Carbazole substituted boron dipyrromethenes.

meso-Substituted BODIPY with N-butylcarbazole () was prepared and derivatized. Dibromo BODIPY , α-formyl BODIPY and β-formyl BODIPY were synthesized. All compounds were characterized by HRMS, NMR, UV-vis absorption, electrochemical and fluorescence techniques. The crystal structures of BODIPY and its dibromo derivative were also solved. In both the X-ray structures, the dihedral angle between the meso-carbazole group and the dipyrrin plane was decreased, suggesting the increased interaction between the two units. meso-Substitution with the N-butylcarbazole group on the BODIPY core rendered huge Stokes shifts (111-168 nm) and higher quantum yields as compared to meso-aryl BODIPY. An efficient energy transfer from the carbazole unit to the BODIPY core was observed by fluorescence spectroscopy for all the compounds . CV studies of compounds showed anodic shifts of the reduction and oxidation potentials, suggesting that the meso-carbazole group is affecting the electronic properties of the BODIPY core and making them easier to reduce.