title: Triarylmethanols bearing bulky aryl groups and the NOESY/EXSY experimental observation of two-ring-flip mechanism for helicity reversal of molecular propellers.
abstract: Triarylmethanols - the direct precursors of persistent trityl radicals - are racemic mixtures of chiral three-bladed molecular propellers. Depending on bulkiness of aryl groups they exhibit various liabilities to interconversion, the half- life time of room temperature racemization varying in a range between 8.4 hours and 1.32 years. NOESY/EXSY experiment performed on two representative models strongly supports the two-ring flip mechanism for the configurational interchange.
authors.affiliation: Vorozhtsov Novosibirsk Institute of Organic Chemistry, 9 Acad. M.A. Lavrentjev Ave., Novosibirsk 630090, Russia ; Department of Natural Sciences, Novosibirsk State University, 2 Pirogov St., Novosibirsk 630090, Russia.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Tormyshev
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Genaev
authors.forename: Georgy E
authors.initials: GE
authors.lastname: Sal'nikov
authors.forename: Olga Yu
authors.initials: OY
authors.lastname: Rogozhnikova
authors.forename: Tatiana I
authors.initials: TI
authors.lastname: Troitskaya
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Trukhin
authors.forename: Victor I
authors.initials: VI
authors.lastname: Mamatyuk
authors.forename: Dmitry S
authors.initials: DS
authors.lastname: Fadeev
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Halpern
keywords: 2D NOESY/EXSY; activation parameters; chirality; epimerization mechanism; triarylmethanols