Analyzing the three-dimensional networks of piperazinium hydrogenisophthalate – Insight on the experimental, theoretical, birefringent behavior and nonlinear optical study

•Title molecule comprises a three-dimensional network of N—H···O, O—H···O and C—H···O types of intermolecular and intra molecular hydrogen bonds.•NBO analysis expose the (O1) → π*(O2-C5) interactions give the strongest stabilization to the tittle molecule by 24.89 kcal/mol.•Fringes are parallel and equidistant without any hindrance representing good optical homogeneity of the grown crystal.•Third order susceptibility is found to be 6.68 × 10−6 esu. Single crystals of piperazinium hydrogenisophthalate have been grown by slow cooling of a saturated ethanol solution. The crystalline compound has been confirmed and the structure refinement of the grown crystal is revealed for the first time in the literature. The title molecule is found to have P21/c space group in the monoclinic crystal system. The crystals are comprised of a 1:2 ratio of piperazinium cations, which lie on a centre of symmetry, and hydrogenisophthalate anions which are linked together into a 3D network by NH…O, O—H···O and C—H···O intermolecular and intra molecular hydrogen bonds. Optical transmittance study revealed that the grown crystal is significantly transparent to be utilized for optical applications. Birefringence study of the grown crystal reveals that the compound has uniform fringes thus proving the optical homogeneity and better quality of the grown crystal. Theoretical calculations were done using Gaussian 09 software and the results are given in comparison with the experimental data. The nonlinear optical property of the grown crystal has been assessed by Z- scan study. [Display omitted]