A series of coordination polymers based on a 5-(3′-amine-1′H-pyrazol-4′-yl)-1H-tetrazole ligand: synthesis, structure and properties

A new family of coordination polymers, {[Co(Hapt) sub(2)].2H sub(2)O} sub(n) (1, H sub(2)apt = 5-(3'-amine-1'H-pyrazol-4'-yl )-1H-tetrazole), {[Zn(Hapt) sub(2)].3H sub(2)O} sub(n) (2), {[Cd(Hapt) sub(2)].2.5H sub(2)O} sub(n) (3) and [Cu(Htpa) sub(2)] sub(n) (4) have been prepared under hydrothermal conditions and characterized by elemental analyses and X-ray structural analyses. The tetrazole ligand adopts two coordination modes generating two kinds of 2D layers. Among them, 1-3 are isomorphous. Furthermore, extended 3D supramolecular architectures are constructed for these complexes viapredictable secondary interactions such as O...H-C and O...H-N hydrogen bonding. Magnetic studies indicate that compound 1 exhibits magnetic ordering below 4.5 K with spin canting. The fluorescence studies show that the emissions of complexes 2-3 are attributed to the ligand pi - pi * transition.