Synthesis, crystal structure, photoluminescence, thermal, laser damage threshold and DFT calculations of 1,10-phenanthrolinium-2-carboxy-6-nitrobenzoate

Abstract Single crystals of 1, 10-Phenanthrolinium-2-carboxy-6-nitrobenzoate (PCNB) were grown by slow solvent evaporation solution growth method from methanol at room temperature. The various functional groups present in the molecule are identified by FT-IR analysis. UV–Vis–NIR spectral studies reveal that the title crystal is transparent in the wavelength region of 300–1200 nm. The presence of different protons and carbon atoms of the grown salt was ascertained by 1H and 13C NMR analyses. Single crystal X-ray diffraction data indicate that the title crystallizes in the monoclinic crystal system with space group P21/c. Thermogravimetric (TG) and Differential Thermal Analysis (DTA) were carried out to characterise the thermal behavior and stability of PCNB crystal. Mechanical behavior of PCNB was studied by Vickers's microhardness test. Dielectric studies reveal that dielectric constant and dielectric loss decrease with increasing frequency and become almost a constant at higher frequencies for all temperatures. Quantum chemical calculations have been performed through DFT method at 6–311++G (d,p) level of theory. Natural bond orbital (NBO) calculations were employed to study the stabilities arising from charge delocalization and intermolecular interactions of PCNB crystal. The atomic charge distributions of the various atoms present in PCNB are obtained by Mulliken charge population analysis.