A kinetic scale for dialkylaminyl radicals was established by measuring unimolecular rate constants for a series of dialkylaminyl radical clocks that spans eight orders of magnitude and using clock reactions to measure the second order rate constants for reactions of several hydrogen atom donors. N-Hydroxypyridine-2-thione derivatives of carbamic acids (so-called PTOC carbamates) were used as radical precursors in direct, laser-flash kinetic measurements and in indirect, radical chain kinetic studies. The calibrated radical clocks are N-methyl-6,6-diphenyl-5-hexenaminyl, N-methyl-trans-5-phenyl-4-pentenaminyl, N-methyl-5,5-diphenyl-4-pentenaminyl, N-methyl-trans-2-phenylcyclobutanaminyl, and N-methyl-trans-2-phenylcyclopropanaminyl. Calibrated hydrogen atom donors are Bu 3 SnH, t-BuSH, PhSH, and PhSeH. Whereas the tin hydride reactions with dialkylaminyl radicals are slower than reactions with alkyl radicals, the polarity-matched reactions of the electron-rich dialkylaminyl radicals with the electronpoor hydrogen donors t-BuSH, PhSH, and PhSeH have rate constants nearly equal to those for reactions of alkyl radicals with the same donor.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.