Effects of the functional groups amino and nitro on the reactivity of benzoxazoles and comparison with homologous benzothiazoles

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Silva, ALR (Author) FCUP; Maria D M C R Ribeiro da Silva (Author) FCUP

Journal

Title: Journal of Physical Organic Chemistry

Vol. 34

ISSN: 0894-3230

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 6 Citations

Scopus - 6 Citations

Other information

Authenticus ID: P-00S-HM2

DOI: 10.1002/poc.4118

Abstract (EN): The energetic study of 2-aminobenzoxazole (ABO) and 2-methyl-6-nitrobenzoxazole (MNBO) has been developed using experimental and computational tools. The enthalpies of combustion, of fusion, and of sublimation of these compounds were measured by static-bomb combustion calorimetry, differential scanning calorimetry, and Calvet microcalorimetry drop-technique and/or the Knudsen-effusion method. Additionally, we calculated the gas-phase standard molar enthalpies of formation of these compounds, as well as of 2-methyl-6-nitrobenzothiazole (MNBT), through high level ab initio calculations, at the G3(MP2)//B3LYP level of theory. Furthermore, the energetic effects associated with the presence of the amino and nitro groups on the core of benzoxazole or benzothiazole molecules were also evaluated, as well as stabilizing electronic interactions occurring in the molecules. The latter were investigated through Natural Bonding Orbital (NBO) of the corresponding wave functions. Finally, the thermodynamic stability of the titled compounds was evaluated and a comparison with their sulfur heteroanalogs was achieved. In the gaseous phase, the oxygen derivatives exhibit the lowest tendency to decompose into their constituent elements at standard conditions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10