Rietveld refinement of the cocrystal 2,4-dihy­droxy­benzoic acid-N'-(pro­pan-2-yl­idene)nicotinohydrazide (1/1)

A further example of using a covalent-bond-forming reaction to alter supra­molecular assembly by modification of hydrogen-bonding possibilities is presented. This concept was introduced by Lemmerer, Bernstein & Kahlenberg [CrystEngComm (2011), 13, 55-59]. The title structure, C₉H₁₁N₃O·C₇H₆O₄, which consists of a reacted niazid mol­ecule, viz. N'-(propan-2-yl­idene)nicotinohydrazide, and 2,4-di­hy­droxy­benzoic acid, was solved from powder diffraction data using simulated annealing. The results further demonstrate the relevance and utility of powder diffraction as an analytical tool in the study of cocrystals and their hydrogen-bond inter­actions.