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

A series of novel heteronuclear Ln(III)-Cu(II) complexes with noncyclic pol yether-amino acid Schiff base were synthesized. The general formula is [lnC u(2)(H(2)TALY) (NO3)(5)](NO3)(2) . nH(2)O (Ln = La, Nd, Sm, Gd, n = 4;Ln = Yb, Y, n = 3),where H(2)TALY = tetraglycol aldehyde bis-lysine Schiff base. It is the first time to report the synthetic method for this new Cu(II) co mplexes and Ln(III)-Cu(II) heteronuclear complexes. The complexes were char acterized by elemental analysis, IR spectra, TG-DTA, magnetic susceptibilit y, and especially by a 500 MHz NMR spectrometer for 2D-COSY NMR. Coordinati on mechanism and structures of complexes have been suggested as well. Of pa rticular interest is the potential that the novel complexes obtained may be used as a catalyst, which prompted us to investigate them. It shows 100% c onversion with the viscosity-average molecular weight 120 000 for the polym erization 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.