Conformational analysis, structure, and normal coordinate analysis of vibrational spectra of hexafluoroacetone. A density functional theory study

Tayyari, Sayyed Faramarz; Gholamhoseinpour, Mahboobeh; Emamian, Saeedreza; Sammelson, Robert Erik

doi:10.1016/j.jfluchem.2016.02.013

Cited by 12 publications

(4 citation statements)

References 37 publications

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“…A normal coordinate analysis is carried out to provide a complete description of the fundamental vibrational wavenumbers for the Ket1 and Ket2 species and its deuterated analogous. The normal coordinates and potential energy distributions (PED) are calculated from appropriate combinations of internal coordinates obtained from the Gaussian outputs, as explained elsewhere [53][54][55][56][57]. The full sets of 50 standard internal coordinates containing 11 redundancies are defined as given in Table S1 (Supplementary material).…”

Section: Methods Of Calculationsmentioning

confidence: 99%

Vibrational spectra, normal coordinate analysis, and structure of keto form of acetylacetone. A DFT approach

et al. 2019

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I N this paper, we discuss the stability, structure, and vibrational assignment of possible keto forms (Ket1 and Ket2) of acetylacetone, AA, in the gas phase and solutions. The geometry optimization and harmonic and anharmonic vibrational frequencies are calculated at the B3LYP/6-311++G** level. In addition, we also optimize the molecular structure at the MP2/6-311++G(p,d) level. The investigation in solutions is carried out by means of the PCM-SCRF method. We study the relative stability of Ket1 and Ket2 in different media using B2PLYP/6-31+G(d,p) and CBS-QB3 levels. By comparing the IR spectra of AA in a polar solvent, CH 3 CN, and a nonpolar solvent, CCl 4 , and considering the theoretical results, the vibrational band frequencies of both keto and enol tautomers are distinguished. Our calculations and vibrational spectra confirm the coexisting of two keto forms in the solutions, designated as Ket1 and Ket2.According to both theoretical and experimental results, Ket1 and Ket2 are predominant in the nonpolar and polar solutions, respectively. In addition, we also do a normal coordinate analysis by using the normal mode eigenvectors obtained at the B3LYP/6-311++ G(d,p) level. The observed vibrational wavenumbers, IR and Raman relative intensities, and Raman depolarization ratios of AA and its deuterated analogous agree satisfactorily with the calculated results obtained at the B3LYP/6-311++G(d,p) method.

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Section: Methods Of Calculationsmentioning

confidence: 99%

Vibrational spectra, normal coordinate analysis, and structure of keto form of acetylacetone. A DFT approach

et al. 2019

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“…Also for HFA, we found that the conformer more stable corresponds to one already reported, the symmetrical

C_{2}

(structure in Figure 1E). 28 On the lowest energy conformers structures, we calculated the new atomic charges reported in Table 1, and the corresponding topology file for each cosolvent molecule is provided in Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

“…The additional oxygen atom increases the acidity (pKa = 6.58). 27 The molecular structure of HFA in the gas phase was studied by Tayyari et al 28 at B3LYP/6-311G* level of theory, suggesting the symmetrical C 2 as major conformer (structure in Figure 1E).…”

Section: Introductionmentioning

confidence: 99%

Upgrading of the general AMBER force field 2 for fluorinated alcohol biosolvents: A validation for water solutions and melittin solvation

Casoria,

Macchiagodena,

Rovero

et al. 2023

Journal of Peptide Science

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The standard GAFF2 force field parameterization has been refined for the fluorinated alcohols 2,2,2‐trifluoroethanol (TFE), 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP), and 1,1,1,3,3,3‐hexafluoropropan‐2‐one (HFA), which are commonly used to study proteins and peptides in biomimetic media. The structural and dynamic properties of both proteins and peptides are significantly influenced by the biomimetic environment created by the presence of these cosolvents in aqueous solutions. Quantum mechanical calculations on stable conformers were used to parameterize the atomic charges. Different systems, such as pure liquids, aqueous solutions, and systems formed by melittin protein and cosolvent/water solutions, have been used to validate the new models. The calculated macroscopic and structural properties are in agreement with experimental findings, supporting the validity of the newly proposed models.

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“…From these internal coordinates, a non-redundant set of the local symmetry coordinates was constructed by a suitable linear combination of internal coordinates (Table S1). Then all symmetry coordinates were normalized through all 39 normal coordinates, as described elsewhere [36,43,44]. The normalized symmetry coordinates were used to calculate the potential energy distributions (PEDs) for each normal mode [36,43,44].…”

Section: Calculation Methodsmentioning

confidence: 99%

Normal coordinate analysis of the enol form of pentane-2,4-dione and its 2H-isotopomers

et al. 2020

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The harmonic and anharmonic vibrational frequencies of the cis-enol form of pentane-2,4-dione (PD) and its 2 H-isotopomers were calculated by density functional theory method (DFT), performed at the B3LYP level. The results of the DFT calculations were subjected to a normal coordinate analysis, giving potential energy distribution (PED) and detailed assignments. Excellent agreement between observed and calculated anharmonic vibrational frequencies was obtained. It is well illustrated that the band frequencies resulted from movements of the enolic ring atoms are considerably coupled with the terminal groups' vibrations.

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Conformational analysis, structure, and normal coordinate analysis of vibrational spectra of hexafluoroacetone. A density functional theory study

Cited by 12 publications

References 37 publications

Vibrational spectra, normal coordinate analysis, and structure of keto form of acetylacetone. A DFT approach

Vibrational spectra, normal coordinate analysis, and structure of keto form of acetylacetone. A DFT approach

Upgrading of the general AMBER force field 2 for fluorinated alcohol biosolvents: A validation for water solutions and melittin solvation

Normal coordinate analysis of the enol form of pentane-2,4-dione and its 2H-isotopomers

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