PHOTOCHEMICAL-REACTIONS OF GERMOXANES - GENERATION OF GERMYL AND GERMOXY RADICALS

Photochemical reactions of phenyl-substituted digermoxanes, (PhnMe3-nG e)2O (n = 1-3), and a cyclic germoxane, (Me2GeO)4, have been investiga ted by chemical trapping and laser flash-photolysis. On irradiation, p henylated digermoxanes undergo homolysis of the germanium-oxygen bond to give germyl radicals and germoxy radicals. In the presence of nonha logenated solvents, these germyl radicals and germoxy radicals couple to yield digermanes and digermyl peroxides, respectively. In polyhalom ethanes (CCl4, CHCl3, and BrCCl3), germyl radicals are converted to th e corresponding halides by abstraction of a halogen atom. Germoxy radi cals do not react with polyhalomethanes; they couple to produce digerm yl peroxides which decompose to give either a pair of germoxy radicals or germyl radicals and germylperoxy radicals. Photolysis of a cyclic germoxane also results in cleavage of the germanium-oxygen bond.