Binuclear copper(II) and nickel(II) complexes of N,N′-bis(dimethylaminoalkylaminoalkyl)oxamides

Abstract

N,N′-Disubstituted oxamides (H 2L), [(CH 3) 2N(CH 2) mNH(CH 2) lNHCO] 2 (m = 2, 3; l = 2, 3, 4, 6) form binuclear copper(II) and nickel(II) complexes [M 2L]X 2·nH 2O (X = Cl, ClO 4, Ph 4B). The oxamide moiety is deprotonated and bridged between two metal ions coordinating through two oxygen and two deprotonated nitrogen atoms. The diamagnetic, square planar nickel complexes are obtained for the ligands with m, l = 2, 3. The magnetic moments of all the copper complexes at room temperature are subnormal and the values vary with chelate ring sizes and counter anions X. The antiferromagnetic interaction through the oxamide moiety decreases with increasing sizes of chelate rings (with the exception of l = 6). The electronic spectra are also affected by these factors.