Fig. 1. (A) Proposed formation of the push–pull fluorescent click product. R = dioxolane moiety of d-TCO (as drawn for compound 16 in Scheme 3). (B) Normalized absorption (solid line) and emission spectra (dashed line) of the click product in PBS buffer. (C) Fluorescence intensity increase upon click reaction (black line for 6 and orange line for 6 + d-TCO). (D) Absorption and emission spectra of 17 in different solvents. The quantum yields were determined using Rhodamine 6G as standard (Ø = 0.94 in EtOH).
