Structural and energetic characterization of anhydrous and hemihydrated 2-mercaptoimidazole: Calorimetric, X-ray diffraction, and computational studies

• Tipo: Artigo em Revista Científica Internacional
• Data: 2016

Autores

Ana L.R Silva (Autor) Outra; Victor M.F Morais (Autor) Outra; Maria D.M.C Ribeiro da Silva (Autor) FCUP; Ricardo G Simões (Autor) Outra; Carlos E.S Bernardes (Autor) Outra; Fátima F M Piedade (Autor) Outra; Manuel E Minas da Piedade (Autor) Outra

Revista

Título: Journal of Chemical Thermodynamics

Vol. 95

Páginas: 35-48

ISSN: 0021-9614

Editora: Elsevier

Indexação

ISI Web of Knowledge - 8 Citações

Scopus - 8 Citações

Outras Informações

ID Authenticus: P-00J-Z2Y

DOI: 10.1016/j.jct.2015.11.010

Abstract (EN): This paper reports an experimental and theoretical study on the structural and energetic characterization of the 2-mercaptoimidazole (2-MI) in the solid and in the gaseous phases. The single crystal X-ray diffraction determinations on the anhydrous and hemihydrate 2-MI forms were carried out at T = (296 +/- 2) K and T = (150 +/- 2) K, respectively, and suggest that in both forms the 2-MI molecule is closer to the thione conformation, albeit some single bond character is possible. The energy of combustion of the title compound was measured by rotating-bomb combustion calorimetry, being used to derive the corresponding enthalpy of formation in the crystalline-phase. The enthalpy of sublimation of 2-MI, at T = 298.15 K, was obtained from high temperature Calvet microcalorimetry measurements. These two parameters yielded the gas-phase enthalpy of formation, allowing the inherent energetic analysis of the molecule. This result was discussed together with the corresponding predictions for 2-MI and its tautomer, 1,3-dihydro-2H-imidazole-2-thione, by the G3 method. The dehydration reaction of 2-MI center dot 0.5H(2)O(cr) was also investigated and the corresponding enthalpy of dehydration was determined by Calvet microcalorimetry.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 14