POLYMERIC POLYNUCLEAR SYSTEMS OF PR, YB AND PR-CU TRICHLOROACETATES -THEIR SPECTROSCOPY AND MAGNETISM

Heteronuclear copper-lanthanide compounds are the subject of the studi es for the reason of their unusual structure features, optical, magnet ic, catalytic properties and because of their potential application in superconducting ceramics. Synthesis, spectroscopic and magnetic chara cterisation of polymeric one-dimensional lanthanide (Pr, Yb) trichloro acetates (I, II) and heteronuclear CuPr2(Cl3CCOO)(8)-6H(2)O (III) sing le crystals were undertaken. Structures of I, II are isomorphic with e rbium trichloroacetate and that of III with respective neodymium compo und. In the structure of III the polymeric chain is built of dimers of two crystallographically independent types of PrO8/9 polyhedra linked by carboxyl bridges. These dimers are separated by square planar coor dinated cooper ions bridged to the lanthanide by four carboxyl groups and two water molecules. High resolution spectra down to 4 K were inve stigated and cooperative effects were analysed. Magnetic susceptibilit y measurements in the range 300-1.8 K were carried out. Optical and ma gnetic properties are discussed on the basis of X-ray data. Electron t ransition probabilities were calculated and cooperative interaction of ion-pairs coupled in polymeric chain was considered. Vibronic compone nts were observed and assigned on the basis of Raman data. (C) 1998 El sevier Science B.V. All rights reserved.