In this Article, we present a series of cyclometalated iridium(III) polypyridine complexes of the formula [Ir(N^C)2(N^N)](PF6) that showed dual emission under ambient conditions. The structures of the cyclometalating and diimine ligands were changed systematically to investigate the effects of the substituents on the dual-emission properties of the complexes. On the basis of the photophysical data, the high-energy (HE) and low-energy (LE) emission features of the complexes were assigned to triplet intraligand ((3)IL) and triplet charge-transfer ((3)CT) excited states, respectively. Time-dependent density functional theory (TD-DFT) calculations supported these assignments and indicated that the dual emission resulted from the interruption of the communication between the higher-lying (3)IL and the lower-lying (3)CT states by a triplet amine-to-ligand charge-transfer ((3)NLCT) state. Also, the avidin-binding properties of the biotin complexes were studied by emission titrations, and the results showed that the dual-emissive complexes can be utilized as ratiometric probes for avidin. Additionally, all the complexes exhibited efficient cellular uptake by live HeLa cells. The MTT and Annexin V assays confirmed that no cell death and early apoptosis occurred during the cell imaging experiments. Interestingly, laser-scanning confocal microscopy revealed that the complexes were selectively localized on the cell membrane, mitochondria, or both, depending on the nature of the substituents of the ligands. The results of this work will contribute to the future development of dual-emissive transition metal complexes as ratiometric probes and organelle-selective bioimaging reagents.
Herein, we demonstrate a novel one‐pot synthetic method towards a series of boron‐doped polycyclic aromatic hydrocarbons (B‐PAHs, 1 a–1 o), including hitherto unknown B‐doped zethrene derivatives, from ortho‐aryl substituted diarylalkynes with high atom efficiency and broad substrate scopes. A reaction mechanism is proposed based on the experimental investigation together with the theoretical calculations, which involves a unique 1,4‐boron migration process. The resultant benchtop‐stable B‐PAHs are thoroughly investigated by X‐ray crystallography, cyclic voltammetry, UV/Vis absorption, and fluorescence spectroscopies. The blue and green organic light‐emitting diode (OLED) devices based on 1 f and 1 k are further fabricated, demonstrating the promising application potential of B‐PAHs in organic optoelectronics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.