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Herein, we report the synthesis and characterization of a small family of Ir(I) and Ir(III) complexes supported by β‐thioketoiminates (SacNac) ligands. All complexes were fully characterized by IR, 1D and 2D NMR, and Elemental Analysis (e.a.) experiments. X‐ray diffraction studies were carried out to corroborate the structure of compounds [Ir(cod)(SacNac)] (1) (cod=1,5‐cyclooctadiene), [Ir(dmb)(SacNac)] (2) (dmb=2,3‐dimethyl‐1,3‐butadiene) and [IrCp*(SacNac‐H)(Cl)2] (8) (Cp*=pentamethyl‐cyclopentadienyl). Complexes 1 and 2 are Ir(I) species and have square‐planar geometry in solid state, with bond angles and distances that suggest semi‐aromaticity in the six‐membered ring. To the best of our knowledge, we report the first mono‐coordination mode of a SacNac ligand via sulfur atom in complex 8. Also, we report the first application of iridium‐SacNac complexes as catalytic precursors in hydroboration reactions, where Ir(III) species give the best results. [ABSTRACT FROM AUTHOR]

We here report the multicolor electrochemiluminescence (ECL) of binary microcrystals prepared from a blue‐emissive iridium complex 1 and an orange‐emissive ruthenium complex 2. These materials display a plate‐like morphology with high crystallinity, as demonstrated by microscopic and powder X‐ray diffraction analyses. Under light excitation, these microcrystals exhibit gradient emission color changes as a result of the efficient energy transfer between two complexes. When modified on glass carbon electrodes, these microcrystals exhibit tunable ECLs with varied emission colors including sky‐blue, white, orange, and red, depending on the doping ratio of complex 2 and the applied potential. Furthermore, organic amines with different molecular sizes are used as the co‐reactant to examine their influences on the ECL efficiency of the porous microcrystals of 1. The analysis on the luminance and RGB values of ECL suggests the existence of energy transfer in the generation of multicolor ECLs in these binary crystals. [ABSTRACT FROM AUTHOR]

In X‐ray structures of the isomorphic mer‐[IrX3(THT)(CNXyl)2] (X=Cl 1, Br 2; THT=tetrahydrothiophene; Xyl=2,6‐Me2C6H3−) complexes, we revealed short intermolecular contacts between the C‐atom of an isocyanide methyl group and halide ligands of another molecule. Geometrical consideration of the X‐ray data and analysis of appropriate DFT studies allowed the attribution of these contacts to CMe⋅⋅⋅X−IrIII (X=Cl, Br) tetrel bond. Specifically, through the application of DFT calculations and various theoretical models, the presence of tetrel bonding interactions was validated, and the contribution of the CMe⋅⋅⋅X−IrIII interaction was assessed. The reinforcement of the tetrel bond upon the isocyanide coordination to iridium(III) is substantiated by molecular electrostatic potential (MEP) surface calculations. To distinguish the tetrel bonding characteristics of CMe⋅⋅⋅X−IrIII (X=Cl, Br) interactions from conventional hydrogen bonding, we employed multiple computational methodologies, including Natural Bond Orbital (NBO) analysis and Electron Localization Function (ELF) analysis. Additionally, Energy Decomposition Analysis (EDA) was applied to selected model systems to explore the underlying physical nature of these interactions. [ABSTRACT FROM AUTHOR]

In this work, two new biscyclometalated Ir(III) complexes with diimine ligands were synthesized. The compounds were characterized by 1D and 2D NMR spectroscopy and HR ESI mass spectrometry. All complexes exhibit efficient phosphorescence with pronounced sensitivity to the presence of oxygen. The photophysical properties of the obtained compounds, including absorption, emission spectra, lifetimes and quantum yields of phosphorescence were measured in various aqueous and model biological media with variations in pH, temperature and at various O2 concentrations. The complexes exhibit a very good sensory response to the changes in oxygen concentration, resulting in an increase in quantum yields and lifetimes by 2.8–5.5 times upon oxygen removal from aerated aqueous solutions. Biological tests with CHO‐K1 cell line have shown that these compounds display low toxicity, rapid internalization into cells and localization predominantly in lysosomes. For the most promising complex the phosphorescence lifetime imaging experiments were conducted, revealing that this sensor markedly changes the phosphorescence lifetime values in cells from 1.8 to 4.1 μs upon transition from normoxia to simulated hypoxia. The obtained results indicate that this type of iridium chromophores can be effectively used for assessing the oxygen status of living objects by using time‐resolved luminescent microscopy. [ABSTRACT FROM AUTHOR]

