Thermochemical and theoretical studies of 2-hydroxyquinoxaline, 2,3-dihydroxyquinoxaline, and 2-hydroxy-3-methylquinoxaline

• Type: Article in International Scientific Journal
• Date: 2000

Authors

da Silva, MAVR (Author) FCUP; Matos, MAR (Author) FCUP; Rio, CMA (Author) Other; Miranda, MS (Author) Other; Morais, VMF (Author) ICBAS

Journal

Title: Journal of Physical Chemistry A

Vol. 104

Pages: 6644-6648

ISSN: 1089-5639

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 14 Citations

Scopus - 15 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-ZGB

DOI: 10.1021/jp000694y

Abstract (EN): The standard (p degrees = 0.1 MPa) molar enthalpies of formation for crystalline 2-hydroxyquinoxaline, 2,3-dihydroxyquinoxaline, and 2-hydroxy-3-methylquinoxaline were derived from the standard molar enthalpies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The standard molar enthalpies of sublimation, at T = 298.15 K, of the three compounds were measured by Calvet microcalorimetry. The derived standard molar enthalpies of formation in the gaseous phase are 45.9 +/- 4.3 kJ.mol(-1) for 2-hydroxyquinoxaline, -(179.2 +/- 5.3) kJ.mol(-1) for 2,3-dihydroxyquinoxaline, and -(8.8+/- 4.9) kJ.mol(-1) for 2-hydroxy-3-methylquinoxaline. In addition, theoretical calculations using the density functional theory and the B3LYP/6-311G** hybrid exchange-correlation energy functional were performed for these molecules in order to obtain the most stable geometries and to access their relative stability. The theoretical results are in general good agreement with experimental findings.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5