SYNTHESIS, CHARACTERIZATION, AND STRUCTURE OF LANTHANIDE PICRATE COMPLEXES WITH TETRAMETHYLENESULFOXIDE (TMSO)

A series of complexes with composition M(pic)(3)(TMSO)(3) (M = La, Nd, Sm, Eu, Gd, Er, Yb, and Y) were synthesized and characterized. The el ectronic absorption spectrum of the Nd complex and the emission spectr um of the Eu complex were recorded and assigned. The unique compound, Sm(pic)(3)(TMSO)(2.5)(EtOH)(0.5), obtained by recrystallization of Sm( pic)(3)(TMSO)(3) from ethanol, was characterized by single-crystal X-r ay analysis. The complex crystallizes in a monoclinic cell space group P2(1)/n with a = 21.809(4) Angstrom, b = 15.811(3) Angstrom, c = 12.8 00(3) Angstrom and beta = 99.87(4)degrees. The coordination polyhedron about the Sm center is a tricapped trigonal prism involving the three picrates, which act as bidentate ligands via the phenoxo oxygen and a n oxygen of an adjacent nitro group, as well as the oxygens of two TMS O ligands. The ninth position is statistically (50%) occupied by an ox ygen atom of a third TMSO ligand and an oxygen atom of an ethanol mole cule.