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Jason G Gillmore

Publications and source records attributed to Jason G Gillmore.

2 recordsLinked to original sources

Peroxyl radical clocks.

A series of peroxyl radical clocks has been developed and calibrated based on the competition between the unimolecular beta-fragmentation (k(beta)) of a peroxyl radical and its bimolecular reaction with a hydrogen atom donor (k(H)). These clocks are based on either methyl linoleate or allylbenzene and were calibrated directly with alpha-tocopherol or methyl linoleate, which have well-established rate constants for reaction with peroxyl radicals (k(H-tocopherol) = 3.5 x 10(6) M(-1) s(-1), k(H-linoleate) = 62 M(-1) s(-1)). This peroxyl radical clock methodology has been successfully applied to determine inhibition and propagation rate constants ranging from 10(0) to 10(7) M(-1) s(-1).

Calibration↗

Cyclopropylcarbinyl --> homoallyl-type ring opening of ketyl radical anions. Structure/reactivity relationships and the contribution of solvent/counterion reorganization to the intrinsic barrier.

[reaction: see text] Following a protocol developed by Mathivanan, Johnston, and Wayner (J. Phys. Chem. 1995, 99, 8190-8195), the radical anions of several cyclopropyl- and oxiranyl-containing carbonyl compounds were generated in an effort to measure the rate constants for their ring opening (k(o)) by laser flash photolysis. The results of these experiments are compared to those obtained from earlier electrochemical studies, and the combined data set is used to rationalize the kinetics of radical anion ring opening in a general context by using Saveant's theory pertaining to stepwise dissociative electron transfer (Acc. Chem. Res. 1993, 26, 455-461). Compared to cyclopropylcarbinyl --> homoallyl rearrangements of neutral free radicals, at comparable driving force, the radical anion ring openings are slightly slower. The small difference in rate is attributed to the contribution of an additional, approximately 2 kcal/mol, solvent reorganization component for the radical anion rearrangements. The solvent reorganization energy for ring opening of these radical anions is believed to be small because the negative charge does not move appreciably in the progression reactant --> transition state --> product.

Journal Article↗