Radical clocks have been used to study the kinetics of the coupling of the nitroxyl radical 1, 1, 3, 3-tetra-methylisoindoline-2-oxy1 (T) in cyclohexane or benzene with a variety of carbon- centered radicals including simple unhindered primary, secondary, and tertiary radicals (1, 2, 3, 4, 5, 8, and 9), neopentyl radicals (6 and 7), an alkoxyalkyl radical (lo), an acyl radical (ll), and alkoxycarbonyl radicals (12 and 13). The reaction rates are slower than expected ...