Highly Efficient Triplet Photosensitizers: A Systematic Approach to the Application of IrIII Complexes containing Extended Phenanthrolines

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• 作者：Yue Lu ; Dr. Niamh McGoldrick ; Dr. Frances Murphy ; Dr. Brendan Twamley ; Xiaoneng Cui ; Dr. Colm Delaney ; Dr. Gearó ; id M. &#211 ; Má ; ille ; Junsi Wang ; Prof. Dr. Jianzhang Zhao and Prof. Dr. Sylvia M. Draper
• 刊名：Chemistry - A European Journal
• 出版年：2016
• 出版时间：August 1, 2016
• 年：2016
• 卷：22
• 期：32
• 页码：11349-11356
• 全文大小：2492K
• ISSN：1521-3765

文摘

A series of Ir^III 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 Ir^III complexes with two light-harvesting groups at the 3- and 8-positions of the phenanthroline. The asymmetric Ir^III 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 (m>Φm>_UC=28.1 %) and ¹O₂ sensitization (m>Φm>_Δ=97.0 %) were achieved for the asymmetric Ir^III complex, which showed intense absorption in the visible region (m>λm>_abs=482 nm, m>ϵm>=50900 mallCaps">m^−1 cm^−1) and had a long-lived triplet excited state (53.3 μs at RT).