Substituent effects on enthalpies of formation: Benzene derivatives

• Type: Article in International Scientific Journal
• Date: 2003

Authors

Mo, O (Author) Other; Yanez, M (Author) Other; Elguero, J (Author) Other; Roux, MV (Author) Other; Jimenez, P (Author) Other; Davalos, JZ (Author) Other; da Silva, MAV (Author) FCUP; da Silva, MDDMC (Author) FCUP; Cabildo, P (Author) Other; Claramunt, R (Author) Other

Journal

Title: Journal of Physical Chemistry A

Vol. 107

Pages: 366-371

ISSN: 1089-5639

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 21 Citations

Scopus - 22 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-J07

DOI: 10.1021/jp0265790

Abstract (EN): High level density functional theory calculations have been carried out for a benchmark set of benzene derivatives, including methyl, ethyl, n-propyl, i-propyl, tert-butyl, phenyl, and benzyl groups as substituents. Geometries were obtained using the B3LYP method and three basis set expansions, namely 6-31G(d), 6-311G(d,p), and 6-311++G(d,p). Final energies were calculated in B3LYP/6-311+G(3df,2p) single-point calculations. Based on these calculations the performance of different theoretical schemes aiming at reproducing substituent effects on enthalpies of formation has been assessed. The poorest performance is obtained when atomization energies or isodesmic reactions are used. No significant improvement is found when using homodesmotic processes. A significant improvement is achieved when the isodesmic processes used involve the unsubstituted parent compound. That means that this procedure can be a good alternative to explore substituent effects on the enthalpies of formation, although the absolute values of this thermodynamical magnitude have still a significant error. The best performance is obtained when different atom equivalent schemes are used, the correlation coefficient of the linear relationship between calculated and experimental values being greater than 0.999.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6