Characterization of the thermal and photoinduced reactions of photochromic spiropyrans in aqueous solution.

ABSTRACT: Six water-soluble spiropyran derivatives have been characterized with respect to the thermal and photoinduced reactions over a broad pH-interval. A comprehensive kinetic model was formulated including the spiro- and the merocyanine isomers, the respective protonated forms, and the hydrolysis products. The experimental studies on the hydrolysis reaction mechanism were supplemented by calculations using quantum mechanical (QM) models employing density functional theory. The results show that (1) the substitution pattern dramatically influences the pKa-values of the protonated forms as well as the rates of the thermal isomerization reactions, (2) water is the nucleophile in the hydrolysis reaction around neutral pH, (3) the phenolate oxygen of the merocyanine form plays a key role in the hydr

SUBMITTER: Hammarson M 

PROVIDER: S-EPMC3814652 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature