Novel Asymmetric Boron-dipyrromethenes Fluorescent Dyes:Synthesis And Properties

Boron-dipyrromethenes fluorescent dyes have received more and more attention due to its high molar extinction efficient, sharp absorption and emission spectra, high fluorescence quantum yield, photo-and chemo-stability. In the recent years, BODIPY have been developed rapidly, and used as the fluorophore for the construction of molecular sensors.Here, in this paper a general procedure for the introduction of pyridone moiety was developed, using a Friedlander reaction, for post-modification of ready-made BODIPY core, from which three pyridone-fused BODIPYs1,2and3were generated. This method is complementary to the classical method for obtaining aromatic ring-fused BODIPYs, which begins with the condensation of the corresponding aromatic ring-fused pyrroles. These pyridone-fused BODIPYs are distinctive, possessing favorable photophysical characteristics with strong absorption, high bright orange fluorescence and easy reduction due to the electron-withdrawing effect of the fused pyridone moiety. More important, these BODIPYs bear reactive functions which are applicable in proteins labeling by bioorthogonal chemical reactions.Two new borondipyrromethene-based probes BODIPY-SN and BODIPY-SON were reported here, designed by combining two chelators8-aminoquinoline (AQ) and toluenethiol (BODIPY-SN) or benzylsulfoxide (BODIPY-SON) into one borondipyrromethene molecule. These two receptors in one molecule are expected to coordinate to metals in a synergic manner, thus improve the binding selectivity. As expected, these probes displayed high Zn2+selectivity with a dramatic emission enhancement, and the detection limit is above10-6mol/L. Although Cd2+also induces emission enhancement, the interference is less pronounced. In order to improve the selectivity of Zn2+, strategy like introduction of TPEA instead of8-aminoquinoline will be performed.