Reaction of Cd(NO 3) 2·4H 2O with 4,4'–bipyridine (bpy) in MeOH solvent: synthesis and characterization of T-shaped [Cd(bpy) 1.5(NO 3) 2]·3H 2O, square grid [Cd(bpy) 2(H 2O) 2](NO 3) 2·4H 2O and linear polymeric [Cd(bpy)(H 2O) 2(NO 3) 2

Abstract

The influence of concentration of water and metal salt in the reaction between Cd(NO 3) 2·4H 2O and 4,4′–bipyridine in MeOH has been studied and three compounds namely, T-shaped [Cd(bpy) 1.5(NO 3) 2]·3H 2O, 1 square grid [Cd(bpy) 2(H 2O) 2](NO 3) 2 4H 2O, 2 and one dimensional linear polymer, [Cd(bpy)(H 2O) 2(NO 3) 2], 3 were isolated quantitatively in this process. Compound 1 forms in MeOH at high dilution of the metal salt (5.0 mg/mL or less) and for the metal-to-ligand ratio 1:(1.5–2.0). Compound 2 forms exclusively in the concentration range, 17–33% for water in MeOH by volume and 12–28 mg/mL for the metal salt of the solution. Outside these limits, mixtures of 2 and 3 were isolated. For 1:1 ratio of metal salt to bpy, the linear polymer, 3 was obtained in major quantity and its formation was found to be independent of concentration of water or the metal salt. Compounds 1 and 2 have been characterized by X-ray crystallography. On heating all the compounds decompose through a common intermediate [Cd(bpy)(NO 3) 2] and finally to CdO as monitored by TG.