Thermodynamic study on the relative stability of 2-amino-1,3,4-thiadiazole and two alkyl-substituted aminothiadiazoles

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Lima, ACMO (Author) Other; Silva, ALR (Author) Other; Goncalves, JM (Author) FCUP; Maria D M C R Ribeiro da Silva (Author) FCUP

Journal

Title: Journal of Thermal Analysis and Calorimetry

ISSN: 1388-6150

Publisher: Springer Nature

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Other information

Authenticus ID: P-017-53B

DOI: 10.1007/s10973-024-13498-6

Abstract (EN): A thermochemical study of 2-amino-1,3,4-thiadiazole, 2-amino-5-methyl-1,3,4-thiadiazole and 2-amino-5-ethyl-1,3,4-thiadiazole has been performed, aiming to establish possible correlations between energetic properties and structural characteristics of these compounds, as well as to assess to their thermodynamic stability. Calorimetric techniques (rotating bomb combustion calorimetry and Calvet microcalorimetry) complemented with a mass loss effusion method and computational calculations were used to determine the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of the three thiadiazole derivatives. Theoretical calculations at the G3(MP2)//B3LYP level of theory were also performed to obtain the enthalpies of hypothetical reactions in the gaseous phase, as well as to calculate the gas-phase enthalpy of formation for the three thiadiazoles. From the two sets of results, it is possible to make a comparison between the experimental and computational values of the gas-phase enthalpy of formation. The standard Gibbs energies of formation in the crystalline and gaseous phases were also calculated, in order to evaluate the relative thermodynamic stability of the compounds. Additionally, a tautomeric analysis of the structure of each compound was performed, resulting in the establishment of a relationship between energy versus structure of the respective tautomeric forms.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12