(E)-6-(4-Chlorophenyl)-4-[(2-cyano-3-phenylallyl)sulfanyl]-2,2-difluoro-3-phenyl-1,3,2-oxazaborinin-3-ium-2-uide

In the title compound, C25H18BClF2N2OS, the characteristic B—N and B—O bond lengths are 1.571 (3) and 1.458 (3) Å, respectively. The phenyl rings form dihedral angles of 83.1 (1) and 64.6 (1)° with the chlorophenyl ring. In the crystal, weak C—H⋯N, C—H⋯F, C—H⋯π and π–π interactions [centroid–centroid distances 3.877 (6) Å between the chlorophenyl rings of neighbouring molecules] held molecules together, forming ladders along the b axis.


Experimental
Cg1 is the centroid of the C1-C6 ring.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV5394). Thioacetanilides being novel enaminones (Peruncheralathan et al., 2005) with four active reaction sites show structural feature of highly polarized push-pull interaction C=C double bond (Li et al., 2010). BF 2 complexes, such as the Bodipy family, are most intriguing due to their outstanding optical properties, extraordinary chemical versatility, and variety of applications spanning from biolabeling (Wu et al., 2009) to solar cells (Erten-Ela et al., 2008) and nanoparticle engineering (Tokoro et al., 2010). Synthetic studies have been conducted on various phosphorescent materials with heavy metals such as iridium (Tsuboyama et al., 2003) and platinum (Lu et al., 2002) and on fluorescent boron complexes (Zhang et al., 2006). In order to explore the chemical reactivities of thioacetanilides, we obtained the title compound, (I).

Experimental
A 25 ml volumetric flask was charged with 8 ml THF and 1.01 g (5 mmol) 2-cyano-1-phenylallyl acetate. Then 1.45 g (5 mmol) 3-(4-chlorophenyl)-3-oxo-N-phenylpropane thioamide and 0.09 g (3.75 mmol) sodium hydride were added. The mixture was stirred at room temperature for 4 h, and then 8 ml BF 3 .Et 2 O (10 mmol) was added with stirring for a further 4 h at room temperature. The reaction was monitored by TLC, and after TLC indicated the completion of the reaction, the solution was filtered, and the inorganic salts were removed. The solvent of the filtrate was removed with the aid of a rotary evaporator, and the residue was purified by column chromatography on silica gel, using petroleum ether/ethyl acetate (6:1) as eluent to provide the desired product yielding 2.01 g (84%) of pure BF2 complex, m.p. 462-463 K.

Refinement
All H atoms were found on difference maps, but placed in idealized positions (C-H = 0.95-0.99 Å), and included in the final cycles of refinement using a riding model, with U iso (H) = 1.2U eq (C).

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.