Synthesis and structures of gallaarsenes LGaAsGa(X)L featuring a Ga-As double bond.

Three equivalents of LGa {L = HC[C(Me)N(2,6-i-Pr2C6H3)]2} react with AsX3 (X = Cl, Br) by insertion into two As-X bonds, followed by the elimination of LGaX2 and formation of LGaAsGa(Cl)L (1) and LGaAsGa(Br)L (2). According to single crystal X-ray analysis, 1 and 2 each exhibit one Ga-As single bond and one Ga-As double bond. The π-bonding contribution (9.71 kcal mol-11 and 9.44 kcal mol-12) was proved by variable temperature (VT) 1H NMR spectroscopy, while the electronic structure of 1' was studied by quantum chemical calculations.