Synthesis and properties of complexes between lanthanide trifluoro-acetates and 2-picoline-n-oxide (2-picNO)

Complexes of lanthanide trifluoroacetates with 2-picoline-N-oxide (2-picNO), with composition Ln- (CF₃COO)₃·2(2-picNO), are described. They were characterized by elemental analysis, electrolytic conductance measurements, X-ray powder patterns, IR and absorption (neodymium) and emission (europium) spectra. The compounds were grouped in three isomorphous series: (a) La, Pf;(b), Nd, Sm and (c) Eu-Lu, Y. They behave as non-electrolytes in acetonitrile. Two types of coordination of the anion and coordination of 2-picNO through the oxygen are suggested. Absorption spectra indicate an essentially electrostatic interaction between Ln³⁺ and ligands. The fluorescence spectrum was interpreted in terms of a C_2v symmetry for the europium complex.