STRUCTURE OF A NEODYMIUM DIGLYCINE COMPLEX, [ND(GLY-GLY)2(H2O)2](CLO4)3.2H2O

Diaquabis(glycylglycine)neodymium(III) perchlorate dihydrate, C8H20N4NdO8.3ClO4.2H2O, M(r) = 778.89, monoclinic, P2(1)/n, a = 12.082 (1), b = 8.965 (1), c = 22.888 (2) angstrom, beta = 91.25 (1)-degrees, V = 2478.5 (3) angstrom 3, Z = 4, D(m) = 2.09, D(x) = 2.0874 (3) Mg m-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 2.529 mm-1, F(000) = 1548, R = 0.036 for 8594 reflections collected at room temperature. The Nd3+ cations are nine-coordinated and occur pairwise, bridged by four carboxyl groups. The coordination around each cation is completed by two carbonyl O atoms and two crystal water molecules. One of the two peptide ligands of the asymmetric unit is coordinated to a pair of neodymium ions whereas the other is bonded to three different Nd3+ ions, thus interlinking the cation pairs. Accordingly, endless polymeric chains are formed in the crystallographic b direction. The perchlorate counterions together with two non-coordinating water molecules fill up the space between the polymeric chains.