of metal-germavinylidene complexes. Treatment of 1 with M(PPh ₃)₄ (M = Ni, Pd) afforded the metal-germavinylidene complexes [{(Me₃SiN=PPh₂)₂C=Ge} ₂Ni(PPh₃)₂] (2) and [{(Me₃SiN= PPh₂)₂C= Ge-μ₂}Pd(PPh₃)] ₂ (3), respectively. The germavinylidene moiety from 1 acts as a two-electron terminal and bridging ligand, respectively. Similar reaction of 1 with AgCl or Aul gave [(Me₃-SiN=PPh₂)₂C=Ge(Ag) (Cl)]₂ (5) and [(Me₃SiN=PPh₂) ₂C=Ge(Au)(I)]₂ (6), respectively. The result has shown that the germavinylidene moiety from 1 behaves as a Lewis base and undergoes an insertion reaction into the metal-halogen bond. X-ray structures of 2, 3, 5, and 6 have been determined.

Full text of DOI:10.1021/om0503085

Organometallics 2005, 24, 5033-5037
5033
Synthesis of Novel Metal-Germavinylidene Complexes
from Bisgermavinylidene
Wing-Por Leung,* Cheuk-Wai So, Kwok-Wai Kan, Hoi-Shan Chan, and
Thomas C. W. Mak
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories,
Hong Kong, China
Received April 19, 2005
The bisgermavinylidene [(Me3SiNdPPh2)2CdGefGedC(PPh2dNSiMe3)2] (1) has been used
as the source of unstable germavinylidene for the synthesis of a series of metal-
germavinylidene complexes. Treatment of 1 with M(PPh3)4 (M ) Ni, Pd) afforded the metal-
germavinylidene complexes [{(Me3SiNdPPh2)2CdGe}2Ni(PPh3)2] (2) and [{(Me3SiNdPPh2)2Cd
Ge-µ2}Pd(PPh3)]2 (3), respectively. The germavinylidene moiety from 1 acts as a two-electron
terminal and bridging ligand, respectively. Similar reaction of 1 with AgCl or AuI gave [(Me3-
SiNdPPh2)2CdGe(Ag)(Cl)]2 (5) and [(Me3SiNdPPh2)2CdGe(Au)(I)]2 (6), respectively. The
result has shown that the germavinylidene moiety from 1 behaves as a Lewis base and
undergoes an insertion reaction into the metal-halogen bond. X-ray structures of 2, 3, 5,
and 6 have been determined.
Introduction
that the reactive intermediate germavinylidene “:Ged
C(PPh2dNSiMe3)2” can be generated in situ for subse-
quent formation of metal-germavinylidene complexes.
Herein, we report the synthesis and structures of
unprecedented group 10 metal-germavinylidene com-
plexes and germavinylidyl group 11 metal complexes.
The chemistry of transition metals bonded to heavy
group 14 element carbene analogues, :MR2 (M ) Ge,
Sn, Pb), has attracted much attention in the past few
decades and has been the focus of several reviews.1
Carbene analogues can behave as a Lewis base toward
the transition metal or they can undergo insertion into
transition-metal-halogen or metal-alkyl bonds.
Results and Disscussion
Synthesis of Nickel(0) and Palladium(0) Germa-
vinylidene Complexes. The reaction of bisgermavi-
nylidene 1 with Ni(PPh3)4 in THF afforded [{(Me3SiNd
PPh2)2CdGe}2Ni(PPh3)2] (2) as dark red crystalline
solids (Scheme 1). The X-ray structure analysis of 2
showed that it contains two germavinylidene moieties
bonded to the nickel(0) center. It is suggested that the
intermediate germavinylidene generated from 1 in
solution acted as a two-electron ligand and displaced
two PPh3 molecules from Ni(PPh3)4 to form the 18-
electron nickel(0) complex 2. Similar reaction of 1 with
stoichiometric amounts of Pd(PPh3)4 gave the binuclear
14-electron Pd(0) complex [{(Me3SiNdPPh2)2CdGe-µ2}-
Pd(PPh3)]2 (3) with two bridging germavinylidene ligands
(Scheme 2). Compound 3 reacts readily with CH2Cl2 to
give Cl2Pd(PPh3)2. Similar Lewis base type behavior of
germylene has been demonstrated in the reaction of
M(PR3)4 (M ) Ni, Pd) with [Ge{N(SiMe3)2}2] to form
[(R3P)2MGe{N(SiMe3)2}2].4 Moreover, the reaction of 1
with Cl2Pd(PPh3)2 in THF afforded Pd(PPh3)4 (4), show-
ing that germavinylidene acts as a reducing agent.
