A combined experimental and theoretical (DFT and AIM) studies on synthesis, molecular structure, spectroscopic properties and multiple interactions analysis in a novel Ethyl-4-[2-(thiocarbamoyl)hydrazinylidene]-3,5-dimethyl-1H-pyrrole-2-carboxylate and it

•FT-IR spectrum of the title compound was recorded and compared with the theoretical results.•The theoretical calculations were made using DFT/B3LYP/6-31G(d,p) method.•By using TD-DFT/6-31G method, electronic spectra for title compound have been predicted.•Chemical reactivity has been explained with the aid of global and local electronic descriptors.•The computed value of first hyperpolarizability have been also predicted.

In the present work, ethyl-4-[2-(thiocarbamoyl)hydrazinylidene]-3,5-dimethyl-1H-pyrrole-2-carboxylate (3) has been synthesized and characterized by 1H NMR, UV–Vis, FT-IR and Mass spectroscopy. The formation of the compound and its properties have also been evaluated by quantum chemical calculations using DFT, B3LYP functional and 6-31G(d,p) as basis set. The calculated thermodynamic parameters show that the formation of 3 is an exothermic and spontaneous reaction at room temperature. 1H NMR chemical shifts are calculated using gauge including atomic orbitals (GIAO) approach in DMSO-d6 as solvent. Time dependent density functional theory (TD-DFT) is used to calculate the energy (E), oscillator strength (f) and wavelength absorption maxima (λmax) of various electronic transitions and their nature within the molecule. NBO analysis is carried out to investigate the charge transfer or charge delocalization in various intra- and intermolecular interactions of molecular system. The vibrational analysis indicates the formation of dimer in the solid state by intermolecular heteronuclear hydrogen bonding (NH⋯O). Topological parameters at bond critical points (BCP) are calculated to analyze the strength and nature of various types of intra and intermolecular interactions in dimer by Bader’s ‘Atoms in molecules’ AIM theory in detail. The binding energy of intermolecular multiple interactions is calculated to be 15.54 kcal/mol, using AIM calculation. The local reactivity descriptors such as Fukui functions (fk+,fk-), local softnesses (sk+,sk-) and electrophilicity indices (ωk+,ωk-) analyses are performed to determine the reactive sites within molecule.

Graphical abstractEthyl-4-[2-(thiocarbamoyl)hydrazinylidene]-3,5-dimethyl-1H-pyrrole-2-carboxylate has been synthesized and characterized by 1H NMR, 13C NMR, UV–Vis, FT-IR and Mass spectroscopy. All the quantum chemical calculations have been performed using density functional theory (DFT), B3LYP functional and 6-31G (d,p) as basis set. The 1H and 13C NMR chemical shifts are calculated using gauge including atomic orbitals (GIAO) approach in DMSO-d6 as solvent at 25 °C. Time dependent density functional theory (TD-DFT) is used to calculate the energy, oscillatory strength and wavelength absorption maxima (λmax) of various electronic transitions and their nature within molecule. Potential energy distribution (PED) analyses of calculated wavenumbers are used to assign the wavenumbers observed in FT-IR spectrum experimentally. Thermodynamic parameters show that the chemical reaction involved in the formation of product is an exothermic and non-spontaneous at room temperature. The global elecrophilicity index (ω = 2.672 eV) shows that title molecule behaves as a moderate electrophile. The local reactivity descriptors, Fukui functions (fk+,fk-), local softnesses (sk-,sk+) and electrophilicity indices (ωk+,ωk-) analyses are performed to determine the reactive sites within molecule. Non linear optical (NLO) behavior of title compound is investigated by the computed value of first hyperpolarizability (β0).Figure optionsDownload full-size imageDownload as PowerPoint slide