Here in, we report a rollover iridacycle complex cis-[Ir(κ²-C–N-L₁)(κ²-N–N-L₁)Cl₂], which can be easily obtained as yellow solid, through the reaction of two equivalents of new 2-(6-bromopyridin-2-yl)imidazo[1,2-a]pyridine (L₁) type ligand and IrCl₃ in dimethylformamide at 70 °C for a week. Rollover complex have an unusual κ²-C–N-cyclometallated ligand fragment, which involves the C–H bond activation reaction in remote position on bromo-pyridine, with a second one in classic κ²-N–N-donor mode. The structure of both compounds was studied by NMR, IR, and high-resolution mass spectrometry. Rollover complex UV/Vis absorption spectrum showed a dominating π–π* absorption band at 350 nm. Excitation at 385 nm gave a narrow emission band with maximum at 541 nm, which was associated to ligand-centred emission. The ligand shows antiproliferative activities against breast cancer lines. Density Functional Theory (DFT) calculations suggest that the rollover C–H bond activation occurs after a first κ²-N–N coordination during the complexation of the second ligand and is supported by DMF molecules.

中文翻译：

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2-(6-溴吡啶-2-基)咪唑并[1,2-a]吡啶的翻转 Ir(III) 络合物

在这里，我们报告了一种翻转虹膜环络合物顺式-[Ir(κ ² -C–NL ₁ )(κ ² -N–NL ₁ )Cl ₂ ]，它可以通过两个当量的反应轻松获得黄色固体新的 2-(6-bromopyridin-2-yl)imidazo[1,2- a ]pyridine ( L ₁ ) 型配体和 IrCl ₃在二甲基甲酰胺中在 70 °C 下反应一周。翻转配合物有一个不寻常的 κ ² -C-N-环金属化配体片段，它涉及溴吡啶远程位置的 C-H 键活化反应，经典 κ ^{2中的第二个}-N–N-供体模式。通过核磁共振、红外和高分辨率质谱研究了这两种化合物的结构。翻转复合 UV/Vis 吸收光谱显示 350 nm 处的主要 π–π* 吸收带。385 nm 的激发产生一个窄的发射带，最大值为 541 nm，这与配体中心发射有关。该配体显示出针对乳腺癌细胞系的抗增殖活性。密度泛函理论 (DFT) 计算表明，翻转 C-H 键激活发生在第二个配体络合期间的第一个 κ ² -N-N 配位之后，并得到 DMF 分子的支持。