Synthesis and structural characterization of trifluoromethyl-substituted β-ketoimino copper(II) complex and its catalytic behavior for methyl acrylate polymerization

Abstract

A new trifluoromethyl-substituted bis(β-ketoimino)copper complex (II) was synthesized and characterized by FTIR, elemental analysis, and X-ray diffraction (CIF file CCDC no. 1023178). XRD refinement revealed that the copper complex adopted a perfect central symmetric square planar structure with the copper center coordinated by two trans β-ketoimine ligands with delocalized double bonds. On activation with modified methylaluminoxane (MMAO), the bis(β-ketoimino)copper complex can polymerize methyl acrylate effectively. Introduction of trifluoromethyl group into the N-aryl ring of the ligands, which leads to strong electron-withdrawing effect, can improve significantly the catalytic activities. The activity of II/MMAO can reach 89.4 kg/mol Cu h, which is among the highest values reported for copper complexes in acrylic monomer polymerization.