| Autor: |
Lu, Yue, McGoldrick, Niamh, Murphy, Frances, Twamley, Brendan, Cui, Xiaoneng, Delaney, Colm, Máille, Gearóid M. Ó, Wang, Junsi, Zhao, Jianzhang, Draper, Sylvia M. |
| Předmět: |
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| Zdroj: |
Chemistry - A European Journal; 8/1/2016, Vol. 22 Issue 32, p11349-11356, 8p |
| Abstrakt: |
A series of IrIII complexes, based on 1,10-phenanthroline featuring aryl acetylene chromophores, were prepared and investigated as triplet photosensitizers. The complexes were synthesized by Sonogashira cross-coupling reactions using a 'chemistry-on-the-complex' method. The absorption properties and luminescence lifetimes were successfully tuned by controlling the number and type of light-harvesting group. Intense UV/Vis absorption was observed for the IrIII complexes with two light-harvesting groups at the 3- and 8-positions of the phenanthroline. The asymmetric IrIII complex (with a triphenylamine (TPA) and a pyrene moiety attached) exhibited the longest lifetime. Red emission was observed for all the complexes in deaerated solutions at room temperature. Their emission at low temperature (77 K) and nanosecond time-resolved transient difference absorption spectra revealed the origin of their triplet excited states. The singlet-oxygen (1O2) sensitization and triplet-triplet annihilation (TTA)-based upconversion were explored. Highly efficient TTA upconversion ( ΦUC=28.1 %) and 1O2 sensitization ( ΦΔ=97.0 %) were achieved for the asymmetric IrIII complex, which showed intense absorption in the visible region ( λabs=482 nm, ϵ=50900 m−1 cm−1) and had a long-lived triplet excited state (53.3 μs at RT). [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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