Syntheses, structures and luminescence properties of cadmium(II) coordination polymers with in situ formed oxalate and bis(chelating) bridging ligands

Hydrothermal reactions of 2-cyanopyrimidine and CdCl2 in the absence and presence of sodium azide yielded two coordination polymers, [Cd-3(ox)(2)(pymc)(2)]center dot 2H(2)O (1) and [Cd-2(pymtz)(2)(ox)]center dot H2O (2), respectively, where pymc 2-pyrimidinecarboxylate, pymtz 5-(2'-pyrimidyl) tetrazolate and ox oxalate. All the ligands in these compounds were generated in situ by the hydrolysis of 2-cyanopyrimidine (pymCN) or the [2 + 3] cycloaddition of the azide ion to the nitrile. In compound 1, seven-coordinated Cd ions are linked by oxalate bridges into a diamond network based on Cd2O2 nodes, and eight-coordinated Cd ions are linked to the network through pymc and oxalate bridges. In compound 2, seven-coordinated Cd ions are bridged by oxalate ions into 1D Cd-2(ox) ribbons, which are further linked by bis(chelating) pymtz to give a 3D framework that exhibits the 5-connected 4(4)6(6) net topology based on Cd2O2 nodes. The compounds exhibit intense luminescence in the solid state.