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

Synthesis, spectral and electrochemical study of coordination molecules Cu₄OX₆L₄: 4-cyanopyridine Cu₄OBr_nCl_(6−n)(4-CNpy)₄ complexes

Gregor Ondrejovič, Adela Kotočová, Marian Koman, and Peter Segľa

Institute of Inorganic Chemistry, Technology and Materials, Faculty of Chemical and Food Technology, Slovak University of Technology, SK-812 37 Bratislava, Slovak Republic

E-mail: gregor.ondrejovic@stuba.sk

Received: 4 September 2009  Revised: 19 November 2009  Accepted: 30 November 2009

Abstract: New 4-cyanopyridine halide and mixed-halide Cu₄OBr _n Cl_(6−n)(4-CNpy)₄ complexes (4-CNpy = 4-cyanopyridine, n = 0–6) were synthesised, characterised, and studied by infrared spectra, electronic spectra, and cyclic voltammetry. Infrared spectra revealed donor-acceptor vibrational couplings of the Cu₄O, Cu-Cl, and Cu-N stretching vibrations with the in-plane and out-of-plane pyridine ring vibrations. The infrared spectra, electronic spectra, and half-wave potentials correspond to a weak donor and a strong acceptor behaviour of the 4-cyanopyridine ligands and to π-back bonding, Cu(II)→pyridine rings. The results were compared with the related pyridine and 4-substituted pyridine complexes.

Keywords: copper(II) 4-cyanopyridine complexes - donor-acceptor vibrational coupling - electronic spectra - electrochemistry -  π-back bonding

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-010-0015-9

Chemical Papers 64 (3) 329–338 (2010)