Y-shaped potential third-order nonlinear optical material – 3-(2-amino-2-oxoethyl)-5-methyl hexanoic acid: an analysis of structural, spectroscopic and docking studies

Abstract

The present work reports an analysis of the structure, spectroscopic signatures, nonlinear optical properties and docking studies of synthesized 3-(2-amino-2-oxoethyl)-5-methylhexanoic acid (abbreviated as AOEMHA) with the empirical formula C₁₉H₁₇NO₃. The structure in the solid state determined by the single crystal X-ray diffraction technique revealed that AOEMHA is Y-shaped with the methine carbon atom acting as a junction point. The dihedral angles between the three segments forming the Y-shaped structure are 77.7(3)°, 86.2(9)° and 19.9(2)°. In the crystal structure, the O–H⋯O and N–H⋯O hydrogen bonded chains result in an infinite two-dimensional architecture parallel to the ac-plane. Intermolecular interactions were further visualized and topologically analyzed (using the quantum theory of atoms in molecules) with the support of the Crystal Explorer and Multiwfn program. The reactivity parameters (the frontier molecular orbital, molecular electrostatic surface potential, atomic charges and Fukui function) and topological studies (localized orbital locator and electron localization function) were also estimated for the investigated compound. For hydrogen and all the other single acyclic bonds, bond dissociation energy calculations have been performed to assess the possible degradation properties by the autoxidation mechanism. The linear refractive index and the third-order nonlinear susceptibility (χ⁽³⁾) are calculated as a function of the electric field frequency by using the supermolecule approach (SM) at the DFT/CAM-B3LYP/aug-cc-pVTZ level for analyzing the nonlinear optical properties in a simulated crystalline environment. The χ⁽³⁾ value for the AOEMHA crystal at ω = 0.086 a.u. is significant when compared to experimental results from other organic crystals which demonstrate the opportunities for the AOEMHA crystal as a nonlinear optical (NLO) material. Molecular docking studies were performed with AKR1C3 inhibitors for the AOEMHA compound.