ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

ESR spectra of copper(II) complexes in the solids

M. Valko, P. Pelikán, S. Biskupič, and M. Mazúr

Department of Physical Chemistry, Faculty of Chemical Technology, Slovak Technical University, CS-81237 Bratislava

Abstract: The ESR spectra of Cu(sal)₂ . 4H₂O, Cu(sal)₂(2-pycar)₂ and Cu(sal)₂(3-pycar)₂ (sal = salicylate ion; pycar = pyridinemethanol) at 77 K were studied. The spin Hamiltonian parameters indicate that the unpaired electron is in the antibonding ψ_blg molecular orbital. The ESR spectra of pentacoordinated Cu(II) complexes of the [Cu(phen)₂X]ClO₄ (phen = 1,10-phenantroline; X = Cl, Br) exhibit axial symmetry. The compressed trigonal-bipyramidal (TBP) configuration with D3h symmetry points (z² > ground electronic state) is consistent with the spin Hamiltonian parameters of the ESR spectra. The ESR spectra of the pentacoordinated complex of [Co(1,3-diaminopropane)₃] [CuCl₅].3H₂O have been studied in the temperature range 100-290 K. At higher temperature (T > 160 K) the ESR spectra change their symmetry into the orthorhombic one, the square pyramidal (SP) structure of [CuCl₅]^3- polyhedrons is violated and a dynamical transition between the SP and TBP structures takes place.

Full paper in Portable Document Format: 446a805.pdf

Chemical Papers 44 (6) 805–813 (1990)