Aqua(di-2-pyridylamine-κ2 N 2,N 2′)(pyridine-2,6-dicarboxylato-κ3 O 2,N,O 6)zinc monohydrate

In the title compound, [Zn(C7H3NO4)(C10H9N3)(H2O)]·H2O, the ZnII atom has a distorted octahedral coordination geometry. One of the water molecules is coordinated with the ZnII ion and this molecule forms an O—H⋯O interaction with the lattice water molecule. The pyridine-2,6-dicarboxylate ligand is almost planar (r.m.s. deviation = 0.0242 Å). In the crystal, C—H⋯O, C—H⋯N, O—H⋯O and N—H⋯O hydrogen bonds are present.


Comment
The large amount of the 2,6-pyridinedicarboxylic acid (dipicolinic acid, DPA) is contain by bacterial spores and may be related to heat resistance of bacterial spores (Chung et al., 1971;Tang et al., 1968).
In the Figure 1 is shown that the pyridine-2,6-dicarboxylato ligand has connected to Zn II ion through the carboxyl group and ring nitrogen. The metal atom has also connected to 2,2-dipyridylamine ligand thought two ring nitrogens. Thus, the Zn(II) atom has a distorted octahedral coordination geometry by two N atoms from the dipyridylamine ligand, one N atom and two O atoms from the pyridine-2,6-dicarboxylato ligand and one O atom from aqua ligand.

Experimental
To ethanol/water (30ml, ca. 1:1, v/v) containing ZnCl 2 .4H 2 O (1mmol) and disodium dipicolinate (1mmol), 2,2-dipyridylamine (1mmol) was added slowly with continuous stirring. The resulting solutions were refluxed for 1h and then filtered. The blue filtrates were allowed about 2 weeks at room temperature, and then the colorless crystals of title complex suitable for X-ray diffraction analyses were collected.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.