Interaction of the (O → Ge)-chelate bis-(lactamo-N-methyl)-cis-dichlorogermanes with trimethyltriflate. Synthesis of bis-(lactamo-N-methyl)-trans-(trifluoromethylsulfonyloxy)chlorogermanes
Regardless of the ratio of reagents, the interaction of the (O -> Ge)-chelate, bis-(lactamo-N-methyl)-cis-dichlorogermanes with trimethylsilyltriflate in acetonitrile, proceeds with substitution of one chlorine atom by the triflate group resulting in products with an inversion of configuration at the germanium atom, viz. (O -> Ge)-chelate bis-(lactamo-N-methyl)-trans-(trifluorosulfonyloxy) chlorogermanes. This result as well as conductometric studies allow us to suppose an easy ionization of the final products with formation of a triflate anion and a cation with a pentacoordinated germanium atom. According to X-ray structural studies of the prepared compounds, the Ge atom has an octahedral coordination strongly distorted towards a capped trigonal bipyramid configuration. The Ge-Cl bond (2.13-2.17 Angstrom is the shortest among those observed by us in hypervalent germanium compounds and the Ge-OTf bond is, on the contrary, the longest (3.02-3.36 Angstrom).