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|Title:||Photoinduced electron transfer between the interlocked components of porphyrin catenanes: effect of the presence of nonequivalent reduction sites on the charge recombination rate||Contributor(s):||Flamigni, L (author); Talarico, AM (author); Serroni, S (author); Puntoriero, F (author); Gunter, MJ (author); Johnston, M (author); Jeynes, T (author)||Publication Date:||2003||DOI:||10.1002/chem.200204502||Handle Link:||https://hdl.handle.net/1959.11/596||Abstract:||Catenanes made up of several polyether-strapped porphyrin macrocycles interlinked with the cyclic electron acceptor cyclobis(paraquat-p-phenylene) were spectroscopically, photophysically, and electrochemically characterized. The catenanes exhibit very rich redox behavior due to the presence of several different and interacting electro-active subunits. The redox patterns represent useful fingerprints that provide detailed information on the electronic interactions and the chemical environments that the electroactive subunits experience in the supramolecular arrays. A photoinduced electron transfer from the porphyrin excited state (charge separation CS) occurs with ґ=20 ps in the catenanes with a larger strap and faster than 20 ps (instrumental resolution) in the catenanes with a shorter strap. The resulting charge-separated state recombines to the ground state (charge recombination CR) with lifetimes similar in all cases, 41±4 ps. Comparison of the electron transfer rates CS and CR in the host-guest complexes of the same porphyrins with the noncyclic electron acceptor paraquat, indicate slower reactions in the catenanes. This behavior is assigned to the different separation between reacting partners determined by the type of bond (weak interaction or mechanical) and to a two-step consecutive electron transfer to different sites of the macrocyclic electron acceptor in the catenanes which retards charge recombination.||Publication Type:||Journal Article||Source of Publication:||Chemistry: A European Journal, 9(11), p. 2649-2659||Publisher:||Wiley-VCH Verlag GmbH & Co KGaA||Place of Publication:||Weinheim, Germany||ISSN:||0947-6539||Field of Research (FOR):||030302 Nanochemistry and Supramolecular Chemistry||Peer Reviewed:||Yes||HERDC Category Description:||C1 Refereed Article in a Scholarly Journal||Statistics to Oct 2018:||Visitors: 151
|Appears in Collections:||Journal Article|
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