Chettri Avinash, Roque John A, Schneider Kilian R A, Cole Houston D, Cameron Colin G, McFarland Sherri A, Dietzek Benjamin
Department Functional Interfaces Department, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany.
Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany.
ChemPhotoChem. 2021 May;5(5):421-425. doi: 10.1002/cptc.202000283. Epub 2021 Jan 19.
TLD1433 is the first Ru(II) complex to be tested as a photodynamic therapy agent in a clinical trial. In this contribution we study TLD1433 in the context of structurally-related Ru(II)-imidozo[4,5-f][1,10]phenanthroline (ip) complexes appended with thiophene rings to decipher the unique photophysical properties which are associated with increasing oligothiophene chain length. Substitution of the ip ligand with ter- or quaterthiophene changes the nature of the long-lived triplet state from metal-to-ligand charge-transfer to ππ* character. The addition of the third thiophene thus presents a critical juncture which not only determines the photophysics of the complex but most importantly its capacity for O generation and hence the potential of the complex to be used as a photocytotoxic agent.
A low-lying triplet intraligand state (IL) determines the properties of the long-lived excited states in a series of Ru(II) complexes. The IL state can be accessed by increasing the length of an oligothiophene chain. The IL state is extremely efficient at generating O and thus enhances the potency of the complexes as PDT agents.
TLD1433是首个在临床试验中作为光动力治疗剂进行测试的钌（II）配合物。在本论文中，我们在结构相关的钌（II）-亚氨基氮杂[4,5-f][1,10]菲咯啉（ip）配合物的背景下研究TLD1433，这些配合物带有噻吩环，以解读与寡聚噻吩链长度增加相关的独特光物理性质。用三联噻吩或四联噻吩取代ip配体，会使长寿命三重态的性质从金属到配体的电荷转移转变为ππ*性质。因此，第三个噻吩的添加呈现出一个关键节点，它不仅决定了配合物的光物理性质，更重要的是决定了其产生活性氧的能力，进而决定了该配合物用作光细胞毒性剂的潜力。
一个低能三重态配体内态（IL）决定了一系列钌（II）配合物中长寿命激发态的性质。通过增加寡聚噻吩链的长度可以实现IL态。IL态在产生活性氧方面极其高效，从而增强了这些配合物作为光动力治疗剂的效力。
