Cooperative Initiation in a Dinuclear Indium Complex for CO₂ Epoxide Copolymerization

Abstract

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 2 and cyclohexene oxide. In particular, the neutral indium chloride complex (±)-[(O Nap N i N)InCl 2 ] 2 (4) showed high conversion of cyclohexene oxide and selectivity for poly(cyclohexene carbonate) formation without cocatalysts at 80 °C under various CO 2 pressures (2−30 bar). Importantly, the reactivity of the dinuclear indium chloride complex 4 is drastically different from that of the mononuclear indium chloride complex (±)-(NN i O tBu )InCl 2 (5), suggesting a cooperative initiation mechanism involving the two indium centers in 4.

One-pot terpolymerization of CHO, CO2andl-lactide using chloride indium catalysts

“…Generally, the molecular weights obtained for the polycarbonate materials proved to be approximately five times lower than the theoretical values calculated from the conversion obtained (Table 2), which was indicative of the presence of water or cyclohexenediol acting as chain-transfer agents, and thus, reducing the molecular weight of the polycarbonates obtained. 66,70,71 The polycarbonate materials synthesized were characterized by 1 H-NMR (Fig. S9 †) and 13 C-{ 1 H}-NMR spectroscopy (Fig.…”

Epoxide/CO2 Cycloaddition Reaction Catalyzed by Indium Chloride Complexes Supported by Constrained Inden Schiff‐Base Ligands

“…13 C NMR (150 MHz, C 6 D 6 , 30 °C): δ 180.53(C=N), 156. 24,145.74,136.18,134.18,129.10,125.31,124.56,122.08 (CAr),35.40,35.02 (ArÀ CH 2 ), 30.99 ((CH 3 ) 3 ), 30.58 (C(CH 3 ) 3 ), 29.80((CH 3 ) 3 ), 29.52 H,8.84;N,4.73.Found: C,80.93;H,9.05;N,4.51.…”