Dinuclear iridium(iii) complexes as phosphorescent trackers to monitor mitochondrial dynamics

Abstract

5Mitochondria dynamic processes are essential for mammalian development and engaged in several diseases. However, commercial mitochondrial probes are currently too limited to satisfactorily track these dynamics. In this present work, seven dinuclear iridium(III) complexes [(ppy) 2 Ir(L 1-7 )Ir(ppy) 2 ] 2+ (Ir1-Ir7, ppy = 2-phenylpyridine, L = 1,3-bis(1-substituted-1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)benzene) were synthesized. Possessing high specificity to mitochondria, low cytotoxicity and high resistance to the 10 loss of mitochondrial membrane potential, Ir2-Ir7 can serve as mitochondrial imaging dyes. Ir3 and Ir6 are further developed to track the mitochondrial morphological changes during the early stages of apoptosis. In addition, the relationship of the electron drawing/withdrawing groups in these systems with the photophysical properties and photostability is also discussed. 65 to red. 18 Recently, Grazulevicius and co-workers reported the development of the "warm-white" OLEDs that based on the application of bifunctional molecules via attachment of carbazole-based fragments to the phosphorescent iridium(III) complexes core. The triplet excited state of these bimolecular 70 complex were confirmed by the DFT and (TD) DFT methods. [19][20] In addition to OLED, iridium(III) complexes have also been applied as sensors, 21-22 in vivo tumour imaging, 23-24 , live cell compartmentalization staining and so on. Huang, Li and Schubert have reviewed these fields. [25][26][27] It is interesting that various 75 iridium(III) complexes have been developed as cytoplasm, nucleus, nucleolus, Golgi apparatus, lysosomes and vacuoles imaging dyes, 28-31 reports on iridium(III) complexes as mitochondrial dyes are quite less, although cationic species are Graphical AbstractDinuclear iridium(III) complexes [(ppy) 2 Ir(L 1-7 )Ir(ppy) 2 ] 2+ (Ir1-Ir7) serve as mitochondrial imaging dyes, Ir3 and Ir6 are further developed to track the mitochondrial morphological changes during the early stages of apoptosis.

Cyclometalated Iridium(III) Complexes as Two‐Photon Phosphorescent Probes for Specific Mitochondrial Dynamics Tracking in Living Cells

“…These processes are involved in the remodeling of mitochondrial cristae and the mobilization of cytochrome c, which is considered an irreversible process associated with the collapse of the membrane potential 39. Similar results were observed when we used IrL1 , IrL3 , IrL4 and IrL5 to conduct this experiment (Figures S32–S35 in the Supporting Information), which is consistent with previous results from our laboratory with similar complexes 16c…”

Luminescent Diiridium Complexes with Bridging Pyrazolates: Characterization and Fabrication of OLEDs Using Vacuum Thermal Deposition

“…For comparison, several ditopic chelates linked via pyrimidine, pyrazine and pyridazine, or functional 2‐phenylpyrimidine, diarylhydrazide, isocyanate, terpyridine dicarboxylate, and oxamidato based bridging ligands have been employed in the preparation of charge‐neutral luminescent diiridium complexes ( 5 – 8 ) ( Scheme ). Also, the bridging entities with iminopyridine, dipyridylpyrazine, and phenanthroline were found useful in making the cationic dinuclear Ir(III) complexes. Despite that the majority of these complexes have exhibited excellent luminescence versus representative di‐iridium complexes reported earlier, fabrication of OLED using the same is limited to the solution processes due to the poor volatility.…”

Cyclometalated iridium(III) complexes as mitochondria-targeted anticancer agents

“…As one of the most important cell signaling center, mitochondria are essential organelles required for cellular energy production and are involved in many other cellular activities, one of which is to produce reactive oxygen species (ROS) and leads to mitochondria-mediated apoptosis [19][20][21]. Our previous works showed that mitochondria is the main target of cyclometalated iridium(III) complexes [22][23][24][25][26][27]. Herein, four novel cyclometalated iridium(III) complexes were developed as mitochondria-targeted theranostic agents.…”