New Silver(I) Coordination Polymers with Hetero Donor Ligands: Synthesis, Structure, Luminescence Study and Photo-Catalytic Behavior

Two new Ag(I) coordination polymers, namely, [Ag-2(dmt)(2)(tph)](n) (1), [Ag-2(dmt)(2)(oxalate)](n) (2), and a discrete neutral complex [Ag-2(dmt)(4)(SO4)].2(dmt).2(H2O) (3) (where dmt=2,4-diamino-6-methyl-1,3,5-triazine, ox=oxalate anion and H(2)tph=terephthalic acid) were synthesized and characterized using elemental analysis, IR, UV-vis and fluorescence spectroscopy. The solid-state structures of complexes 1-3 were determined using single crystal X-ray crystallography. Compounds 1 and 2 are 1D and 3D coordination polymers, respectively, with the packing reinforced by weak interactions such as H-bonds and pi-pi stacking. The most intriguing aspect of the crystal structure of 3 is a pseudo hexagonal arrangement of six dmt, connected by pairs of N-H center dot center dot center dot N hydrogen bonds, around a sulfate anion. The band gap energies of the coordination polymers were determined. All the complexes were found to be photo-catalytically active and complex 1 displays the higher catalytic activity toward the photo degradation of methylene blue (MB) in water. The higher content of aromatic moieties in 1 plays a significant role in effective charge separation and transport to make it the best catalyst in the series.