Physico-chemical characterization and computational studies of a new organic adduct 3-amino-2-chloropyridine: Benzilic acid, crystal for third order harmonic generation

Abstract

Single crystals of 3-amino-2-chloropyridine:benzilic acid, an organic adduct have been grown by slow evaporation technique successfully. The structure of the adduct was confirmed by single crystal X-ray diffraction studies. The presence of functional groups was identified by Fourier transform infrared (FT-IR) spectroscopy. UV–vis analysis was performed to study the optical properties of the organic crystal. The thermal property of the crystal was studied by thermogravimetry (TG) and differential thermal analysis (DTA). Hirshfeld surface analysis was carried out to explore various interatomic interactions. Density functional theory (DFT) with appropriate basis set was used to optimize the molecular geometry of the adduct in the ground state and to compute the first-order hyperpolarizability. Based on optimized ground state geometry, natural bond orbital (NBO) analysis was performed to study the donor-acceptor interactions and stability of the molecule arising from hyperconjugative interactions leading to charge delocalization. The HOMO-LUMO energy gap value also supports the optical activity in the adduct crystal. Non-linear refractive index (n2), absorption coefficient (β) and third order non-linear susceptibility (χ3) of the adduct were determined by Z-scan technique.