Synthesis and structural characterization of indium compounds with bidentate amide ligands

Abstract

Indium trichloride reacts with 1 equivalent of MeN(SiMe₂NMeLi)₂ to give the dimer [ClIn(NMeSiMe₂)₂NMe]₂ and with 4 equivalents of HNMeSiMe₂NMeLi to give [Li{In(HNMeSiMe₂NMe)₂(MeNSiMe₂NMe)}]₂. In the structure of [ClIn(NMeSiMe₂)₂NMe]₂ a chloride and one amide group of a [MeN(SiMe₂NMe)₂]^2– ligand are bonded to each In atom in terminal positions and the other amide group of the chelating ligand is shared between two In atoms. The terminal chlorides have an anti-ClIn· · ·InCl arrangement. The amine group of the [MeN(SiMe₂NMe)₂]^2– ligand does not interact with In. Variable temperature NMR spectra show [ClNn(NMeSiMe₂)₂NMe]₂ undergoes a fluxional process, and a mechanism involving bridge–terminal amide exchange is proposed to account for the data. The molecule [Li{In(HNMeSiMe₂NMe)₂(MeNSiMe₂NMe)}]₂ has a Li₂In₂Si₂N₄ adamantane-like core and overall virtual D₂ symmetry.