Crystal Structure, Hirshfeld Analyses, Spectral, Thermal, Two-Photon Absorption Properties and Optical Limiting Applications of Novel 4-Fluoro-N-[4-(diethylamino)benzylidene]aniline (FDEABA)

Abstract

The novel third-order nonlinear optical organic material 4-fluoro-N-[4-(diethylamino)benzylidene]aniline (FDEABA) is synthesized and single crystals of FDEABA are grown using the slow evaporation method. The placement of the protons is confirmed by nuclear magnetic resonance spectral analysis. Employing Fourier transform infrared spectral analysis, vibrational frequencies of various functional groups of the FDEABA compound are identified. The three-dimensional crystal structure of the grown crystal is elucidated using single crystal X-ray diffraction studies, which reveal that the compound FDEABA crystallized in the monoclinic non-centrosymmetric space group P2₁. Intermolecular interactions are studied using Hirshfeld surface analysis and compared with similar structures of halogen-substituted benzylideneaniline derivatives. Thermal stability of FDEABA is measured using thermogravimetric and differential thermal analyses and the melting point of the synthesized FDEABA compound is 51 °C. Open aperture Z-scan measurements carried out at 532 nm using 5 ns laser pulses reveal nonlinear optical absorption leading to strong optical limiting behaviour, which can be useful in the protection of eyes and sensitive optical detectors from harmful laser radiation.

Graphical Abstract