Synthesis, structural-spectral characterization and theoretical studies of Pyridinium-4-carbohydrazide 2,4,6-trinitrophenolate

Abstract

The synthesis and crystal growth of the new cocrystal, Pyridinium-4-carbohydrazide 2,4,6- trinitrophenolate (PCTNP), has been carried out by solution growth technique. Single crystal X-ray diffraction method has been employed to determine the structure of this new cocrystal and it has been found to crystallize in the monoclinic space group P21/c with a = 7.0451(6) Å, b = 27.506(2) Å, c = 7.7059(6) Å and α = γ = 90°, β = 95.921(3)°. PCTNP has been characterized further by powder X-ray diffraction, FTIR, UV-Vis, dielectric and thermal analysis. The optical band gap has been estimated to be 3.35 eV. Thermal analysis showed that the cocrystal is stable up to a temperature of 181.8 °C. PCTNP exhibits 70% transparency in almost the entire visible region with a lower cut-off wavelength of 467 nm. DFT analysis carried out on the optimized crystal structure of PCTNP has established the presence of multiple intermolecular hydrogen bonding interactions that stabilize the crystal lattice. The electronic transitions, charge distribution and the stability of the cocrystal have been further evaluated by Natural bond orbital analysis and Mulliken atomic charges studies. Also, the non-linear refractive index (n2), absorption coefficient (β) and third order susceptibility χ(3) have been estimated to be 1.09 × 10−9 cm2/W, 2.24 × 10−5 cm/W and 4.49 × 10−6 esu respectively.