Two new copper (II) complexes with the same NNO donor Schiff base ligand: A monomer and a dimer

摘要

Two new copper(II) complexes, [(CuL) _2(μ _(1,1)-N _3) _2]·2H _2O (1) and [Cu(HL)(2,2'-bipy)- (CH _3COO)]·ClO _4·H _2O (2), have been synthesized using the tridentate NNO Schiffbase ligand 2-[(2-aminoethylimino) methyl]-6-methoxyphenol (HL). They have been characterized by elemental analysis, IR spectroscopy, thermal analysis, and single-crystal X-ray analysis. The copper environment is distorted square pyramidal in complex 1: two nitrogen atoms and one oxygen atom from the ligands and two nitrogen atoms from two azido ligands build the coordination polyhedron around the copper atom. The Cu-N _(azide)-Cu angle in complex 1 is 85.6°. This is unusually small in comparison with the same angle in other end-on doubly azido-bridged dimers. Complex 2 is mononuclear with the Cu atom having a slightly distorted octahedral geometry. Magnetic measurements of 1 have been performed in the temperature range from 2 to 300 K. The experimental data indicate an antiferromagnetic exchange interaction between copper(II) ions bridged by the azido ligand. The best-fit parameters for complex 1 are g = 2.18 and J = -1.31 cm ~(-1).