Laser flash photolysis study of triplets of cyclobutanethiones

Bhattacharyya, K and Das, PK and Rao, Nageshwara B and Ramamurthy, V (1986) Laser flash photolysis study of triplets of cyclobutanethiones. In: Journal of Photochemistry, 32 (3). pp. 331-340.

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Abstract

Five cyclobutanethiones with different chromophores at the 3-position were examined for triplet state behaviour in benzene using laser excitation into their low lying nπ*1 band systems. A weak transient absorption attributable to the triplet state is observed in all these cases. Results concerning triplet lifetimes, intersystem crossing yields (S1 → T1), self-quenching kinetics and kinetics of energy transfer to all-trans-1,6-diphenyl-1,3,5-hexatriene and oxygen and quenching by di-t-butyl nitroxide (DTBN) are presented. Intersystem crossing yields estimated with reference to p,p′-dimethoxythiobenzophenone are roughly unity in all five cases. Self-quenching rates are found to be less than diffusion limited and this is attributed to steric crowding at the α positions (dimethyl group). The rates of oxygen and DTBN quenching compare well with those reported for several other thiones in the literature. No transients other than the triplet were detected in the above cyclobutane-thiones.

Item Type:	Journal Article
Publication:	Journal of Photochemistry
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	31 Aug 2009 06:11
Last Modified:	19 Sep 2010 05:40
URI:	http://eprints.iisc.ac.in/id/eprint/22159

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