title: Nitric Oxide Catalysis of Diazene E/Z Isomerization.
abstract: Nitric oxide is an efficient catalyst for the cis-trans (E/Z) isomerization of diazenes. We compare the effect of room temperature solutions bearing low concentrations of nitric oxide, nitrogen dioxide, or oxygen on the rate of cis-trans isomerization, CTI, of the alkene bond in stilbene and on the azo double bond in azobenzene, as well as in four azo derivatives as measured by UV-vis spectroscopy. These rate enhancements can be as large as 3 orders of magnitude for azobenzene in solution. A mechanism is proposed where catalysis is promoted by the interaction of the nitric oxide with the diazene nitrogen lone pairs. Density functional theory, B3LYP/6-311++g** suggests that the binding of NO to the diazene should be weak and reversible but that its NO adduct has an E/Z isomerization barrier of 7.5 kcal/mol.
authors.affiliation: Department of Chemistry, McGill University, 801 Sherbrooke Street W., Montreal H3A 0B8, Canada.
authors.forename: D Scott
authors.initials: DS
authors.lastname: Bohle
authors.affiliation: Department of Chemistry, McGill University, 801 Sherbrooke Street W., Montreal H3A 0B8, Canada.
authors.forename: Kristopher A
authors.initials: KA
authors.lastname: Rosadiuk