Vibrational spectroscopy investigation using ab initio and density functional theory on 3'-chloropropiophenone and 3'-nitropropiophenone

Experimental, quantum chemical and molecular dynamic simulations studies on the corrosion inhibition of mild steel by some carbazole derivatives

Five selected carbazole derivatives, namely carbazole, 3,6-dibromocarbazole, 2-hydroxycarbazole, 1,2,3,4-tetrahydrocarbazole and 9-(2-ethylhexyl)carbazole-3,6-dicarboxaldehyde were investigated for their inhibitive effects on Desulfovibrio vulgaris (D. vulgaris) induced corrosion of mild steel and in 1 M HCl medium using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The carbazole derivatives were found to be mixed type inhibitors with predominantly cathodic inhibitive effects for mild steel in 1 M HCl. Surface morphology results showed the compounds formed adsorbed film on mild steel surface in both aqueous acid and sulphate reducing bacteria (SRB) media. Quantum chemical calculations were used to provide molecular based explanations for the inhibitive effects of the compounds. The interactions of the molecules with mild steel surface was simulated based on molecular dynamic simulations approach using Fe(110) crystal surface as representative metallic surface.

Molecular geometry, conformational, vibrational spectroscopic, molecular orbital and Mulliken charge analysis of 2-acetoxybenzoic acid

The Fourier transform infrared (FT-IR) and FT-Raman spectra of 2-acetoxybenzoic acid (2ABA), a painkiller agent were recorded in the region 4000-450 cm(-1) and 5000-50 cm(-1) respectively. Hartree Fock (HF) and Density functional theory (DFT) methods have been used to determine its optimized geometrical parameter, atomic charges, and vibrational wavenumbers and intensity of the vibrational bands of the title molecule. The computed vibrational wave numbers were compared with the FT-IR and FT-Raman experimental data. The computational calculations were done at HF and DFT/B3LYP level with 6-311++G(d,p) basis set. The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) analysis. The Mulliken charges, UV-Visible spectral analysis and HOMO-LUMO energy gap have been calculated and reported. The B3LYP method of calculated parameters is a good complement with the experimental findings. The thermodynamic properties like entropy, heat capacity and zero vibrational energy have been calculated and discussed. The electrostatic potential (ESP) contour surface and molecular electrostatic potential (MESP) of the molecule were constructed.

Natural bond orbital analysis, electronic structure and vibrational spectral analysis of N-(4-hydroxyl phenyl) acetamide: a density functional theory

The Fourier transform infrared (FT-IR) and FT-Raman spectra of N-(4-hydroxy phenyl) acetamide (N4HPA) of painkiller agent were recorded in the region 4000-450 cm(-1) and 4000-50 cm(-1) respectively. Density functional theory (DFT) has been used to calculate the optimized geometrical parameter, atomic charges, and vibrational wavenumbers and intensity of the vibrational bands. The computed vibrational wave numbers were compared with the FT-IR and FT-Raman experimental data. The computational calculations at DFT/B3LYP level with 6-31G(d,p), 6-31++G(d,p), 6-311G(d,p) and 6-311++G(d,p) basis sets. The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes calculated using Vibrational energy distribution analysis (VEDA 4) program. The oscillator's strength calculated by TD-DFT and N4HPA is approach complement with the experimental findings. The NMR chemical shifts 13C and 1H were recorded and calculated using the gauge independent atomic orbital (GIAO) method. The molecular electrostatic potential (MESP) and electron density surfaces of the molecule were constructed. The Natural charges and intermolecular contacts have been interpreted using Natural Bond orbital (NBO) analysis the HOMO-LUMO energy gap has been calculated. The thermodynamic properties like entropy, heat capacity and zero vibrational energy have been calculated.