Ground- and Excited-State Succinimidyl Radicals in Chain Reactions: A Reexamination

Article abstract of DOI:10.1021/ja00261a020

The succinimidyl radical chemistry reported earlier and previously attributed to the ? state is reproduced, leaving unsettled only its assignment to the ? and ? state.This chemistry, observed in the presence of small amounts of alkenes which scavenge bromine, includes the following: (1) additions to alkenes, (2) additions to arenes, (3) Cl-like substitution selectivities, and (4) ring-openings.The chemistry previously reported under the title "?" is neither as simple nor conclusive as thought earlier.As reported earlier, ring-opening is suppressed by inclusion of bromine, benzene, bromotrichloromethane, or larger amounts of alkenes.These observations indicate the presence of a different chain carrier, formerly labeled as S_?.We show now that the S_? explanation was not correct with addends benzene, bromotrichloromethane, and olefins, and we identify the specific competitive processes.Reactions in the presence of bromine still show evidence for a third hydrogen abstractor besides an imidyl radical and a bromine atom.At this time there is no unambiguous identification of this third chain intermediate.