Higher BODIPY Homologues–Synthesis, Reactivity, and Photoluminescence Investigations

The synthesis of ^MesDPM group 13 (B─In, ^MesDPM = 1,5,9-trimesityldipyrromethene) compounds with halide substituents (Cl─I) is described. All compounds were fully characterized including NMR and IR spectroscopy as well as mass spectrometry. In addition, the solid state molecular structures have been determined by X-ray diffraction (XRD) analysis. As higher representatives of BODIPY (boron difluoride dipyrromethene) dyes, some of these ^MesDPM triel dihalides also exhibit an intense green fluorescence when exposed to sunlight. In this regard, the optical properties were investigated by UV/Vis and photoluminescence spectroscopy giving absorption maxima around 520 nm and fluorescence emission in the range between 550 and 660 nm. Fluorescence quantum efficiencies up to 42% could be obtained from measurements in toluene solution. Further, reactivity studies were carried out which opened-up access to mixed substituted ^MesDPM triels with one alkyl and one halide substituent.