EPR studies on Cu2+ and Co2+ complexes of tetraaza porphyrin derivatives

Abstract

The electron paramagnetic resonance (EPR) investigations on 2,9,17,23-tetra-((1,1,2-(tricarbethoxyethyl)) phthalocyanine, 2,9,16,23-tetra-( carboxymethyl)-3,10,17,24-tetrachloro-phthalocyaninato complexes and octakis-(1-naphthyl-methylthio) substituted porphyrazine derivatives coordinated by Co2+ and Cu2+ ions have been performed in the temperature range of 10-300 K. The EPR spectra indicate axially symmetric character of ligand field at site of the Co2+ and Cu2+ paramagnetic ions consistent with the planar structure of each complex. Especially, the Cu2+ coordinated compounds show important covalency effects with neighbouring N atoms with decreasing temperature, whereas absorption intensities obey the Curie law for both type paramagnetic ion coordinated complexes. The computer programs have been written to determine Spin-Hamiltonian and EPR linewidth parameters for both solid powder and solution forms of ion coordinated complexes. Orbital energy levels for magnetic electrons were determined from Spin-Hamiltonian parameters as well. (C) 2005 Elsevier B.V. All rights reserved.