1058 Organometallics, Vol. 30, No. 5, 2011
Samanamu et al.
vacuo, and the resulting solid was crystallized from 5/1 benzene/
cyclohexane to yield 3 (0.071 g, 65%) as colorless crystals. H
Crystallographic data for the X-ray analysis for 1 and 3-5 are
collected in Table 6. The crystal-to-detector distance was 60 mm,
and the exposure time was 20 s per frame using a scan width of
0.5ꢀ. Data collection was 100% complete to 25.00ꢀ in θ, except
in the case of 5, where CheckCIF indicated data coverage to
only 92%. However, the protocols for data coverage indicated
100% coverage with high redundancy. Currently, we are not
sure of the reason for this discrepancy. The data were integrated
using the Bruker SAINT software program and scaled using the
SADABS software program. Solution by direct methods (SIR-
2004) produced a complete heavy-atom phasing model consis-
tent with the proposed structures. All non-hydrogen atoms were
refined anisotropically by full-matrix least squares (SHELXL-
97). Aside from the germanium-bound hydrogen in 1, all hy-
drogen atoms were placed using a riding model. Their positions
were constrained relative to their parent atom using the appro-
priate HFIX command in SHELXL-97.
Computational Details. Gaussian 03 was utilized for all
computations.80 Energy calculations, geometry optimizations,
and frequency calculations were performed using the hybrid
density functional method including Becke’s three-parameter
nonlocal-exchange functional81 with the Lee-Yang-Parr cor-
relation functional, B3LYP.82 The 6-31G* basis set83 was
employed for all atoms except iodine. For iodine, the LanL2DZ
basis set, which includes the D95 double-ζ basis set84 combined
with Hay and Wadt’s effective core potential,76 was utilized. All
atomic positions are optimized without geometry constraints.
Frequency calculations were performed at a lower level to
confirm that the stable geometries have real vibrational fre-
quencies. The time-dependent density functional computations,
as implemented by Gaussian 03, were utilized to explore the
excited manifold and compute the possible electronic transitions
and oscillator strengths.
1
NMR (C6D6, 25 ꢀC, 300 MHz): δ 7.34 (d, J=6.6 Hz, 18H, o-
C6H5), 7.05 (t, J=7.2 Hz, 9H, p-C6H5), 6.93 (t, J=7.2 Hz, 18H,
m-C6H5). 13C NMR (C6D6, 25 ꢀC, 75.5 MHz): δ 137.0 (ipso-C),
136.3 (o-C), 129.2 (p-C), 128.5 (m-C) ppm. UV/visible (CH2Cl2):
λmax 245 nm (ε = 2.8 ꢀ 104 M-1 cm-1). Anal. Calcd for
C78H75ClGe4 (3 3C6H6 C6H12): C, 69.98; H, 5.65. Found: C,
3
3
69.76; H, 5.67.