Germanium(II) compounds behave as a reducing agent,
as reported in the synthesis of Pd[Ge{N(SiMe3)2}2]3.5
Insertion Reaction of Ag(I) and Au(I) Halides
with Germavinylidene. The reaction of 1 with 2 equiv
We have recently reported the synthesis of the bis-
germavinylidene [(Me3SiNdPPh2)2CdGefGedC(PPh2d
NSiMe3)2] (1), and its role as a carbene ligand {(Me3-
SiNdPPh2)2C:} transfer reagent has been demonstrated
in the reaction of 1 with Mo(CO)5THF to form the mol-
ybdenum carbene complex mer-/fac-(Me3SiNdPPh2)2Cd
Mo(CO)5.2 We also reported the synthesis of chalcogen-
bridged dimers of the germaketene analogues [(Me3-
SiNdPPh2)2CdGe(µ-E)]2 (E ) S, Se, Te) from the direct
reaction of elemental chalcogens with 1.3 By the dis-
sociation of Ge-Ge interaction in 1, we anticipated
* To whom correspondence should be addressed. E-mail:
kevinleung@cuhk.edu.hk.
(1) Selected recent reviews and examples: (a) Petz, W. Chem. Rev.
1986, 86, 1019. (b) Lappert, M. F.; Rowe, R. S. Coord. Chem. Rev. 1990,
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Klingan, F.-R.; Bock, H.; Solouki, B.; Wagner, M. Angew. Chem., Int.
Ed. Engl. 1992, 31, 1485. (d) Lappert, M. F.; Power, P. P. J. Chem.
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J. W.; Banaszak Holl, M. M. Angew. Chem., Int. Ed. Engl. 1997, 36,
496. (l) Litz, K. E.; Henderson, K.; Gourley, R. W.; Banaszak Holl, M.
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(4) (a) Bender, J. E.; Shusterman, A. J.; Banaszak Holl, M. M.;
Kampf, J. W. Organometallics 1999, 18, 1547. (b) Cygan, Z. T.; Bender,
J. E., IV; Litz, K. E.; Kampf, J. W.; Banaszak Holl, M. M. Organome-
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(2) (a) Leung, W.-P.; Wang, Z.-X.; Li, H.-W.; Mak, T. C. W. Angew.
Chem., Int. Ed. 2001, 40, 2501. (b) Leung, W.-P.; So, C.-W.; Wang, J.-
Z.; Mak, T. C. W. Chem. Commun. 2003, 248.
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W. Organometallics 2003, 22, 4305.
10.1021/om0503085 CCC: $30.25 © 2005 American Chemical Society
Publication on Web 09/09/2005

5034 Organometallics, Vol. 24, No. 21, 2005
Leung et al.
Scheme 1
Scheme 2
Scheme 3
of AgCl or AuI in THF afforded [(Me3SiNdPPh2)2Cd
GeAgCl]2 (5) and [(Me3SiNdPPh2)2CdGeAuI]2 (6), re-
spectively (Scheme 3). The X-ray structures of 5 and 6
showed that the germanium atom of germavinylidene
moieties inserted into the M-X bond to form 5 and 6.
This result is consistent with the theoretical calculation
reported by Frenking and co-workers in which the
germylene donor-acceptor complexes with group 11
metal chlorides.6 To our knowledge, the (phosphine)-
gold-trichlorogermyl complex [{R3PAuGeCl3}2] (R )
Ph, o-Tol) is the only example demonstrating the inser-
tion of a Ge(II) compound into a gold-chlorine bond.7
yellow crystalline solids, respectively. They are air-
sensitive, soluble in THF, and sparingly soluble in Et2O.
The 31P NMR spectrum of 2 displayed four singlets at
δ 9.18, 35.96, 43.57, and 45.78 ppm, corresponding to
four different phosphorus environments, as shown in
the noncentrosymmetric molecular structure of 2. It also
indicates that 2 is fluxional in solution. The 31P NMR
spectrum of 3 displayed three signals at δ 33.45, 38.44,
and 40.12 ppm due to three different phosphorus
environments as in the solid-state structure. The 1H and
13C NMR spectra of 3 displayed one set of signals
corresponding to the ligand backbone. The 31P NMR
spectra of 5 and 6 displayed one singlet (δ 46.17 (5); δ
43.42 (6)) due to fluxional motion in solution.
