Synthesis, Crystal Struicture and Optical Properties of a Cerium(IV) Complex with Chelidamic Acid

A new cerium complex, (C7H8)[Ce(C7H3NO5)(2)(H2O)(3)]center dot 2H(2)O or (C7H8)[Ce(HChel)(2)(-)(H2O)(3)]center dot 2H(2)O (1, H(3)Chel = 4-hydroxypyridine-2,6-dicarboxylic (chelidamic) acid), has been prepared by the hydrothermal reaction, and its crystal structure was determined based on single-crystal diffraction data. Compound I crystallizes in monoclinic, space group P2(1)/c with a = 12.4267(9), b = 10.8195(7), c = 19.5650(13) angstrom, beta = 92.898(3)degrees, V = 2627.2(3) angstrom(3), D-c = 1.733 g/cm(3), Z = 4, M-r = 685.55, mu = 1.809 mm(-1), lambda(MoK alpha) = 0.71073 angstrom and F(000) = 1372. The final R = 0.0455 and wR = 0. 1984 for 5983 observed reflections with I > 2 sigma(I), and R = 0.0490 and wR = 0.2053 for all data. Complex 1 contains one cerium ion, two chelidamic acid ligands, three coordinated water molecules, one discrete toluene molecule, and two discrete water molecules. The Ce(IV) ion is nine-coordinate with the coordination polyhedron made up of four oxygen atoms and two nitrogen atoms from two tridentate chelating chelidamic acid ligands, and three coordinated water molecules. A three-dimensional network is formed by the H-bonds. Moreover, optical properties are investigated and the results show that this complex has sharp optical absorption at 221, 396 and 571 nm but no marked fluorescent emission.