title: A carbon-centered radical unreactive toward oxygen: unusual radical stabilization by a lactone ring
abstract: A lactone ring confers unusual stability to a diphenylmethyl-like radical that is virtually unreactive toward oxygen. Thus, the radical derived from HP-136 is about 10,000 times less reactive than typical carbon-centered radicals. A reversible reaction with oxygen is proposed by analogy with triphenylmethyl; however, the association constant is about 1000 times smaller for HP-136 than for triphenylmethyl. While the lactone ring greatly influences the reactivity, the spectroscopy of the HP-136-derived radical is in line with that expected for a substituted diphenylmethyl radical.
authors.affiliation: Department of Chemistry, University of Ottawa, Ontario, Canada.
authors.initials: JC
authors.lastname: Scaiano
authors.initials: A
authors.lastname: Martin
authors.initials: GP
authors.lastname: Yap
authors.initials: KU
authors.lastname: Ingold