Abstract

SILVA, Monica Teixeira da  and  NETTO-FERREIRA, José Carlos. Laser flash photolysis study of the reaction of 1H-benz[f]indane-1,2,3-trione with olefins. J. Braz. Chem. Soc. [online]. 2004, vol.15, n.4, pp. 577-581. ISSN 0103-5053.  http://dx.doi.org/10.1590/S0103-50532004000400021.

The photochemistry of 1H-benz[f]indane-1,2,3-trione (1) in the presence of olefins has been examined in benzene solution at room temperature by laser flash photolysis. The triplet excited state of 1 (t = 3 ms, l = 460 and 490 nm, in benzene) is quenched by olefins containing allylic hydrogen with rate constants ranging from 10⁵ L mol^-1s^-1 (for 1,5-hexadiene) to 10⁹ L mol^-1s^-1 (for 2,5-dimethyl-2,4-hexadiene). A comparison of the reactivity of 1 with that of 1,2,3-indantrione (2) shows that a similar mechanism for the quenching by olefins is operating for the two cyclic vicinal triketones and involves essentially the lowest triplet excited state of n,p* character.

Keywords : cyclic vicinal triketone; laser flash photolysis; triplet state.