Multiantenna artificial photosynthetic reaction center complex.
In order to ensure efficient utilization of the solar spectrum, photosynthetic organisms use a variety of antenna chromophores to absorb light and transfer excitation to a reaction center, where photoinduced charge separation occurs. Reported here is a synthetic molecular heptad that features two bis(phenylethynyl)anthracene and two borondipyrromethene antennas linked to a hexaphenylbenzene core that also bears two zinc porphyrins. A fullerene electron acceptor self-assembles to both porhyrins via dative bonds. Excitation energy is transferred very efficiently from all four antennas to the porphyrins. Singlet-singlet energy transfer occurs both directly and by a stepwise funnel-like pathway wherein excitation moves down a thermodynamic gradient. The porphyrin excited states donate an electron to the fullerene with a time constant of 3 ps to generate a charge-separated state with a lifetime of 230 ps. The overall quantum yield is close to unity. In the absence of the fullerene, the porphyrin excited singlet state donates an electron to a borondipyrromethene on a slower time scale. This molecule demonstrates that by incorporating antennas, it is possible for a molecular system to harvest efficiently light throughout the visible from ultraviolet wavelengths out to approximately 650 nm.
Department of Chemistry and Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, USA.
Yuichi
Y
Terazono
Gerdenis
G
Kodis
Paul A
PA
Liddell
Vikas
V
Garg
Thomas A
TA
Moore
Ana L
AL
Moore
Devens
D
Gust
D000042:Absorption; D000873:Anthracenes / Q000737:chemistry; D001554:Benzene / Q000737:chemistry; D032701:Biomimetics; D004583:Electrons; D004735:Energy Transfer; D037741:Fullerenes / Q000737:chemistry; D005663:Furans / Q000737:chemistry; D008027:Light; D008665:Metalloporphyrins / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D011162:Porphobilinogen / Q000031:analogs & derivatives / Q000737:chemistry; D013057:Spectrum Analysis; D013997:Time Factors
D000873:Anthracenes; D037741:Fullerenes; D005663:Furans; D008665:Metalloporphyrins; D045322:Photosynthetic Reaction Center Complex Proteins; C507544:dipyrromethene; C017802:zinc hematoporphyrin; C018674:tetrahydrofuran; D011162:Porphobilinogen; C034020:anthracene; D001554:Benzene