Luminescence excitation and de-excitation involving one-electron transfer
- 1 January 1978
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
- Vol. 74, 2077-2091
- https://doi.org/10.1039/f19787402077
Abstract
The radiation-induced chemiluminescence (RCL) in aqueous solutions of 1-aminonaphthalene-4-(Na)sulphonate (AnsH) predominantly involves: AnsH·++ eaq→ AnsH*. This conclusion is due to quantitative correlations found between the transient absorption, assigned to AnsH·+, and the RCL emission under various conditions modifying the AnsH·+ formation. Phosphates act on AnsH·+via the reaction: AnsH·++ HPO2– 4⇌ Ans·+ H2PO– 4. Azide radicals (·OH + N– 3→ OH–+ N˙ 3) are about 7.5 times more efficient than ·OH in generating AnsH·+, at the expense of Ans· and AnsH·OH. Analogous phosphate and azide effects were found for a number of other efficient RCL compounds. Direct electron impact excitation of AnsH appears to occur 75 % by charge recombination. Halide type compounds are capable of perturbing this recombinational excitation process. Fluorescence quenching, on the other hand, is particularly efficient with electron-affinic compounds (A). A fairly good correlation was found between the fluorescence quenching rates k(AnsH*+ A) and the corresponding reaction rate constants k(e– aq+ A), suggesting that AnsH* de-excitation occurs by electron transfer to A. For ionic acceptors k(AnsH*+ A) depends upon the ionic strength of the solution.Keywords
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