Spectroscopic Properties. Compounds 2 and 3 and
compounds 5 and 6 were isolated as dark red and pale
X-ray Structures. The molecular structures of 2, 3,
5, and 6 are shown in Figures 1-4, respectively.
(6) Boehme, C.; Frenking, G. Organometallics 1998, 17, 5801.
(7) Bauer, A.; Schmidbaur, H. J. Am. Chem. Soc. 1996, 118, 5324.

Novel Metal-Germavinylidene Complexes
Organometallics, Vol. 24, No. 21, 2005 5035
Figure 4. Molecular structure of [(Me3SiNdPPh2)2CdGe-
(Au)(I)]2 (6).
1.908(7) Å in 1. One of the imino nitrogens coordinates
to Ge(1) at a distance of 2.032(4) Å, and Ge(1) is
subtended at an angle of 153.5(1)° with Ni(1) and C(4),
instead of a linear NirGedC< moiety. The difference
in the P-N bond distances of 1.557(4) and 1.641(4) Å
suggests the delocalization of π electrons resulting from
the conjugation of PdN and CdGe double bonds. The
Ni(1)-P(3) bond distance of 2.224(1) Å is similar to that
of 2.181(1) Å in [(Ph3P)2NiGe{2,4,6-(CF3)3C6H2}2].4a
Figure 1. Molecular structure of [{(Me3SiNdPPh2)2Cd
Ge}2fNi(PPh3)2] (2).
The molecular structure of compound 3 is comprised
of two germavinylidenes bridged to two Pd(0) centers.
The C(16)P(1)N(1)Ge(1) plane is perpendicular to the
Pd(1)Ge(1)Pd(1A)Ge(1A) plane. Therefore, the geometry
around the germanium center is tetrahedral. The Ge-
(1)-C(16) distance of 1.906(13) Å is similar to those of
1.905(8) and 1.908(7) Å in 1. The Ge-Pd bond distances
of 2.476(2) and 2.465(2) Å are significantly longer than
that of 2.328(1) Å in [(Ph3P)2PdGe{N(SiMe3)2}2] and
2.337(2) Å in [(dppe)PdGe{N(SiMe3)2}2]2.4b The distance
between the Pd atoms (2.684(2) Å) is shorter than that
of Pd(0) in the bulk metal (2.751 Å) but is slightly longer
than the Pd(I)-Pd(I) distance of [Pd(µ-Br)(PBut3)]2
(2.628(2) Å)9 in Pd(I) complexes with a linear R3P-Pd-
Pd-PR3 moiety. The geometry of the Pd atom is trigonal
planar, as the sum of Pd bond angles is 359.6°. The
Pd-P bond distance of 2.274(4) Å is similar to that of
2.301(9) Å in [(Ph3P)2PdGe{N(SiMe3)2}2].4b
Figure 2. Molecular structure of [{(Me3SiNdPPh2)2Cd
Ge-µ2}Pd(PPh3)]2 (3).
The molecular structures of 5 and 6 are isostructural
and are comprised of two halogermenes forming the
Ge-N chelating bridges with the Ag(I) and Au(I) metal
centers. The metal-halogen distances of 3.88 Å in 5 and
3.95 Å in 6 are longer than the group 11 metal-halogen
single bond. These structures have shown that the
germavinylidene underwent insertion into a M-X bond
instead of forming a donor-acceptor interaction. The
Ag‚‚‚Ag distance of 2.979(2) Å in 5 is longer than that
of 2.654(1) Å in [{2-(Me3Si)2C(Ag)C5H4N}]210 and 2.733-
(3) Å in [{Ag(C6H2Me3-2,4,6)}4]11 but is still shorter than
the sum of van der Waals radii of two Ag atoms (∼3.4
Å), suggesting that a weak silver-silver interaction is
possible. The Au‚‚‚Au distance of 3.092(7) Å in 6 is
within the range of 2.5-3.2 Å for similar interactions
Figure 3. Molecular structure of [(Me3SiNdPPh2)2CdGe-
(Ag)(Cl)]2 (5).
