LANTHANIDE TRIFLUOROMETHANESULFONATE COMPLEXES WITH EPSILON-CAPROLACTAM - SYNTHESIS, CHARACTERIZATION AND STRUCTURE OF THE PRASEODYMIUM COMPOUND

Complexes of formulas [Ln(epsilon-cl)(8)] (F3C-SO3)(3) (Ln = La-Eu) an d [Ln(epsilon-cl)(7)] (F3C-SO3)(3) (Ln = Gd, Tb, Dy, Yb, Lu, epsilon-c l = epsilon-caprolactam) were synthesized and characterized by element al analysis, infrared spectroscopy, visible absorption spectroscopy of the Nd compound and emission spectroscopy of the Eu compound and the Gd compound, doped with Eu. LR experimental data suggest that the epsi lon-caprolactams are bonded to the central ions through the carbonyl o xygen and that the anions are not coordinated. The parameters calculat ed from the visible absorption spectrum of the Nd compound suggest ele ctrostatic metal-ligand bonds. The emission spectrum of the europium c ompound suggests a D-2d distorted towards C-2v symmetry. X-ray single crystal analysis of the Pr compound shows that the anions are not coor dinated and that the coordination polyhedron around the Pr3+ ion has a slightly distorted D-2d (dodecahedral) symmetry.