Experimental and computational thermochemistry of three nitrogen-containing heterocycles: 2-benzimidazolinone, 2-benzoxazolinone and 3-indazolinone

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Morais, VMF (Author) ICBAS; Miranda, MS (Author) Other; Matos, MAR (Author) FCUP; Liebman, JF (Author) Other

Journal

Title: Molecular Physics

Vol. 104 No. 22-24

Pages: 325-334

ISSN: 0026-8976

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 24 Citations

Scopus - 23 Citations

Scientific classification

FOS: Natural sciences > Physical sciences

Other information

Authenticus ID: P-004-N9H

DOI: 10.1080/00268970500290300

Abstract (EN): The standard molar enthalpies of combustion, sublimation, and formation of three nitrogen-containing heterocycles, namely, 2-benzimidazolinone, 2-benzoxazolinone and 3-indazolinone were determined calorimetrically. The standard (p degrees similar to 0.1 MPa) molar enthalpies of formation in the gas phase were derived from the standard molar enthalpies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry and from the standard molar enthalpies of sublimation at T 298.15 K, measured by Calvet microcalorimetry. Moller-Plesset calculations at the MP2 level and density functional calculations with the B3LYP functional and extended basis sets were also performed to determine the energetically preferred tautomeric form of the molecules. The results were qualitatively independent of the calculational level, where in general the DFT calculations were in better agreement with experiment than those from MP2. The gas and solid phase enthalpic differences between imines and amides, wherein -CH = N- is contrasted with -CONH-, have been studied and roughly constant values have been found.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10