Substituent and ring effects on enthalpies of formation: 2-methyl- and 2-ethylbenzimidazoles versus benzene- and imidazole-derivatives

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Jimenez, P (Author) Other; Roux, MV (Author) Other; Davalos, JZ (Author) Other; Temprado, M (Author) Other; Da Silva, MAVR (Author) FCUP; Da Silva, MDMCR (Author) FCUP; Amaral, LMPF (Author) Other; Cabildo, P (Author) Other; Claramunt, RM (Author) Other; Mo, O (Author) Other; Yanez, M (Author) Other; Elguero, J (Author) Other

Journal

Title: Molecular Physics

Vol. 102

Pages: 711-721

ISSN: 0026-8976

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 15 Citations

Scopus - 16 Citations

Scientific classification

FOS: Natural sciences > Physical sciences

Other information

Authenticus ID: P-000-ATV

DOI: 10.1080/00268970410001687434

Abstract (EN): The enthalpies of combustion, heat capacities, enthalpies of sublimation and enthalpies of formation of 2-methylbenzimidazole (2MeBIM) and 2-ethylbenzimidazole (2EtBIM) are reported and the results compared with those of benzimidazole itself (BIM). Theoretical estimates of the enthalpies of formation were obtained through the use of atom equivalent schemes. The necessary energies were obtained in single-point calculations at the B3LYP/6-311G(d,p) on B3LYP/6-31G* optimized geometries. The comparison of experimental and calculated values of benzenes, imidazoles and benzimidazoles bearing H (unsubstituted), methyl and ethyl groups shows remarkable homogeneity. The energetic group contribution transferability is not followed, but either using it or adding an empirical interaction term, it is possible to generate an enormous collection of reasonably accurate data for different substituted heterocycles (pyrazole-derivatives, pyridine-derivatives, etc.) from the large amount of Delta(f)H(m)(o)(g) values available for substituted benzenes and those of the parent (pyrazole, pyridine) heterocycles.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11