COMMUNICATIONS
[1] A. D. Norman, J. Am. Chem. Soc. 1968, 90, 6556.
[2] M. Baudler, G. Scholz, W. Oehlert, Z. Naturforsch. B 1989, 44, 627.
[3] A. E. Finholt, C. Helling, V. Imhof, L. Nielsen, E. Jacobsen, Inorg.
Chem. 1963, 2, 504; M. Driess, K. Merz, H. Pritzkow, R. Janoschek,
Angew. Chem. 1996, 108, 2688; Angew. Chem. Int. Ed. Engl. 1996, 35,
2507.
[4] A. D. Norman, D. C. Wingeleth, Inorg. Chem. 1970, 9, 98.
[5] The spectrum simulation was carried out with the program Perch,
Version 1/96, University of Kuopio (Finland).
[6] A single crystal of 2 was formed in a capillary tube with a diameter of
0.3 mm on a four-circle diffractometer at 242 K by miniaturized zone
melting with focused infra-red radiation.[9] 2: monoclinic, space group
P21/c, a 10.659(3), b 7.137(2), c 10.832(3) , b 101.72(2)8, V
806.8(4) 3, Z 4, 1 1.318 gcm 3, Vmax 308; of 2464 measured
reflections, 2316 were independent (Rmerg 0.0379) and 1752 observed
(I > 2s(I)). The intensities were measured on a Nicolet R3m/V four-
circle diffractometer (MoKa radiation, l 0.71073 , w scan, T
123 K). The structure was solved by direct methods,[10a] and refined
with all measured reflections against F2.[10b] The Si and P atoms were
anisotropic, and hydrogen-atom positions were determined from a
difference Fourier and refined as riding groups with P H distances
taken from the sum of the covalent radii (1.42) with group isotropic
temperature factors. A refinement without imposing certain restric-
tions led to unreasonably small P H distances. R1 0.0479, wR2
0.1306 (all data), 50 parameters. Models with higher local symmetry
(D2d or S4) led to significantly higher R values (R1 > 0.10). Further
details on the crystal structure investigation can be obtained from the
Fachinformationszentrum Karlsruhe, D-76344 Eggenstein-Leopold-
shafen, Germany (fax: (49)7247-808-666; e-mail: crysdata@fiz-
karlsruhe.de), on quoting the depository number CSD-408423.
[7] GAUSSIAN 94, Revision B.3., M. J. Frisch, G. W. Trucks, H. B.
Schlegel, P. M. W. Gill, B. G. Johnson, M. A. Robb, J. R. Cheeseman,
T. Keith, G. A. Petersson, J. A. Montgomery, K. Raghavachari, M. A.
Al-Laham, V. G. Zakrzewski, J. V. Oritz, J. B. Foresman, C. Y. Peng,
P. Y. Ayala, W. Chen, M. W. Wong, J. L. Andres, E. S. Replogle, R.
Gomperts, R. L. Martin, D. J. Fox, J. S. Binkley, D. J. Defrees, J. Baker,
J. P. Stewart, M. Head-Gordon, C. Gonzalez, J. A. Pople, Gaussian,
Inc., Pittsburgh PA, 1995.
Figure 4. Packing and pair formation of 2 in the crystal.
temperature interval from 8 to 55 K gave no indication of the
voluntary formation of a dimer.
Owing to the strongly oxidizing effect of tetravalent
germanium, PH3 and an insoluble yellow solid are formed
spontaneously on reaction of GeCl4 with Li[Al(PH2)4] in
ethylene glycol dimethyl ether at 458C. After filtration and
removal of PH3, the clear reaction solution contains only
tetraphosphanylgermane (3) and triphosphanylgermane
(HGe(PH2)3, 6) in the ratio 1:2.5, as determined by GC-MS.
In the EI mass spectrum of 3, the molecular ion peak is at
m/z 206 with a relative intensity of 10% and a correct
isotope distribution. The new compounds 2, 3, and 6 are
indeed thermolabile single-source precursors for CVD proc-
esses. They react at the relatively low temperature of 80 8C
under cleavage of PH3 to readily form Si and Ge phosphides.
