trans-Diaquabis[2,5-bis(pyridin-2-yl)1,3,4-thiadiazole]nickel(II) bis(tetrafluoridoborate)

The bidentate 1,3,4-thiadiazole ligand, namely, 2,5-bis(2pyridyl)-1,3,4-thiadiazole (denoted L), untested as a polydentate ligand, has been found to form the monomeric title complex, [Ni(C12H8N4S)(2)(H2O)(2)](BF4)(2). The complex shows an octahedral environment of the nickel cation in which the Ni2+ ion is located on a center of symmetry, linked to two ligands and two water molecules. In this 1:2 complex (one metal for two organic ligands) each thiadiazole ligand uses one pyridyl and one thiadiazole N atom for chelate binding. In the second pyridyl substituent, the N atom is oriented towards the same direction as the S atom of the 1,3,4-thiadiazole ring. The mean plane of the thiadiazole and pyridyl rings linked to the nickel cation forms a dihedral angle with the other pyridine ring of 18.63 (8)degrees. The tetrafluoridoborate ions can be regarded as free anions in the crystal lattice. Nevertheless, they are involved in an infinite two-dimensional network parallel to ((1) over bar 01) through O-H center dot center dot center dot F hydrogen bonds.