Comparison of the Catalytic Activity of Mono‐ and Multinuclear Ga Complexes in the ROCOP of Epoxides and Cyclic Anhydrides

Tetranuclear Schiff‐base complexes L 1–3 2 Ga 4 ( t ‐Bu) 8 1 – 3 are highly active and selective (>99 %) catalyst in the alternating ring‐opening copolymerization (ROCOP) of epoxides and anhydrides, yielding polyesters with high molecular weights ( M n ) and narrow dispersity ( Đ ). The thermal properties ( T g ) of the resulting polyester range from 18 °C to 124 °C and increase with increasing steric bulk or rigidity along the polymer backbone. Comparative studies using structurally related complexes L 4 Ga( t ‐Bu) 2 4 , [L 5 GaR 2 ] 2 (R= t ‐Bu 5 , R=Me 6 ) and L 6 Ga( t ‐Bu) 2 7 proved that the Ga 2 O 2 core of catalyst 1 is the catalytically active species.