Química Nova (Jan 2010)
Transferência de elétron inversa na quimiexcitação da reação peróxi-oxalato usando ativadores facilmente redutíveis Inverse electron transfer in peroxyoxalate chemiexcitation using easily reducible activators
Abstract
Chemiluminescence properties of the peroxyoxalate reaction in the presence of activators bearing electron withdrawing substituents were studied, to evaluate the possible occurrence of an inverse electron transfer, from the peroxide intermediate to the activator, in its chemiexcitation step. Relative catalytic rate constants and singlet quantum yields were obtained for the peroxyoxalate reaction, using 9-chloro, 9,10-dichloro, 9-cyano and 9,10-dicyanoanthracenes as activators. The linear free-energy correlation of the relative rate constants with the activators' reduction potentials and the dependence of the quantum yields on the released energy confirm, for the first time, the occurrence of this inverse electron transfer.
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