Photolysis primary products of alkylcobaloximes controlled by the cobalt-carbon bond strength

• Tipo: Artigo em Revista Científica Internacional
• Data: 1999

Autores

Rangel, M (Autor) ICBAS; Arcos, T (Autor) Outra; de Castro, B (Autor) FCUP

Revista

Título: Organometallics

Vol. 18

Páginas: 3451-3456

ISSN: 0276-7333

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 16 Citações

Scopus - 19 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-001-3MR

DOI: 10.1021/om990078s

Abstract (EN): Anaerobic photolysis of several methyl- and benzylpyridinecobaloximes was studied by electron spin resonance spectroscopy in aprotic solvents, at three temperatures of irradiation and with use of visible and UV light sources, Homolysis of the cobalt-carbon bond is photochemically induced when irradiation with visible light is pet-formed at room temperature, giving risc to Co(II) five-coordinate species and organic radicals. Irradiation with visible light of fluid (250 K) or frozen (77 K) solutions does not cause homolysis of the cobalt-carbon bond, in contrast with the results reported for other alkylpyridinecobaloximes. Homolysis of the cobalt-carbon bond is achieved at all temperatures if a UV light source is used, and the results are rationalized in terms of the values of the cobalt-carbon bond dissociation energies. The results obtained at 250 K for a series of isotopically substituted methylpyridinecobaloximes allowed the definitive assignment of the spectrum obtained upon photolysis at 250 K to a cobalt(III) nitroxide radical and not to a Co(II) center as has been proposed earlier.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6