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-car boxylate and its dimer

作者：Singh R N^*; Kumar Amit; Tiwari R K; Rawat Poonam

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2013, 112: 182-190.

DOI：10.1016/j.saa.2013.04.002

• TD-DFT
• NBO analysis
• Multiple interactions
• Hydrogen bonded dimer
• AIM calculation
• Global electronic descriptor

In the present work, ethyl-4-2-(thiocarbamoyl)hydrazinylidene]-3,5-dimethyl-1H-pyrrole-2-carboxylate (3) has been synthesized and characterized by H-1 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. H-1 NMR chemical shifts are calculated using gauge including atomic orbitals (MO) approach in DMSO-d(6) as solvent. Time dependent density functional theory (TD-DFT) is used to calculate the energy (E), oscillator strength (f) and wavelength absorption maxima (lambda(max)) 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 (N-H center dot center dot center dot 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(f(k)(+),f(k)(-)), local softnesses (s(k)(+),s(k)(-)) and electrophilicity indices (omega(+)(k), omega(-)(k)) analyses are performed to determine the reactive sites within molecule.

• 出版日期2013-8