In recent years, there has been growing exploration of organometallic transition metal complexes as promising options for developing anticancer agents that offer the potential of reduced toxicity compared with the commonly utilized cisplatin analogs. In this respect, iridium complexes containing 2-phenylimidazo- [4,5-f][1,10]-phenanthroline derivatives with different substituents were investigated in different cell lines as potential anticancer agents. All the compounds exhibited potent cytotoxic activity against Caco-2, HeLa, A549, and MDA-MB-231 cell lines. EC50 values of compound 1 were found to be 6.44 μM for Caco-2, 24.78 μM for HeLa, 9.14 μM for A549, and 4.45 μM for the MDA-MB-231 cell line. Similarly, EC50 of 3 was found at 15.07, 14.15, 10.33, and 4.48 μM respectively. The EC50 value of 2 was found to be 12.71 μM for Caco-2, 24.31 μM for HeLa, and 7.44 μM for MDA-MB-231 cells. EC50 values of compound 4 were found to be 28.20 μM for Caco-2, 12.79 μM for HeLa, 8.33 μM for A549, and 3.76 μM for the MDA-MB-231 cell line. The results of gene expression and flow-cytometry analysis showed that the compounds caused the induction of apoptosis in all cancer cell lines by changing caspase 3, Bcl-2, and Bax proteins. The obtained results demonstrate that compounds could be introduced as potent agents to prevent the progression of certain types of cancer. However, preclinical and clinical trials will be needed to evaluate these complexes to obtain safe, effective, and optimal therapeutic drugs for cancer patients. [ABSTRACT FROM AUTHOR]

• Synthesis and characterization of half-sandwich imino pyridine iridium catalysts. • The structure of an iridium complex was confirmed by X-ray diffraction. • One-pot amidation reaction of aldehyde to amide was investigated. • Excellent conversion, with catalytic turnover number > 850. A series of stable mononuclear half-sandwich iridium(III) complexes of the general formula [(η5-C 5 Me 5)Ir(L)Cl](BPh 4) has been synthesized in dry methanol using different imino pyridine ligands (L 1 –L 6) and [(η5-C 5 Me 5) 2 Ir 2 (µ-Cl) 2 Cl 2 ] in a 2:1 molar ratio. All complexes were fully characterized by melting point, CHN analysis, FT-IR, UV–visible, 1H NMR, 13C NMR spectroscopy and mass spectrometry. The structure of complex 3 [(η5-C 5 Me 5)Ir(L 3)Cl](BPh 4) was determined by single crystal X-ray structure analysis, showing a chelating coordination mode of the imino pyridine L 3. One pot organic transformations of aldehyde to amide were carried out by complexes 1–6 in toluene at 110 °C in the presence of hydroxyl amine hydrochloride and sodium bicarbonate. The catalytic activity of complex 3 was found to be excellent, showing high conversion with catalytic turnover frequency up to 500. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present report, a novel dual pH-O 2 sensor based on covalent conjugate of rhodamine 6G and cyclometalated iridium complex with poly(vinylpyrrolidone-block-vinyltetrazole) copolymer is reported. In model physiological solutions the sensor chromophores display independent phosphorescent and fluorescent lifetime responses onto variations in oxygen concentration and pH, respectively. Colocalization studies on Chinese hamster ovary cells demonstrate the preferential localization in endosomes and lysosomes. The fluorescent lifetime imaging microscopy-phosphorescent lifetime imaging microscopy (FLIM-PLIM) experiments show that the phosphorescent O 2 sensor provides unambiguous information onto hypoxia versus normoxia cell status as well as semi-quantitative data on the oxygen concentration in cells in between these two states. However, the results of FLIM measurements indicate that dynamic lifetime interval of the sensor (≈0.5 ns between pH values 5.0 and 8.0) is insufficient even for qualitative estimation of pH in living cells because half-width of lifetime distribution in the studied samples is higher than the sensor dynamic interval. Nevertheless, the variations in rhodamine emission intensity are much higher and allow rough discrimination of acidic and neutral cell conditions. Thus, the results of this study indicate that the suggested approach to the design of dual pH-O 2 sensors makes possible to prepare the biocompatible and water-soluble conjugate with fast cellular uptake., (© 2024 Wiley‐VCH GmbH.)

In X-ray structures of the isomorphic mer-[IrX 3 (THT)(CNXyl) 2 ] (X=Cl 1, Br 2; THT=tetrahydrothiophene; Xyl=2,6-Me 2 C 6 H 3 -) complexes, we revealed short intermolecular contacts between the C-atom of an isocyanide methyl group and halide ligands of another molecule. Geometrical consideration of the X-ray data and analysis of appropriate DFT studies allowed the attribution of these contacts to C Me ⋅⋅⋅X-Ir III (X=Cl, Br) tetrel bond. Specifically, through the application of DFT calculations and various theoretical models, the presence of tetrel bonding interactions was validated, and the contribution of the C Me ⋅⋅⋅X-Ir III interaction was assessed. The reinforcement of the tetrel bond upon the isocyanide coordination to iridium(III) is substantiated by molecular electrostatic potential (MEP) surface calculations. To distinguish the tetrel bonding characteristics of CMe⋅⋅⋅X-Ir III (X=Cl, Br) interactions from conventional hydrogen bonding, we employed multiple computational methodologies, including Natural Bond Orbital (NBO) analysis and Electron Localization Function (ELF) analysis. Additionally, Energy Decomposition Analysis (EDA) was applied to selected model systems to explore the underlying physical nature of these interactions., (© 2024 Wiley-VCH GmbH.)

