Two new halo-bridged cadmium(II) polymers: Effect of halogen towards metal coordination

Two new one-dimensional coordination polymers have been synthesised by the reaction of cadmium(II) halides with the chelating bidentate ligand, 2-aminomethylpyridine (2-ampy). X-ray single crystal structure analysis shows an octahedral environment around the cadmium atom in the complex, [CdCl2(NC5H4CH2NH2)]n (1) forming a doubly chloro-bridged polymeric chain, and a rare five-coordinated square-pyramidal geometry in the bromide complex, [CdBr2(NC5H4CH2NH2)]n (2), which forms an unusual singly bromo-bridged 1D polymer. Both the complexes have been characterised by elemental analysis, spectroscopic studies and thermal analysis.