Synthesis, crystal growth and characterization on a novel third-order nonlinear optical single crystal: 2-amino-3,5-dibromopyridinium-2-chloro-4-nitrobenzoate

Novel organic compound with significant third-order nonlinear optical properties, namely, 2-amino-3,5-dibromopyridinium-2-chloro-4-nitrobenzoate (ADBPCN), was successfully synthesized, and optical-quality single crystals are grown at room temperature through the slow evaporation method, employing methanol as a solvent. Single-crystal X-ray diffraction (SCXRD) investigation showed that ADBPCN was crystallized in centrosymmetric space group \(P\overline{1}\). Phase purity and crystallinity of the grown sample were evaluated by powder X-ray diffraction (PXRD) analysis. The transmittance range, cut-off wavelength and optical band gap of the grown crystal were determined through ultraviolet-visible (UV-Vis) spectral analysis. The optical parameters of the ADBPCN crystal, including refractive index (n_o) and reflectance (R), were also measured. Fourier transform infrared (FTIR) analysis was used to determine vibrational properties and main functional groups. The photoluminescence spectrum showed sharp emission peaks, indicating the violet and blue light emission. Thermogravimetric (TG) and differential thermal analysis (DTA) techniques are used to analyze the thermal characteristics of the ADBPCN crystals. The percentage of hydrogen bonding interactions was evaluated through the Hirshfeld surface fingerprint plot. The third-order nonlinear optical parameters of the ADBPCN compound were analyzed by the Z-scan method using a nanosecond Nd:YAG laser.