The temperature dependence of EPR spectra of Cu(II)-doped hexakis(imidazole)cadmium(II) perchlorate

EPR spectra of powder samples of Cu(II)-doped Cd(Im)(6)(ClO4)(2) are studied at X-band over a wide temperature range, 7-300 K. The observed g and copper hyperfine tensors are found to be strongly temperature dependent and are interpreted in terms of Jahn-Teller effect involving a d(x2-y2) ground state. Single crystal spectra indicate the presence of two misaligned elongated tetragonal octahedral CuN6 chromophores. The g tensor of Cu(II)-doped Cd(Im)(6)(ClO4)(2) is axially symmetric, implying that the orthorhombic strain component is insignificant. Influence of the structure of host crystals on the observed behaviour is discussed by comparing the EPR results of Cu(Im)(6)(2+) in different lattices. (C) 1999 Elsevier Science B.V. All rights reserved.