Multiple ethylene activation by heteroleptic L(Cl)Ga-substituted germylenes

Abstract

Ethylene insertion into the Ga–Ge bond of the L(Cl)Ga-substituted germylene LGa(μ-Cl)GeDMP 1 (L = HC(C(Me)NAr)₂, Ar = 2,6-ⁱPr₂C₆H₃; DMP = 2,6-Mes₂C₆H₃, Mes = 2,4,6-Me₃C₆H₂) at ambient temperature is followed by dimerization of the as-formed germylene to give the digermene 3, which further reacted with ethylene in a [2 + 2] cycloaddition to give the 1,2-digermacyclobutane 4. In marked contrast, the amino-substituted germylene L(Cl)GaGeN(SiMe₃)Ar 2 reacted directly to the 1,2-digermacyclobutane 5. Quantum chemical calculations confirmed the assumed reaction mechanism, hence demonstrating the crucial role of the substituent on the reaction mechanism.