Synthesis and Optical Properties of BODIPY with Active Group on meso- Position

Background: In this work a few approaches for the synthesis of 4,4-difluoro-8-(4’- carboxyphenyl)-4-bora-3a,4a-diaza-s-indacene are considered. The process of obtaining this boron fluoride complex involves the following stages: introduction of the protective group (methoxy-, 1’- pyrrolidine-2,5-dion-, trichloroethoxy-) on the carboxy-group of 4-formylbenzoic acid, condensation with pyrrole, removal of protection, oxidation, and complexation proper. A method of direct condensation of pyrrole with the 4-formylbenzoic acid in the presence of a catalytic amount of 0.1 M HCl was proposed to achieve a high yield of the target product. All synthesized compounds were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis. Values of fluorescence quantum yield and Stokes shift were calculated for boron fluoride complexes of dipyrrolylmethenes. Keywords: BODIPY, fluorescence, quantum yield, Stokes shift, extinction coefficient.