Cooperative Initiation in a Dinuclear Indium Complex for CO Epoxide Copolymerization.

Dinuclear indium complexes have been synthesized and characterized. These include neutral and cationic indium complexes supported by a Schiff base ligand bearing a binaphthol linker. The new compounds were investigated for alternating copolymerization of CO and cyclohexene oxide. In particular, the neutral indium chloride complex (±)-[(ONN)InCl] () showed high conversion of cyclohexene oxide and selectivity for poly(cyclohexene carbonate) formation without cocatalysts at 80 °C under various CO pressures (2-30 bar). Importantly, the reactivity of the dinuclear indium chloride complex is drastically different from that of the mononuclear indium chloride complex (±)-(NNO)InCl (), suggesting a cooperative initiation mechanism involving the two indium centers in .