Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany.
Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany.
J Phys Chem A. 2021 Aug 19;125(32):6985-6994. doi: 10.1021/acs.jpca.1c04900. Epub 2021 Aug 9.
We explore the photophysical properties of a family of Ru(II) complexes, , designed as photosensitizers (PSs) for photodynamic therapy (PDT). The complexes incorporate a 1-imidazo[4,5-][1,10]-phenanthroline (ip) ligand appended to one or more thiophene rings. One of the complexes studied herein, (known as TLD1433), is currently in phase II human clinical trials for treating bladder cancer by PDT. The potent photocytotoxicity of is attributed to a long-lived intraligand charge-transfer triplet state. The accessibility of this state changes upon varying the length () of the oligothiophene substituent. In this paper, we highlight the impact of on the ultrafast photoinduced dynamics in , leading to the formation of the function-determining long-lived state. Femtosecond time-resolved transient absorption combined with resonance Raman data was used to map the excited-state relaxation processes from the Franck-Condon point of absorption to the formation of the lowest-energy triplet excited state, which is a triplet metal-to-ligand charge-transfer excited state for - and an oligothienyl-localized triplet intraligand charge-transfer excited state for -. We establish the structure-activity relationships with regard to changes in the excited-state dynamics as a function of thiophene chain length, which alters the photophysics of the complexes and presumably impacts the photocytotoxicity of these PSs.
我们探索了一系列钌（II）配合物的光物理性质，这些配合物被设计为光动力疗法（PDT）的光敏剂（PS）。这些配合物包含一个 1-咪唑并[4,5-][1,10]-菲咯啉（ip）配体，连接到一个或多个噻吩环上。本文研究的其中一个配合物，（称为 TLD1433），目前正处于治疗膀胱癌的 PDT 二期人体临床试验中。 的强光细胞毒性归因于长寿命的内配体电荷转移三重态。这种状态的可及性在改变寡噻吩取代基的长度（）时会发生变化。在本文中，我们强调了 对 中超快光诱导动力学的影响，导致形成决定功能的长寿命状态。飞秒时间分辨瞬态吸收结合共振拉曼数据用于绘制从吸收的 Franck-Condon 点到形成最低能量三重态激发态的激发态弛豫过程，对于 - 而言，这是三重态金属到配体电荷转移激发态，对于 - 而言，这是寡噻吩基局域三重态内配体电荷转移激发态。我们建立了结构活性关系，即随着噻吩链长度的变化，激发态动力学的变化，这改变了配合物的光物理性质，并可能影响这些 PS 的光细胞毒性。
