A switchable dimeric yttrium complex and its three catalytic states in ring opening polymerization

A dimeric yttrium phenoxide complex supported by a ferrocene Schiff base ligand, [(salfen)Y(OPh)](2) (salfen = (N,N '-bis(2,4-di-tert-butylphenoxy)-1,1 '-ferrocenediimine), was synthesized and characterized. According to electrochemical studies and H-1 NMR spectroscopy, [(salfen)Y(OPh)](2) can be oxidized in a stepwise fashion to access three oxidation states. The catalytic activity of the three states toward the ring opening polymerization of cyclic esters and epoxides was investigated. The activity toward cyclic esters decreases upon oxidation while the opposite trend was observed in epoxide polymerization. Block copolymer syntheses using a redox switch were also performed.

Automated summary

A dimeric yttrium phenoxide complex supported by a ferrocene Schiff base ligand was synthesized and studied for its catalytic activity in ring opening polymerization. Oxidation was found to affect the catalytic activity differently in cyclic esters and epoxides polymerization. Block copolymer syntheses using a redox switch were also performed.