Water-soluble Py-BIPS spiropyrans as photoswitches for biological applications

The ultrafast photochemistry of a new spiropyran photoswitch (Py-BIPS) has been investigated, revealing many advantages in the application in water over the previously studied spiropyrans. Functionalized Py-BIPS derivatives are presented for the study of pH dependence, stability, toxicity, and the thermal and photochemical behavior on longer time scales in aqueous media using several spectroscopic methods. These investigations pave the way for the practical use of Py-BIPS derivatives as photoswitchable ligands of biomolecules.