Synthesis, spectral characterization and X-ray crystal structure studies of 3-(benzo[d][1,3]dioxol-5-yl)-5-(3-methylthiophen-2-yl)-4,5-dihydro-1H-pyrazole-l-carboxamide: Hirshfeld surface, DFT and thermal analysis

A novel pyrazole derivative, 3-(benzo[d][1,3]dioxol-5-yl)-5-(3-methylthiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-carboxamide was synthesized and characterized by elemental analysis, FT-IR, NMR (H-1 and C-13), MS, UV-visible spectra and finally the structure was confirmed by the single crystal X-ray diffraction studies. The title compound (C16H15N3O3S) crystallized in the triclinic crystal system, with the space group In A dihedral angle of 65.84(1)degrees between the pyrazole and the thiophene rings confirms the twisted conformation between them. The X-ray structure revealed that the pyrazole ring adopts an E-form and an envelope conformation on C7 atom. The crystal and molecular structure of the title compound is stabilized by inter molecular hydrogen bonds. The compound possesses three dimensional supramolecular self-assembly, in which C-H center dot center dot center dot O and N-H center dot center dot center dot O chains build up two dimensional arrays, which are extended to 3D network through C-H center dot center dot center dot Cg and C-O center dot center dot center dot Cg interactions. The structure also exhibits intramolecular hydrogen bonds of the type N-H center dot center dot center dot N and pi-pi stacking interactions, which contributes to the crystal packing. Further, Hirshfeld surface analysis was carried out for the graphical visualization of several short intermolecular interactions on the molecular surface while the 2D fingerprint plot provides percentage contribution of each individual atom-to-atom interactions. The thermal decomposition of the compound has been studied by thermogravimetric analysis. The molecular geometries and electronic structures of the compounds were fully optimized, calculated with ab-initio methods by HF, DFT/B3LYP functional in combination of different basis set with different solvent environment and the structural parameters were compared with the experimental data. The Mulliken atomic charges and molecular electrostatic potential on molecular van der Waals (vdW) surface were calculated to know the electrophilic and nucleophilic regions of the molecular surface. Nonlinear optical properties of the title compound were also discussed based on the polarizability and hyperpolarizability values. (C) 2018 Elsevier B.V. All rights reserved.