State Key Laboratory of Organic Electronics and Information Displays, Institute of Advanced Materials (IAM) & Institute of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
Department of Applied Biology and Chemical Technology and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
Inorg Chem. 2022 Nov 7;61(44):17703-17712. doi: 10.1021/acs.inorgchem.2c02854. Epub 2022 Oct 26.
The development of highly efficient cyclometalated phosphorescent iridium(III) complexes is greatly promoted by their rational molecular design. Manipulating the excited states of iridophosphors could endow them with appealing photophysical properties, which play vital roles in triplet state-related photofunctional applications (, electroluminescence, photodynamic therapy, ). In general, the most effective approach for decreasing the emission energies of iridophosphors is to extend the π-skeleton of ligands. However, the π-extension strategy often results in decreased solubility, lower synthetic yield, decreased photoluminescence quantum yield, and so forth. In this work, a simple yet efficient strategy is proposed for the effective excited-state manipulation of 2-phenyllepidine-based iridophosphors. Surprisingly, dramatic tuning of phosphorescence wavelength (∼70 nm) is achieved by simply controlling the position of a single methoxyl substituent on these iridophosphors. An oxygen-responsive iridophosphor featuring far-red emission (660 nm), long emission lifetime (1.60 μs), and high singlet oxygen quantum yield (0.73) is employed to realize accurate oxygen sensing and , and it also shows efficient photodynamic therapy in cancer cells, making it a promising candidate for the efficient image-guided photodynamic therapeutic agent. This molecular design strategy clearly demonstrates the advantages of designing novel long-wavelength emissive iridophosphors without increasing the π-conjugation of the ligand.
高效的环金属化磷光铱(III)配合物的发展很大程度上得益于其合理的分子设计。操纵铱磷光体的激发态可以赋予它们吸引人的光物理性质，这些性质在三重态相关的光功能应用中起着至关重要的作用（例如，电致发光、光动力疗法）。通常，降低铱磷光体发射能的最有效方法是扩展配体的π骨架。然而，π-扩展策略往往会导致溶解度降低、合成产率降低、光致发光量子产率降低等问题。在这项工作中，提出了一种简单而有效的策略，用于有效调控基于 2-苯基菲啶的铱磷光体的激发态。令人惊讶的是，通过简单地控制这些铱磷光体上单个甲氧基取代基的位置，可以实现磷光波长的显著调谐（约 70nm）。设计了一种具有远红色发射（660nm）、长发射寿命（1.60μs）和高单线态氧量子产率（0.73）的氧响应型铱磷光体，用于实现精确的氧传感和，并且在癌细胞中也表现出高效的光动力治疗效果，使其成为一种很有前途的高效图像引导光动力治疗剂。这种分子设计策略清楚地表明了在不增加配体π共轭的情况下设计新型长波长发射铱磷光体的优势。
