Excitation energy transfer from BODIPY to self-aggregate of zinc bacteriochlorophyll-d analog in supramolecule

• Boron dipyrromethene (BODIPY) was appended to zinc 3 1 -hydroxy-13 1 -oxo-chlorin (ZnC). • The BODIPY and ZnC species absorbs green and violet-to-blue/red lights, respectively. • The ZnC moiety in the synthetic conjugate self-aggregated in 1%( v / v ) THF–hexane. • Excitation energy of BODIPY was efficiently transferred to (ZnC) n in a supramolecule. • The system is a functional model of chlorosomes as natural light-harvesting antennas. In the main light-harvesting antennas (chlorosomes) of anoxygenic photosynthetic green bacteria, photoexcited carotenoids absorbing green light donate singlet excitation energy to self-aggregates of bacteriochlorophylls(BChls)- c / d / e with their site energies in a far-red light region. To mimic the energy transfer systems, a zinc BChl- d analog covalently linked with a boron dipyrromethene (BODIPY) derivative was investigated in 1%( v / v ) tetrahydrofuran and hexane. In the less polar organic solvent, the Zn-BChl- d part in the conjugate self-aggregated similarly as in chlorosomes and accepted excitation energy from the BODIPY part with absorption around 500 nm in a green light region. The excitation energy transfer from BODIPY* to (Zn-BChl- d ) n in the supramolecular self-assembly of the conjugate was analyzed by visible absorption and fluorescence emission spectroscopy.