Aqua[2,6-bis(2-pyridylamino)pyridine]sulfatonickel(II) monohydrate

The Ni atom in the title complex, [Ni(SO4)(C15H13N5)(H2O)]·H2O, has a distorted trigonal-bipyramidal coordination formed by the tridentate 2,6-bis(2-pyridylamino)pyridine (tpdaH2) ligand, one sulfate and one coordinated water molecule. The tpdaH2 ligand is three-coordinated, with the N atom of the central pyridine ring in the equatorial position [Ni—N = 1.9961 (14) Å] and the N atoms of the peripheral pyridine rings in the axial positions [Ni—N = 1.9668 (15) and 1.9895 (15) Å]. The remaining equatorial positions are occupied by the O atoms of the sulfate ligand and the water molecule. The H atoms of both NH groups of the tpdaH2 ligand are involved in hydrogen bonds with the O atoms of the uncoordinated water molecule and the sulfate group which link the complex molecules, forming an infinite three-dimensional network.

The Ni atom in the title complex, [Ni(SO 4 )(C 15 H 13 N 5 )(H 2 O)]Á-H 2 O, has a distorted trigonal-bipyramidal coordination formed by the tridentate 2,6-bis(2-pyridylamino)pyridine (tpdaH 2 ) ligand, one sulfate and one coordinated water molecule. The tpdaH 2 ligand is three-coordinated, with the N atom of the central pyridine ring in the equatorial position
Aqua[2,6-bis(2-pyridylamino)pyridine]sulfatonickel(II) monohydrate Lu Lu, Jun Wang, Bin Xie and Li-Ke Zou S1. Comment Transition metal complexes with polypyridylamine ligands, possessing diverse structures and special optical and electromagnetic properties (Wang et al.,1999), have aroused great interest among researchers, Tri-pyridyldiamine ligand usually exhibits donor as well as acceptor properties and can be used as a popular chelating ligand (Jing et al., 2000). In recent years great efforts have been taken to synthesize and characterize metal chain complexes which can be used to study the metal-metal interactions (Yang et al., 1997;Cotton et al., 1998). Herein we report the synthesis and crystal structure of the title complex with tri-pyridyldiamine ligand.
The Ni1 atom in the title complex has a distorted trigonal-bipyramidal coordination formed by the tridentate tpdaH 2 ligand, one sulfate and one coordinated water molecule. (Fig. 1). The tpdaH 2 ligand is tri-coordinated, with the peripheral The three pyridine rings of the tpdaH 2 ligand are not coplanar. The dihedral angles between the planes of the central pyridine ring and two peripheral rings are 15.0 (7) and 22.7 (3)° respectively. In the title complex the two H atoms of both NH groups of tpdaH 2 act as active H atoms in forming inter-molecular classical hydrogen bonds ( Table 2). The intermolecular hydrogen bonds function greatly in linking the complex to be a infinite three-dimensional network.

S2. Experimental
Tripyridyldiamine (0.031 g, 0.12 mmol), NiSO4 (0.26 g, 0.13 mmol), were added in a solvent of acetonitrile, the mixture was heated for six hours under reflux. during the process stirring and influx were required. The resultant was then filtered to give a pure solution which was infiltrated by diethyl ether freely in a closed vessel, three weeks later some single crystals of the size suitable for X-Ray diffraction analysis.

S3. Refinement
Carbon H atoms were positioned geometrically and treated as riding on their parent atoms, with C-H distances of 0.93Å (pyridine ring) with U iso H) 1.2U eq (C). The amine H atoms were located in difference maps and freely refined with U iso (H) 1.2U eq (N). The water H atoms were located in different map and, in the first stage of refinement, refined with the O-H and H-H distances restraints to 0.85Å and 1.39Å respectively and with U iso (H) 1.5U eq (O). In the last cycle, they were treated as riding on their parent O atoms.  View of compound (I) with the atom-labeling scheme. Displacement ellipsoids are drawn at the 30% probability level.
Only H atoms attached to water have been represented as small spheres of arbitrary radii. H bond is shown as dashed line. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.24 e Å −3 Δρ min = −0.32 e Å −3 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 > σ(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.