Cadmium(II) and Copper(II) coordination polymers based on 5-(Pyrazinyl) tetrazolate ligand: Structure, photoluminescence, theoretical calculations and magnetism

Two μ2-tetrazolyl bridged metal complexes, {[CdI(PTZ)(H2O)]·H2O}n1 and {[Cu(PTZ)2]·H2O}n2 (HPTZ=5-(pyrazinyl) tetrazolate), were hydrothermally synthesized and fully characterized by X-ray crystallography, elemental analyses and spectrum techniques. In 1, cadmium ions are bridged by tridentate μ2-κ2N2,N5:κ1N1 chelating PTZ– ligand and halide linkers into an infinite 1D chain, while in 2 copper ions are connected by tridentate μ2-κ2N7,N12:κ1N8 and bidentate μ2-κ1N1:κ1N2 chelating-bridging PTZ– ligands to form a 1D castellated chain structure. Compound 1 displays phosphorescence with a lifetime of ∼7.74 ms in the visible region, and the origin of the luminescent emission is primary assigned to the combination of ligand-centered emission, metal-to-ligand charge transfer and ligand-to-ligand charge transfer, which has been probed by the density of states (DOS) calculations. Magnetic measurement reveals that compound 2 displays an anti-ferromagnetic ordering.

Graphical abstractTwo new complexes based on 5-(pyrazinyl) tertrazolate, namely {[CdI(PTZ)(H2O)]·H2O}n and {[Cu(PTZ)2]·H2O}n have been synthesized and characterized. Compound 1 exhibits interesting green luminescence. Compound 2 displays an anti-ferromagnetic ordering.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We report two novel 1D μ2-tetrazolyl bridged Cd(II) and Cu(II) compounds. ► The cadmium(II) compound exhibits a green luminescence. ► Theoretical calculations were conducted to elucidate the green luminescence. ► The Cu(II) compound exhibits an anti-ferromagnetic ordering.