Facile, High-Yield Functionalization of Germanium and Tin by Oxidative Insertion of Tetrelenes into the E–H Bonds of Inorganic Acids (E = C, N, O, F): Arene Elimination versus Oxidative Addition and Formation of a Germanium Cation–Water Complex

Reaction of the diarylgermylene Ge­(ArMe6)2 [ArMe6 = C6H3-2,6-(C6H2-2,4,6-(CH3)3)2] with various inorganic acids (HCN, HN3,
and HBF4) led to the facile oxidation of the germanium
atom to yield the corresponding Ge­(IV) products (ArMe6)2Ge­(H)­X (X = CN (1), N3 (2), F (3)). The cationic germanium–water
complex [(ArMe6)2GeH­(OH2)]­[SO3CF3] (4) was prepared by
treating Ge­(ArMe6)2 with triflic
acid in the presence of trace amounts of moisture. The reactions provide
an efficient method of installing a variety of functional groups at
a germanium atom and can be used in the preparation of germanium complexes
that are analogous to lighter carbon species. The tin species Sn­(ArMe6)2 was also oxidized to the Sn­(IV)
analogue of 3. In all reactions, no evidence of arene
elimination was observed, which was in contrast to the reaction of
the stannylene (or bulkier germylenes) with hydrogen or ammonia, which
yielded H­(ArMe6), [(ArMe6)­Sn­(μ-H)]2, and [(ArMe6)­Sn­(μ-NH2)]2.