We will report on these elsewhere.
[8] Review: W. S. Sheldrick in The Chemistry of Organic Silicon
Compounds (Eds.: Z. Rappoport, S. Patai), Wiley, New York, 1989,
p. 254.
Experimental Section
[9] R. Boese, M. Nussbaumer in In Situ Crystallisation Techniques in
Organic Crystal Chemistry (Ed.: D. W. Jones), Oxford University
Press, Oxford, 1994, pp. 20 ± 37.
[10] a) G. M. Sheldrick, SHELXS86, Universität Göttingen, 1986; b) G. M.
Sheldrick, SHELXL93, Universität Göttingen, 1993.
2: SiCl4 (11.46 g, 67.4 mmol) was added to a solution of Li[Al(PH2)4]
(0.25m, 75 mmol) in tetraethylene glycol dimethyl ether (300 mL) at
30 8C over a period of 10 min under continuous stirring. The solution
turned orange. The volatile components (PH3, HSi(PH2)3, and 2) were
removed under vacuum (10 3 Torr) at 20 8C and collected in a cold trap at
1968C. These were then fractionated by condensation in a series of cold
traps at 10, 60, and 196 8C. Compound 2 was collected in the trap at
10 8C, HSi(PH2)3 at
608C, and PH3 at
1968C. Yield: 1.94 g
(12.1 mmol, 18%); m.p. 258C; 1H NMR (250 MHz, C6D6, 258C): d
2.04 (dm); 31P NMR (101 MHz, C6D6, 25 8C): d 205.0 (tm, 1J(P,H)
185.51, 2J(P,P) 14.28, 2J(H,H) 0.37, 4J(P,H) 4.35 Hz); 29Si NMR
(49 MHz, C6D6, 258C): d 12.17 (n of quint, 1J(Si,P) 52.5, 2J(Si,H)
7.5 Hz); IR (Ar matrix, 2188C): nÄ 2289 (vs), 1183 (vs), 840 (w), 721 (m),
Rate Enhancement of the Radical 1,2-Acyloxy
Shift (Surzur± Tanner Rearrangement) by
Complexation with Lewis Acids**
633 (m), 566 (w), 478 cm 1 (vs); MS (EI): m/z (%): 160 (30) [M ], 127 (100)
[M
PH2], 93 (61) [SiPH(PH2) ], 61 (17) [SiPH2 ].
Ã
Emmanuel Lacote and Philippe Renaud*
3/6: GeCl4 (0.60 g, 2.8 mmol) was added dropwise under stirring to a
solution of Li[Al(PH2)4] (0.31m, 3.1 mmol) in ethylene glycol dimethyl
ether (10 mL) at 458C. The release of gas (PH3) was accompanied by
formation of a yellow suspension, which was filtered. According to GC-MS,
the clear filtrate contained only 3 and 6 in the ratio 1:2.5. 3: MS(EI): m/z
Owing to their mildness and their compatibility with many
functional groups, radical reactions have become a very
powerful tool for organic synthesis.[1] For instance, unique
(%) 206 (10) [M ], 173 (100) [M
PH2], 137 (100) [GeP2H ], 107 (82)
[GePH ], 74 (19) [Ge ], 67 (19) [P2H5 ]. 6: MS(EI): m/z (%): 174 (23)
Ã
[*] Prof. P. Renaud, E. Lacote
[M ], 140 (90) [M
PH3], 107 (100) [M
PH2PH3], 74 (40) [Ge ].
Institut de chimie organique
Â
Universite de Fribourg
Â
Perolles, CH-1700 Fribourg (Switzerland)
Received: March 30, 1998 [Z11658IE]
German version: Angew. Chem. 1998, 110, 2389 ± 2391
Fax: (41)263-009-739
[**] This work was supported by the fonds national suisse de la recherche
scientifique. We thank Prof. H. Zipse for drawing our attention to his
calculation results and for helpful suggestions.
Keywords: germanium ´ NMR spectroscopy ´ phosphorus ´
silanes ´ silicon
Angew. Chem. Int. Ed. 1998, 37, No. 16
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