N′-(2,4-Dichlorobenzylidene)-4-methoxybenzohydrazide methanol solvate

In the title compound, C15H12Cl2N2O2·CH3OH, the hydrazone molecule displays an E configuration about the C=N bond. The dihedral angle between the two benzene rings is 4.6 (2)°. In the crystal structure, the hydrazone and methanol molecules are linked into a chain propagating along the a axis via N—H⋯O and O—H⋯O hydrogen bonds.

In the title compound, C 15 H 12 Cl 2 N 2 O 2 ÁCH 3 OH, the hydrazone molecule displays an E configuration about the C N bond. The dihedral angle between the two benzene rings is 4.6 (2) . In the crystal structure, the hydrazone and methanol molecules are linked into a chain propagating along the a axis via N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds.   Table 1 Hydrogen-bond geometry (Å , ).
The asymmetric unit of the title compound contains a hydrazone molecule and a methanol molecule. In the hydrazone molecule, the dihedral angle between the two benzene rings is 4.6 (2)°. The hydrazone molecule exists in an E configuration with respect to the methylidene group. All the bond lengths are normal and comparable to those in similar hydrazone compounds (Wu, 2009;Peng & Hou, 2008;Mohd Lair et al., 2009).
In the crystal structure of the title compound, the hydrazone molecules are linked by the methanol molecules through N-H···O and O-H···O hydrogen bonds (Table 1), forming chains propagating along the a axis (Fig. 2).

Experimental
Equimolar quantities (1.0 mmol each) of 2,4-dichlorobenzaldehyde and 4-methoxybenzohydrazide were mixed and refluxed in methanol. The reaction mixture was cooled to room temperature to give a clear colourless solution. Colourless single crystals of the title compound were formed by slow evaporation of the solution in air.

Refinement
Atom H2 was located in a difference map and refined isotropically, with the N-H distance restrained to 0.90 (1) Å. Other H atoms were placed in calculated positions (C-H = 0.93-0.96 Å and O-H = 0.82 Å) and refined as riding with U iso (H) = 1.2U eq (C) and 1.5U eq (O,C methyl ).

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 Rfactors(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.