A new coordination complex based on a polynitrile ligand: bis(4-amino-3,5-di-2-pyridyl-4H-1,2,4-triazole)diaquairon(II) bis(1,1,3,3-tetracyano-2-methylsulfanylpropenide).

The new high-spin iron(II) complex, [Fe(C(12)H(10)N(6))(2)(H(2)O)(2)](C(8)H(3)N(4)S)(2) or [Fe(abpt)(2)(H(2)O)(2)](tcnsme)(2) [where abpt is 4-amino-3,5-di-2-pyridyl-4H-1,2,4-triazole and tcnsme is the 1,1,3,3-tetracyano-2-methylthiopropenide anion], consists of discrete [Fe(abpt)(2)(H(2)O)(2)](2+) dications, where the Fe(II) ion is coordinated by two N,N'-bidentate chelating abpt ligands in the equatorial plane and two water molecules in trans positions, generating a distorted octahedral [FeN(4)O(2)] environment. The cationic unit is neutralized by two polynitrile tcnsme anions, in which the C-N, C-C and C-S bond lengths indicate extensive electronic delocalization. In the crystal structure, the dications and anions are linked through O-H...N and N-H...N hydrogen bonds involving the water H atoms and those of the NH(2) groups and the N atoms of the CN groups, leading to the formation of a three-dimensional network.