Near-Infrared-Emitting Iridium(III) Complexes as Phosphorescent Dyes for Live Cell Imaging
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- 作者：Guoliang Zhang ; Huiyuan Zhang ; Yuan Gao ; Ran Tao ; Lijun Xin ; Junyang Yi ; Fuyou Li ; Wanli Liu ; Juan Qiao
- 刊名：Organometallics
- 出版年：2014
- 出版时间：January 13, 2014
- 年：2014
- 卷：33
- 期：1
- 页码：61-68
- 全文大小：393K
- ISSN：1520-6041
文摘
The three near-infrared-emitting cationic iridium(III) complexes [Ir(pbq-g)2(NN)]+PF6鈥?/sup> (pbq-g = phenylbenzo[g]quinoline; NN = bipyridine (1), 1,10-phenanthroline (2), 4,7-diphenyl-1,10-phenanthroline (3)) have been demonstrated as phosphorescent dyes in live cell imaging. These complexes with different ancillary ligands show similar near-infrared (NIR) emission with 位max,peak at 698 nm and 位max,shoulder at 760 nm in CH2Cl2 solutions, with a moderate quantum yield of around 3%. However, these complexes behave quite differently as NIR dyes for live cell imaging. Complexes 1 and 2 exhibit exclusive staining in the cytoplasm with good cell membrane permeability under excitation at 488 nm, while 3 gives almost no cell uptake, as further determined by flow cytometry. Although the lipophilicities of these complexes follow the order 1 < 2 < 3, their cytotoxicities are in the reverse order. The exceptionally low cytotoxicity of 3 could be attributed to its poor solubility in aqueous buffer and thus substantially low exposure dose. This comparative study suggested that the ancillary ligands could fine-tune the amphiphilicity and cytotoxicity of the cyclometalated iridium(III) complexes and thus might play a key role in the design of NIR-emitting iridium(III) complexes for practical applications in bioimaging.