Cobalt and cadmium complexes with N-heterocyclic dicarboxylic acid ligands: Syntheses, structures, magnetic and fluorescent properties

Two new complexes, [Co(Himdc)(2)(H(2)O)(2)] (1) and {[Cd(pzdc)(H(2)O)]center dot H(2)O}(n) (2) (H(2)imdc = imidazole-4, 5-dicarboxylic acid, H(2)pzdc = pyrazine-2, 3-dicarboxylic acid), have been synthesized and structurally characterized. Compound 1 is a new triclinic mononuclear complex formed by two Himdc ligands trans coordinated to the Co(II) center in bidentate chelate mode and two water ligands. Compound 2 shows a two dimensional layer structure in which pzdc(2) dianion ligand adopts unique doubly bridging bis-bidentate mu(4) coordination mode. Temperature-dependent magnetic susceptibilities and thermal stability for 1 and solid-state fluorescent properties for 2 have been discussed in detail. (C) 2011 Elsevier B.V. All rights reserved.