Synthesis and structure of a novel tetranuclear erbium (III) complex with α-alanine [Er4(HAla)6•(μ3-OH)4(H2O)8](ClO4)8•3H2O

The title complex was synthesized in an aqueous solution and its crystal structure was determined by X-ray diffraction. The crystal crystallizes in a triclinic system, space group P1 with a = 1.306 3(2) nm, b = 1.319 4(4) nm, c = 1.950 2(4) nm, alpha = 90. 597(14)degrees, beta = 93.998(11)degrees, gamma = 94.093 (13)degrees, V = 3.344 1(12) nm(3), Z = 2, the final R indices are R-1 = 0.065 4, wR(2) = 0.126 2 respectively. The complex contains a novel tetranuclear cluster cation with four Er3+ ions connected by four mu(3)-OH ions and six bridging carboxyl groups. Each erbium ion is coordinated by three mu(3)-OH, three carboxylic oxygen atoms from three alpha-alanine and two Oxygen atoms from water molecules, forming a square-antiprismatic coordination polyhedron.