Bis[4-amino-3,5-bis(pyridin-2-yl)-4H-1,2,4-triazole-κ2 N 1,N 5]diaquacobalt(II) bis(perchlorate)

In the title structure, [Co(C12H10N6)2(H2O)2](ClO4)2, the CoII atom lies on an inversion centre and is coordinated in a slightly distorted octahedral geometry by four N atoms from two 4-amino-3,5-bis(pyridin-2-yl)-4H-1,2,4-triazole (adpt) ligands in equatorial positions and two O atoms from two water molecules in axial positions. An intramolecular N—H⋯N interaction stabilizes the molecular conformation. Intermolecular N—H⋯O and O—H⋯O interactions involving the perchlorate counter-anions extend the monomeric compound into a two-dimensional network parallel to the bc plane.

In the title structure, [Co(C 12 H 10 N 6 ) 2 (H 2 O) 2 ](ClO 4 ) 2 , the Co II atom lies on an inversion centre and is coordinated in a slightly distorted octahedral geometry by four N atoms from two 4-amino-3,5-bis(pyridin-2-yl)-4H-1,2,4-triazole (adpt) ligands in equatorial positions and two O atoms from two water molecules in axial positions. An intramolecular N-HÁ Á ÁN interaction stabilizes the molecular conformation. Intermolecular N-HÁ Á ÁO and O-HÁ Á ÁO interactions involving the perchlorate counter-anions extend the monomeric compound into a two-dimensional network parallel to the bc plane.
As shown in Figure 1, compound (I) consists of one Co(II) atom located on an inversion centre, two adpt ligands, two water molecules and two isolated perchlorate counter anions. The Co(II) is six-coordinated by four N atoms from two adpt ligands and two O atoms from two water molecules, giving a slightly distorted octahedral coordination environment.
The equatorial plane is defined by four N atoms from two adpt ligands with a chelate formation, and the axial positions are occupied by two O atoms of water molecules. The dihedral angle between the non-coordinated pyridine ring and the coordinating pyridine ring is 11.94 (16) ° and that between the coordinating pyridine ring and the triazole ring is 6.76 (6)°. In the mononuclear unit, an intramolecular N-H···N hydrogen-bonding interaction between the NH 2 group attached to the the triazole ring and the non-coordinating N atom of pyridine is observed (Kitchen et al., 2008).
Intermolecular N-H···O and O-H···O hydrogen-bonding interactions exist between the amine group and the coordinating water molecules, respectively, with the O atoms of the isolated perchlorate counter anions. In the crystal, the molecular entities are linked by O-H···O hydrogen bonds generating chains along the b axis. These chains in turn aggregate into a two-dimensional network parallel to the bc plane ( Fig. 2).

Refinement
All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C-H = 0.93 Å and with U iso (H) = 1.2U eq (C). H atoms bonded to N and O atoms were located in a difference map and refined program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figure 1
The molecular structure of the title compound, with atom labels and 30% probability displacement ellipsoids for non-H atoms. N-H···N and O-H···O interactions are shown as dashed lines.

Figure 2
The crystal packing of the title compound. O-H···O interactions are shown as dashed lines. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.87 e Å −3 Δρ min = −0.50 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq