Evaluations of steric effects on rates of radical bimolecular self-reaction by fast-scan cyclic voltammetry
Conference
·
· Journal of the Tennessee Academy of Science; (United States)
OSTI ID:6605837
- Austin Peay State Univ., Clarksville, TN (United States) Southern Illinois Univ., Carbondale, IL (United States)
Delocalized organic radicals previously considered persistent (9-phenylflourenyl, and 9-(2,4,6-trimethylphenyl)fluorenyl) were found to undergo bimolecular self-reactions at rates differing by seven orders of magnitude. Blockage of the 9-C orbital holding the unpaired electron attenuates the combination of these anisotropic radicals. Fast-scan cyclic voltammetry has facilitated these determinations. Irreversible peak potentials were corrected for the observed kinetic effects. By means of a thermochemical cycle, the homolytic C-H bond dissociation energies were calculated for the molecules examined. Previously determined homolytic C-C dimer dissociation energies were combined with radical oxidation potentials measured by the fast-scan cyclic voltammetry to estimate the energetics of a heterolytic cleavage. Evaluation of this data for the 9-phenylxanthenyl and 9-phenylfluorenyl dimers and their associated acids indicates that C-C cleavage is controlled by bond strain while C-H dissociation is determined by the stability of the products.
- OSTI ID:
- 6605837
- Report Number(s):
- CONF-9311244--
- Conference Information:
- Journal Name: Journal of the Tennessee Academy of Science; (United States) Journal Volume: 69:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
ARYL RADICALS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CONDENSED AROMATICS
DISSOCIATION ENERGY
ENERGY
FLUORENE
HYDROCARBONS
KINETICS
ORGANIC COMPOUNDS
RADICALS
REACTION KINETICS
VOLTAMETRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
ARYL RADICALS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CONDENSED AROMATICS
DISSOCIATION ENERGY
ENERGY
FLUORENE
HYDROCARBONS
KINETICS
ORGANIC COMPOUNDS
RADICALS
REACTION KINETICS
VOLTAMETRY