Synthesis of a Gallaarsene {HC[C(Me)N-2,6- i-Pr 2 -C 6 H 3 ] 2 }GaAsCp* Containing a Ga═As Double Bond.

Cp*AsCl2 (Cp* = C5 Me5 ) reacts with one equivalent of LGa (L = HC[C(Me)N(2,6- i-Pr2 C6 H3 )]2 ) with formation of L(Cl)GaAs(Cl)Cp* 1, whereas the reaction with two equivalents of LGa yielded gallaarsene LGaAsCp* 2 containing a Ga═As double bond and (η1 -Ga(Cp*)L(η2 -GaL)(μ-As3 ) 3. Compounds 2 and 3 were structurally characterized by single crystal X-ray diffraction, and the π-bonding contribution in 2 was analyzed by temperature-dependent 1 H NMR spectroscopy (9.65 kcal mol-1 ) and by quantum mechanical computation.