Shining New Light on the Spiropyran Photoswitch: A Photocage Decides between cis–trans or Spiro-Merocyanine Isomerization

Photochromic molecules from the spiropyran family are known to undergo light-induced interconversion between the colorless spiro- and the colored merocyanine forms. Here, we show for the first time that small structural modifications open up for an additional photoisomerization mode: reversible cis–trans isomerization of the merocyanine. Moreover, the introduction of a photocage allows for light-activated switching between the two modes.This project received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 745626. Authors also acknowledge the Swedish Research Council for funding (VR Grant No. 2016-03601). License: ACS AuthorChoic