Oxygen and sulfur heterocyclic compounds

Freitas, Vera L.S.; Silva, Manuel A.V. Ribeiro da

doi:10.1007/s10973-015-4800-0

Cited by 23 publications

(3 citation statements)

References 63 publications

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“…The computational study of the three o-acetylnaphthol isomers (Figure 1) was performed using the G3(MP2)//B3LYP approach [18]. The good agreement obtained between the experimental and the computational values for the gas-phase enthalpy of formation in previous studies of compounds with a similar structural typology, give us confidence for the use of the G3(MP2)//B3LYP approach in this study [17,[28][29][30].…”

Section: Computational Studiessupporting

confidence: 58%

Structural and Energetic Insights on Two Dye Compounds: 1-Acetyl-2-Naphthol and 2-Acetyl-1-Naphthol

Freitas

Silva

2020

Molecules

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The energy involved in the structural switching of acyl and hydroxyl substituents in the title compounds was evaluated combining experimental and computational studies. Combustion calorimetry and Knudsen effusion techniques were used to determine the enthalpies of formation, in the crystalline state, and of sublimation, respectively. The gas-phase enthalpy of formation of both isomers was derived combining these two experimental data. Concerning the computational study, the G3(MP2)//B3LYP composite method was used to optimize and determine the energy of the isomers in the gaseous state. From a set of hypothetical reactions it has been possible to estimate the gas-phase enthalpy of formation of the title compounds. The good agreement between the experimental and computational gas-phase enthalpies of formation of the 1-acetyl-2-naphthol and 2-acetyl-1-naphthol isomers, provided the confidence for extending the computational study to the 2-acetyl-3-naphthol isomer. The structural rearrangement of the substituents in position 1 and 2 in the naphthalene ring and the energy of the intramolecular hydrogen bond are the factors responsible for the energetic differences exhibited by the isomers. The gas phase tautomeric keto « enol equilibria of the o-acetylnaphthol isomers were analyzed using the Boltzmann’s distribution.

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Section: Computational Studiessupporting

confidence: 58%

Structural and Energetic Insights on Two Dye Compounds: 1-Acetyl-2-Naphthol and 2-Acetyl-1-Naphthol

Freitas

Silva

2020

Molecules

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“…Continuing our interest in the establishment of energy− structural correlations for heterocyclic compounds with one or two benzene rings fused to a fiveor six-membered-ring containing oxygen or sulfur heteroatoms, 32 in this work we focused our attention on a set of six pairs of urea/thiourea derivatives (Ur−X, X = O, S) with fiveor six-membered rings containing two nitrogen heteroatoms at positions (1,3). Thus, to understand and predict the thermochemical properties of cyclic urea/thiourea derivatives, their corresponding gas-phase enthalpies of formation were compiled in Table 4.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Comprehensive Thermochemical Study of Cyclic Five- and Six-Membered N,N′-Thioureas

Silva

2017

J. Chem. Eng. Data

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An experimental and computational study of the thermochemical and structural properties of ethylenethiourea (ETU) has been carried out. The enthalpies of combustion and sublimation, measured respectively by rotating-bomb combustion calorimetry and Calvet microcalorimetry, yielded the gas-phase enthalpy of formation of ETU at T = 298.15 K. This latter parameter was also derived from high-level molecular orbital calculations at the G3(MP2)//B3LYP level of theory, leading to a value in excellent agreement with the one obtained from experimental data. With the purpose of evaluating the influence of the ring size in the enthalpy of formation of cyclic N,N′thiourea derivatives, the calculation of the enthalpy of formation of N,N′-trimethylenethiourea (MTU) was performed using the G3-(MP2)//B3LYP approach. The effects of substituents (carbonyl and thiocarbonyl) on the molecular stability of several N-alkyl (cyclic) ureas/thioureas were also studied.

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“…Previous studies have shown that the results obtained by this method of calculation are quite accurate . The hypothetical gas-phase reactions consisted of atomization and group substitution reactions. − The last set of reactions (isodesmic reactions) involve species with structural analogies to those of the compounds under study, being the reactants and the products of the reactions constituted by molecules with related structural and formal bond types, in order to minimize differential errors in the electronic structure computations, enabling the increase of the accuracy of the results …”

Section: Computational Studiesmentioning

confidence: 99%

Assessment of Thermochemical Data of γ-Butyrolactone from Experimental and Computational Studies

2020

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Relevant thermochemical data of γ-butyrolactone (GBL), a compound of considerable industrial and environmental significance, obtained from experimental and computational studies are reported in this work. The standard (p° = 0.1 MPa) molar enthalpy of formation, at T = 298.15 K, in the gaseous phase, was determined from the enthalpy of combustion and vaporization, obtained by static bomb calorimetry in oxygen and by Calvet microcalorimetry, respectively. The enthalpy of formation in the gaseous phase was also determined from G3 calculations. The excellent agreement between the experimental and computational thermochemical data provided a critical literature review of GBL and the proposal of new reference values for this lactone.

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Oxygen and sulfur heterocyclic compounds

Cited by 23 publications

References 63 publications

Structural and Energetic Insights on Two Dye Compounds: 1-Acetyl-2-Naphthol and 2-Acetyl-1-Naphthol

Structural and Energetic Insights on Two Dye Compounds: 1-Acetyl-2-Naphthol and 2-Acetyl-1-Naphthol

Comprehensive Thermochemical Study of Cyclic Five- and Six-Membered N,N′-Thioureas

Assessment of Thermochemical Data of γ-Butyrolactone from Experimental and Computational Studies

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