Crystal Packing Analysis of Picric Acid, Phthalazone and their Cocrystal using Hirshfeld Computational Studies

In this paper we present the investigation of crystal packing of picric acid (PA), phthalazone (PZ) and their cocrystal phthalazone-picric acid (PA-PZ) using Hirshfeld surface computational analysis. The title molecules are synthesized, crystallized and three-dimensional structures are redetermined using XRD analysis. PA exhibit intermolecular hydrogen bonds O---H…N, O---H…O and intermolecular connection N---O...  . PZ shows N---H…O molecular interaction in it. O---H…O molecular contact has been noticed in PA-PZ. These intermolecular contacts within the crystal structure are quantified, evaluated and visualized in terms of 2D-finger print plots and Hirshfeld surfaces. In all crystal structures, O...H intercontact is common. The major contacts observed are O…H in PA and PA-PZ, H…H in PZ, respectively. In addition, electrostatic potential surface mappings are drawn on Hirshfeld surfaces for all the