Selected bond distances (Å) and angles (deg) are listed
in Tables 2 and 3. Compound 2 is comprised of two
germavinylidenes [(Me3SiNdPPh2)2CdGe:] and two
PPh3 groups bonded to the nickel center in a distorted-
tetrahedral geometry. The Ni(1)-Ge(1) bond distance
of 2.273(7) Å is similar to that of 2.240 Å in Ni[Ge{1,8-
8
(PriN)2C10H6}]4 and 2.206 Å in [(Ph3P)2NiGe{N-
(SiMe3)2}2].4a The Ge(1)-C(4) bond distance of 1.933(4)
Å in 2 is slightly longer than those of 1.905(8) and
(9) Vilar, R.; Mingos, D. M. P.; Cardin, C. J. J. Chem. Soc., Dalton
Trans. 1996, 4313.
(10) Papasergio, R. I.; Raston, C. L.; White, A. H. J. Chem. Soc.,
Chem. Commun. 1984, 612.
(8) Bazinet, P.; Yap, G. P. A.; Richeson, D. S. J. Am. Chem. Soc.
2001, 123, 11162.
(11) Gambarotta, S.; Floriani, C.; Chiesi-Villa, A.; Guastini, C. J.
Chem. Soc., Chem. Commun. 1983, 1087.

5036 Organometallics, Vol. 24, No. 21, 2005
Table 1. Crystallographic Data for Compounds 2, 3, 5 and 6
Leung et al.
2
3
5
6
formula
C
98H106Ge2N4-
C
98H106Ge2N4P6-
Pd2Si4
C
62H76Ag2Cl2Ge2-
N4P4Si4
C62H76Au2Ge2I2-
NiP6Si4
N4P4Si4
fw
color
cryst syst
space group
a (Å)
b (Å)
c (Å)
1841.94
1996.03
1545.33
1906.42
dark red
monoclinic
C2
dark red
triclinic
pale yellow
triclinic
pale yellow
monoclinic
P21/n
P1h
P1h
23.502(5)
19.525(4)
13.015(3)
90.00
115.10(3)
90.00
13.317(3)
14.373(3)
17.117(3)
68.11(3)
16.056(3)
22.997(5)
24.380(5)
90.70(3)
16.229(9)
23.225(1)
24.210(1)
90.00(0)
102.36(10)
90.00(0)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
68.23(3)
72.63(3)
105.85(3)
91.27(3)
5408.4(19)
2
2774.0(10)
1
8656.0(3)
4
8913.5(9)
4
dcalcd (g cm-3
)
1.131
1.195
1.186
1.421
µ (mm-1
F(000)
)
0.899
1.026
1.357
4.799
1920
1024
3136
3680
cryst size (mm)
2θ range (deg)
index range
0.45 × 0.40 × 0.30
1.91-25.52
0 e h e 28
-23 e k e 23
-14 e l e 13
8855
0.50 × 0.40 × 0.25
1.73-25.73
-16 e h e 15
-15 e k e 0
-20 e l e 18
5254
0.40 × 0.30 × 0.20
1.32-25.00
-19 e h e 19
0 e k e 27
-28 e l e 28
23 010
0.50 × 0.40 × 0.20
1.23-25.00
-19 e h e 19
-27 e k e 21
-28 e l e 28
47662
no. of rflns collected
no. of indep rflns
8754
5254
23010
15677
R1, wR2 (I > 2σ(I))
R1, wR2 (all data)
0.0456, 0.1377
0.0462, 0.1388
1.135
8754/1/520
+0.736 to -0.608
0.0985, 0.2613
0.1226, 0.2845
1.136
5254/0/523
+0.966 to -0.914
0.0944, 0.2923
0.1071, 0.3074
1.119
23 010/4/1441
+1.249 to -0.923
0.0566, 0.1944
0.0985, 0.2176
1.066
15 677/2/721
+1.900 to -0.910
