The molecular structure of gaseous dimethylamidogallane: characterization of the dimer [Me2NGaH2]2 by electron diffraction and vibrational spectroscopy

Abstract

The structure of gaseous dimethylamidogallane has been determined by electron diffraction. The predominant species is shown to be not the monomer Me₂NGaH₂, as suggested previously, but the dimer [Me₂NGaH₂]₂ with a cyclic Ga₂N₂ skeleton and effective symmetry D_2h. Salient structural parameters (r_a) are: r(Ga–N) 202.7(0.4), r(Ga–H) 148.7(3.6), and r(N–C) 146.3 (1.3) pm; Ga–N–Ga 90.6(0.8) and C–N–C 109.6(1.6)°. The vibrational spectra of the compound, with either hydrogen or deuterium linked to the gallium, indicate that the dimeric unit is retained in benzene solution and in the crystalline state and have been analysed accordingly.