2-(Phenylselenonyl)pyridine

In the title compound, C11H9NO2Se, the pyridine and phenyl rings are almost perpendicular, with the dihedral angle between their mean planes being 79.16 (7)°. In the crystal, the molecules pack so as to form ruffled sheets in the (110) plane connected by weak C—H⋯O interactions. In addition, there are weak π–π interactions between the mean planes of both the phenyl [centroid–centroid perpendicular distance of 3.591 (2) Å and slippage of 1.854 (2) Å] and pyridine rings [centroid–centroid perpendicular distance of 3.348 (2) Å and slippage of 1.854 (2) Å].

In the title compound, C 11 H 9 NO 2 Se, the pyridine and phenyl rings are almost perpendicular, with the dihedral angle between their mean planes being 79.16 (7) . In the crystal, the molecules pack so as to form ruffled sheets in the (110) plane connected by weak C-HÁ Á ÁO interactions. In addition, there are weakinteractions between the mean planes of both the phenyl [centroid-centroid perpendicular distance of 3.591 (2) Å and slippage of 1.854 (2) Å ] and pyridine rings [centroid-centroid perpendicular distance of 3.348 (2) Å and slippage of 1.854 (2) Å ].

Experimental
Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. This work was supported by the Department of Science and Technology, DST, New Delhi (Research Grant SR/S1/IC-37/ 2009). RJB wishes to acknowledge the NSF-MRI program (grant CHE-0619278) for funds to purchase the diffractometer as well as the Howard University Nanoscience Facility for access to liquid nitrogen.

Comment
Organochalcogen compounds, especially containing selenium have continued to attract attention of researchers in academia as anti-cancer (Zhao et al., 2012), anti-oxidant (Hassan et al., 2011;Bhabak et al., 2011), anti-inflammatory and anti-allergic agents (Abdel-Hafez, & Hussein, 2008), and in industry because of their wide involvement as key intermediates for the synthesis of pharmaceuticals (Nogueira, & Rocha, 2011), perfumes, fine chemicals and polymers (Zeng et al., 2013). Curiously, compared to alkyl, aryl and mixed alkyl aryl selenium compounds, the chemistry of selenium compounds bonded directly to pyridine has not yet been exploited extensively (Bhasin et al. 2013). In continuation of our ongoing program directed at the synthesis of novel organoselenium derivatives, we report here the synthesis and crystal structure of 2-(phenylselenonyl)pyridine.

Experimental
A stirred solution of 2-(phenylseleninyl)pyridine (0.235 g, 1 mmol) in glacial acetic acid (10 ml) was treated with (0.550 g, 3.5 mmol) potassium permanganate in small amounts. The reaction mixture was allowed to stir for 3 h at room temperature. The progress of the reaction mixture was monitored by thin layer chromatography. After completion of the reaction, the reaction mixture was neutralized with excess of saturated solution of sodium bicarbonate and extracted with dichloromethane (4 x 25 ml). The combined organic extracts were washed with water and dried over anhydrous MgSO 4 .
Dichloromethane was removed on a rota-evaporator that yielded a white powder. Single crystals of the compound suitable for XRD were prepared by dissolving the obtained white powder in a (1:1) mixture of CHCl 3 and CCl 4 followed by slow evaporation. Yield = 85%. M.p.= 453-455°K.

Refinement
All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with a C-H distance of 0.95 and 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.