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.
Terazono
Yuichi
Y
Department of Chemistry and Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, USA.
Kodis
Gerdenis
G
Liddell
Paul A
PA
Garg
Vikas
V
Moore
Thomas A
TA
Moore
Ana L
AL
Gust
Devens
D
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