N′-[1-(5-Bromo-2-hy­dr­oxy­phen­yl)ethyl­­idene]isonicotinohydrazide monohydrate: crystal structure and Hirshfeld surface analysis

In the title isonicotinohydrazide hydrate, C14H12BrN3O2·H2O {systematic name: N′-[(1E)-1-(5-bromo-2-hy­droxy­phen­yl)ethyl­idene]pyridine-4-carbohydrazide monohydrate}, the central CN2O region of the organic mol­ecule is planar and the conformation about the imine-C=N bond is E. While an intra­molecular hy­droxy-O—H⋯N(imine) hydrogen bond is evident, the dihedral angle between the central residue and the benzene rings is 48.99 (9)°. Overall, the mol­ecule is twisted, as seen in the dihedral angle of 71.79 (6)° between the outer rings. In the crystal, hydrogen-bonding inter­actions, i.e. hydrazide-N—H⋯O(water), water-O—H⋯O(carbon­yl) and water-O—H⋯N(pyrid­yl), lead to supra­molecular ribbons along the a-axis direction. Connections between these, leading to a three-dimensional architecture, are mediated by Br⋯Br halogen bonding [3.5366 (3) Å], pyridyl-C—H⋯O(carbon­yl) as well as weak π–π inter­actions [inter-centroid separation between benzene rings = 3.9315 (12) Å]. The Hirshfeld surface analysis reveals the importance of hydrogen atoms in the supra­molecular connectivity as well as the influence of the Br⋯Br halogen bonding.