Synthesis and studies of covalently linked bodipy-metal dipyrrin conjugates

Three new covalently linked BODIPY-metal dipyrrin conjugates (Pd2+, Zn2+ and Re1+) were synthesized by treating beta-dipyrrinyl BODIPY with appropriate metal salts in toluene in the presence of triethylamine at 120 degrees C. The conjugates were isolated in decent yields either by recrystallization or by column chromatographic purification. The conjugates were thoroughly characterized by 1D and 2D NMR spectroscopy, absorption, cyclic voltammetry and DFT/TD-DFT studies. The studies revealed that the BODIPY and metal dipyrrin moieties in conjugates interact very weakly with each other and retain their individual characteristic features. The conjugates are electron deficient and non-fluorescent in nature.