SYNTHESIS, CHARACTERIZATION AND CRYSTAL-STRUCTURE OF A NOVEL COMPLEX OF MALEIC-ACID WITH GADOLINIUM(III)

A novel ionic complex of gadolinium(III) with maleic acid, [Gd(C4H3O4)2(H2O)7](C4H3O4).H2O, was synthesized and characterized by elemental analysis, molar conductance, TG, DTA and IR. The structure of the complex was determined by single-crystal X-ray diffraction methods and refined to R=0.024, R(w)=0.029 for 4906 reflections with I greater-than-or-equal-to 3sigma(I). Crystals are triclinic with a=10.317(2), b=16.627(3), c=7.192(3)angstrom, alpha=91.99(2), beta=109.18(2), gamma=72.00(2)-degrees, mu(MoK(alpha))=31.047 cm-1, and Z=2. The space group is P1BAR. The gadolinium ion is coordinated by two bimaleates and seven waters forming a positive complex, and another bimaleate anion compensates for charge. The metal coordination number is nine and the coordination polyhedron is a distorted, monocapped square antiprism.