The characterization and the comparison of the crystal structures of lanthanide metal complexes with N-(2-hydroxyethyl)ethylenediamine-N,N′-N′-triacetic acid

Twelve lanthanide metal complexes with N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (H(3)hedtra) have been prepared and characterized by using their infrared absorption spectra, and magnetic susceptibility, thermal analysis, and powder X-ray analysis results. The complexes appear as M(Hhedtra)(H2O)(n) (M = La, Ce, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb), in which hedtra works as a trivalent anion. The results of these characterizations allow these complexes to be classified into three types: the first type includes La and Ce, the second type Nd, Sm, Eu, Gd, Th and Dy, and the third type Ho, Er, Tm and Yb. The crystal and molecular structures of [Tm(hedtra)(H2O)(2)](H2O)(3) were determined by the X-ray diffraction method. This crystal was monoclinic, space group C2/c and the lattice parameters are as follows: a = 30.61(1), b = 7.62(1), c = 15.91(1) Angstrom, beta = 111.30(4)degrees, V = 3458(5) Angstrom(3), Z = 8, R = 0.024, and Rw = 0.024. The central Tm atom is eight-coordinated with three carboxyl oxygen, atoms, a hydroxyl oxygen atom, two nitrogen atoms, and two water molecules, in a square antiprism geometry. (C) 2003 Elsevier B.V. All rights reserved.