Synthesis of (Ph3Ge)3GeBr (4). A Schlenk tube was charged
with 1 (0.103 g, 0.105 mmol) and [Ph3C][PF6] (0.045 g, 0.115
mmol) in dibromomethane (30 mL). The reaction mixture was
heated in an oil bath with stirring at 90 ꢀC for 24 h. The reaction
mixture was filtered through Celite into a Schlenk flask, and the
volatiles were removed in vacuo to yield a pale yellow solid that
was washed with hexane (4 ꢀ 5 mL). The solid was dried in
vacuo, and the resulting solid was crystallized from benzene to
yield 4 (0.062 g, 56%) as colorless crystals. 1H NMR (C6D6, 25 ꢀC,
300 MHz): δ 7.35 (d, J=6.6 Hz, 18H, o-C6H5), 7.07 (t, J=7.8 Hz,
9H, p-C6H5), 6.94 (t, J = 7.5 Hz, 18H, m-C6H5). 13C NMR
(C6D6, 25 ꢀC, 75.5 MHz): δ 137.1 (ipso-C), 136.4 (o-C), 129.2 (p-
C), 128.5 (m-C) ppm. UV/visible (CH2Cl2): λmax 264 nm (ε=
4.0 ꢀ 104 M-1 cm-1). Anal. Calcd for C54H45BrGe4: C, 60.91; H,
4.26. Found: C, 60.55; H, 4.45.
Synthesis of (Ph3Ge)3GeI (5). A Schlenk tube was charged
with 1 (0.100 g, 0.102 mmol) and [Ph3C][PF6] (0.045 g, 0.115
mmol) in diiodomethane (30 mL). The reaction mixture was
heated in an oil bath with stirring at 90 ꢀC for 24 h. The reaction
mixture was filtered through Celite into a Schlenk flask, and the
volatiles were removed in vacuo to yield a pale yellow solid that
was washed with hexane (4 ꢀ 5 mL). The solid was dried in
vacuo, and the resulting solid was crystallized from benzene to
1
yield 4 (0.067 g, 59%) as colorless crystals. H NMR (C6D6,
25 ꢀC, 300 MHz): δ 7.35 (d, J=7.2 Hz, 18H, o-C6H5), 7.07 (t, J=
7.2 Hz, 9H, p-C6H5), 6.95 (t, J=7.2 Hz, 18H, m-C6H5). 13C NMR
(C6D6, 25 ꢀC, 75.5 MHz): δ 137.1 (ipso-C), 136.5 (o-C), 129.2 (p-
C), 128.5(m-C) ppm. UV/visible(CH2Cl2):λmax 271 nm(ε=3.2 ꢀ
104 M-1 cm-1). Anal. Calcd for C54H45IGe4: C, 58.34; H, 4.08.
Found: C, 52.22; H, 4.02. NOTE: We were unable to obtain a
satisfactory carbon analysis for this compound.
Acknowledgment. Funding for this work was provided
by a CAREER grant from the National Science Founda-
tion (No. CHE-0844758) and is gratefully acknowledged.
We are grateful to Prof. Rudolf Pietschnig (Karl-Franzens-
€
Universitat Graz) for helpful discussions.
Synthesis of (Ph3Ge)3GeNMe2 (6). A Schlenk flask was charged
with 3 (0.100 g, 0.098 mol), LiNMe2 (0.005 g, 0.100 mmol), and
THF (40 mL). The reaction mixture was stirred for 24 h at room
temperature and then was filtered through Celite. The resultant
solution was evaporated in vacuo to yield a solid which was
dissolved in hexane and filtered through Celite. The hexane was
removed in vacuo to yield 6 (0.070 g, 69%) as a yellow solid. 1H
NMR (C6D6, 25 ꢀC, 300 MHz): δ7.65 (t, J=7.5 Hz, 18H, m-C6H5),
7.24 (d, J=7.5 Hz, 18H, o-C6H5), 6.93 (t, J=7.2 Hz, 9H, p-C6H5),
2.71 (s, 6H, -N(CH3)2) ppm.13CNMR(C6D6,25ꢀC, 75.5 MHz): δ
138.3 (ipso-C), 135.5 (o-C), 129.7 (p-C), 127.7 (m-C) ppm. Anal.
Calcd for C56H51Ge4N: C, 65.37; H, 5.00. Found: C, 64.98; H, 5.13.
Attempted Synthesis of (Ph3Ge)4Ge. A Schlenk tube was
charged with 6 (0.100 g, 0.097 mmol) and Ph3GeH (0.030 g,
0.098 mmol) in acetonitrile (40 mL). The reaction mixture was
heated in an oil bath at 90 ꢀC with stirring for 72 h. The reaction
mixture was cooled and was transferred to a Schlenk flask. The
volatiles were removed in vacuo to yield 0.072 g of a brown solid,
which was recrystallized from hot benzene (5 mL) to yield
colorless crystals identified as 3-aminocrotononitrile (7) and
2,6-dimethyl-4-aminopyrimidine (8). The combined yield of 7
and 8 was 0.067 g. 1H NMR (C6D6, 25 ꢀC, 300 MHz): 7, δ 4.69
(br s, 2H, -NH2), 3.77 (s, 1H, CdCH), 1.89 (s, 3H, -CH3) ppm;
8, δ 5.36 (s, 1H, C6H), 3.82 (br s, 2H, -NH2), 2.61 (s, 3H,
N-C(CH3)-N), 2.15 (s, 3H, N-C(CH3)-CH) ppm.
Supporting Information Available: CIF files giving crystal-
lographic data for 1 and 3-5 and tables and figures giving
structural details for 7 and 8. This material is available free of
(80) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Montgomery, J., J. A.; Vreven, T.;
Kudin, K. N.; Burant, J. C.; Millam, J. M.; yengar, S. S.; Tomasi, J.;
Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson,
G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai,
H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken,
V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev,
O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.;
Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakr-
zewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.;
Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.;
Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov,
B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.;
Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.;
Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.;
Gonzalez, C.; Pople, J. A. Gaussian 03, Revision C.02; Gaussian, Inc.:
Wallingford, CT, 2004.
(81) Becke, A. D. J. Chem. Phys. 1993, 98, 5648–5652.
(82) Lee, C.; Yang, W.; G, P. R. Phys. Rev. 1988, B 37, 785–789.
(83) Francl, M. M.; Pietro, W. J.; Hehre, W. J.; Binkley, J. S.;
Gordon, M. S.; DeFrees, D. J.; Pople, J. A. J. Chem. Phys. 1982, 77,
3654–3665.
(84) Dunning, T. H.; Hay, P. J. In Methods of Electronic Structure
Theory; Schaefer, H. F., Ed.; Plenum Press: New York, 1977; pp 1-28.
X-ray Crystal Structure Determinations. Diffraction intensity
data were collected with a Siemens P4/CCD diffractometer.
Samanamu, Christian R.
