Triplet-state Photophysics and Transient Photochemistry of Cyclic Enethiones A Laser Flash Photolysis Study


Autoria(s): Bhattacharyya, Kankan; Das, Paritosh K; Ramamurthy, Vaidhyanathan; Rao, V Pushkara
Data(s)

01/02/1986

Resumo

The triplets of four cyclic enethiones, including thiocoumarin, have been investigated by nanosecond laser flash photolysis. Data are presented for transient spectra and kinetics associated with triplets, quantum yields of intersystem crossing and singlet oxygen photosensitization. The quenching of the thiocoumarin triplet (A:, = 485 nm, E:,, = 8.8 x lo3 dm3 mol-' cm-'in benzene) by several olefins, amines and hydrogen donors occurs with rate constants of 107-5 x lo9 dm3 mol-' s-'; the lower limits of quantum yields ( c#+~) for the related photoreactions, estimated from ground-state depletion, are generally small (0.0-0.1 1 in benzene, except for good hydrogen donors, namely, p-methoxythiophenol and tri-n-butylstannane) . The radical anion of thiocoumarin (A,,, = 405-435 nm) is formed in two stages upon triplet quenching by triethylamine in acetonitrile; the fast component is the result of direct electron transfer to the triplet and the slower component is assigned to secondary photoreduction of the thione ground state by the a-aminoalkyl radical derived from the triethylamine radical-cation.

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/22355/1/F29868200135.pdf

Bhattacharyya, Kankan and Das, Paritosh K and Ramamurthy, Vaidhyanathan and Rao, V Pushkara (1986) Triplet-state Photophysics and Transient Photochemistry of Cyclic Enethiones A Laser Flash Photolysis Study. In: Journal of the chemical society-faraday transactions ii, 82 . pp. 135-147.

Publicador

Royal soc chemistry

Relação

http://www.rsc.org/publishing/journals/F2/article.asp?doi=F29868200135

http://eprints.iisc.ernet.in/22355/

Palavras-Chave #Organic Chemistry
Tipo

Journal Article

PeerReviewed