N-[2-(Methylsulfanyl)phenyl]-2-sulfanylbenzamide

In the title compound, C14H13NOS2, the S atom with the methyl group is involved in an intramolecular hydrogen bond with the amido H atom. In the crystal, the sulfanyl H atoms form intermolecular hydrogen bonds with the O atoms, connecting the molecules into zigzag chains along the c axis. The two aromatic rings exhibit a small interplanar angle of 16.03 (9)°.

In the title compound, C 14 H 13 NOS 2 , the S atom with the methyl group is involved in an intramolecular hydrogen bond with the amido H atom. In the crystal, the sulfanyl H atoms form intermolecular hydrogen bonds with the O atoms, connecting the molecules into zigzag chains along the c axis. The two aromatic rings exhibit a small interplanar angle of 16.03 (9) .   Table 1 Hydrogen-bond geometry (Å , ). Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL.

Chang-Chih Hsieh, Hon Man Lee and Yih-Chern Horng Comment
The N-H···S hydrogen bonding interactions are quite often found in proteins, where the sulfur atoms are ususally from cysteine or methionine residues. Many organic compounds containing amide and thiol (or thioether) moieties were investigated to give a deep insight of the N-H···S hydrogen bonding interactions (Du et al. 2009), which may help to understand protein folding processes and enzymatic catalyses. Our group is interesting in the preparation and encapsulation behaviors of organic and inorganic supramolecules with dynamic covalent bonds (Huang et al. 2012;Wu et al. 2012). The title compound is a sulfur-containing secondary amide with two aryl groups. We synthesized and report its structure here, and will atempt to use it as a building block for the construction of more complex organic or inorganic molecules with unique properties.
The title compound crystallizes in the monoclinic space group P 2 1 /c.

Experimental
A CH 2 Cl 2 solution (20 ml) containing 2-methylthioaniline (1.39 g, 10 mmol) and NEt 3 (1.02 g, 10 mmol) was mixed with another CH 2 Cl 2 solution (20 ml) containing 2,2′-dithiosalicyl chloride (1.7 g, 5 mmol). After stirred at room temperature for 12 h, the mixture was washed with saturated NaHCO 3 solution and distilled water. The combined CH 2 Cl 2 portions were collected and dried with anhydrous MgSO 4 . The solvent was then removed under vacuum to afford a yellow powder. An uncapped 50 ml flask, containing the yellow solid and an excess NaBH 4 (0.33 g, 9 mmol), was placed in an ice-water bath. To this flask, 25 ml of MeOH was added slowly. After the resulting mixture stirred at 4°C for 10 minutes, the water bath was removed and the stirring was continued for another 30 minutes. The yellowish mixture was added dropwise with concentrated HCl (aq) to quench excess NaBH 4 . After completion, the solution was extracted with CH 2 Cl 2 and distilled water. The collected CH 2 Cl 2 fractions were dried over anhydrous MgSO 4 , filtered, and vacuum dried to give 2.03 g of light-yellow solid (86% yield). Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation of THF solution of the compound at -4°C.

Refinement
The H on C atoms were positioned geometrically and refined as riding atoms, with C aryl -H = 0.93 and C methyl -H = 0.96 Å while U iso (H) = 1.2U eq (C aryl ) and 1.5U eq (C methyl ). The H on N and S atoms were located from the difference Fourier map and freely refined (N1-H8 = 0.83 (2) Å and S2-H13 = 1.24 (3) Å).   A view of the one-dimensional zigzag hydrogen-bonded chain, displaying the hydrogen bonds as dashed lines.

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.