Linked Life Data

15688656

Source:http://linkedlifedata.com/resource/pubmed/id/15688656

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pubmed-article:15688656rdf:typepubmed:Citationlld:pubmed
pubmed-article:15688656lifeskim:mentionsumls-concept:C0439640lld:lifeskim
pubmed-article:15688656lifeskim:mentionsumls-concept:C0035973lld:lifeskim
pubmed-article:15688656lifeskim:mentionsumls-concept:C0014274lld:lifeskim
pubmed-article:15688656lifeskim:mentionsumls-concept:C0439855lld:lifeskim
pubmed-article:15688656lifeskim:mentionsumls-concept:C1711351lld:lifeskim
pubmed-article:15688656pubmed:issue1lld:pubmed
pubmed-article:15688656pubmed:dateCreated2005-2-3lld:pubmed
pubmed-article:15688656pubmed:abstractTextThe new heptanuclear ruthenium(II) dendron, [Cl(2)Ru{(micro-2,3dpp)Ru[(micro-2,3-dpp)Ru(bpy)2]2}2](PF6)12 (1; 2,3-dpp=2,3-bis(2'-pyridyl)pyrazine; bpy = 2,2'-bipyridine), was prepared by means of the "complexes as ligands/complexes as metals" synthetic strategy, and its absorption spectrum, redox behavior, and luminescence properties were investigated. Compound 1 is a multicomponent species, which contains three different types of chromophores (namely, the {Cl(2)Ru(micro-2,3-dpp)2} core, the {Ru(micro-2,3dpp)3}2+ intermediate, and the {(bpy)2Ru(micro-2,3-dpp)}2+ peripheral subunits) and several redox-active sites. The new species exhibits very intense absorption bands in the UV region (epsilon value in the 10(5)-10(6) M(-1) cm(-1) range) as a result of spin-allowed ligand-centered (LC) transitions, and intense bands in the visible region (epsilon value in the 10(4)-10(5) M(-1) cm(-1) range) as a result of the various spin-allowed metal-to-ligand charge-transfer (MLCT) transitions. The redox investigation (accomplished by cyclic and differential pulse voltammetry) indicates that 1 undergoes a series of reversible metal-centered oxidation and ligand-centered reduction processes within the potential window investigated (+1.90 / -1.40 V vs. the standard calomel electrode, SCE). The assignment of each absorption bond and redox process to specific subunits of 1 was achieved by comparison with the properties of smaller multinuclear species of the same family, namely [Cl(2)Ru{(micro-2,3-dpp)Ru(bpy)2}2]4+ (2), [(bpy)2Ru(u-2,3-dpp)Ru(bpy)2]4+ (4), and [Ru{(micro-2,3-dpp)Ru(bpy)2}3]4+ (5). The title compound exhibits luminescence both at room temperature in acetonitrile fluid solution and at 77 K in butyronitrile rigid matrix. The emission is attributed to the triplet MLCT (3MLCT) state involving the core {Cl(2)Ru(micro-2,3-dpp)2} subunit. Interestingly, the 3MLCT levels involving the peripheral {(bpy)2Ru(micro-2,3-dpp)}2+ subunits are deactivated by energy transfer to the emitting level, in spite of the presence of interposed high-energy (Ru(micro-2,3-dpp)3}2+ components, which, in other dendrimers, acted as "isolating" subunits toward energy-transfer processes. Ultrafast experiments on 1 and on the parent species 2 and 5 allowed us to rationalize this behavior and highlight that a sequential two-step electron-transfer process can be held responsible for the efficient overall energy transfer, which offers a way to overcome a limitation in antenna metal dendrimers.lld:pubmed
pubmed-article:15688656pubmed:languageenglld:pubmed
pubmed-article:15688656pubmed:journalhttp://linkedlifedata.com/r...lld:pubmed
pubmed-article:15688656pubmed:statusPubMed-not-MEDLINElld:pubmed
pubmed-article:15688656pubmed:monthJanlld:pubmed
pubmed-article:15688656pubmed:issn1439-4235lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:PuntorieroFau...lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:SerroniScolas...lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:CampagnaSebas...lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:ChiorboliClau...lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:ScandolaFranc...lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:LicciardelloA...lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:GallettaMauri...lld:pubmed
pubmed-article:15688656pubmed:authorpubmed-author:JurisAlbertoAlld:pubmed
pubmed-article:15688656pubmed:issnTypePrintlld:pubmed
pubmed-article:15688656pubmed:volume6lld:pubmed
pubmed-article:15688656pubmed:ownerNLMlld:pubmed
pubmed-article:15688656pubmed:authorsCompleteYlld:pubmed
pubmed-article:15688656pubmed:pagination129-38lld:pubmed
pubmed-article:15688656pubmed:year2005lld:pubmed
pubmed-article:15688656pubmed:articleTitleA new heptanuclear dendritic ruthenium(II) complex featuring photoinduced energy transfer across high-energy subunits.lld:pubmed
pubmed-article:15688656pubmed:affiliationDipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, V Sperone 31, 98166 Messina, Italy. photochem@chem.unime.itlld:pubmed
pubmed-article:15688656pubmed:publicationTypeJournal Articlelld:pubmed