N′-(5-Bromo-2-methoxybenzylidene)-3-hydroxybenzohydrazide methanol hemisolvate

The asymmetric unit of the title compound, C15H13BrN2O3·0.5CH3OH, contains two Schiff base molecules and a methanol molecule of crystallization. The dihedral angles between the benzene rings in the two molecules are 23.8 (2) and 18.6 (2)°. In the crystal structure, molecules are linked through intermolecular N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds, forming a three-dimensional network.


Related literature
In the crystal structure, molecules are linked through intermolecular N-H···O, O-H···O and O-H···N hydrogen bonds (Table 1) to form a three-dimensional network (Fig. 2).

S2. Experimental
2-Methoxy-5-bromobenzaldehyde (1.0 mmol, 215.0 mg) and 3-hydroxybenzohydrazide (1.0 mmol, 152.1 mg) were dissolved in methanol (30 ml). The mixture was stirred at reflux for 30 min to give a colourless solution. After keeping the solution in air for a few days, colourless block-like crystals were formed.

S3. Refinement
H2 and H4A were located in a difference Fourier map and refined isotropically, with U iso fixed at 0.08 Å 2 . Other H atoms were positioned geometrically and refined using a riding model with d(O-H) = 0.82 Å, U iso = 1.5U eq (O), and d(C-H) = 0.93 -0.96 Å, U iso = 1.2 or 1.5U eq (C).

Figure 1
The molecular structure of (I), with displacement ellipsoids drawn at the 30% probability level.

Figure 2
The molecular packing of (I), viewed along the c axis. Hydrogen bonds are shown 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.