Iridium complexes inhibit tumor necrosis factor-α by utilizing light and mixed ligands

Tuning the Efficiency of Iridium(III) Complexes for Energy Transfer (EnT) Catalysis through Ligand Design

Photoactive Iridium(III) complexes are a popular synthetic tool. The impact of ligand design on their photoredox properties has been widely studied, but similar approaches to develop more potent photosensitizers are still absent. We report herein the preparation, characterization and catalytic application of a new family of Iridium(III) complexes that proved superior to their widely-used commercial peers. The best results were observed when naphthyl pendants were installed to the ligands, which could stabilize the triplet intermediates involved in energy-transfer reactions via radical-π dispersion interactions.

Accumulation of mono-reduced [Ir(piq)2(LL)] photosensitizers relevant for solar fuels production

A series of nine [Ir(piq)₂(LL)]⁺.PF₆^- photosensitizers, where piqH = 1-phenylisoquinoline, was developed and investigated for excited-state electron transfer with sacrificial electron donors that included triethanolamine (TEOA), triethylamine (TEA) and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) in acetonitrile. The photosensitizers were obtained in 57-82% yield starting from the common [Ir(piq)₂µ-Cl]₂ precursor and were all characterized by UV-Vis absorption as well as by steady-state, time-resolved spectroscopies and electrochemistry. The excited-state lifetimes ranged from 250 to 3350 ns and excited-state electron transfer quenching rate constants in the 10⁹ M^-1 s^-1 range were obtained when BIH was used as electron donor. These quenching rate constants were three orders of magnitude higher than when TEA or TEOA was used. Steady-state photolysis in the presence of BIH showed that the stable and reversible accumulation of mono-reduced photosensitizers was possible, highlighting the potential use of these Ir-based photosensitizers in photocatalytic reactions relevant for solar fuels production.

Phosphorescent cationic iridium(iii) complexes bearing a nonconjugated six-membered chelating ancillary ligand: a strategy for tuning the emission towards the blue

Blue and blue-green-emitting cationic Ir(iii) complexes bearing a nonconjugated N^N ligand have been studied.

Antipseudomonal activity enhancement of luminescent iridium(iii) dipyridylamine complexes under visible blue light

Cyclometallated iridium(iii) dipyridylamine complexes present antibacterial activity against P. aeruginosa, a highly resistant pathogenic bacterium. This activity is increased when the complex is conjugated to biotin, a bacterial nutrient, and a MIC of 4 μM (4 μg mL^-1) has been observed. The irradiation of P. aeruginosa cultures with blue LED light potentiates the anti-bacterial activities of these iridium(iii) complexes when they are conjugated to a glycoside.