title: Near-infrared emitting iridium(iii) complexes for mitochondrial imaging in living cells.
abstract: Biocompatible transition metal complexes dyes emitting in the near-infrared (NIR) region, are highly desirable in fluorescence imaging techniques. However, a high-performance mitochondria-specific labeling NIR probe with high photostability is still lacking. Herein we reported two NIR-emitting cationic iridium(iii) complexes [Ir(pbq-g)2(N^N)]+Cl-(pbq-g = phenylbenzo[g]-quinoline; N^N = 2-(1-benzyl-1H-pyrazol-3-yl) pyridine (Ir1) and 2-(1-(naphthalen-1-ylmethyl)-1H-pyrazol-3-yl) pyridine (Ir2)). These two novel Ir(iii) complexes with different N^N ligands exhibited similar NIR emission with λmaxat 751 nm for Ir1 and 750 nm for Ir2 in PBS solution, with luminescence quantum yields of around 0.62 for Ir1 and 0.85 for Ir2. These two complexes showed high mitochondrial specificity, superior photostability, high resistance to the loss of the mitochondrial membrane potential and appreciable tolerance to environmental changes, allowing NIR imaging of mitochondrial morphological changes over long periods of time. These excellent photophysical and imaging properties made them promising NIR luminescent tags for applications in bioimaging.
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China. xuli473@163.com.
authors.forename: Yuying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China. xuli473@163.com.
authors.forename: Peipei
authors.initials: P
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China. xuli473@163.com.
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Fang
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China. xuli473@163.com.
authors.forename: Gongqing
authors.identifier: http://orcid.org/0000-0001-8918-9548
authors.initials: G
authors.lastname: Wu
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China. xuli473@163.com.
authors.forename: Shuting
authors.initials: S
authors.lastname: Chen
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China. xuli473@163.com.
authors.forename: Zhina
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275, P. R. China.
authors.forename: Hui
authors.identifier: http://orcid.org/0000-0003-4153-5303
authors.initials: H
authors.lastname: Chao
authors.affiliation: School of Food Science, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China.
authors.forename: Wenying
authors.initials: W
authors.lastname: Tan
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China. xuli473@163.com.
authors.forename: Li
authors.identifier: http://orcid.org/0000-0001-9823-8225
authors.initials: L
authors.lastname: Xu
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D002470:Cell Survival; D002712:Chlorides / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D003592:Cytophotometry / Q000379:methods*; D006367:HeLa Cells; D006801:Humans; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D049408:Luminescent Agents / Q000138:chemical synthesis / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods; D008928:Mitochondria / Q000648:ultrastructure*; D051336:Mitochondrial Membranes / Q000378:metabolism; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry; D061848:Optical Imaging / Q000379:methods*; D011725:Pyridines / Q000737:chemistry
chemical_list: D016227:Benzoquinones; D002712:Chlorides; D056831:Coordination Complexes; D008024:Ligands; D049408:Luminescent Agents; D009281:Naphthalenes; D011725:Pyridines; C538735:iridium chloride; C031721:naphthalene; C029322:phenylbenzoquinone; D007495:Iridium; C023666:pyridine