Synthesis and structure of lanthanide(III) picrate complexes with 1,3-dithiane-1-oxide

Abstract

Lanthanide picrate complexes with 1,3-dithiane-1-oxide (DTSO) were synthesized by reaction of the hydrated lanthanide picrates (pic) with DTSO in absolute ethanol. Conductance measurements in acetonitrile solutions show that the complexes behave as non-electrolytes. The parameters obtained ( β=0.988, b 1/2=0.0762 and δ=1.17) from the absorption spectrum of the solid Nd compound for the 2G 7/2, 4G 5/2← 4I 9/2 transition indicate that the metal–ligand bonds present weak covalent character. The bands 5D 0→ 7F J ( J=1,2,3) transitions for the emission spectra of the Eu compound were interpreted in terms of a C 4 v symmetry. X-ray single-crystal data of the gadolinium compound showed that the crystal system is monoclinic, a=10.5577(10) Å, b=20.221(3) Å, c=21.4802(12) Å, β=93.969(6)°, space group P2 1/c , Z=4, V=4574.8(8) Å 3. The Gd ion achieves a coordination number of nine by the bonding of three bidentate picrate groups via their phenoxo-oxygen and an oxygen of the adjacent nitro moiety and three oxygens of the three DTSO molecules, in a distorted monocapped square antiprism fashion. X-ray powder patterns show only one isomorphous series.