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

Two new complexes, [Co(Himdc)2(H2O)2] (1) and {[Cd(pzdc)(H2O)]·H2O}n (2) (H2imdc = imidazole-4, 5-dicarboxylic acid, H2pzdc = 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 CoII center in bidentate chelate mode and two water ligands. Compound 2 shows a two dimensional layer structure in which pzdc2− dianion ligand adopts unique doubly bridging bis-bidentate μ4 coordination mode. Temperature-dependent magnetic susceptibilities and thermal stability for 1 and solid-state fluorescent properties for 2 have been discussed in detail.