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论文类型：期刊论文

发表时间：2012-09-21

发表刊物：DALTON TRANSACTIONS

收录刊物：SCIE、EI、PubMed、Scopus

卷号：41

期号：35

页面范围：10680-10689

ISSN号：1477-9226

摘要：Visible light-harvesting cyclometalated Ir(III) complexes with 3-(2-benzothiazoly)-7-diethylaminocoumarin as the C boolean AND N cyclometalation ligands were prepared. The ancillary N boolean AND N ligand is either 6-piperidine naphthalimide-phenanthroline (Ir-1) or 9-aminophenanthroline (Ir-3). Ir(ppy)(2)(Phen) was prepared as model complex (Ir-2). Ir-1 and Ir-3 show strong absorption of visible light (epsilon = 109 000 M-1 cm(-1) or 112 000 M-1 cm(-1) at 486 or 484 nm, respectively). All the complexes show room temperature phosphorescence with drastically different phosphorescence quantum yields (Phi(P) = 4.3%, 44.3% and 46.0% for Ir-1, Ir-2 and Ir-3, respectively). With steady state and time-resolved spectra, as well as DFT calculations, the T-1 excited states of Ir-1 and Ir-3 were proposed to be the (IL)-I-3 state, whereas the (MLCT)-M-3 state was proposed for Ir-2. Long-lived emissive triplet excited states (7.6 mu s and 54.5 mu s) were observed for Ir-1 and Ir-3, compared to the short T-1 excited state lifetime of Ir-2 (1.2 mu s). The complexes were used as triplet photosensitizers for triplet-triplet annihilation upconversion and upconversion quantum yields (Phi(UC)) of 19.3% and 12.7% were observed for Ir-1 and Ir-3, respectively. No upconversion was observed for Ir-2 under the same experimental conditions.