HALIDE-BRIDGED TETRANUCLEAR COPPER(II) COMPLEXES STRUCTURAL, VIBRATIONAL AND MAGNETIC-PROPERTIES OF IS(MU(2)-CHLORO)-TETRAKIS[(MORPHOLINE)-COPPER(II)]

The structure and electronic surrounding of the copper(II) coordinatio n centres of the tetranuclear copper(II) complex [Cu4OCl6(mor)(4)] (mo r = morpholine) have been investigated. The crystal structure of the t itle compound involving one-third acetone solvate molecule per complex was determined by X-ray diffraction. Vibrational spectroscopy (Raman and IR), as well as UV-Vis spectroscopy, and quantum-chemical calculat ions on a semi-empirical level (ZWDO/1) as well as on the HF and on th e DFT level, were performed on solvent free species. The obtained elec tron density distribution sheds light on the reactivity of the coordin ation centres. The temperature-dependent magnetic susceptibility measu rements down to 3.5 K exhibit properties related to four paramagnetic (Jahn-Teller active) copper(II) atoms bridged by diamagnetic atoms, i. e, the six mu(2)-chlorides and the central mu(4)-oxygen. Structural va riations due to the presence of acetone in single crystals are discuss ed. (C) 1998 Elsevier Science B.V.