Bis[μ-3,5-bis(pyridin-2-yl)pyrazolato]bis[(hexafluorophosphato)copper(II)]

The title dinuclear complex molecule, [Cu2(C13H9N4)2(PF6)2], lies about an inversion center. The CuII atom shows a square-pyramidal coordination geometry with the basal plane formed by four N atoms of the two bis-chelating 3,5-bis(pyridin-2-yl)pyrazolate ions and with one F atom of the hexafluorophosphate ion in the apical position. Molecules are stacked in a column along the a axis through C—H⋯F hydrogen bonds. The columns are further linked by other C—H⋯F hydrogen bonds, forming a three-dimensional network.

Data collection: RAPID-AUTO (Rigaku, 2002); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: Il Milione (Burla et al., 2007); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalStructure (Rigaku, 2010); software used to prepare material for publication: CrystalStructure. donors by deprotonation; the two N atoms in a pyrazole moiety and two N atoms in pyridine moieties. This ligand can bind to metal ions by behaving as a bidentate or as a tetradentate ligand and would be possible to form various coordination modes (Yoneda, Adachi, Hayami et al., 2006;Yoneda, Adachi, Nishio et al., 2006). In particular, two bpypzions form a planar dinuclear complex by chelating two metal ions at equatorial position (Washizaki et al., 2012). The dinuclear complex has unique coordination sites at the apical positions, which can trap ions hardly to coordinate. We have previously reported the dinuclear complex with coordinated hydrogensulfate ions at the apical sites (Mishima et al., 2011). The complex consists of a planer dinuclear complex and two hydrogensulfate ions, and forms a 1D chain with methanol molecules by hydrogen-bonding interactions.
The title planer dinuclear Cu II complex with two PF 6ions has a similar structure to the above complex. The basal plane in the complex is formed by four N donors of two deprotnated tetradentate bridging bpypzligands. Cu-N distances are Cu-N1 2.0698 (15) Å, Cu-N2 1.9393 (16) Å, Cu-N3 1.9405 (15) Å, and Cu-N4 2.0577 (17) Å. Cu II ions are each penta-coordinated by occupying PF 6ion at apical positions in the opposite direction and form a near ideal squarepyramidal coordination environment with t value of 0.068. The distance of Cu-F1 is 2.4027 (14) Å. To the best of our knowledge, the crystal structure report of PF 6coordinated Cu II complex is only a few examples (Noro et al., 2011). The adjacent dinuclear complexes are stacked in columns through a weak π-π stacking interaction between pyridyl and pyrazol rings of the bpypzions (centroid-centroid distance 3.879 Å) and C-H···F hydrogen bonds between the bpypzand the PF 6ions ( Table 2). The C-H···F interactions are expected to be weak because of the low acidity of C-H system. However, the interatomic distances are in close contact; the distances of C-H···F bond are H1···F3 2.689 Å, H2···F4 2.666 Å, H8···F5 2.603 Å and H9···F3 2.522 Å. The supramolecular structure results from C-H···F bonds between adjacent columns. The distances between the columns are H3···F3 2.308 Å, H7···F2 2.536 Å and H5···F8 2.634 Å.

Refinement
The C-bound hydrogen atoms in the bpypzion were placed at calculated positions (C-H = 0.95 Å) and were treated as riding on their parent atoms with U iso (H) = 1.2U eq (C).

Figure 1
An ORTEP drawing of the title complex, showing 50% probability displacement ellipsoids.

Figure 2
A fragment of one-dimensional structure of the title compound. Hydrogen bonds are shown as dashed lines.

Figure 3
Packing structures of the title complex viewed along the a axis (a) and the c axis (b).

Special details
Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . R-factor (gt) are based on F. The threshold expression of F 2 > 2.0 sigma(F 2 ) is used only for calculating Rfactor (gt).