Proton-Transfer Dynamics of Photoacidic Merocyanines in Aqueous Solution.

ABSTRACT: Photoacids attract increasing scientific attention, as they are valuable tools to spatiotemporally control proton-release reactions and pH values of solutions. We present the first time-resolved spectroscopic study of the excited state and proton-release dynamics of prominent merocyanine representatives. Femtosecond transient absorption measurements of a pyridine merocyanine with two distinct protonation sites revealed dissimilar proton-release mechanisms: one site acts as a photoacid generator as its pK_a value is modulated in the ground state after photoisomerization, while the other functions as an excited state photoacid which releases its proton within 1.1 ps. With a pK_a drop of 8.7 units to -5.5 upon excitation, the latter phenolic site is regarded a super-photoa

SUBMITTER: Kaiser C 

PROVIDER: S-EPMC8361770 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature