Table 2. Second-Order Rate Constants (k_H) for Reaction of the Cumyloxyl Radical (CumO^•) with Different Substrates.

^aMeasured in Ar- or N₂-saturated MeCN solution at T = 25 °C by 355 nm LFP, [dicumyl peroxide] = 1.0 M. k_H values were determined from the slope of the k_obs vs [substrate] plots, where in turn k_obs values were measured following the decay of the CumO^• visible absorption band at 490 nm. Average of at least two determinations.

^bk_H^′ = k_H/n, where n represents the number of equivalent abstractable hydrogen atoms.

^cCalculated considering n = 2 based on the difference between the C–H BDEs of the two methylene groups in an intramolecular hydrogen-bonded structure (see text).

^dMeasured in isooctane solution.⁴¹⁻⁴⁶