Photohomolysis and photoionization of substituted tetraphenylethanes and C-C fragmentation of 1,1,2,2-tetra(p-R-phenyl)ethane radical cations (R = H, CH3, OCH3, Cl)

• Tipo: Artigo em Revista Científica Internacional
• Data: 1998

Autores

Faria, JL (Autor) FEUP; McClelland, RA (Autor) Outra; Steenken, S (Autor) Outra

Revista

Título: Chemistry - A European Journal

Vol. 4

Páginas: 1275-1280

ISSN: 0947-6539

Editora: Wiley-Blackwell

Indexação

ISI Web of Knowledge - 12 Citações

Scopus - 15 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-001-7H9

DOI: 10.1002/(sici)1521-3765(19980710)4:7<1275::aid-chem1275>3.0.co;2-x

Abstract (EN): On photolysis of a series of tetraphenylethanes in 2,2,2-trifluoroethanol (TFE) solution with 248 nm light, homolysis of the central C-C bond occurs to yield the corresponding substituted diphenylmethyl radicals, in a process requiring one quantum of light. A second process takes place under conditions of high photon fluxes, namely biphotonic photoionization to produce a radical cation, which subsequently undergoes efficient C-C scission of the aliphatic central bond to yield the radical and carbocation fragments. Photoionization and photohomolysis are the preferred processes of excited state deactivation in the solvents acetonitrile, TFE, and 1,1,1,3,3,3-hexafluoroisopropanol. The lifetime of the radical cation could be directly determined by following the formation rates of the fragments in solution. The cations were characterized by their UV absorption spectra and electrophilic reactivities.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6