Synthesis, Crystal Growth, Structure, Crystalline Perfection, Thermal, Linear and Nonlinear Optical Investigations on 2-Amino-5-Nitropyridine 4-Chlorobenzoic Acid (1:1): A Novel Organic Single Crystal for NLO and Optical Limiting Optical Applications

2-amino-5-nitropyridine 4-chlorobenzoic acid (1:1) (2A5NP4CBA), a potentially useful organic adduct compound, has been synthesized and grown as optically transparent single crystals by conventional slow evaporation solution technique (SEST) for the first time in the literature. The formation of new crystalline material was confirmed by the single-crystal X-ray diffraction (SXRD) analysis and it belongs to the monoclinic crystal system. Fourier transform infrared (FTIR) spectrum has been recorded by the KBr pellet technique to determine the various vibrational functional groups in the title material. The powder X-ray diffraction (PXRD) and high-resolution X-ray diffraction (HRXRD) analyses have been carried out to reveal the phase purity and crystalline perfection of the grown crystals. The obtained full width at half maximum (FWHM) for (001) plane in the HRXRD spectrum indicates the excellent crystalline quality of the title 2A5NP4CBA single crystal. The recorded UV–Vis–NIR absorption and transmittance spectra reveal that the grown crystal possesses more than 70% of optical transmittance with the cut-off edge at 419 nm. The thermal analysis discloses that the grown crystal possesses good thermal stability of about 187 °C. To determine the appropriateness of the grown crystal for the high-power laser application, laser damage threshold (LDT) analysis has been carried out by Nd: YAG laser of wavelength of 1064 nm. The third-order nonlinear optical (NLO) coefficients, such as nonlinear absorption (β), nonlinear refraction (n2), and nonlinear susceptibility (χ(3)), have been evaluated by utilizing a solid-state laser of wavelength 532 nm. The calculated value of χ(3) is found to be excellent compared to other organic single crystals. The optical limiting threshold of the grown crystal is found to be 7.8 mW/cm2 when using the solid-state laser of wavelength 532 nm.