Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO, NBO, MEP analysis and molecular docking study of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide

Density functional theory calculations, vibration spectral analysis and molecular docking of the antimicrobial agent 6-(1,3-benzodioxol-5-ylmethyl)-5-ethyl-2-{[2-(morpholin-4-yl)ethyl] sulfanyl}pyrimidin-4(3H)-one

Vibrational spectral analysis and quantum chemical computations based on density functional theory have been performed on the antimicrobial agent 6-(1,3-benzodioxol-5-ylmethyl)-5-ethyl-2-{[2-(morpholin- 4-yl)ethyl]sulfanyl}pyrimidin-4-(3H)-one.The equilibrium structural geometry, various bonding features and harmonic vibrational wavenumbers of the title compound have been investigated using DFT-B3LYP function at 6-311++G(d, p) basis set. The detailed interpretations of the vibrational spectra have been carried out with the aid of VEDA 4 program. The various intramolecular interactions of the title compound have been exposed by natural bond orbital analysis. The FT-IR and FT-Raman spectra of the title molecule have been recorded and analyzed. Blue-shifting of the C-H wavenumber along with a decrease in the C-H bond length attribute for the formation of the C-H...O hydrogrn bonding provide an evidence for a charge transfer interaction. Also, the distribution of natural atomic charges reflects the presence of intramolecular hydrogen bonding. The analysis of the electron density of HOMO and LUMO gives an idea of the delocalization and the low value of energy gap indicates electron transfer within the molecule. Moreover, molecular docking studies revealed the possible binding of the title molecule to different antimicrobial target proteins.

Conformational study of neutral histamine monomer and their vibrational spectra

Molecular modeling and potential energy scanning of histamine molecule, which is an important neurotransmitter, with respect to the dihedral angle of methylamine side chain have done which prefer three different conformers of histamine monomer. We have calculated molecular structures and vibrational spectra with IR and Raman intensities of these conformers using Density Functional Theory (DFT) with the exchange functional B3LYP incorporated with the basis set 6-31++G(d,p) and Hartree-Fock (HF) with the same basis set. We have also employed normal coordinate analysis (NCA) to scale the theoretical frequencies and to calculate potential energy distributions (PEDs) for the conspicuous assignments. Normal modes assignments of some of the vibrational frequencies of all the three conformers are in good agreement with the earlier reported experimental frequencies of histamine whereas others have modified. The standard deviations between the theoretical and experimental frequencies fall in the region 13-20cm(-1) for the three conformers. NBO analyses of histamine conformers were also performed. The net charge transfers from ethylamine side chain to the imidazole ring. The intensive interactions between bonding and anti-bonding orbitals are found in imidazole ring. The HOMO-LUMO energy gap is nearly 5.50eV.

A mechanistic study of carbonyl activation under solvent-free conditions: evidence drawn from the synthesis of imidazoles

An assembly of carbonyls held together by weak-bond interactions (Constitutional Dynamic Chemistry) results in bulk polarisation. Molecules participate in reactions in a cycle rather than as individual moieties leading to higher reaction rates.

Corrosion inhibition of X70 sheets by a film-forming imidazole derivative at acidic pH

Chemisorbed IMPA film on X70 steel sheet has significantly reduced the corrosion rate of the metal substrate (up to 90%) in a chloride-enriched medium at pH 0.

Spectroscopic and theoretical characterization of 2-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 2-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide have been investigated experimentally and theoretically. Gauge-including atomic orbital (1)H NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters are in agreement with that of similar derivatives. Molecular electrostatic potential was performed by the DFT method. Mulliken's net charges have been calculated and compared with the atomic natural charges. First and second hyperpolarizability are calculated in order to find its role in non-linear optics. Molecular docking is also reported.