Substituent effects on enthalpies of formation of nitrogen heterocycles: 2-substituted benzimidazoles and related compounds

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

Authors

Infantes, L (Author) Other; Mo, O (Author) Other; Yanez, M (Author) Other; Roux, MV (Author) Other; Jimenez, P (Author) Other; Divalos, 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, R (Author) Other; Elguero, J (Author) Other

Journal

Title: Journal of Physical Chemistry A

Vol. 110

Pages: 2535-2544

ISSN: 1089-5639

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 14 Citations

Scopus - 17 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-004-N7B

DOI: 10.1021/jp0559557w

Abstract (EN): The enthalpies of combustion, heat capacities, enthalpies of sublimation and enthalpies of formation of 2-tert-butylbenzimidazole (2tBuBIM) and 2-phenylimidazole (2PhIM) are reported and the results compared with those of benzene derivatives and a series of azoles (imidazoles, pyrazoles, benzimidazoles and indazoles). 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/6-311++G(d,p) on B3LYP/6-31G* optimized geometries. The comparison of experimental and calculated values of all studied compounds bearing H (unsubstituted), methyl (Me) ethyl (Et), propyl (Pr), isopropyl (iPr), tert-butyl (tBu), benzyl (Bn) and phenyl (Ph) groups show remarkable homogeneity. The remarkable consistency of both the calculated and experimental results allows us to predict with reasonable certainty the missing experimental values. The crystal and molecular structure of the 2-benzylbenzimidazole (2BnBIM) has been determined by X-ray analysis. The observed molecular conformation permits the crystal being built up through N-H...N hydrogen bonds and van der Waals contacts between the molecules. An attempt has been made to relate the crystal structure to the enthalpies of sublimation.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10