Raman and IR studies and DFT calculations of the vibrational spectra of 2,4-Dithiouracil and its cation and anion

Singh, Ranjan K.; Yadav, R.A.

doi:10.1016/j.saa.2014.02.161

Cited by 7 publications

(3 citation statements)

References 26 publications

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“…Thus, more reliable assignment of IR active modes of vibration can be carried out by comparing experimental FTIR intensities with the computed wavenumbers. The computed (scaled) frequencies as well as the PEDs of selected vibrational modes of DMAB along with the experimentally observed FTIR/FT-Raman frequencies are listed in Table 2 [24,25]. The experimental and calculated scaled vibrational (IR) spectra are shown in Figure 2.…”

Section: Resultsmentioning

confidence: 99%

DFT Study for the Spectroscopic and Structural Analysis of p-Dimethylaminoazobenzene

Ali

Mansha

Asim

et al. 2018

Journal of Spectroscopy

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The study under consideration represents the computational calculations of Azo-based direct dye named p-(dimethylamino)azobenzene (DMAB) under the effect of solvents with different relative permittivities. A density functional theory (DFT) method at the B3LYP level with 6-311G++ was applied for the spectroscopic and structural analysis of the title compound. Calculations of geometric parameters (bond orders, bond lengths, and dihedral angles), electron densities, thermodynamic parameters, and orbital energies were performed for the title compound. Mulliken population analysis (MPA) as well as natural population analysis (NPA) was also performed at the B3LYP level with different solvents for finding solvent effects. In order to predict the reactivity of DMAB, molecular electrostatic potential (MESP) calculations were carried out for it. For vibrational analysis, the infrared (IR) spectra were computed for the title compound at the B3LYP/6-311G++ level in the gas phase and in different solvents with good agreement to the experimental FT-IR spectrum. The different modes of vibrations were assigned using potential energy distribution (PED). The computed Raman spectra also showed appreciable agreement with the experimental recorded Raman spectrum. The electronic absorption spectra of the title compound have been computed employing DFT/B3LYP with the 6-311G++ basis set in the gas phase and in four different solvents, that is, DMSO, ethanol, acetonitrile, and water which were compared with the experimental spectra with appreciable agreement. NBO analysis was carried out for understanding the intramolecular and intermolecular bonding of the compound and the density transfer from completely filled to unfilled orbital was found. The HOMO-LUMO energies were determined for analyzing the mechanism of intramolecular charge transfer.

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Section: Resultsmentioning

confidence: 99%

DFT Study for the Spectroscopic and Structural Analysis of p-Dimethylaminoazobenzene

Ali

Mansha

Asim

et al. 2018

Journal of Spectroscopy

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“…The observed and calculated IR and Raman spectra of cemb are reproduced in Figures 5 and 6. The distribution of the normal modes could be divided under the following sections:-(i) accordance with the assignment reported in literature [52].…”

Section: Vibrational Assignmentsmentioning

confidence: 63%

Synthesis, Characterization, Single Crystal Structural Studies, Antibacterial Activity and DFT Investigations of 2-Chloro-5-Ethoxy-3,6-Bis(Methylamino)-1,4-Benzoquinone

RK¹,

M²,

M³

2015

Pharm Anal Acta

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A new compound 2-chloro-5-ethoxy-3,6-bis(methylamino)-1,4-benzoquinone (cemb) has been synthesized and characterized by various physicochemical techniques. The compound crystallizes in the triclinic system with the space group P-1 and contains extended hydrogen bonding interaction providing supramolecular architecture. The compound contains CH•••π and oxygen•••π interaction which stabilizes the crystal structure and is also responsible for the semiconducting behavior. The DFT calculations in the gaseous phase of cemb with B3LYP hybrid functional show good correlation with experimental results (single crystal XRD data) and are used to predict the molecular properties. Excluding the side ethyl group, the structure possesses C s symmetry. The ring breathing mode of vibration is found to have frequency (551 cm -1 ) which is much lower as compared to the corresponding mode of benzene (991 cm -1 ). The bioefficacy of the compound has been examined against the growth of bacteria in vitro to evaluate antimicrobial potential. The pphotoluminescence properties indicate that the compound has characteristic fluorescence emissions. The HOMO and LUMO energy gap reveals that the energy gap reflects the chemical activity of the molecule.

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“…Secondly the structural and vibrational features for the radicals of these two molecules are compared with those of the neutral molecules. Similar works for the uracil, some organic superconductor and vitamins have also been done by our group recently [23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 61%

Vibrational Studies and DFT Calculations of Cytosine, Thiocytosine and Their Cations and Anions

Ra¹,

Singh²,

Srivastava³

2015

Pharm Anal Acta

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DFT calculations were carried out to compute the optimized molecular geometries, APT charges and fundamental vibrational frequencies along with their corresponding IR intensities, Raman activities and depolarization ratios of the Raman bands for the neutral Cyt and TCyt molecules and their cations and anions using the DFT/B3LYP method with the 6-311++G** basis set using the Gaussian-03 software. TCyt, Cyt + and TCyt + show planar structures and belong to C s point group symmetry while Cyt, Cytand TCytpossess non-planar structures with C 1 point group symmetry. Conformational analysis was carried out to obtain the most stable configurations of these molecules. The normal modes of vibration for all the species have been assigned on the basis of PEDs obtained from normal coordinate analysis using the GAR2PED software. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping the electron density isosurface with molecular electrostatic potential (MEP) surfaces. The energy gap from HOMO to LUMO of the Cyt is 5.2963 eV and that of TCyt is 5.0062 eV.

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Raman and IR studies and DFT calculations of the vibrational spectra of 2,4-Dithiouracil and its cation and anion

Cited by 7 publications

References 26 publications

DFT Study for the Spectroscopic and Structural Analysis of p-Dimethylaminoazobenzene

DFT Study for the Spectroscopic and Structural Analysis of p-Dimethylaminoazobenzene

Synthesis, Characterization, Single Crystal Structural Studies, Antibacterial Activity and DFT Investigations of 2-Chloro-5-Ethoxy-3,6-Bis(Methylamino)-1,4-Benzoquinone

Vibrational Studies and DFT Calculations of Cytosine, Thiocytosine and Their Cations and Anions

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