Energy and photoinduced electron transfer in a wheel-shaped artificial photosynthetic antenna-reaction center complex.
Functional mimics of a photosynthetic antenna-reaction center complex comprising five bis(phenylethynyl)anthracene antenna moieties and a porphyrin-fullerene dyad organized by a central hexaphenylbenzene core have been prepared and studied spectroscopically. The molecules successfully integrate singlet-singlet energy transfer and photoinduced electron transfer. Energy transfer from the five antennas to the porphyrin occurs on the picosecond time scale with a quantum yield of 1.0. Comparisons with model compounds and theory suggest that the Förster mechanism plays a major role in the extremely rapid energy transfer, which occurs at rates comparable to those seen in some photosynthetic antenna systems. A through-bond, electron exchange mechanism also contributes. The porphyrin first excited singlet state donates an electron to the attached fullerene to yield a P(*+)-C(60)(*-) charge-separated state, which has a lifetime of several nanoseconds. The quantum yield of charge separation based on light absorbed by the antenna chromophores is 80% for the free base molecule and 96% for the zinc analogue.
Kodis
Gerdenis
G
Department of Chemistry and Biochemistry, Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, AZ 85287-1604, USA.
Terazono
Yuichi
Y
Liddell
Paul A
PA
Andréasson
Joakim
J
Garg
Vikas
V
Hambourger
Michael
M
Moore
Thomas A
TA
Moore
Ana L
AL
Gust
Devens
D
D000873:Anthracenes / Q000138:chemical synthesis / Q000737:chemistry*; D040761:Biomimetic Materials / Q000138:chemical synthesis / Q000737:chemistry*; D004583:Electrons; D007700:Kinetics; D010777:Photochemistry; D045322:Photosynthetic Reaction Center Complex Proteins / Q000138:chemical synthesis / Q000737:chemistry*; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
D000873:Anthracenes; D045322:Photosynthetic Reaction Center Complex Proteins; D011166:Porphyrins