Aluminium salabza complexes for fixation of CO 2 to organic carbonates

A highly stable and easy to synthesize aluminium complex bearing a flexible N2O2-donor salabza ligand (N,N'-bis(salicylene)-2-aminobenzylamine) in combination with tetrabutylammonium bromide forms an active binary catalytic system for the cycloaddition of CO2 to epoxides (TOFs 120-3434 h(-1)) under mild conditions (10 bar, 80 °C) and low catalyst loadings (0.05-0.2 mol%). Kinetic experiments have shown that the cycloaddition of CO2 to styrene oxide catalyzed by 1/TBAB is first order in 1, TBAB, CO2 and epoxide. A reaction mechanism is proposed based on these observations. Fe(iii) and Co(iii) related complexes are less active catalysts for this reaction.