Bis(O-Si)-chelate fluorobis(2-oxohexahydroazepinomethyl)silylium tetrafluoroborate, a cation-anionic complex containing a silylium ion stabilized by O->Si coordination

摘要

Reactions of dichlorodi(lactamomethyl)germanes [L~(n)]_2GeCl_2 (L is a bidentate lactamomethyl C,O-chelat- ing ligand; n = 5-7, the size of the lac tam ring) with lithium salts LiX or silanes Me_3SiX (X = I, OTf, or ClO_4) occur, as a rule, without complications yielding the substitution products of a nucleophile for the halo- gen atom, viz., monochlorides L~(n)]_2Ge(Cl)X, whose C and O atoms and monodentate ligands are in trans positions with respect to each other according to X-ray diffraction analysis data.l In the solid state, the monochlorides mentioned above are complexes of six- coordinate germanium with the covalent Ge-Cl bond and essentially ionic character of the X—>Ge bond. These complexes display rather high electric conductiv- ity in CH_2Cl_2, which suggests the presence of germylium ions {[L~(n)]_2Ge(CI)}+ in solutions stabilized by O—>Ge coordination.l