Synthesis and structures of 5-(pyridyl)tetrazole complexes of Mn(II)

New Mn(II) complexes containing 5-(2-pyridyl)tetrazole, 5-(3-cyano-4-pyridyl)tetrazole or 5-(4-pyridyl)tetrazole ligands are described. The complexes are prepared by reaction of the corresponding cyanopyridines with sodium azide in the presence of Mn(II) salts. All the complexes have been characterized by X-ray crystallography, which reveals that 5-(pyridyl)tetrazole ligands can coordinate to Mn through either type of nitrogen atom in the tetrazole residue or via the pyridyl group. In the solid state, extended 2D and 3D structures are produced through networks of hydrogen bonding (involving water molecules and the tetrazolate residue). Acidification of the complexes produces the corresponding free 5-(pyridyl)-1H-tetrazole.