1-(6-Chloro-1,3-benzothiazol-2-yl)-2-[1-(4-methoxyphenyl)ethylidene]hydrazine

The asymmetric unit of the title compound, C16H14ClN3OS, contains two independent molecules (A and B) linked into dimers via N—H⋯N hydrogen bonds. The 1,3-benzothiazol-2-yl ring system and the benzene ring form dihedral angles of 17.08 (8) and 8.63 (7)° in molecules A and B, respectively.


Experimental
A mixture of 1-(6-chloro1,3-benzothiazol-2-yl)hydrazine (1.99 g, 10 mmol) and 4-methoxyacetophenone (1.5 g, 10 mmol) in ethanol (50 ml) was refluxed for 4 h. Completion of the reaction was monitored by TLC. After completion of the reaction, the reaction-mixture was poured into ice water. Brown colored solid separated out. The product obtained was washed with water and dried. The crude product was recrystallized from ethanol. Single crystals were grown by slow evaporation from solvent ethanol (m.p. 451-453 K).

Refinement
N-bound H atoms were located in a difference Fourier map and isotropically refined with a restraint N-H = 0.85 (3) Å.
The remaining H atoms were positioned geometrically and refined using a riding model with C-H = 0.95 or 0.98 Å and U iso (H) = 1.2 or 1.5U eq (C). A rotating group model was applied to the methyl groups.

Figure 1
The content of asymmetric unit of (I) showing 50% probability displacement ellipsoids for non-H atoms. Intermolecular hydrogen bonds are shown as dashed lines.

1-(6-Chloro-1,3-benzothiazol-2-yl)-2-[1-(4-methoxyphenyl)ethylidene]hydrazine
Special details Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 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.