Light is indispensable to every aspect of our life. It is also a very important component of photodynamic therapy to cure cancer. Photodynamic therapy is a modern and effective technique among all these prevailing anticancer therapies because of its uniqueness in selectivity. Organometallic complexes are seen to be better candidates for photodynamic therapy. Cyclometalated complexes have been developed for targeting cellular organelles with remarkable photoactivity. Different types of metal complexes can display PDT activity. Considering its photophysical characteristics, the iridium complex is the most effective alternative to use as a PDT agent. Iridium-based cyclometalated complexes have shown decent results as a PDT-active anti-cancer agent. Reactive oxygen species (ROS) and singlet oxygen with high singlet oxygen quantum yield are both extremely capable of being produced by complexes. High cytotoxicity has been exhibited by various Iridium-based cyclometalated complexes in the presence of light and negligible cytotoxicity in dark conditions. These complexes are considerably fluorescent with the capability of cellular imaging and have displayed very significant potency against HeLa, A549, MCF-7, and other various cell lines. Complexes can arrest the different paths of the cell cycle through different mechanisms and help to force cellular apoptosis. Hence, a galore of organelle-targeted cyclometalated iridium complexes has been showcased in this review article. • Summarizing Current Research: This review papers provide an overview of existing literature on a particular topic. It summarizes the current research and advancements in the field of photodynamic therapy using cyclometalated iridium complexes. • Identifying Trends and Gaps: By analyzing various studies, the review can identify trends in research, such as the most effective types of complexes or promising targeting strategies. It highlights gaps in knowledge or areas where further research is needed. • Consolidating Information: Research in the field of photodynamic therapy using cyclometalated iridium complexes may be scattered across various journals and publications. This review paper consolidates this information into one place, making it easier for researchers and clinicians to access and understand. • Informing Future Research Directions: This review paper can suggest future research directions or areas that warrant further investigation. This can help guide researchers in their studies and experiments. • Educational Resource: This review paper serves as a valuable educational resource for students, researchers, and practitioners. It provides an in-depth understanding of this specific topic and can be used as a reference in academic settings. • Impact on Clinical Practice: Ultimately, the goal of research in this area is to develop more effective treatments for various diseases, such as cancer. This review paper highlights the promising cyclometalated iridium complexes for photodynamic therapy that could have a direct impact on clinical practice by informing the development of new therapeutic strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Increasing the nitrogen content of the cyclometallated ligands lower the energy of the highest occupied molecular orbital, which was achieved by introducing 2,4′-bpy moieties. • Decreasing the electron donating ability of the ancillary ligand raise the energy of the lowest unoccupied molecular orbital, which was achieved by introducing diamine ligands. • Combining both approaches produced unexpected deep-blue emission at wavelengths shorter than 400 nm, which, to the best of the author's knowledge, has never been reported. Deep-blue emitters based on combining two approaches are reported here. In the first approach, the nitrogen content of the cyclometallated ligand is increased using 2,4′-bpy ligands, leading to a low highest occupied molecular orbital energy. In the second approach, 2,2′-bpy is replaced with a lower electron donating ligand, leading to a high lowest unoccupied molecular orbital (LUMO) energy. Thus, three new ionic transition metal complexes of [Ir(2,4′-bpy) 2 (NN)]PF 6 [where NN is 2,2′-bpy (1), o -phenylenediamine (2), and 4-methoxy- o -phenylenediamine (3)] were synthesized, and their electronic and photophysical features were studied. In solution, [Ir(2,4′-bpy) 2 bpy]PF 6 emits blue light centered at 396 nm, which is blue-shifted compared to [Ir(ppy) 2 bpy]PF 6. The low electron donation of the diamine ancillary ligands introduces the contribution of the cyclometallated ligand to the LUMO, changing the nature of the emission and leading to different photophysical features. Density functional theory calculations indicate the long bond distances of Ir–Ns at the diamine ligands, suggesting weak metal–ligand interactions and low quantum yields. 1 1 DFT Density functional theory, ECP Effective core potential, FMO Frontier molecular orbitals, HOMO Highest occupied molecular orbital, LEEC Light-emitting electrochemical cells, LUMO Lowest unoccupied molecular orbital, NMR Nuclear magnetic resonance, OLED Organic light-emitting diodes, SCF Self-consistent-field, ILCT Interligand charge transfer, LLCT Ligand to ligand charge transfer, PLQY Photoluminescence quantum yield. [ABSTRACT FROM AUTHOR]