goodness of fit, F2
no. of data/restraints/params
largest diff peaks, e Å-3
Table 2. Selected Bond Distances (Å) and Angles
(deg) for Compounds 2 and 3
Table 3. Selected Bond Distances (Å) and Angles
(deg) for Compounds 5 and 6
[{(Me3SiNdPPh2)2CdGe}2fNi(PPh3)2] (2)
[(Me3SiNdPPh2)2CdGe(M)(X)]2
Ge(1)-Ni(1)
Ni(1)-P(3)
C(4)-Ge(1)
Ge(1)-N(2)
2.273(7)
2.224(1)
1.933(4)
2.032(4)
C(4)-P(1)
C(4)-P(2)
P(1)-N(1)
P(2)-N(2)
1.751(4)
1.726(4)
1.557(4)
1.641(4)
M ) Ag, X ) Cl (5)
M ) Au, X ) I (6)
Ge(1)-M(1)
2.438(2)
2.277(4)
1.910(8)
1.944(10)
1.641(10)
1.699(11)
1.724(10)
1.603(10)
2.158(9)
2.409(2)
2.273(4)
1.906(8)
1.961(9)
1.636(9)
1.690(12)
1.733(11)
2.979(2)
131.0(3)
171.5(3)
110.9(1)
108.0(4)
110.3(5)
109.8(5)
126.5(6)
92.1(5)
2.330(1)
2.666(2)
1.860(1)
1.953(10)
1.641(13)
1.703(13)
1.750(10)
1.624(10)
2.111(10)
2.341(1)
2.648(2)
1.860(1)
1.955(10)
1.622(11)
1.708(12)
1.744(10)
3.092(7)
132.0(4)
175.7(3)
103.4(6)
111.0(4)
109.8(5)
107.6(5)
126.9(6)
93.5(4)
Ge(1)-X(1)
Ge(1)-C(4)
P(3)-Ni(1)-P(3A)
108.6(6) C(4)-P(2)-N(2)
96.9(2)
119.5(2)
91.6(2)
Ge(1)-N(1)
Ge(1)-Ni(1)-Ge(1A) 103.9(4) P(2)-C(4)-P(1)
P(1)-N(1)
P(3)-Ni(1)-Ge(1)
107.3(3) P(2)-N(2)-Ge(1)
C(4)-P(1)
C(4)-P(2)
[{(Me3SiNdPPh2)2CdGe-µ2}Pd(PPh3)]2 (3)
P(2)-N(2)
Pd(1)-Pd(1A)
Ge(1)-Pd(1)
C(16)-Ge(1)
Ge(1)-N(1)
Pd(1)-P(3)
2.684(2)
2.476(2)
1.906(13)
1.954(10)
2.274(4)
C(16)-P(1)
C(16)-P(2)
P(1)-N(1)
P(2)-N(2)
1.737(14)
1.745(13)
1.650(10)
1.545(13)
N(2)-M(2)
M(2)-Ge(2)
Ge(2)-X(2)
Ge(2)-C(54)
Ge(2)-N(3)
P(3)-N(3)
Pd(1)-Ge(1)-Pd(1A)
65.8(6) C(16)-Ge(1)-N(1)
80.5(5)
92.7(5)
94.8(6)
126.0(8)
C(54)-P(3)
Ge(1)-Pd(1)-Ge(1A) 114.2(6) Ge(1)-N(1)-P(1)
C(54)-P(4)
P(3)-Pd(1)-Ge(1)
P(3)-Pd(1)-Ge(1A)
127.4(1) N(1)-P(1)-C(16)
118.1(1) P(1)-C(16)-P(2)
M(1)-M(2)
M(1)-Ge(1)-C(4)
Ge(1)-M(1)-N(4)
X(1)-Ge(1)-M(1)
C(4)-Ge(1)-X(1)
M(1)-N(4)-P(4)
N(4)-P(4)-C(54)
P(4)-C(54)-Ge(2)
P(3)-C(54)-Ge(2)
C(54)-Ge(2)-M(2)
C(54)-Ge(2)-X(2)
X(2)-Ge(2)-M(2)
Ge(2)-M(2)-N(2)
N(2)-P(2)-C(4)
P(2)-C(4)-Ge(1)
P(1)-C(4)-Ge(1)
reported.12 The Ge-Ag bond distances of 2.438(2) and
2.409(2) Å in 5 are longer than the theoretically
calculated Ge-Ag donor-acceptor bond distance in [{N-
(H)CHdCHN(H)}GefAgCl] (2.349 Å).6 The Ge-Au
bond distances of 2.329(1) and 2.341(1) Å in 6 are
comparable to that of 2.376(1) Å in [{(o-Tol3P)AuGe-
Cl3}2].7 The average Ge-C bond distance of 1.908 Å in
5 and 1.860 Å in 6 are similar to those of 1.905(8) and
1.908(7) Å in 1.
