[Ru(bipy)(3)](2+) and [Os(bipy)3](2+) chromophores as sensitisers for near-infrared luminescence from Yb(III) and Nd(III) in d/f dyads: contributions from Forster, Dexter, and redox-based energy-transfer mechanisms

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dc.contributor.authorLazarides, T.en
dc.contributor.authorTart, N. M.en
dc.contributor.authorSykes, D.en
dc.contributor.authorFaulkner, S.en
dc.contributor.authorBarbieri, A.en
dc.contributor.authorWard, M. D.en
dc.date.accessioned2015-11-24T16:46:32Z
dc.date.available2015-11-24T16:46:32Z
dc.identifier.issn1477-9226-
dc.identifier.urihttps://olympias.lib.uoi.gr/jspui/handle/123456789/9082
dc.rightsDefault Licence-
dc.subjectlanthanide luminescenceen
dc.subjectphotophysical propertiesen
dc.subjectcoordination propertiesen
dc.subjectdinuclear complexesen
dc.subjectmacrocyclic spaceren
dc.subjectcrystal-structureen
dc.subjectelectron-transferen
dc.subjectquantum yieldsen
dc.subjectbinding-sitesen
dc.subjectcrown-ethersen
dc.title[Ru(bipy)(3)](2+) and [Os(bipy)3](2+) chromophores as sensitisers for near-infrared luminescence from Yb(III) and Nd(III) in d/f dyads: contributions from Forster, Dexter, and redox-based energy-transfer mechanismsen
heal.abstractcomplexes RuL and OsL contain [M(bipy)3](2+) chromophores with a pendant aza-18-crown-6 macrocycle for binding of lanthanide(III) ions. The photophysical properties of the adducts RuL.Ln and OsL.Ln, prepared by addition of excess Ln(NO3)(3) (Ln = Nd, Yb) to solutions of RuL and OsL in MeCN, were examined using time-resolved and steady-state luminescence methods. Whereas RuL does not act as an energy-donor to Yb(III), it will transfer energy to (and generate sensitised near-infraredluminescence from) Nd(III) with a Ru(II). Nd(III) energy-transfer rate constant of 6.8 106 s(-1). In contrast, OsL is quenched by both Yb(III) and Nd(II), but with faster energy-transfer to Yb(III) (2.6 x 10(7) s(-1)) than to Nd(III) (1.4 x 10(7) s(-1)). Thus d -> energy transfer is in both cases faster for Os(II) than for Ru(II), but the relative ability of Nd(III) and Yb(III) to act as energy-acceptors is inverted from RuL.Ln to OsL.Ln. Reasons for this are discussed with reference to contributions from the Forster and Dexter mechanism for energy-transfer in RuL.Nd and OsL.Nd, using calculated spectroscopic overlap integrals coupled with molecular modelling to estimate inter-chromophore separations. The particular effectiveness of Os(II) -> Yb(III) energy-transfer in OsL.Yb is explained in terms of the Horrocks redox mechanism involving an initial *Os(II) -> Yb(III) photoinduced electron transfer step generating an Os(III)/Yb(II) state, which is shown to be marginally favourable for OsL.Yb, but not for RuL center dot Yb in which the [Ru(bipy)(3)](2+) unit is a poorer excited- state electron-donor by about 0.1 eV.en
heal.accesscampus-
heal.fullTextAvailabilityTRUE-
heal.identifier.primaryDoi 10.1039/B901560d-
heal.identifier.secondary<Go to ISI>://000266035000013-
heal.identifier.secondaryhttp://pubs.rsc.org/en/content/articlepdf/2009/dt/b901560d-
heal.journalNameDalton Transactionsen
heal.journalTypepeer reviewed-
heal.languageen-
heal.publicationDate2009-
heal.publisherRoyal Society of Chemistryen
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείαςel
heal.typejournalArticle-
heal.type.elΆρθρο Περιοδικούel
heal.type.enJournal articleen

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