Chalcogenido-Dimethylgallates and -Indates DMPyr2 [Me2 M(μ2 -E)]2 (M=Ga, In; E=S, Se): Building Blocks for Higher and Lower Order Chalcogenidoindates.

Abstract

Metalation of the anions in the ionic liquids DMPyr[SH] and DMPyr[SeH] (DMPyr=1,1‐dimethylpyrrolidinium) by trimethylgallium and trimethylindium is investigated. The reaction proceeds via pre‐coordination of [EH]−, methane elimination and formation of an unprecedented series of chalcogenido metalates DMPyr2[Me2M(μ2−E)]2 (M=Ga, In; E=S, Se). These show the presences of dinuclear dianions with four‐membered ring structures displaying highly nucleophilic bridging chalcogenide ligands in their crystallographically determined molecular structures. Some representative reactions of these building blocks with amphoteric electrophiles were studied: Addition of two equivalents of E(SiMe3)2 (E=S, Se) to the indates DMPyr2[Me2In(μ 2−S)]2 and DMPyr2[Me2In(μ2−Se)]2 leads to a cleavage of the ring, E silylation and formation of mononuclear, monoanionic indates DMPyr[Me2In(SSiMe3)2], DMPyr[Me2In(SeSiMe3)2], and even a mixed sulfido‐selenido dimethylindate DMPyr[Me2In(SSiMe3)(SeSiMe3)]. Reaction of DMPyr2[Me2In(μ2−S)]2 with two equivalents of Lewis acid Me3In leads to charge delocalization, ring expansion and formation of six‐membered ring DMPyr3[Me2In(μ 2−S−InMe3)]3. The latter is a key intermediate in the formation of dianionic sulfidoindate DMPyr2[(Me2In)6(μ 3−S)4] displaying an unusual inverse heteroadamantane cage structure with four capping sulfido ligands.