Cyclotrigermenium Ion by Oxidation of Cyclotrigermene with Trityl Tetrakis {3,5-Bis(Trifluoromethyl)Phenyl}Borate and Trityl Tetrakis(Pentafluoro-Phenyl)Borate. A Stable Free Germyl Cation in the Condensed Phase

摘要

The reaction of tetrakis(tri-t-butylsilyl) cyclotrigermene with Ph_3C~+ centre dot [3,5-(CF_3)_2C_6H_3]_4B~- (TFPB) and Ph_3C~+ centre dot (C_6F_5)_4B~- (TPFPB) in benzene produced the stable free tris (tri-t-butylsilyl)cyclotrigermenium ion (2a) with the corresponding tetraarylborate as a counter anion. The crystal structure of 2a centre dot TFPB reveals a free germyl cation with 2#pi#-electron system. The three-membered germanium atoms constitute almost an equilateral triangle, similar to that of 2a centre dot TPB (TPB = Ph_4B~-). In contrast to 2a centre dot TPB, both 2a centre dot TFPB and 2a centre dot TPFPB are thermally stable in solution.