Theoretical, photophysical and biological investigations of an organic charge transfer compound 2-aminobenzimidazolium-2-oxyisoindolate-1,3-dione-2-hydroxyisoindoline-1,3-dione

Abstract

An organic charge transfer compound, 2-aminobenzimidazolium-2-oxyisoindolate-1,3-dione-2-hydroxyisoindoline-1,3-dione (ABOH), was synthesized and fully characterized using elemental analysis, FT IR and UV-Vis spectroscopic techniques. The structure of the grown crystal was determined by single crystal X-ray diffraction analysis. Structural parameters from the crystallographic and DFT studies are in good agreement with each other. HOMO–LUMO energy levels were constructed and the corresponding theoretical frontier energy gaps are calculated to realise the charge transfer occurring in the molecule. The optical transmittance data was taken from the polished crystal of ABOH and cut-off wavelength was identified by UV-Vis spectral studies. The ABOH crystal exhibits negative optical non-linearity. The sample at 62% transmittance exhibited a non-linear refractive coefficient in the order of 10⁻⁸ cm² W⁻¹, a non-linear absorption coefficient in the order of 10⁻⁴ cm W⁻¹ and non-linear susceptibility in the order of 10⁻⁶ esu. These results show that the ABOH crystal has potential applications in non-linear optics. A pharmacological study of ABOH shows excellent antibacterial activity, when compared with standard drugs. Molecular docking studies were carried out in order to find the binding affinity of ABOH with cyclin-dependent kinase 2 (CDK2).