Synthesis and fluorescence properties of covalently linked homo and hetero porphyrin dyads containing meso-tolyl porphyrin and meso-furyl porphyrin sub-units

Abstract

Three porphyrin building blocks with N₄, N₃S and N₂S₂ cores having three meso-furyl groups and one meso-iodophenyl group were synthesized and characterized. The porphyrin building blocks were used to synthesize six porphyrin dyads such as N₄–N₄, N₃S–N₃S, N₂S₂– N₂S₂, N₄–N₃S, N₄– N₂S₂ and N₃S– N₂S₂ containing meso-tolyl and meso-furyl porphyrin sub-units under mild Pd(0) mediated coupling conditions. Steady state fluorescence studies indicated an efficient energy transfer from the meso-tolyl porphyrin sub-unit to the meso-furyl porphyrin sub-unit in all six dyads. This study supported the argument that the meso-furyl porphyrins can be used as good energy acceptors when meso-aryl porphyrins act as energy donors in their metal free form.