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

• Tipo: Artigo em Revista Científica Internacional
• Data: 2004

Autores

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

Revista

Título: Molecular Physics

Vol. 102

Páginas: 711-721

ISSN: 0026-8976

Editora: Taylor & Francis

Indexação

ISI Web of Knowledge - 15 Citações

Scopus - 16 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Física

Outras Informações

ID Authenticus: 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.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 11