EPR, mass, electronic, IR spectroscopic and thermal studies of bimetallic copper(II) complexes with tetradentate ligand, 1,4-diformyl piperazine bis(carbohydrazone)

The synthesis of novel bimetallic Cu(II) complexes with general stoichiometry [Cu-2(H2L)X-2(H2O)(2)], [Cu-2(H2L)(CH3COO)(2)] and [Cu-2(H2L)SO4(H2O)(2)] (where H2L = dideprotonated ligand and X = NO3- and Cl-) derived from tetradentate ligand obtained by the condensation of 1,4-diformyl piperazine with carbohydrazide has been discussed. The complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, UV, EPR spectral studies and thermogravimetric analyses. The value of magnetic moments indicates that the complexes are paramagnetic and show the antiferromagnetic interaction between the two metal centres. The complexes possess the square planar coordination environment. The values of covalency measurements, i.e., in-plane sigma-bonding alpha(2), in-plane pi-bonding beta(2) and orbital reduction factor k indicate the covalent nature of complexes. (c) 2008 Elsevier B.V. All rights reserved.