Synthesis and catalytic activity of novel heteronuclear Ln(III)-Cu(II) complexes with noncyclic polyether-amino acid Schiff base

Abstract

A series of novel heteronuclear Ln(III)-CU(II) complexes with noncyclic polyether-amino acid Schiff base were synthesized. The general formula is (LnCu2(H2TALY) (NO3)5] (NO3)2·nH2O (Ln= La, Nd, Sm, Gd,n = 4; Ln = Yb, Y,n = 3), where H2TALY = tetraglycol aldehyde bis-lysine Schiff base. It is the first time to report the synthetic method for this new Cu(II) complexes and Ln(III)-Cu(II) heteronuclear complexes. The complexes were characterized by elemental analysis, IR spectra. TG-DTA, magnetic susceptibility, and especially by a 500 MHz NMR spectrometer for 2D-COSY NMR. Coordination mechanism and structures of complexes have been suggested as well. Of particular interest is the potential that the novel complexes obtained may be used as a catalyst. which prompted us to investigate them. It shows 100% conversion with the viscosity-average molecular weight 120 000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst. Furthermore, the complexes with such aliphatic Schiff bases can be used as a good catalyst, which has been confirmed and discussed here. They may be a new kind of catalyst system with the above speciality.