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Synthesis, Photophysical and TD-DFT Evaluation of Triphenylphosphonium-Labeled Ru(II) and Ir(III) Luminophores

Year: 2026

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The chemistry of 5-acetamido derivatized 1,10-phenanthroline was developed to yield a series of pro-ligands ( L 1–4 ) and related triphenylphosphonium (TPP + ) appended cationic variants ( L 5–8 ). The resulting heteroleptic complexes [Ru(bipy) 2 ( L 1–8 )] n + (where bipy = 2,2′-bipyridine) and cyclometalated species [Ir(tmq) 2 ( L 1–8 )] n + (where tmq = 2,6,7-trimethyl-3-phenylquinoxaline) were isolated and fully characterized using a range of analytical and spectroscopic methods, including electrochemistry and time-resolved photophysics. Multinuclear NMR spectroscopies were used to characterize the compounds, including 31 P NMR showing δ P 21.3–24.4 ppm for the phosphonium species. Two X-ray crystal structures were successfully obtained on TPP + functionalized Ru(II) and Ir(III) species: key features include the distorted octahedral coordination spheres, and the defined spatial relationships between the complex core and the TPP + unit. All Ru(II) and Ir(III) complexes were phosphorescent in the red region with 3 MLCT or 3 MLCT/ 3 LLCT character, respectively. Comparison across the series suggest the presence of the TPP + unit induced moderate quenching of the complex phosphorescence. A comparison with quaternary ammonium analogues suggests this may be due to differences in ion pairing and solvation phenomena in the TPP + complexes.

Source: Inorganic Chemistry

DOI: 10.1021/acs.inorgchem.5c04913