Probing Nanocavities with Proton‐Transfer Fluorescence

Abstract

A spectral shift of up to 70 nm is observed for the dye HPIP depending on the size of the cyclodextrin cavity in which it is encapsulated. The fluorescence results from a phototautomerization in which proton transfer and twisting of the molecule are influenced by its surroundings. A model of a 1:2 complex of HPIP with a cyclodextrin is depicted on the right.