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The Effect of a Mild Base on Curcumin in Methanol and Ethanol
journal contribution
posted on 2012-03-08, 00:00 authored by Yuval Erez, Itay Presiado, Rinat Gepshtein, Dan HuppertSteady-state and time-resolved emission techniques were
employed
to study the effect of acetate, a mild base, on the luminescence of
curcumin in methanol and ethanol. We found that the steady-state emission
intensity as well as the average fluorescence decay time are reduced
by a factor of 5 when the acetate concentration is raised to about
1.8 M. We attribute this large effect to an excited-state proton transfer
(ESPT) from the acidic groups of curcumin to the acetate anion. We
analyze the experimental data in terms of an ESPT reaction occurring
between a photoacid and a base.