Synthesis and magnetic resonance of new heteropolynuclear Ln(III)-Cu(II) complexes with noncyclic polyether Schiff base

A series of novel heteropolynuclear complexes of Ln(III)\|Cu(II) and Cu(II) complex with noncyclic polyether Schiff base, salicylidene diethylene glycol diamine (SALDA), have been synthesized for the first time. The isolated complexes are formulated as [LnCu\-2(SALDA)\-3(NO\-3)\-5](NO\-3)\-2·4H\-2O (Ln=La, Pr, Nd, Sm, Gd, Tb, Er, Yb, Y) and [Cu(SALDA)(NO\-3)](NO\-3)·H\-2O. Synthesis methods are reported herein. The differences in their compositions, structures and coordination have been investigated by UV, IR, magnetic susceptibility, especially by 1 H and 13 C NMR spectra. It has been found that ν (CN) in the Ln(III)\|Cu(II) complexes are split up into two peaks with a far distance and it may be used as a probe for distinguishing them from others. In addition, it is suggested that the ethereal oxygen donors are not all coordinated. The good catalysis effect for the polymerization of methyl methacrylate (MMA) are reported for the first time. The results show that the catalytic activity of Nd\|Cu\|SALDA complex is better than that of the others and its syndiotactic sequence is ～72% as well, the conversion increases to 88%.