Molecular properties, crystal structure, Hirshfeld surface analysis and computational calculations of a new third order NLO organic crystal, 2-aminopyridinium benzilate

A third order nonlinear optically active (NLO) organic proton transfer compound was synthesized by the reaction between 2-aminopyridine and benzilic acid. Single crystals of the product, 2-aminopyridinium benzilate, (2-APB) were grown by slow evaporation technique and the structure of 2-APB was confirmed by single crystal X-ray diffraction. In the structural network, cations and anions are linked through N+- H center dot center dot center dot O- intermolecular hydrogen bonding interactions. Elemental analysis, thermal analysis, UV-Vis, FT-IR and H-1 and C-13 NMR spectroscopic analyses were carried out to assess the structure and chemical makeup of the 2-APB crystal. Computational studies that include optimization of molecular geometry, natural bond orbital (NBO), Mulliken atomic charge and HOMO-LUMO analyses were also performed using B3LYP method at 6-311+G(d,p) level of theory to explore various intermolecular interactions especially hydrogen bonding. Hirshfeld surface analysis indicates that the contacts involving hydrogen such as H center dot center dot center dot H, C center dot center dot center dot H and O center dot center dot center dot H have great influence on the molecular properties of 2-APB. (C) 2018 Elsevier B.V. All rights reserved.