Efficient light-induced pK(a) modulation coupled to base-catalyzed photochromism

Johannes Gurke ... [et al.]

Gurke Johannes (20%)

Budzák Šimon 1982- (20%) UMBFP08 - Katedra chémie
Schmidt Bernd M. (20%)
Jacquemin Denis (20%)
Hecht Stefan (20%)

Angewandte Chemie : international edition : a journal of the German Chemical Society. Vol. 57, no. 17 (2018), pp. 4797-4801. - Weinheim : Wiley-VCH, 2018

fotoprepínače - photoswitches

 

acidity

 

aromaticity

 

diarylethenes

 

fotochromizmus - photochromism

 

angličtina

Nemecko

54

Photoswitchable acid-base pairs, whose pK(a) values can be reversibly altered, are attractive molecular tools to control chemical and biological processes with light. A significant, light-induced pK(a) change of three units in aqueous medium has been realized for two thermally stable states, which can be interconverted using UV and green light. The light-induced pK(a) modulation is based on incorporating a 3-H-thiazol-2-one moiety into the framework of a diarylethene photoswitch, which loses the heteroaromatic stabilization of the negatively charged conjugate base upon photochemical ring closure, and hence becomes significantly less acidic. In addition, the efficiency of the photoreactions is drastically increased in the deprotonated state, giving rise to catalytically enhanced photochromism. It appears that protonation has a significant influence on the shape of the ground- and excited-state potential energy surfaces, as indicated by quantum-chemical calculations.

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