10.1021/jp802257m.s001 Linhong Jing Linhong Jing Leonard P. Guler Leonard P. Guler George Pates George Pates Hilkka I. Kenttämaa Hilkka I. Kenttämaa The Selectivity of Charged Phenyl Radicals in Hydrogen Atom Abstraction Reactions with Isopropanol American Chemical Society 2008 ion cyclotron resonance selectivity CH 3 group isotope effects decrease CD 3 group CH group phenyl radicals correlates Hydrogen Atom Abstraction Reactions hydrogen atom abstraction isopropanol electron affinity deuterium atom abstraction Charged Phenyl Radicals OH electron affinity increases 2008-10-09 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/The_Selectivity_of_Charged_Phenyl_Radicals_in_Hydrogen_Atom_Abstraction_Reactions_with_Isopropanol/2908501 The vertical electron affinity is demonstrated to be a key factor in controlling the selectivity of charged phenyl radicals in hydrogen atom abstraction from isopropanol in the gas phase. The measurement of the total reaction efficiencies (hydrogen and/or deuterium atom abstraction) for unlabeled and partially deuterium-labeled isopropanol, and the branching ratios of hydrogen and deuterium atom abstraction, by using a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer, allowed the determination of the selectivity for each site in the unlabeled isopropanol. Examination of hydrogen atom abstraction from isopropanol by eight structurally different radicals revealed that the preferred site is the CH group. The selectivity of the charged phenyl radicals correlates with the radical’s vertical electron affinity and the reaction efficiency. The smaller the vertical electron affinity of a radical, the lower its reactivity, and the greater the preference for the thermodynamically favored CH group over the CH<sub>3</sub> group or the OH group. As the vertical electron affinity increases from 4.87 to 6.28 eV, the primary kinetic isotope effects decrease from 2.9 to 1.3 for the CD group, and the mixture of primary and α-secondary kinetic isotopes decreases from 6.0 to 2.4 for the CD<sub>3</sub> group.