Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-chou, Matsuyama, Ehime 790-8577, Japan.
Department of Chemistry, College of Humanities & Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
Dalton Trans. 2021 Oct 5;50(38):13256-13263. doi: 10.1039/d1dt01960k.
The coordinatively unsaturated bis-chelated iridium(III) complex, [Ir(2-Bubzq)Cl] (2-BubzqH = 2-butyl-benzo[]quinoline), denoted as complex 1, was obtained by reacting iridium(III) trichloride with 2-BubzqH in a 1 : 2 molar ratio. The results were in contrast to the common view that a chlorine-bridged dimer, [Ir(L)Cl] (L = bis-chelate ligand), is formed under the corresponding conditions. A single-crystal X-ray diffraction structural analysis revealed that complex 1 has a five-coordinate geometry with a distorted square pyramidal configuration. The optical resolution of complex 1 was measured chromatographically on a chiral column, yielding Δ and Λ as enantiomers. The resolved enantiomers were stable enough against racemization in CDCl as confirmed by the vibrational circular dichroism measurements. Complex 1 reacted with carbon monoxide (CO) to give [Ir(2-Bubzq)(CO)Cl] and with 1,10-phenanthroline (phen) to give [Ir(2-Bubzq)(phen)]Cl within a minute with its absolute configuration (ΔΛ chirality) maintained.
具有配位不饱和双螯合作用的三氯化铱（III）配合物，[Ir(2-Bubzq)Cl]（2-BubzqH=2-丁基苯并[]喹啉），表示为配合物 1，是通过在 1:2 的摩尔比下用三氯化铱（III）与 2-BubzqH 反应得到的。这与常见的观点相反，即在相应的条件下形成氯桥联二聚体[Ir(L)Cl]（L=双螯合配体）。单晶 X 射线衍射结构分析表明，配合物 1具有五配位几何形状，呈扭曲的四方锥构型。通过手性柱进行色谱分析测量了配合物 1 的光学拆分，得到了Δ和Λ作为对映异构体。通过振动圆二色性测量证实，拆分的对映异构体在 CDCl 中足够稳定，不会发生外消旋。配合物 1 与一氧化碳（CO）反应生成[Ir(2-Bubzq)(CO)Cl]，与 1,10-菲咯啉（phen）反应生成[Ir(2-Bubzq)(phen)]Cl，其绝对构型（ΔΛ手性）在一分钟内得以保持。
