118070-85-2Relevant academic research and scientific papers
Steric Inhibition of Photochemical Reactions: The -Cycloaddition Reaction
Penn, John H.,Gan, Li-Xian,Chan, Edward Y.,Loesel, Paul D.,Hohlneicher, Georg
, p. 601 - 606 (1989)
Photochemical -cycloaddition reactions of a number of diphenylcycloalkenes to tetrachloroethylene (TCE) have been examined. 1,2-Diphenylcyclobutene (1) reacts efficiently with TCE to yield the cyclobutane anticipated for a -photocycloaddition reaction.In contrast, 1,2-diphenyl-3,3,4,4-tetramethylcyclobutene (1TM), 1,2-diphenylcyclopentene (2), and 1,2-diphenylcyclohexene (3) yield only phenanthrene products.Photochemical quantum yields have been determined for all four reactions.For 1 and 1TM, excited-state lifetimes have been measured as a function ofthe concentration of added TCE and 2,5-dimethyl-2,4-hexadiene (DMHD).The observed data indicate that the methyl groups in 1TM effectively inhibit the interaction of possible -reactants with the 1TM* excited state.
