Pure Appl. Chem., 2007, Vol. 79, No. 8, pp. 1369-1382
doi:10.1351/pac200779081369
Bond-dissociation enthalpies in the gas phase and in organic solvents: Making ends meet*
Rui M. Borges dos Santos1, Benedito J. Costa Cabral2,3, and José A. Martinho Simões3
1Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of Algarve, Gambelas Campus, 8005-139 Faro, Portugal; 2Group of Mathematical Physics of the University of Lisbon, Av. Professor Gama Pinto 2, 1649-003 Lisbon, Portugal; 3Department of Chemistry and Biochemistry, Faculty of Science, University of Lisbon, 1749-016 Lisbon, Portugal
Abstract:
Solvent effects are responsible for the difference between gas- and solution-phase bond-dissociation enthalpies (BDEs), and are thus crucial for understanding reactivity in solution. While solvation effects can be negligible (e.g., in reactions involving carbon-centered radicals), they may be rather significant (e.g., when oxygen-centered radicals are formed). This paper reviews a number of models which have been proposed to deal with the difference between the solvation energetics of a radical and its parent molecule. It is concluded that the radical-solvent interaction may be larger than previously anticipated.
Keywords: bond-dissociation enthalpy; photoacoustic calorimetry; quantum chemistry; solvation; thermochemistry.
Full text is not freely available, please see subscription information for options to obtain it.
| References (67)