Variable Photophysical Properties of Phosphorescent Iridium(III) Complexes Triggered bycloso- andnido-Carborane Substitution

Palladium catalyzed regioselective mono-alkenylation of o-carboranes via Heck type coupling reaction of a cage B–H bond

Palladium catalyzed electrophilic B–H activation for regioselective mono-alkenylation of o-carborane on B(8) and B(9).

Ir(iii) complexes designed for light-emitting devices: beyond the luminescence color array

This Perspective highlights the photophysics and recent breakthroughs in the study of emissive Ir(iii) compounds, including a personal account elucidating the role of molecular and electronic structures in controlling the photophysics of heteroleptic [Ir(N^C)₂(L^X)]⁺ complexes.

Core-shell structured phosphorescent nanoparticles for detection of exogenous and endogenous hypochlorite in live cells via ratiometric imaging and photoluminescence lifetime imaging microscopy

Core-shell phosphorescent nanoparticles were used to detect intracellular ClO^– via ratiometric and photoluminescence lifetime imaging.

We report a ratiometric phosphorescence sensory system for hypochlorite (ClO^–) based on core–shell structured silica nanoparticles. Two phosphorescent iridium(iii) complexes were immobilised in the inner solid core and outer mesoporous layer of the nanoparticles, respectively. The former is insensitive to ClO^– and thus serves as an internal standard to increase the accuracy and precision, while the latter exhibits a specific and significant luminogenic response to ClO^–, providing high selectivity and sensitivity. Upon exposure to ClO^–, the nanoparticles display a sharp luminescence colour change from blue to red. Additionally, intracellular detection of exogenous and endogenous ClO^– has been demonstrated via ratiometric imaging and photoluminescence lifetime imaging microscopy. Compared to intensity-based sensing, ratiometric and lifetime-based measurements are independent of the probe concentration and are thus less affected by external influences, especially in intracellular applications.

Phosphorescent cyclometalated iridium(III) complexes that contain substituted 2-acetylbenzo[b]thiophen-3-olate ligand for red organic light-emitting devices

We report the synthesis of a new class of thermally stable and strongly luminescent cyclometalated iridium(III) complexes 1-6, which contain the 2-acetylbenzo[b]thiophene-3-olate (bt) ligand, and their application in organic light-emitting diodes (OLEDs). These heteroleptic iridium(III) complexes with bt as the ancillary ligand have a decomposition temperature that is 10-20 % higher and lower emission self-quenching constants than those of their corresponding complexes with acetylacetonate (acac). The luminescent color of these iridium(III) complexes could be fine-tuned from orange (e.g., 2-phenyl-6-(trifluoromethyl)benzo[d]thiazole (cf3 bta) for 4) to pure red (e.g., lpt (Hlpt=4-methyl-2-(thiophen-2-yl)quinolone) for 6) by varying the cyclometalating ligands (C-deprotonated C^N). In particular, highly efficient OLEDs based on 6 as dopant (emitter) and 1,3-bis(carbazol-9-yl)benzene (mCP) as host that exhibit stable red emission over a wide range of brightness with CIE chromaticity coordinates of (0.67, 0.33) well matched to the National Television System Committee (NTSC) standard have been fabricated along with an external quantum efficiency (EQE) and current efficiency of 9 % and 10 cd A(-1) , respectively. A further 50 % increase in EQE (>13 %) by replacing mCP with bis[4-(6H-indolo[2,3-b]quinoxalin-6-yl)phenyl]diphenylsilane (BIQS) as host for 6 in the red OLED is demonstrated. The performance of OLEDs fabricated with 6 (i.e., [(lpt)2Ir(bt)]) was comparable to that of the analogous iridium(III) complex that bore acac (i.e., [(lpt)2 Ir(acac)]; 6a in this work) [Adv. Mater.- 2011, 23, 2981] fabricated under similar conditions. By using ntt (Hnnt=3-hydroxynaphtho[2,3-b]thiophen-2-yl)(thiophen-2-yl)methanone) ligand, a substituted derivative of bt, the [(cf3bta)2Ir(ntt)] was prepared and found to display deep red emission at around 700 nm with a quantum yield of 12 % in mCP thin film.

Metal–metal redox synergy in selective B–H activation of ortho-carborane-9,12-dithiolate

Metal–metal redox synergy is introduced, for the first time, for B–H functionalization of inert dicarba-dodecaboranes under mild conditions in high yields.