Experimental and theoretical studies on new 2-amino-6-methylpyridinium 2,4-dihydroxybenzoate monohydrate organic single crystal for second order nonlinear optical applications

Abstract

In this new work, 2-amino-6-methylpyridinium 2,4-dihydroxybenzoate monohydrate (2A6MDH) organic single crystal was grown by slow evaporation method. The grown 2A6MDH single crystal structural parameters were examined by using a single crystal X-ray diffraction technique. It revealed that the grown 2A6MDH crystal belongs to a monoclinic crystal system with a P1n1 non-centrosymmetric space group. The functional groups of the entire vibrational bands of grown 2A6MDH complex were identified using FT-IR and 1H NMR spectral analysis. The optical parameters such as cut-off wavelength, transmittance percentage, band gap energy, and excitation, emission value of the 2A6MDH crystal were studied by UV-Visible and photoluminescence analyses. TG-DSC analysis was carried out on the grown 2A6MDH crystal to understand its thermal properties. Micro hardness analysis ensures the mechanical strength of the as-grown crystal. The nonlinear optical property of 2A6MDH crystal was evidenced from the second harmonic generation (SHG) analysis. Density functional theory (DFT) was computed by the Gaussian 09 program using the basis set of B3LYP/6-311++G (d,P) to find out the molecular geometry, frontier molecular orbital energies, molecular electrostatic potential (MEP), Mulliken charge analysis, natural bond orbital (NBO) analysis and first-order hyperpolarizability of the grown 2A6MDH crystal.