title: Persilylated phosphoranyl radicals: the first persistent noncyclic phosphoranyl radicals.
abstract: Persistent noncyclic phosphoranyl radicals have been prepared and observed by electron paramagnetic resonance (EPR) for the first time. They were obtained by UV-photolysis of a solution containing a bis(trialkylsilyl) peroxide (R = Me, Et) and a tris(trialkylsilyl) phosphite (R = Me, Et, iPr). EPR parameters (a(P) approximately 100 mT) are typical of phosphoranyl radicals exhibiting a trigonal-bipyramidal structure, with the odd electron in an equatorial site. Analysis of the pseudo-first-order decay shows that these phosphoranyl radicals decay by S(H)2 homolytic substitution on the bis(trialkylsilyl) peroxide and by loss of a trialkylsilyloxyl radical (alpha-scission reaction). Both the S(H)2 and alpha-scission reactions depend on the steric bulk of the alkyl groups, that is, the bulkier the alkyl group, the slower the S(H)2 and alpha-scission reactions.
authors.affiliation: Universités d'Aix-Marseille 1-3, CNRS--UMR 6517, Faculté des Sciences de St. Jérôme, case 542, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Berchadsky
authors.forename: Christiane
authors.initials: C
authors.lastname: Bernard-Henriet
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Finet
authors.forename: Robert
authors.initials: R
authors.lastname: Lauricella
authors.forename: Sylvain R A
authors.initials: SR
authors.lastname: Marque
authors.forename: Paul
authors.initials: P
authors.lastname: Tordo