New 8-substituted BODIPY-based chromophores: synthesis, optical and electrochemical properties
Résumé
BODIPY-based chromophores, in which an electron withdrawing difluoro-boraindacene fragment is connected via position 8 to different donor fragments, were synthesized. Their electrochemical and photophysical properties were studied. All compounds exhibit a quasi-reversible oxidation corresponding to the formation of a BODIPY p-radical cation at around 0.8 V vs. FeCp2+/FeCp2 that is slightly sensitive to the nature of the electron donating group. A reversible reduction is observed around - 1.6 V vs. FeCp2+/FeCp2 corresponding to the formation of the BODIPY p-radical anion. Cyclic voltammetry analysis of a gamma-methylenepyran substituted BODIPY indicates the formation of redox bistable system with high bistability. In dichloromethane solution, the chromophores exhibit an intense absorption band around 502 nm and an emission in the 516-528 nm range. A significant emission quench is observed in case of amino and gamma-methylenepyran substituents.