title: Photosynthetic reaction center mimicry of a "special pair" dimer linked to electron acceptors by a supramolecular approach: self-assembled cofacial zinc porphyrin dimer complexed with fullerene(s).
abstract: Biomimetic bacterial photosynthetic reaction center complexes have been constructed using well-defined self-assembled supramolecular approaches. The "special pair" donor, a cofacial porphyrin dimer, was formed via potassium ion induced dimerization of meso-(benzo-[15]crown-5)porphyrinatozinc. The dimer was subsequently self-assembled with functionalized fullerenes via axial coordination and crown ether-alkyl ammonium cation complexation to form the donor-acceptor pairs, mimicking the noncovalently bound entities of the photosynthetic reaction center. The adopted self-assembly methodology yielded supramolecular complexes of higher stability, with defined geometry and orientation. Efficient forward electron transfer from the singlet excited zinc porphyrin dimer to the fullerene entity and relatively slow reverse electron transfer, important steps in the photosynthetic light energy conversion have been achieved in these novel biomimetic model systems.
authors.affiliation: Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA. Francis.DSouza@wichita.edu
authors.forename: Francis
authors.initials: F
authors.lastname: D'Souza
authors.forename: Raghu
authors.initials: R
authors.lastname: Chitta
authors.forename: Suresh
authors.initials: S
authors.lastname: Gadde
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Rogers
authors.forename: Paul A
authors.initials: PA
authors.lastname: Karr
authors.forename: Melvin E
authors.initials: ME
authors.lastname: Zandler
authors.forename: Atula S D
authors.initials: AS
authors.lastname: Sandanayaka
authors.forename: Yasuyaki
authors.initials: Y
authors.lastname: Araki
authors.forename: Osamu
authors.initials: O
authors.lastname: Ito
mesh_terms: D019281:Dimerization; D004563:Electrochemistry; D004583:Electrons; D037741:Fullerenes / Q000737:chemistry*; D046911:Macromolecular Substances / Q000138:chemical synthesis* / Q000737:chemistry; D008665:Metalloporphyrins / Q000737:chemistry*; D008954:Models, Biological; D008968:Molecular Conformation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D013237:Stereoisomerism; D013997:Time Factors; D015032:Zinc / Q000737:chemistry*
chemical_list: D037741:Fullerenes; D046911:Macromolecular Substances; D008665:Metalloporphyrins; D045322:Photosynthetic Reaction Center Complex Proteins; D015032:Zinc