Spectral analysis, structural elucidation, and evaluation of both nonlinear optical properties and chemical reactivity of a newly synthesized ethyl-3,5-dimethyl-4-[(toluenesulfonyl)-hydrazonomethyl]-1H-pyrrole-2-carboxylate through experimental studies and quantum chemical calculations

Antimycobacterial, antimicrobial activity, experimental (FT-IR, FT-Raman, NMR, UV-Vis, DSC) and DFT (transition state, chemical reactivity, NBO, NLO) studies on pyrrole-isonicotinyl hydrazine

As part of a study of pyrrole hydrazone, we have investigated quantum chemical calculations, molecular geometry, relative energy, vibrational properties and antimycobacterial/antimicrobial activity of pyrrole-2-carboxaldehyde isonicotinyl hydrazone (PCINH), by applying the density functional theory (DFT) and Hartree Fock (HF). Good reproduction of experimental values is obtained and with small percentage error in majority of the cases in comparison to theoretical result (DFT). The experimental FT-IR and Raman wavenumbers were compared with the respective theoretical values obtained from DFT calculations and found to agree well. In crystal structure studies the hydrated PCINH (syn-syn conformer) shows different conformation than from anhydrous form (syn-anti conformer). The rotational barrier between syn-syn and syn-anti conformers of PCINH is 12.7kcal/mol in the gas phase. In this work, use of FT-IR, FT-Raman, ¹H NMR, ¹³C NMR and UV-Vis spectroscopies has been made for full characterization of PCINH. A detailed interpretation of the vibrational spectrum was carried out with the aid of normal coordinate analysis using single scaling factor. Our results support the hydrogen bonding pattern proposed by reported crystalline structure. The calculated nature of electronic transitions within molecule found to be π→π*. The electronic descriptors study indicates that PCINH can be used as robust synthon for synthesis of new heterocyclic compounds. The first static hyperpolarizability (β₀) of PCINH is calculated as 33.89×10^-30esu_, (gas phase); 68.79×10^-30 (CHCl₃), esu; 76.76×10^-30esu (CH₂Cl₂), 85.16×10^-30esu (DMSO). The solvent induced effects on the first static hyperpolarizability were studied and found to increase as dielectric constants of the solvents increases. Investigated molecule shows better NLO value than Para nitroaniline (PNA). The compound PCINH shows good antifungal and antibacterial activity against Aspergillus niger and gram-positive bacteria Bacillus subtilis, respectively. The compound also shows good antituberculosis activity against Mycobacterium tuberculosis H37Rv using the microplate alamar blue assay (MABA).

Antimicrobial activity, structural evaluation and vibrational (FT-IR and FT-Raman) study of pyrrole containing vinyl derivatives

In this paper we present structural and vibrational study of three vinylpyrrole derivatives: 2-Cyano-3-(1H-pyrrol-2-yl)-acrylamide (CPA), 1-(1H-Pyrrol-2-yl)-Pent-1-en-3-one (PP) and 1-(1H-Pyrrol-2-yl)-but-1-en-3-one (PB), using ab initio, DFT and experimental approaches. The quantum chemical calculation have been performed on B3LYP method and 6-311+G(d,p) basis set. The experimental FT-IR and Raman wavenumbers were compared with the respective theoretical values obtained from DFT calculations and found to agree well. The experimental FT-IR and Raman study clearly indicate that the compound exist as dimer in solid state. The binding energies of (CPA), (PP) and (PB) dimers are found to be 20.95, 18.75 and 19.18 kcal/mol, respectively. The vibrational analysis shows red shifts in v(N-H) and v(C=O) stretching as result of dimer formation. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using NBO analysis. Topological and energetic parameters reveal the nature of interactions in dimer. The local electronic descriptors analyses were used to predict the reactive sites in the molecule. Calculated first static hyperpolarizability of CPA, PP and PB is found to be 10.41×10(-30), 18.93×10(-30), 18.29×10(-30) esu, respectively, shows that investigated molecules will have non-linear optical response and might be used as non-linear optical (NLO) material. These vinylpyrrole compounds (CPA), (PP) and (PB) showed antifungal and antibacterial activity against Aspergillus niger and gram-positive bacteria Bacillus subtili.

Assessment of conformational, spectral, antimicrobial activity, chemical reactivity and NLO application of Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone)

An orange colored pyrrole dihydrazone: Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone) (PDBO) has been synthesized by reaction of oxalic acid dihydrazide with 2,5 diformyl-1H-pyrrole and has been characterized by spectroscopic analysis (1H, 13C NMR, UV-visible, FT-IR and DART Mass). The properties of the compound has been evaluated using B3LYP functional and 6-31G(d,p)/6-311+G(d,p) basis set. The symmetric (3319, 3320 cm(-1)) and asymmetric (3389, 3382 cm(-1)) stretching wave number confirm free NH2 groups in PDBO. NBO analysis shows, inter/intra molecular interactions within the molecule. Topological parameters have been analyzed by QTAIM theory and provide the existence of intramolecular hydrogen bonding (N-H⋯O). The local reactivity descriptors analyses determine the reactive sites within molecule. The calculated first hyperpolarizability value (β0=23.83×10(-30) esu) of pyrrole dihydrazone shows its suitability for non-linear optical (NLO) response. The preliminary bioassay suggested that the PDBO exhibits relatively good antibacterial and fungicidal activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Candida albicans, Aspergillus niger. The local reactivity descriptors--Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (ωk+, ωk-) analyses have been used to determine the reactive sites within molecule.

Vibrational spectra, electronic absorption, nonlinear optical properties, evaluation of bonding, chemical reactivity and thermodynamic properties of ethyl 4-(1-(2-(hydrazinecarbonothioyl)hydrazono)ethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate molecule by ab initio HF and density functional methods

In this work, detailed vibrational spectral analysis of ethyl 4-(1-(2-(hydrazinecarbonothioyl)hydrazono)ethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate (EHCHEDPC) molecule has been carried out using FT-IR spectroscopy and potential energy distribution (PED). Theoretical calculations were performed by ab initio RHF and density functional theory (DFT) method, using 6-31G(d,p) and 6-311+G(d,p) basis sets. The other carried outwork cover: structural, thermodynamic properties, electronic transitions, bonding, multiple interaction, chemical reactivity and hyperpolarizability analysis. The results of the calculation were applied to the simulated spectra of (EHCHEDPC), which show excellent agreement with observed spectra. The vibrational analysis shows red shift in both group, the proton donor (pyrrole N-H) and proton acceptor (C=O of ester) indicating the presence of intermolecular hydrogen bonding. Time dependent density functional theory (TD-DFT) has been used to find electronic excitations and their nature. The results of natural bond orbital (NBOs) analysis show the charges transfer and delocalization in various intra- and intermolecular interactions. The binding energy of intermolecular multiple interactions is calculated to be 12.54 kcal mol(-1) using QTAIM calculation. The electronic descriptors analyses reveal the investigated molecule used as precursor for heterocyclic derivatives synthesis. First hyperpolarizability (β0) has been computed to evaluate non-linear optical (NLO) response.