LANTHANIDE PERRHENATE COMPLEXES WITH DELTA-VALEROLACTAM - SYNTHESIS, CHARACTERIZATION AND STRUCTURE

Complexes of the general formula Ln(ReO4)(3).8(VL) (Ln=Pr, Nd, Sm, Eu; VL=delta-valerolactam) and Ln(ReO4)(3).7(VL) (Ln=Tb) were synthesized and characterized by elemental analysis, infrared absorption spectros copy, Raman spectroscopy, visible absorption spectroscopy (for the Nd complex), emission spectroscopy (for the Eu and Tb compounds) and sing le-crystal X-ray diffraction (for the Eu compound). These techniques p rovide evidence that the anions are not coordinated, as well as the fa ct that the valerolactams coordinate through their carbonyl oxygens. T he metal-ligand bonds are essentially electrostatic. The symmetry of t he coordination polyhedron in the Eu complex is D-4d (square antiprism ). The compound is isomorphous with the corresponding perchlorate octa -coordinated complexes. (C) 1998 Elsevier Science S.A.