Donor-stabilized germylium cations. To the scheme of formation of bis(chelate) germylium ions using the complexes with lactamomethyl (С,О)-chelate ligand (enantolactam derivatives) as an example

Abstract

Bis(chelate) dichlorogermane (L⁸CH₂)₂GeCl₂ (1) with the monoanionic lactamomethyl (С,О)-chelate ligand based on enantolactam (L⁸H) was synthesized, and its molecular and crystal structures were studied. The germanium atom is characterized by the octahedral configuration with the mutual cis-arrangement of the Cl and O atoms and trans-arrangement of the C atoms. The scheme of transformation of dichlorogermane 1 into the bis(chelate) cationic complex (L⁸CH₂)₂Ge(Cl)OTf (2) was proposed. The H-bonded complexes of dichlorogermane 1 with HOSO₂CF₃ and HCl assumed to be intermediates in this process were studied by quantum chemical calculation. The energy necessary for the dissociation of the H-bonded complexes to the germylium cation and HCl₂^– and СlHOSO₂CF₃^– anions depends on the relative arrangement of the Cl atoms in the coordination polyhedron of the Ge atom. In the case of the cis-arrangement of the Cl atoms in the H-bonded complexes, the dissociation energy was estimated as 11.5—16.1 kcal mol^–1.