Observing Aqueous Proton-Uptake Reactions Triggered by Light
J. Am. Chem. Soc. , Volume 145 - Issue 12 p. 6682- 6690
Proton-transfer reactions in water are essential to chemistry and biology. Earlier studies reported on aqueous proton-transfer mechanisms by observing light-triggered reactions of strong (photo)acids and weak bases. Similar studies on strong (photo)base-weak acid reactions would also be of interest because earlier theoretical works found evidence for mechanistic differences between aqueous H+ and OH- transfer. In this work, we study the reaction of actinoquinol, a water-soluble strong photobase, with the water solvent and the weak acid succinimide. We find that in aqueous solutions containing succinimide, the proton-transfer reaction proceeds via two parallel and competing reaction channels. In the first channel, actinoquinol extracts a proton from water, after which the newly generated hydroxide ion is scavenged by succinimide. In the second channel, succinimide forms a hydrogen-bonded complex with actinoquinol and the proton is transferred directly. Interestingly, we do not observe proton conduction in water-separated actinoquinol-succinimide complexes, which makes the newly studied strong base-weak acid reaction essentially different from previously studied strong acid-weak base reactions.
|NWO-I , European Research Council (ERC) , European Union Horizon 2020|
|J. Am. Chem. Soc.|
Antalicz, B, Versluis, J, & Bakker, H.J. (2023). Observing Aqueous Proton-Uptake Reactions Triggered by Light. J. Am. Chem. Soc., 145(12), 6682–6690. doi:10.1021/jacs.2c11441