Chapter Open for the Excited-State Intramolecular Thiol Proton Transfer in the Room-Temperature Solution.

We report here, for the first time, the experimental observation on the excited-state intramolecular proton transfer (ESIPT) reaction of the thiol proton in room-temperature solution. This phenomenon is demonstrated by a derivative of 3-thiolflavone (), namely, 2-(4-(diethylamino)phenyl)-3-mercapto-4-chromen-4-one (), which possesses an -S-H···O═ intramolecular H-bond (denoted by the dashed line) and has an S absorption at 383 nm. Upon photoexcitation, exhibits a distinctly red emission maximized at 710 nm in cyclohexane with an anomalously large Stokes shift of 12 230 cm.

Generation and spectroscopic profiles of stable multiarylaminium radical cations bridged by fluorenes.

A series of arylaminofluorene derivatives (DTFA-1, TTFA-2, TAFB-3, and TAFA-4) were synthesized, and the generation of their corresponding arylaminium cation radicals was readily achieved by Cu(ClO(4))(2) in CH(3)CN. Moreover, the cation radicals were stable at ambient temperature with substantially long life times and exhibited distinct colors. The oxidation mechanism and spectroscopic features of the resulting cation radicals were probed by UV-vis-NIR spectroscopy and electron spin resonance experiments.