title: On the Route to the Photogeneration of Heteroaryl Cations. The Case of Halothiophenes.
abstract: 2-Chloro-, 2-bromo-, and 2-iodothiophenes undergo photochemical dehalogenation via the triplet state. In the presence of suitable π-bond nucleophiles, thienylation occurs with modest yield from chloro and bromo derivatives (via photogenerated triplet 2-thienyl cation). Specific trapping by using oxygen along with computational analysis carried out by means of a density functional method support that, in the case of iodo derivatives, homolytic thienyl-I bond fragmentation occurs first and heteroaryl cations are formed by electron transfer within the triplet radical pair, thus opening an indirect access to such cations.
authors.affiliation: PhotoGreen Lab, Department of Chemistry, University of Pavia , Viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Raviola
authors.affiliation: Department of Chemistry, University of Pavia , Viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Chiesa
authors.affiliation: PhotoGreen Lab, Department of Chemistry, University of Pavia , Viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Protti
authors.affiliation: PhotoGreen Lab, Department of Chemistry, University of Pavia , Viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Albini
authors.affiliation: PhotoGreen Lab, Department of Chemistry, University of Pavia , Viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Fagnoni