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Article: Complete charge pooling is prevented in viologen-based dendrimers by self-protection

TitleComplete charge pooling is prevented in viologen-based dendrimers by self-protection
Authors
KeywordsBipyridinium units
Dendrimers
Electrochemistry
Photosensitization
Redox chemistry
Viologen
Issue Date2004
Citation
Chemistry - A European Journal, 2004, v. 10, n. 24, p. 6361-6368 How to Cite?
AbstractWe have investigated the electrochemical behavior, and chemical and photosensitized reduction of two dendrimers based on a 1,3,5-trisubstituted benzenoid core, which contain 9 and 21 4,4′-bipyridinium (usually called viologen) units, respectively, in their branches and are terminated with tetraarylmethane groups. For comparison purposes, the behavior of reference compounds that contain a single viologen unit have also been investigated. We have found that only part of the viologen units can be reduced in the dendrimer species. For the larger dendrimer, the number of reducible viologens (out of the 21 present) is 14 in electrochemical experiments (in MeCN), 9 on reduction with bis(benzene)chromium (in MeCN), and 13 by photoinduced electron transfer with 9-methylanthracene as a photosensitizer and triethanolamine as a sacrificial reductant in CH2Cl2. The reduced viologen units undergo partial dimerization. The photochemical experiments have shown that only monomeric, one-electron-reduced viologen units are formed at the beginning of the irradiation, followed by dimer formation, until a photostationary state is reached that contains 40 % nonreduced, 33 % monomeric reduced, and 27 % reduced units associated in the dimeric form. The results suggest that, upon reduction of a fraction of the viologen units, the dendrimer structure shrinks, with the result that the bulky terminal groups protect other viologen units from being reduced.
Persistent Identifierhttp://hdl.handle.net/10722/332571
ISSN
2023 Impact Factor: 3.9
2023 SCImago Journal Rankings: 1.058
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorMarchioni, Filippo-
dc.contributor.authorVenturi, Margherita-
dc.contributor.authorCeroni, Paola-
dc.contributor.authorBalzani, Vincenzo-
dc.contributor.authorBelohradsky, Martin-
dc.contributor.authorElizarov, Arkadij M.-
dc.contributor.authorTseng, Hsian Rong-
dc.contributor.authorStoddart, J. Fraser-
dc.date.accessioned2023-10-06T05:12:33Z-
dc.date.available2023-10-06T05:12:33Z-
dc.date.issued2004-
dc.identifier.citationChemistry - A European Journal, 2004, v. 10, n. 24, p. 6361-6368-
dc.identifier.issn0947-6539-
dc.identifier.urihttp://hdl.handle.net/10722/332571-
dc.description.abstractWe have investigated the electrochemical behavior, and chemical and photosensitized reduction of two dendrimers based on a 1,3,5-trisubstituted benzenoid core, which contain 9 and 21 4,4′-bipyridinium (usually called viologen) units, respectively, in their branches and are terminated with tetraarylmethane groups. For comparison purposes, the behavior of reference compounds that contain a single viologen unit have also been investigated. We have found that only part of the viologen units can be reduced in the dendrimer species. For the larger dendrimer, the number of reducible viologens (out of the 21 present) is 14 in electrochemical experiments (in MeCN), 9 on reduction with bis(benzene)chromium (in MeCN), and 13 by photoinduced electron transfer with 9-methylanthracene as a photosensitizer and triethanolamine as a sacrificial reductant in CH2Cl2. The reduced viologen units undergo partial dimerization. The photochemical experiments have shown that only monomeric, one-electron-reduced viologen units are formed at the beginning of the irradiation, followed by dimer formation, until a photostationary state is reached that contains 40 % nonreduced, 33 % monomeric reduced, and 27 % reduced units associated in the dimeric form. The results suggest that, upon reduction of a fraction of the viologen units, the dendrimer structure shrinks, with the result that the bulky terminal groups protect other viologen units from being reduced.-
dc.languageeng-
dc.relation.ispartofChemistry - A European Journal-
dc.subjectBipyridinium units-
dc.subjectDendrimers-
dc.subjectElectrochemistry-
dc.subjectPhotosensitization-
dc.subjectRedox chemistry-
dc.subjectViologen-
dc.titleComplete charge pooling is prevented in viologen-based dendrimers by self-protection-
dc.typeArticle-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1002/chem.200400747-
dc.identifier.scopuseid_2-s2.0-11144268005-
dc.identifier.volume10-
dc.identifier.issue24-
dc.identifier.spage6361-
dc.identifier.epage6368-
dc.identifier.isiWOS:000225706900017-

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