Tetrasupersilyl-tetrahedro-tetragallan (tBu3Si)4Ga4—ein Tetrahedran mit besonders kompaktem Ga4-Tetraedergerüst
摘要:
Reaction of R-2*GaX (R* = Supersilyl Si'Bu-3, X = Cl, Br) with R*Na leads in heptane at room temperature to the dark blue radical R-2(*.)-GaR* which transforms at 100 degrees C in heptane into (Bu3Si.)-Bu-t and dark violet R-4*Ga-4 (1). According to X-ray structure analysis. 1 contains a very compact Ga-4 tetrahedron (average Ga-Ga bond length 2.572 Angstrom). With oxygen, the thermo- and water-stable compound 1 reacts under formation of colorless R-4*Ga4O4 = [R*GaO](4), which after X-ray structure analysis contains a Ga4O4 heterocubane. By hydrolysis, tetrameric oxogallane R*GaO transforms into a tetrameric dihydrooxogallane R*Ga(OH)(2) which, according to X-ray structure analysis, forms chains of molecules [R*Ga(OH)(2)](4), held together by water molecules. (C) 1999 Elsevier Science S.A. All rights reserved.
Blue‐black trisupersilyldigallanyl, a new metastable inorganic radical, forms in the reaction of GaCl3 with tBu3SiNa in pentane at room temperature according to Equation (a). The X‐ray structure analysis reveals that it contains a planar Si2GaIIGaI and a nearly linear GaIIGaISi framework; according to the ESR spectrum the unpaired electron resides in both Ga atoms. Surprisingly, the analogous reaction of AlCl3 and tBu3SiNa (Al instead of Ga in Equation (a)) does not lead to trisupersilyldialanyl, but to red tetrasupersilyldialane (tBu3Si)2Al–Al(SitBu3)2. equation image