A theoretical analysis of the explanation of the significant differences in antiferromagnetic interactions between homologous mu-alkoxo and acetate bridged dicopper(II) complexes: ab initio and semi-empirical calculations

Zeyrek C., Elmali A., Elerman Y.

JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, vol.680, no.1-3, pp.159-164, 2004 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 680 Issue: 1-3
  • Publication Date: 2004
  • Doi Number: 10.1016/j.theochem.2004.03.033
  • Journal Name: JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.159-164
  • Keywords: magnetic properties, dinuclear copper(II) complex, antiferromagnetic coupling, ab initio calculations, molecular orbitals, MAGNETIC EXCHANGE INTERACTIONS, TRANSITION-METAL DIMERS, COPPER(II) DIMERS, CRYSTAL-STRUCTURE
  • Ankara University Affiliated: No

Abstract

A magnetostructural classification of dimmers, containing the Cu (mu-alkoxo) Cu core, based on data obtained from X-ray diffraction analysis reported in the literature has been performed. In these complexes, the local geometry around the copper ions is generally a square planar and each copper ion is surrounded by one N atom and three O atoms. The influence of the overlap interactions between the bridging ligands and the metal (Cu) d orbitals on the super-exchange coupling constant has been studied by means of ab initio Restricted Hatree-Fock molecular orbital calculations. The interaction between the magnetic d orbitals and highest occupied molecular orbitals of the acetate oxygens has been investigated in homologous mu-acetato-bridged dicopper(II) complexes which have significantly different -2J values (the energy separation between the spin-triplet and spin-singlet states). In order to determine the nature of the fronter orbitals, Extended Huckel molecular Orbital calculations are also reported. Ab initio restricted Hartree-Fock calculations have shown that the acetato bridge and the alkoxide bridge contribute to the magnetic interaction countercomplementarily to reduce antiferromagnetic interaction. (C) 2004 Elsevier B.V. All rights reserved.