Bis(tetraphenylphosphonium) tetrachloridocobaltate(II)

The title compound, (C24H20P)2[CoCl4], was prepared under hydrothermal conditions. In the crystal, the tetraphenylphosphonium cations are linked by pairs of weak C—H⋯π interactions into supramolecular dimers; the CoII cations lie on twofold rotation axes and the tetrahedral [CoCl4]2− anions are linked with the tetraphenylphosphonium cations via weak C—H⋯Cl hydrogen bonds.

The title compound, (C 24 H 20 P) 2 [CoCl 4 ], was prepared under hydrothermal conditions. In the crystal, the tetraphenylphosphonium cations are linked by pairs of weak C-HÁ Á Á interactions into supramolecular dimers; the Co II cations lie on twofold rotation axes and the tetrahedral [CoCl 4 ] 2À anions are linked with the tetraphenylphosphonium cations via weak C-HÁ Á ÁCl hydrogen bonds.

Comment
Research on supramolecular compounds has become popular because of their potential applications in areas such as gas storage (Rowsell & Yaghi, 2005), selective absorption (Dong et al., 2007), catalysis (Wu & Lin, 2007), magnetics (Zhao et al., 2003;Neville et al., 2008) and optics . P-Ligands are important structural motifs in organic syntheses, coordination chemistry and also in various catalytically active compounds, the tetraphenylphosphonium ion have been widely used in supramolecular chemistry and numerous coordination polymers with versatile structures and potential properties have been reported (Zacharie et al., 1985;Schlueter & Geiser, 2007). Thus, we report here the synthesis of title compound [L 2 .CoCl 4 ], were L is tetraphenylphosphonium and its crystal structure.
The asymmetric unit of (I) and atomic numbering are illustrated in Fig. 1. The (I) contains tetraphenylphosphonium cations linked by weak C-H···π supramolecular interactions into dimmers. The Co II ion lies on a twofold axis and has a distorted tetrahedral coordination. The [CoCl 4 ] -2 anions are linked with the cation via weak C-H···Cl hydrogen bonds ( Fig. 2, 3).
The bond lengths for coordination Co II sphere is ranging from 2.2791 (6) to 2.2873 (6) Å for Co-Cl distances ( Table   1). The crystal packing in the title structure can be described by altering CoCl 4 tetrahedral of complex along the a axis at b = 1/4 and 3/4 (Fig. 2).

Experimental
A mixture of CoCl 2 (2.50 g, 10 mmol), tetraphenylphosphonium chloride hydrate (3.92 g,10 mmol) was dissolved in a 20 ml EtOH/H 2 O(v/v,1:2). The mixture was then sealed in a 25 ml stainless steel reactor and heated to 433 K for 3 days.
Then the reactant mixture was cooled to room temperature at the rate of 5 degrees per hour. Evaporation of the resulting solution for a few days afforded pink crystals of title compound.

Refinement
The aromatic H atoms were placed at calculated positions with C-H = 0.93, and refined in riding mode with U iso (H) = 1.2U eq (C).    A view along the c axis of the crystal structure of the title compound, showing C-H···Cl hydrogen-bonds.

Bis(tetraphenylphosphonium) tetrachloridocobaltate(II)
Crystal data (C 24  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 1.51 e Å −3 Δρ min = −0.22 e Å −3 Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s 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.