130.4(3)
108.8(4)
109.7(1)
171.6(2)
108.0(5)
126.1(6)
93.0(4)
133.1(4)
109.0(4)
105.4(6)
173.7(3)
108.0(5)
131.0(7)
93.7(4)
Experimental Section
General Procedures. All manipulations were car-
ried out under an inert atmosphere of dinitrogen gas
by standard Schlenk techniques. Solvents were dried
over and distilled from CaH2 (hexane) and/or Na (Et2O,
toluene, and THF). Ni(PPh3)4, Pd(PPh3)4, Cl2Pd(PPh3)2,
AgCl, and AuI were purchased from Aldrich Chemicals
and used without further purification. The 1H, 13C, and
31P spectra were recorded on Bruker WM-300 and
Varian 400 spectrometers. The NMR spectra were
(12) Grohmann, A.; Schmidbaur, H. In Comprehensive Organome-
tallic Chemistry; Abel, E. W., Stone F. G. A., Wilkinson, G., Eds.;
Pergamon: Oxford, U.K., 1995; Vol. 3.

Novel Metal-Germavinylidene Complexes
Organometallics, Vol. 24, No. 21, 2005 5037
recorded in THF-d8, and the chemical shifts δ are
a pale yellow solution was formed. After filtration and
concentration, 5 was obtained as pale yellow crystals.
Yield: 0.28 g (40%). Mp: 187.5 °C dec. Anal. Found:
C, 47.92; H, 4.81; N, 3.39. Calcd for C62H76Ag2Cl2-
Ge2N4P4Si4: C, 48.19; H, 4.96; N, 3.63. 1H NMR (THF-
d8, 300 MHz): δ -0.13 (s, 36H, SiMe3), 6.90-7.72 (m,
40H, Ph). 13C{1H} NMR (THF-d8, 75.5 MHz): 4.54
(SiMe3), 129.05, 129.20, 131.54, 132.64, 132.71, 132.78
(Ph). 31P{1H} NMR (THF-d8, 121.5 MHz): δ 46.17.
[(Me3SiNdPPh2)2CdGe(Au)(I)]2 (6). A solution of
1 (0.61 g, 0.49 mmol) in THF (30 mL) was added
dropwise to a suspension of AuI (0.42 g, 0.97 mmol) in
THF (30 mL) at 0 °C in the absence of light. The reaction
mixture was stirred at room temperature for 2 days, and
a pale yellow solution was formed. After filtration and
concentration, 6 was obtained as pale yellow crystals.
Yield: 0.45 g (60%). Mp: 202.2 °C dec. Anal. Found:
C, 39.40; H, 4.32; N, 2.90. Calcd for C62H76Au2Ge2I2N4P4-
1
relative to SiMe4 and 85% H3PO4 for H and 13C and
for 31P, respectively.
[{(Me3SiNdPPh2)2CdGe}2fNi(PPh3)2] (2). A solu-
tion of 1 (0.81 g, 0.64 mmol) in THF (30 mL) was added
dropwise to Ni(PPh3)4 (0.70 g, 0.64 mmol) in THF (30
mL) at -90 °C in the absence of light. The reaction
mixture was stirred at room temperature for 18 h, and
a dark red solution was formed. Volatiles in the mixture
were removed under reduced pressure, and the residue
was extracted with Et2O. After filtration and concentra-
tion of the filtrate, 2 was obtained as dark red crystals.
Yield: 0.84 g (75%). Mp: 87-88 °C. Anal. Found: C,
65.73; H, 5.82; N, 2.90. Calcd for C98H106Ge2N4NiP6Si4:
C, 66.01; H, 5.99; N, 3.14. 1H NMR (THF-d8, 300 MHz):
δ -0.57 (s, 18H, SiMe3), -0.15 (s, 18H, SiMe3), 6.88-
7.70 (m, 70H, Ph). 13C{1H} NMR (THF-d8, 75.5 MHz):
δ 2.84 (SiMe3), 4.15 (SiMe3), 128.29, 128.50, 128.57,
128.66, 129.09, 129.18, 129.33, 131.14, 132.38, 132.87,
134.38, 134.63, 134.75, 138.65 (Ph). 31P{1H} NMR (THF-
d8, 121.5 MHz): δ 9.18, 35.96, 43.57, 45.78.
