A series of Ru(II) complexes incorporating two 4,4′-bis(trifluoromethyl)-2,2′-bipyridine (4,4′-btfmb) coligands and thienyl-appended imidazo[4,5-f][1,10]phenanthroline (IP-nT) ligands was characterized and assessed for phototherapy effects toward cancer cells. The [Ru(4,4′-btfmb)₂(IP-nT)]²⁺ scaffold has greater overall redox activity compared to Ru(II) polypyridyl complexes such as [Ru(bpy)₃]²⁺. Ru-1T–Ru-4T have additional oxidations due to the nT group and additional reductions due to the 4,4′-btfmb ligands. Ru-2T–Ru-4T also exhibit nT-based reductions. Ru-4T exhibits two oxidations and eight reductions within the potential window of −3 to +1.5 V. The lowest-lying triplets (T₁) for Ru-0T–2T are metal-to-ligand charge-transfer (³MLCT) excited states with lifetimes around 1 μs, whereas T₁ for Ru-3T–4T is longer-lived (∼20–24 μs) and of significant intraligand charge-transfer (³ILCT) character. Phototoxicity toward melanoma cells (SK-MEL-28) increases with n, with Ru-4T having a visible EC₅₀ value as low as 9 nM and PI as large as 12,000. Ru-3T and Ru-4T retain some of this activity in hypoxia, where Ru-4T has a visible EC₅₀ as low as 35 nM and PI as high as 2900. Activity over six biological replicates is consistent and within an order of magnitude. These results demonstrate the importance of lowest-lying ³ILCT states for phototoxicity and maintaining activity in hypoxia.

中文翻译：

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Ru(II) 寡噻吩基与氟化配体的配合物：光物理、电化学和光生物学特性


一系列包含两个 4,4'-双(三氟甲基)-2,2'-联吡啶 (4,4'-btfmb) 共配体和噻吩基连接的咪唑并[4,5-f][1, 10]菲咯啉（IP-nT）配体被表征并评估其对癌细胞的光疗效果。与 Ru(II) 聚吡啶复合物（例如 [Ru( bpy) ₃ ] ²⁺ 。 Ru-1T–Ru-4T 由于 nT 基团而具有额外的氧化作用，并且由于 4,4'-btfmb 配体而具有额外的还原作用。 Ru-2T–Ru-4T 也表现出基于 nT 的还原。 Ru-4T 在 -3 至 +1.5 V 的电势窗口内表现出两次氧化和八次还原。Ru-0T–2T 的最低三重态 (T ₁ ) 是金属到配体的电荷-转移 ( ³ MLCT) 激发态的寿命约为 1 μs，而 Ru-3T–4T 的 T ₁ 寿命较长 (∼20–24 μs)，并且具有显着的配体内电荷-传输（ ³ ILCT）字符。对黑色素瘤细胞 (SK-MEL-28) 的光毒性随着 n 的增加而增加，Ru-4T 的可见 EC ₅₀ 值低至 9 nM，PI 高达 12,000。 Ru-3T 和 Ru-4T 在缺氧条件下保留了部分活性，其中 Ru-4T 的可见 EC ₅₀ 低至 35 nM，PI 高达 2900。六个生物重复的活性是一致的，在一个数量级之内。这些结果证明了最低的 ³ ILCT 状态对于光毒性和在缺氧条件下维持活性的重要性。