[3-Chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinato](pyridine-2,6-dicarboxylato)nickel(II) dihydrate

In the title compound, [Ni(C11H9ClN3O2)(C7H3NO4)]·2H2O, the NiII atom is coordinated by two N atoms and one O atom of 3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinate and by one N atom and two O atoms of pyridine-2,6-dicarboxylate in a distorted octahedral coordination. In the crystal structure, molecules are linked together by intermolecular O—H⋯O hydrogen bonds. One water molecule is disordered over two positions; the site occupancies are ca 0.53 and 0.47.

In the title compound, [Ni(C 11 H 9 ClN 3 O 2 )(C 7 H 3 NO 4 )]Á2H 2 O, the Ni II atom is coordinated by two N atoms and one O atom of 3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinate and by one N atom and two O atoms of pyridine-2,6-dicarboxylate in a distorted octahedral coordination. In the crystal structure, molecules are linked together by intermolecular O-HÁ Á ÁO hydrogen bonds. One water molecule is disordered over two positions; the site occupancies are ca 0.53 and 0.47.

Comment
In recent years, there has been an increasing interest in the coordination chemistry due to the increased recognition of it's role in catalysis enzymatic reactions, magnetism and molecular architectures (Costamagna et al., 1992;Bhatia et al., 1981).
The title compound, (I), consists of a central asymmetric Triclinic nickel(II) complex cation,two uncoordinated water molecules. In the cation (Fig. 1 In the title compound, the oxygen atoms contribute to the formation of intermolecular hydrogen bonds involving water O atom. (Table 1 and Fig. 2).
The mixture was stirred to give a clear solution, To this solution was added NiCl 2 ·6H 2 O (0.5 mmol, 113 mg) in anhydrous alcohol (10 ml). After keeping the resulting solution in air to evaporate about half of the solvents, dark red prisms of the title compound were formed. The crystals were isolated, washed with alcohol three times and dried in a vacuum desiccator using silica gel (Yield 75%).

Refinement
All the H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C-H distances of 0.93 Å and 0.96 Å for aromatic and methyl C atoms with U iso (H) = 1.2U eq (C) and U iso (H) = 1.5U eq (C), respectively. One of two water molecules is disorder on two positions with ratio 0.531 (7)/0.469. The H atoms of water molecules were located from the difference Fourier map and constrained to ride on their parent atoms with O-H distances of 0.85 Å with and U iso (H) = 1.2U eq (O). Fig. 1. The structure of the title compound (I) showing 50% probability displacement ellipsoids and the atom-numbering scheme.  supplementary materials sup-9