Characterization of the thermal and photoinduced reactions of photochromic spiropyrans in aqueous solution
Journal article, 2013

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 hydrolysis reaction. Hence, the nonprotonated merocyanine isomer is susceptible to hydrolysis, whereas the corresponding protonated form is stable toward hydrolytic degradation.

Author

Martin Hammarson

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Jesper Nilsson

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Shiming Li

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Tamas Beke-Somfai

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Joakim Andreasson

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Journal of Physical Chemistry B

1520-6106 (ISSN) 1520-5207 (eISSN)

Vol. 117 43 13561-71

Photochromic Systems for Solid State Molecular Electronic Devices and Light-Activated Cancer Drugs (PHOTOCHROMES)

European Commission (FP7), 2008-09-01 -- 2013-08-31.

Subject Categories

Physical Chemistry

DOI

10.1021/jp408781p

More information

Created

10/7/2017