Functionalized 1,3-dipyrrolyl-1,3-diketone difluoroboron complexes

Abstract

BF₂ complexes of 1,3-dipyrrolyl-1,3-diketones are highly emissive compounds and well known to be π-electronic anion-responsive systems because of their role in the formation of ion-pair assemblies. Despite their impressive electronic properties, their broader potential remains unexplored. Here, we synthesized a series of novel mono-functionalized π-electronic BF₂ complexes of 1,3-dipyrrolyl-1,3-diketones. Controlled functionalization was achieved by selectively introducing formyl, iodo, nitro and amine groups at the α-position of the unsubstituted pyrrole of 1,3-dipyrrolyl-1,3-diketone BF₂ complexes. Single crystal X-ray diffraction studies of compounds 2 and 4 provided definitive evidence of their molecular structures and confirmed selective functionalization. Detailed photophysical and electrochemical studies revealed the alteration of electronic properties through the choice of functional groups as evidenced by distinct absorption and emission profiles. Furthermore, DFT calculations complemented the experimental findings by providing insights into the bandgap energies and molecular stability of the compounds. These functionalized BF₂ complexes represent valuable building blocks for developing new derivatives with applications spanning organic electronics, bioimaging, and chemosensors.