Theoretical Thermochemistry of the FSOx (x=1 to 5) Radical Series

MARÍA P. BADENES; ADELA E. CROCE; CARLOS J. COBOS

Thermochemistry: New Research

Nova Science Publishers, Inc.

Lugar: New York, EE.UU; Año: 2008;

Standard enthalpies of formation at 298 K for the FSOx (x=1 to 5) radical series are determined at the B3LYP, B3PW91, mPW0, B98, B97-2 and PBE0m levels of density functional theory and at the ab initio Gaussian-3 models G3MP2B3, G3B3, BAC-G3MP2B3 and BAC-G3B3. Enthalpies of formation were calculated from total atomization energies and from isodesmic reaction energies. The B98, B97-2 and PBE0m hybrids lead to the most reliable results of the tested functionals. However, the Gaussian-3 and mainly the computations with bond additivity corrections (BAC) combined with the 6-311+G(3df) basis set provide the more accurate results. The best values obtained for FSO, FSO2, FSO3, FS(O2)OO and FS(O2)OOO radicals are -66.6, -94.0, -120.9, -109.8 and -126.3 kcal mol-1,  with an stated error limit of ±2 kcal mol-1. A comparison with previous values is reported.