Synthesis and structural characterization of a novel polymeric gadolinium(III)-copper(II) complex of iminodiacetic acid

A novel polymeric Gd2Cu3 complex of iminodiacetic acid (H2L1 = NH{CH2COOH}(2)), namely, Gd2Cu3(L1)(6), 1, has been synthesized and structurally characterized. In the title complex, the Gd3+ ion is nine-coordinated by six O atoms from three bidentate chelating carboxylate groups and three O atoms from three anti-anti bridging carboxylic groups of six L-1 ligands; the Cu2+ ion is six-coordinated by four O and two N atoms from two chelating L-1 ligands. Each pair of Gd(III) atoms is bridged by three L-1 ligands, each of which also chelates with one copper(II) ion, thus forming a Gd2Cu3 cluster unit. Such cluster units are cross-linked by flexible L-1 ligands into a three-dimensional coordination framework. The title complex crystallizes in the trigonal space group P-3c1 (No. 165) with a = b = 13.433(4), c = 14.770(6) Angstrom; V = 2308(1) Angstrom(3); D-calca = 1.859 g cm(-3); Z = 2.