Vibrational spectroscopy of Methyl benzoate (original) (raw)
Related papers
Structural sensitivity of CH vibrational band in methyl benzoate
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2018
The CH vibrational bands of methyl benzoate are studied to understand its coupling pattern with other vibrational bands of the biological molecule. This will facilitate to understand the biological structure and dynamics in spectroscopic as well as in microscopic study. Due to the congested spectroscopic pattern, near degeneracy, and strong anharmonicity of the CH stretch vibrations, assignment of the CH vibrational frequencies are often misleading. Anharmonic vibrational frequency calculation with multidimensional potential energy surface interprets the CH vibrational spectra more accurately. In this article we have presented the importance of multidimensional potential energy surface in anharmonic vibrational frequency calculation and discuss the unexpected red shift of asymmetric CH stretch vibration of methyl group. The CD stretch vibrational band which is splitted to double peaks due to the Fermi resonance is also discussed here.
Unexpected red shift of C-H vibrational band of Methyl benzoate
arXiv: Chemical Physics, 2016
The C-H vibrational bands become more and more important in the structural determination of biological molecules with the development of CARS microscopy and 2DIR spectroscopy. Due to the congested pattern, near degeneracy, and strong anharmonicity of the C-H stretch vibrations, assignment of the C-H vibrational bands are often misleading. Anharmonic vibrational spectra calculation with multidimensional potential energy surface interprets the C-H vibrational spectra more accurately. In this article we have presented the importance of multidimensional potential energy surface in anharmonic vibrational spectra calculation and discuss the unexpected red shift of C-H vibrational band of Methyl benzoate.
2016
Extensive quantum chemical calculations of energy, geometrical structure, harmonic vibrational frequencies and the construction of theoretical spectrograms of IR and Raman spectra of the molecule, methyl 2,4-dihydroxy-6-methyl benzoate(methyl orsellinate) have been carried out by Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) method with 6311++G(d, p) basis set. The assignments of normal modes of the vibration of the title molecule along with the observed frequencies (FT-IR and FTR) and scaled frequencies have been obtained by HF/DFT computation. The simulated NMR spectra are obtained by (GIAO) gauge independent atomic orbital method and their chemical shifts are compared with the experimental 13 C NMR and 1 H NMR spectra. Molecular geometric parameters, dipole moment, mullikan charge, thermodynamic properties, FMO analysis and NLO properties have also been computed and discussed in a detailed manner.The electrostatic potential surface and the mullikan charge analysis i...
International Journal of Research and Analytical Reviews (IJRAR), 2018
The FT-IR and FT-Raman spectra of 4-Carboxylphenylboronic acid (4CPBA) have been recorded in the range 4000-400 cm-1 and 4000-100 cm-1 respectively. Also the UV spectra of 4CPBA have been recorded and analyzed. The molecular structures, fundamental vibrational frequencies and intensity of the vibrational bands are investigated and interpreted theoretically with the use of structure optimization and normal coordinate factor filed calculations based on density functional theory (DFT) with basis set 6-311++G(d,p). The hyper conjugative interaction energy E (2) and electron densities of donor (i) and acceptor (j) bonds were calculated using NBO analysis. The energy gap of the molecule was found using HOMO-LUMO calculations. In addition studies of 1 H & 13 C NMR chemical shift values of 4CPBA in the ground state for LANL2DZ/6-311++G(d,p) basis set were also calculated using Gauge independent atomic orbital (GIAO) method. The UV-Visible analysis of the 4CPBA with LANL2DZ/6-311++G(d,p) level of basis set. From the title molecule various ligand are using in the cervical cancer protein by docking. The 4CPBA has been screened to antimicrobial activity and found to exhibit antibacterial effects. From, these the geometric parameters, harmonic vibrational frequencies, IR intensities, Raman intensities and absorption wavelength was compared with the available experimental data of the molecule.
Materials
The dynamics of 2-methoxybenzaldehyde, 4-methoxybenzaldehyde, and 4-ethoxybenzaldehyde in the solid state are assessed through INS spectroscopy combined with periodic DFT calculations. In the absence of experimental data for 4-ethoxybenzaldehyde, a tentative crystal structure, based on its similarity with 4-methoxybenzaldehyde, is considered and evaluated. The excellent agreement between calculated and experimental spectra allows a confident assignment of the vibrational modes. Several spectral features in the INS spectra are unambiguously assigned and torsional potential barriers for the methyl groups are derived from experimental frequencies. The intramolecular nature of the potential energy barrier for methyl rotation about O–CH3 bonds compares with the one reported for torsion about saturated C–CH3 bonds. On the other hand, the intermolecular contribution to the potential energy barrier may represent 1/3 of the barrier height in these systems.
Theoretical modeling of infrared spectra of benzoic acid and its deuterated derivative
Journal of Molecular Structure, 2004
Theoretical simulation of the n s stretching band is presented for benzoic acid and its OD derivative at 300 K. The simulation takes into account an adiabatic coupling between the high-frequency O-H(D) stretching and the low-frequency intermolecular O• • •O stretching modes, linear and quadratic distortions of the potential energy for the low-frequency vibrations in the excited state of the O-H(D) stretching vibration, resonance interaction between the two hydrogen bonds in the dimer, and Fermi resonance between the fundamental n OH(D) stretching and the overtone of the d O-H(D) bending vibrations. Infrared, far-infarared, Raman and low-frequency Raman spectra of the polycrystalline benzoic acid and its deuterated form have been measured. The geometry and experimental frequencies are compared with the results of our B3LYP/6-311þþG** and B3LYP/cc-pVTZ calculations.