MOLECULAR-STRUCTURE OF TRIMETHYLAMINE-GALLANE, ME3N-CENTER-DOT-GAH3 -AB-INITIO CALCULATIONS, GAS-PHASE ELECTRON-DIFFRACTION AND SINGLE-CRYSTAL X-RAY-DIFFRACTION STUDIES

The structure of the gallane adduct Me3N . GaH3 has been investigated by ab initio quantum chemical calculations. The results of gas-phase e lectron-diffraction (GED) measurements, together with earlier microwav e measurements, have been reanalysed using the SARACEN method to deter mine the most reliable structure of the gaseous molecule. Salient stru ctural parameters (r(alpha)degrees structure) were found to be: r(Ga-H ) 151.1(13), r(Ga-N) 213.4(4), r(N-C) 147.6(3), r (C-H) 108.4(4) pm; H -Ga-N 99.3(8) and Ga-N-C 108.8(2)degrees. Unlike the corresponding ala ne derivative, the adduct is monomeric in the crystalline phase with d imensions very close to those of the gaseous molecule, as confirmed by a redetermination of the structure of a single crystal at 150 K.