Poly[[(μ2-di-3-pyridylmethanone-κ2 N:N′)(μ2-hexafluorosilicato-κ2 F:F′)copper(II)] dihydrate]

In the title complex, {[Cu(SiF6)(C11H8N2O)2]·2H2O}n, the CuII atom adopts an N4F2-octahedral coordination geometry with four pyridine N atoms in the equatorial sites and two F atoms in the axial sites. The di-3-pyridylmethanone and hexafluorosilicate ligands act as bidentate ligands, linking symmetry-related CuII atoms. Water molecules form O—H⋯O and O—H⋯F hydrogen bonds with the di-3-pyridylmethanone and hexafluorosilicate ligands. The Cu2+ and SiF6 2− ions are each located on a twofold axis.

In the title complex, {[Cu(SiF 6 )(C 11 H 8 N 2 O) 2 ]Á2H 2 O} n , the Cu II atom adopts an N 4 F 2 -octahedral coordination geometry with four pyridine N atoms in the equatorial sites and two F atoms in the axial sites. The di-3-pyridylmethanone and hexafluorosilicate ligands act as bidentate ligands, linking symmetryrelated Cu II atoms. Water molecules form O-HÁ Á ÁO and O-HÁ Á ÁF hydrogen bonds with the di-3-pyridylmethanone and hexafluorosilicate ligands. The Cu 2+ and SiF 6 2À ions are each located on a twofold axis.
Poly [[( 2 -di-3-pyridylmethanone-2 Pyridyl-based building blocks are widely used in construction various supramolecules of transition metal complexes (Manriquez et al. 1991;Wang et al., 2009). Among them, dipyridylmethanone derivates are famous for their versatile linkage behavior in numbers of coordination supramolecular assemblies (Boudalis et al., 2003). Di-3-pyridinylmethanone was provided to act as a flexible µ 2 -bridging mode in many coordination frameworks, such as one-dimensional helical and zigzag chains , two-dimensional nets  as well as honeycomb-like three-dimensional frameworks (Chen et al., 2009). Herein, we report a new structure derived from di-3-pyridinylmethanone, namely In the title complex, the Cu II atom adopts an N4F2-octahedral coordination geometry with four pyridyl N atoms at the equatorial sites and two F atoms at the axial sites (Fig. 1). The di-3-pyridylmethanone and hexafluorosilicate ligands act as bidentate ligands linking symmetry-related Cu II atoms. Water molecules form hydrogen bonds with di-3-pyridylmethanone and hexafluorosilicate ligands bridging them together (Table 1). Cu 2+ and SiF 6 2ions are located on a twofold axis, see di-3-pyridylmethanone, , where the Cu II adopts a square-plane N4-geometry with four ligands around the metal center, forming a (4,4) net structure.

Experimental
The ligand was obtained according to the reported procedure  and di-3-pyridylmethanone (38 mg, 0.2 mmol) were dissolved in a mixed solvent of 1ml methanol and 3 ml acetonitrile with stirring at room temperature. The (NH 4 ) 2 SiF 6 (18 mg, 0.1 mmol) was subsequently added to the solution. After 4 hours, the resulted clear solution was filtered and the filtrate was left to stay in air. The block crystals suitable for x-ray diffraction analysis were obtained after about one weak (29.9 mg, 49% yield).

Refinement
All the H atoms were located in the difference electron density maps but were placed in idealized positions and allowed to ride on the carrier atoms, with C-H = 0.93 Å and with U iso (H) = 1.2U eq (C).
supplementary materials sup-2 Figures Fig. 1. The title complex showing the atom-numbering scheme, with displacement ellipsoids shown at the 30% probability level. Hydrogen atoms are omitted for clarity. Symmetry codes:

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The 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.

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