[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
Φόρτωση...
Ημερομηνία
Συγγραφείς
Lazarides, T.
Tart, N. M.
Sykes, D.
Faulkner, S.
Barbieri, A.
Ward, M. D.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Royal Society of Chemistry
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Dalton Transactions
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
complexes 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.
Περιγραφή
Λέξεις-κλειδιά
lanthanide luminescence, photophysical properties, coordination properties, dinuclear complexes, macrocyclic spacer, crystal-structure, electron-transfer, quantum yields, binding-sites, crown-ethers
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000266035000013
http://pubs.rsc.org/en/content/articlepdf/2009/dt/b901560d
http://pubs.rsc.org/en/content/articlepdf/2009/dt/b901560d
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας