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Article: Ru(II)-polypyridine complexes covalently linked to electron acceptors as wires for light-driven pseudorotaxane-type molecular machines

TitleRu(II)-polypyridine complexes covalently linked to electron acceptors as wires for light-driven pseudorotaxane-type molecular machines
Authors
KeywordsCharge transfer
Energy transfer
Molecular devices
Rotaxanes
Self- assembly
Issue Date1998
Citation
Chemistry - A European Journal, 1998, v. 4, n. 12, p. 2413-2422 How to Cite?
AbstractAn investigation has been performed on the design of light-driven, pseudorotaxane-type, mechanical molecular machines based on wires made up of an electron-transfer photosensitizer covalently linked to an electron acceptor. Compounds (2,2'-bipyridine)2Ru(2,2'-bipyridine-5-(CH2)-1-(4,4'- bipyridinium)-1'-CH2-R)4+ (14+), (4,4'-(Me)2-2,2'-bipyridine)2Ru(2,2'- bipyridine-5-(CH2)4-1-(4,4'-bipyridinium)1'-CH2-Me)4+ (24+), and (2,2':6',2''-terpyridine)Ru(2,2'.6',2''-terpyridine-4'-phenylene-2-(2,7- diazapyrenium)-7-CH2-R)4+ (34+), where R = -C6H4-(O-CH2-CH2)2-O- Ph) have been prepared and their photochemical and photophysical processes have been investigated in butyronitrile fluid solution (room temperature) and rigid matrix (77 K). At room temperature the triplet metal-to-ligand charge- transfer (3MLCT) excited state of the Ru-based unit of 14+ is quenched by a very fast (k(q) > 5 x 109 s-1) electron-transfer process. For 24+, where the Ru-based and electron-acceptor units are separated by four methylene groups, the value of the quenching constant is 6.2 x 108 s-1. In 34+, the potentially fluorescent S1 excited state of the diazapyrenium unit is quenched by the Ru-based moiety with a rate constant ≥1 x 1011 s-1. In rigid matrix at 77 K, the 3MLCT excited state of the Ru-based moiety is not quenched by the bipyridinium or diazapyrenium moiety, whereas both the fluorescence and phosphorescence of the diazapyrenium moiety of 34+ are completely quenched by the MLCT levels of the Ru-based moiety through energy transfer. Excitation spectra of the Ru-based emission show that, in a rigid matrix at 77 K, the excitation of the bipyridinium moiety leads to population of the 3MLCT excited state of the Ru-based moiety. The above wires and a crown ether (1/5DN38C10) containing two 1,5-dioxynaphthalene electron-donor units self-assemble to give pseudorotaxane systems. Light-induced dethreading of a pseudorotaxane has been achieved and valuable information has been gathered concerning the design of more efficient systems. A spin-off of these studies has been the design of pseudorotaxanes in which the dethreading/rethreading process can be controlled by chemical stimuli.
Persistent Identifierhttp://hdl.handle.net/10722/332421
ISSN
2023 Impact Factor: 3.9
2023 SCImago Journal Rankings: 1.058

 

DC FieldValueLanguage
dc.contributor.authorAshton, Peter R.-
dc.contributor.authorBallardini, Roberto-
dc.contributor.authorBalzani, Vincenzo-
dc.contributor.authorConstable, Edwin C.-
dc.contributor.authorCredi, Alberto-
dc.contributor.authorKocian, Oldrich-
dc.contributor.authorLangford, Steven J.-
dc.contributor.authorPreece, Jon A.-
dc.contributor.authorProdi, Luca-
dc.contributor.authorSchofield, Emma R.-
dc.contributor.authorSpencer, Neil-
dc.contributor.authorStoddart, J. Fraser-
dc.contributor.authorWenger, Sabine-
dc.date.accessioned2023-10-06T05:11:21Z-
dc.date.available2023-10-06T05:11:21Z-
dc.date.issued1998-
dc.identifier.citationChemistry - A European Journal, 1998, v. 4, n. 12, p. 2413-2422-
dc.identifier.issn0947-6539-
dc.identifier.urihttp://hdl.handle.net/10722/332421-
dc.description.abstractAn investigation has been performed on the design of light-driven, pseudorotaxane-type, mechanical molecular machines based on wires made up of an electron-transfer photosensitizer covalently linked to an electron acceptor. Compounds (2,2'-bipyridine)2Ru(2,2'-bipyridine-5-(CH2)-1-(4,4'- bipyridinium)-1'-CH2-R)4+ (14+), (4,4'-(Me)2-2,2'-bipyridine)2Ru(2,2'- bipyridine-5-(CH2)4-1-(4,4'-bipyridinium)1'-CH2-Me)4+ (24+), and (2,2':6',2''-terpyridine)Ru(2,2'.6',2''-terpyridine-4'-phenylene-2-(2,7- diazapyrenium)-7-CH2-R)4+ (34+), where R = -C6H4-(O-CH2-CH2)2-O- Ph) have been prepared and their photochemical and photophysical processes have been investigated in butyronitrile fluid solution (room temperature) and rigid matrix (77 K). At room temperature the triplet metal-to-ligand charge- transfer (3MLCT) excited state of the Ru-based unit of 14+ is quenched by a very fast (k(q) > 5 x 109 s-1) electron-transfer process. For 24+, where the Ru-based and electron-acceptor units are separated by four methylene groups, the value of the quenching constant is 6.2 x 108 s-1. In 34+, the potentially fluorescent S1 excited state of the diazapyrenium unit is quenched by the Ru-based moiety with a rate constant ≥1 x 1011 s-1. In rigid matrix at 77 K, the 3MLCT excited state of the Ru-based moiety is not quenched by the bipyridinium or diazapyrenium moiety, whereas both the fluorescence and phosphorescence of the diazapyrenium moiety of 34+ are completely quenched by the MLCT levels of the Ru-based moiety through energy transfer. Excitation spectra of the Ru-based emission show that, in a rigid matrix at 77 K, the excitation of the bipyridinium moiety leads to population of the 3MLCT excited state of the Ru-based moiety. The above wires and a crown ether (1/5DN38C10) containing two 1,5-dioxynaphthalene electron-donor units self-assemble to give pseudorotaxane systems. Light-induced dethreading of a pseudorotaxane has been achieved and valuable information has been gathered concerning the design of more efficient systems. A spin-off of these studies has been the design of pseudorotaxanes in which the dethreading/rethreading process can be controlled by chemical stimuli.-
dc.languageeng-
dc.relation.ispartofChemistry - A European Journal-
dc.subjectCharge transfer-
dc.subjectEnergy transfer-
dc.subjectMolecular devices-
dc.subjectRotaxanes-
dc.subjectSelf- assembly-
dc.titleRu(II)-polypyridine complexes covalently linked to electron acceptors as wires for light-driven pseudorotaxane-type molecular machines-
dc.typeArticle-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1002/(SICI)1521-3765(19981204)4:12<2413::AID-CHEM2413>3.0.CO;2-A-
dc.identifier.scopuseid_2-s2.0-0031742995-
dc.identifier.volume4-
dc.identifier.issue12-
dc.identifier.spage2413-
dc.identifier.epage2422-

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