Publication Type |
Journal Article |
Title |
Structural and energetic characterization of anhydrous and hemihydrated 2-mercaptoimidazole: Calorimetric, X-ray diffraction, and computational studies |
Authors |
Ana L. R. Silva Victor M. F. Morais Maria D. M. C. Ribeiro da Silva R. A. G. Simões Carlos E. S. Bernardes M.Fatima M.Piedade M. E. M. Piedade |
Groups |
MET BioMol |
Journal |
JOURNAL OF CHEMICAL THERMODYNAMICS |
Year |
2016 |
Month |
April |
Volume |
95 |
Number |
|
Pages |
35-48 |
Abstract |
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. (C) 2015 Elsevier Ltd. All rights reserved. |
DOI |
http://dx.doi.org/10.1016/j.jct.2015.11.010 |
ISBN |
|
Publisher |
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD |
Book Title |
|
ISSN |
0021-9614 |
EISSN |
1096-3626 |
Conference Name |
|
Bibtex ID |
ISI:000368762600005 |
Observations |
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