{S-Benzyl 3-[(6-methylpyridin-2-yl)methylidene]dithiocarbazato}nickel(II) monohydrate

The structure of the title compound, [Ni(C15H14N3S2)2]·H2O, has one molecule in the asymmetric unit, along with a solvent water molecule. The two different Schiff base moieties coordinate to the central NiII ion as tridentate N,N′,S-chelating ligands, creating a six-coordinate distorted octahedral environment [the smallest angle being 77.43 (7)° and the widest angle being 169.99 (7)°]. The mean planes of the two ligands are nearly orthogonal to each other with an angle of 89.53 (6)°. The packing of the complex is supported by O—H⋯N and O—H⋯S hydrogen bonding between the solvent water molecule and the uncoordinated N and S atoms of neighbouring ligands.

The structure of the title compound, [Ni(C 15 H 14 N 3 S 2 ) 2 ]ÁH 2 O, has one molecule in the asymmetric unit, along with a solvent water molecule. The two different Schiff base moieties coordinate to the central Ni II ion as tridentate N,N 0 ,Schelating ligands, creating a six-coordinate distorted octahedral environment [the smallest angle being 77.43 (7) and the widest angle being 169.99 (7) ]. The mean planes of the two ligands are nearly orthogonal to each other with an angle of 89.53 (6) . The packing of the complex is supported by O-HÁ Á ÁN and O-HÁ Á ÁS hydrogen bonding between the solvent water molecule and the uncoordinated N and S atoms of neighbouring ligands.

Experimental
Crystal data [Ni(C 15

Crouse Comment
The title compound was preferentially formed during the synthesis of the tridentate Schiff base with Ni II saccharinate, by eliminating the saccharinate anion and instead coordinating one metal ion with two tridentate deprotonated Schiff base moieties. Background on the coordination chemistry of hydrazine carbodithioates were given by Ravoof et al. (2010). This compound has been previously synthesized by Ali et al. (1997), but its crystal structure has not been reported so far.
There is one independent molecule in the asymmetric unit which contains the Ni II ion coordinated to two tridentate Schiff bases via the pyridyl nitrogen (N_115, N_215) azomethine nitrogen (N_102, N_202) and thiolate sulfur (S_106, S_205) atoms (Fig. 1). A solvent water molecule in also present in the lattice. The coordination of the metal ion is distorted octahedral with equatorial angles ranging from 77.43 (7)° to 108.62 (7)°. The distortion from the ideal geometry maybe due to the restricted bite angles (80.83 (5) and 81.03 (5) °) of the Schiff base ligands.
There is some weak hydrogen bonding (Fig. 2, Table 2) as evidenced by the interaction between the oxygen atom from the independent water molecule with the uncoordinated nitrogen (N_203) and sulfur atoms (S_205) of neighbouring ligands.

Experimental
The Schiff base ligand was prepared according to Ali et al. (1997). The metal complex of the Schiff base was prepared by adding nickel(II) acetate in hot ethanol (25 ml) to an equimolar quantity of the Schiff base in ethanol (30 ml). The resulting mixture was heated on a water bath until the volume reduced to 30 ml. On standing overnight, the mixture yielded crystals which were filtered off, washed with ethanol and dried in a desiccator over anhydrous silica gel, overnight. The crystals were then dissolved in a solvent mixture of acetonitrile:chloroform in 2:1 mole ratio. To this solution, excess sodium saccharin in water was added (20 ml) in a 1:4 mole ratio. The resulting mixture was heated on a water bath until the volume reduced to 30 ml. On standing overnight inside the fridge, crystals obtained were filtered off, washed with ethanol and dried in desiccator over anhydrous silica gel, overnight. Crystals of the nickel complex suitable for X-ray diffraction analysis were obtained by slow evaporation from a mixture of acetonitrile and THF over a few supplementary materials weeks.

Refinement
The H atoms were all located in a difference map, but those attached to carbon atoms were repositioned geometrically.
The H atoms were initially refined with soft restraints on the bond lengths and angles to regularize their geometry (C-H in the range 0.93-0.98 Å, O-H = 0.82 Å) and U iso (H) (in the range 1.2-1.5 times U eq of the parent atom), after which the positions were refined with riding constraints.  et al., 1996); software used to prepare material for publication: CRYSTALS (Betteridge et al., 2003).

Figure 1
The title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are omitted for clarity.