Bis[3-(pyrazin-2-yl)-5-(pyridin-2-yl-κN)-1,2,4-triazol-1-ido-κN 1]copper(II)

In the mononuclear title complex, [Cu(C11H7N6)2], the CuII atom lies on a crystallographic inversion centre and is coordinated by four N atoms from two bidentate chelate monoanionic 3-(pyrazin-2-yl)-5-(pyridin-2-yl-1,2,4-triazol-1-ido ligands, two from the triazolide rings [Cu—N = 1.969 (2) Å] and two from the pyridine rings [Cu—N = 2.027 (2) Å], giving a slightly distorted square-planar geometry.


Related literature
For details of the synthesis and properties of related copper compounds showing a similar coordination environment, see: Meng et al. (2009) ;Cheng et al. (2007); Zhang et al. (2005). For the structure of an Ru II complex with the same ligand, see: Browne et al. (2002).
As shown in Fig. 1, this complex is a discrete neutral monomer, in which the Cu II atom resides on a crystallographic inversion centre. The Cu II atom is in a slightly distorted [N 4 ] square planar environment, with the coordination sphere defined by two pyridyl N-atom donors [Cu-N pyridine = 2.027 (2) Å] and two triazolate N-atom donors [Cu-N triazolide = 1.969 (2) Å] from two bidentate chelate ptpanion ligands. The dihedral angle between the coordinated pyridyl group and the triazolato ring is 1.33 (9)°. In the crystal packing there are only minor weak intermolecular C-H···N hydrogenbonding interactions (Table 1).

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).

Bis[3-(pyrazin-2-yl)-5-(pyridin-2-yl-κN)-1,2,4-triazol-1-ido-κN 1 ]copper(II)
Crystal data [Cu(C 11  Hydrogen site location: inferred from neighbouring sites H-atom parameters constrained w = 1/[σ 2 (F o 2 ) + (0.0356P) 2 + 0.5521P] where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.28 e Å −3 Δρ min = −0.27 e Å −3 Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles 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 Cu1