2-(2,4-Difluorophenyl)-5-fluoropyridine (DFFPPy), CAS number 1426047-01-9, normally serving as a chelating ligand, is a trifluorinated phenyl-pyridine derivative. Phenyl-pyridine building blocks are popular candidates in the synthesis of iridium complexes for catalytic photoredox reactions, assisting the formation of Ir(III)* (excited triplet state) upon visible light irradiation. 2-(2,4-Difluorophenyl)-5-fluoropyridine also shows its effectiveness for visceral leishmaniasis in preclinical screening assay. The increase lipophilicity brought by the fluorine substituents has higher potency against Leishmania infantum.
As a cyclometalating ligand used for photoemitter and being electron deficient with the help of three fluorine, DFFPPy introduces blue shift to the emission wavelength (typically by reducing the highest occupied molecular orbital energy level) and increases the photoluminescence quantum yield (from 6.5% to 50.8%).