Fig. 1.
Synthesis of aryloxy KFL-1 derivatives. (A) General scheme of the synthesis of aryloxy KFL-1 derivatives. (B) Aryloxy KFL-1 derivatives (1–5) synthesized in this study. (C) Plot of the fluorescence quantum efficiency (ϕfl) and uncaging quantum efficiency (ϕu) of aryloxy BODIPY or KFL-1 derivatives against the HOMO energy level of the corresponding phenols. The HOMO energy levels of the phenols were calculated (solvent = dichloromethane) at the B3LYP/6-31G level by Gaussian09. Black and red circles represent data of BODIPY-caged compounds (26) and KFL-1–caged compounds, respectively. The numerals on the red circles indicate aryloxy KFL-1 derivatives (1–4).