We report the synthesis and characterisation of 32 half sandwich phenylazopyridine OsII arene complexes [Os(η6-arene)(phenylazopyridine)X]+ in which X is chloride or iodide, the arene is p-cymene or biphenyl and the pyridine and phenyl rings contain a variety of substituents (F, Cl, Br, I, CF3, OH or NO2). Ten X-ray crystal structures have been determined. Cytotoxicity towards A2780 human ovarian cancer cells ranges from high potency at nanomolar concentrations to inactivity. In general the introduction of an electron-withdrawing group (e.g. F, Cl, Br or I) at specific positions on the pyridine ring significantly increases cytotoxic activity and aqueous solubility. Changing the arene from p-cymene to biphenyl and the monodentate ligand X from chloride to iodide also increases the activity significantly. Activation by hydrolysis and DNA binding appears not to be the major mechanism of action since both the highly active complex [Os(η6-bip)(2-F-azpy)I]PF6 (9) and the moderately active complex [Os(η6-bip)(3-Cl-azpy)I]PF6 (23) are very stable and inert towards aquation. Studies of octanolâwater partition coefficients (log P) and subcellular distributions of osmium in A2780 human ovarian cancer cells suggested that cell uptake and targeting to cellular organelles play important roles in determining activity. Although complex 9 induced the production of reactive oxygen species (ROS) in A2780 cells, the ROS level did not appear to play a role in the mechanism of anticancer activity. This class of organometallic osmium complexes has new and unusual features worthy of further exploration for the design of novel anticancer drugs.
我们报告了 32 个半夹心苯并
吡啶 OSII 炔配合物 [OS(δ-6-烯)(苯并
吡啶)X]+ 的合成和表征,其中 X 是
氯化物或
碘化物,炔是
对伞花烃或
联苯,
吡啶和苯基环含有各种取代基(F、Cl、Br、I、
CF3、OH 或
NO2)。已测定了十种 X 射线晶体结构。对 A2780 人卵巢癌细胞的细胞毒性从纳摩尔浓度的高效力到无活性不等。一般来说,在
吡啶环上的特定位置引入一个抽电子基团(如 F、Cl、Br 或 I)可显著提高细胞毒性活性和
水溶性。将
对伞花烃改为
联苯,将单齿
配体 X 从
氯化物改为
碘化物,也会显著提高活性。
水解和 DNA 结合活化似乎不是主要的作用机制,因为高活性复合物 [OS(δ-6-bip)(2-F-azpy)I]PF6 (9) 和中度活性复合物 [OS(δ-6-bip)(3-Cl-azpy)I]PF6 (23) 都非常稳定,而且不溶于
水。对
锇在 A2780 人卵巢癌细胞中的
辛醇-
水分配系数(log P)和亚细胞分布的研究表明,细胞摄取和细胞器靶向在决定活性方面起着重要作用。虽然复合物 9 能诱导 A2780 细胞产生活性氧(ROS),但 ROS
水平在抗癌活性机制中似乎并不起作用。这一类有机
金属
锇配合物具有新颖而不寻常的特点,值得在设计新型抗癌药物方面进一步探索。