1
Si4‚1/2THF: C, 39.57; H, 4.15; N, 2.88. H NMR (THF-
d8, 300 MHz): δ -0.06 (s, 36H, SiMe3), 6.98-7.52 (m,
40H, Ph). 13C{1H} NMR (THF-d8, 75.5 MHz): 3.71
(SiMe3), 128.98, 129.15, 129.31, 131.55, 132.01, 133.17,
134.94 (Ph). 31P{1H} NMR (THF-d8, 121.5 MHz): δ
43.42.
[{(Me3SiNdPPh2)2CdGe-µ2}Pd(PPh3)]2 (3). A so-
lution of 1 (0.42 g, 0.33 mmol) in THF (30 mL) was
added dropwise to Pd(PPh3)4 (0.75 g, 0.65 mmol) in THF
(30 mL) at -90 °C in the absence of light. The reaction
mixture was stirred at room temperature for 18 h, and
a dark red solution was formed. Volatiles in the mixture
were removed under reduced pressure, and the residue
was extracted with Et2O. After filtration and concentra-
tion of the filtrate, 3 was obtained as dark red crystals.
Yield: 0.18 g (27%). Mp: 128-129 °C. Anal. Found: C,
58.67; H, 5.14; N, 2.46. Calcd for C98H106Ge2N4P6Pd2-
X-ray Crystallography. Single crystals were sealed
in Lindemann glass capillaries under nitrogen. X-ray
data of 2, 3, 5, and 6 were collected on a Rigaku R-AXIS
II imaging plate using graphite-monochromatized Mo
KR radiation (I ) 0.710 73 Å) from a rotating-anode
generator operating at 50 kV and 90 mA. Crystal data
are summarized in Table 1. The structures were solved
by direct phase determination using the computer
program SHELXTL-PC13 on a PC 486 and refined by
full-matrix least squares with anisotropic thermal pa-
rameters for the non-hydrogen atoms. Hydrogen atoms
were introduced in their idealized positions and included
in structure factor calculations with assigned isotropic
temperature factor calculations. Full details of the
crystallographic analysis of 2, 3, 5, and 6 are given in
the Supporting Information.
1
Si4: C, 58.97; H, 5.35; N, 2.81. H NMR (THF-d8, 300
MHz): δ 0.03 (s, 18H, SiMe3), 0.11 (s, 18H, SiMe3),
7.38-7.47 (m, 40H, Ph), 7.64-7.68 (m, 10H, Ph), 7.71-
7.79 (m, 10H, Ph), 7.85-7.94 (m, 10H, Ph). 13C{1H}
NMR (THF-d8, 75.5 MHz): δ 1.38, 1.63 (SiMe3), 128.52,
128.77, 129.03, 129.19, 131.29, 131.56, 131.92, 133.27,
132.76, 132.88, 134.67 (Ph). 31P{1H} NMR (THF-d8, 161
MHz): δ 33.45 (PdP), 39.44, 40.12 (PCP).
Reaction of 1 with PdCl2(PPh3)2. A solution of 1
(0.54 g, 0.43 mmol) in THF (30 mL) was added dropwise
to Cl2Pd(PPh3)2 (0.63 g, 0.90 mmol) in THF (30 mL) at
0 °C. The reaction mixture was stirred at room temper-
ature for 18 h. Volatiles in the mixture were removed
under reduced pressure, and the residue was extracted
with Et2O. After filtration and concentration of the
filtrate, 4 was obtained as yellow crystals. Yield: 0.49
g (47%).
Acknowledgment. This work was supported by the
Hong Kong Research Grants Council (Project No. CUHK
401404).
Supporting Information Available: Details about the
X-ray crystal structures, as CIF files, for 2, 3, 5, and 6. This
material is available free of charge via the Internet at
http://pubs.acs.org.
[(Me3SiNdPPh2)2CdGe(Ag)(Cl)]2 (5). A solution of
1 (0.46 g, 0.37 mmol) in THF (30 mL) was added
dropwise to a suspension of AgCl (0.11 g, 0.73 mmol) in
THF (30 mL) at 0 °C in the absence of light. The reaction
mixture was stirred at room temperature for 2 days, and
OM0503085
(13) Sheldrick G. M. In Crystallographic Computing 3: Data Col-
lection, Structure Determination, Proteins, and Databases; Sheldrick,
G. M., Kruger, C., Goddard, R., Eds.; Oxford University Press: New
York, 1985; p 175.