Tautomerism, conformational analysis, and spectroscopy studies of 3-bromo-pentane-2,4-dione

Dolati, Fatemeh; Tayyari, Sayyed Faramarz; Vakili, Mohamad

doi:10.1016/j.molstruc.2015.04.014

Cited by 11 publications

(2 citation statements)

References 49 publications

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“…The position of tautomerization is determined by several parameters, such as temperature [1-3], state of samples [4][5][6][7], nature of solvent [8][9][10][11][12], concentration [13], and substitution on the αand β-positions [14][15][16][17][18][19]. The vibrational spectra of the enol form of several β-diketones have been extensively investigated several decades [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. In an extensive work, Tayyari and Milani-Nejad [21] considered the vibrational spectra and possible stable structures of the enol form of acetylacetone.…”

Section: Introductionmentioning

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: Introductionmentioning

confidence: 99%

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

et al. 2019

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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, tautomerization, and vibrational spectra of methyl acetoacetate

et al. 2021

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Tautomerism, conformational analysis, and spectroscopy studies of 3-bromo-pentane-2,4-dione

Cited by 11 publications

References 49 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

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

Conformational analysis, tautomerization, and vibrational spectra of methyl acetoacetate

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