A rational designed thiols fluorescence probe: the positional isomer in PET

It was reported here a devised and synthesized thiol fluorescent probes ortho -Z3 , meta -Z3 and para -Z3 based on photoinduced electron transfer (PET) pathway utilizing fluorophore naphthalimide as the electron donor and responsive group maleimide as the electron acceptor . The fluorescence intensity of these probes varied significantly depending on the position of the maleimide toward the naphthalimide fluorophore. Comparing to the meta and para isomers, the ortho isomer displayed the best fluorescence response performances upon addition of thiols. The results indicated that relative position of the electron acceptor played key role in the PET process, and probe ortho -Z3 could detect endogenous biothiols in serum samples and live cells successfully.