Reactions of iridium trichloride hydrate with bulky 2-(9-anthracenyl)-1-phenyl-benzimidazole (anbi) in the presence of N-donor ligands afforded a number of unique noncyclometalated complexes, while attempts to prepare a common μ-chloro-bridged bis-cyclometalated dimer systematically gave a monocyclometalated complex cis-[Ir(C,N-anbi)(N-anbi)Cl₂] instead. The obtained complexes were characterized by ¹H NMR, high-resolution mass spectrometry, single-crystal and powder X-ray diffraction, UV–vis spectroscopy, and cyclic voltammetry. The noncyclometalated complexes fac-[Ir(N-anbi)(N^N)Cl₃)], where N^N are 4,4′-disubstituted 2,2′-bipyridines, are octahedral and contain the anthracene and 2,2′-bipyridine units in a close cofacial arrangement. These complexes were found to be exceptionally inert to the chloride ligand exchange even in the presence of silver triflate, forming a rare trinuclear Ir-μ-Cl₃–Ag-μ-Cl₃–Ir structure instead. In the monocyclometalated complex, the Ir(III) ion is pentacoordinated in a rare square-pyramidal geometry, where the bulky anthracene fragment is involved in the steric shielding of the metal center. This is in line with the results of gas-phase density functional theory calculations, demonstrating that the experimentally observed structure is energetically most preferable. The monocyclometalated complex is deeply colored due to intense charge-transfer absorption bands in the range 450–650 nm with ε = 2000–5000 M^–1 cm^–1, superior to the noncyclometalated complexes. The synthesis, structures, and properties of the new complexes are discussed in the context of the related mono-, bis-, and noncyclometalated iridium(III) compounds.

中文翻译：

---

基于蒽修饰苯并咪唑配体的非平凡铱(III)配合物的合成、结构和性能


在 N-供体配体存在下，三氯化铱水合物与大体积 2-(9-蒽基)-1-苯基-苯并咪唑 (anbi) 的反应提供了许多独特的非环金属化配合物，同时尝试制备常见的 μ-氯桥联配合物双环金属化二聚体系统地生成单环金属化配合物顺式-[Ir( C , N -anbi)( N -anbi)Cl ₂ ]。通过¹ H NMR、高分辨率质谱、单晶和粉末 X 射线衍射、紫外-可见光谱和循环伏安法对所得配合物进行了表征。非环金属化配合物fac -[Ir( N -anbi)(N^N)Cl ₃ )]，其中 N^N 是 4,4'-二取代的 2,2'-联吡啶，是八面体并包含蒽和 2,2 '-联吡啶单元紧密共面排列。研究发现，即使在三氟甲磺酸银存在的情况下，这些配合物对氯配体交换也表现出异常惰性，从而形成罕见的三核 Ir-μ-Cl ₃ –Ag-μ-Cl ₃ –Ir 结构。在单环金属化配合物中，Ir(III) 离子以罕见的方锥体几何结构进行五配位，其中庞大的蒽片段参与金属中心的空间屏蔽。这与气相密度泛函理论计算的结果一致，表明实验观察到的结构在能量上是最优选的。单环金属化配合物由于 450–650 nm 范围内的强电荷转移吸收带而呈深颜色，ε = 2000–5000 M ^–1 cm ^–1 ，优于非环金属化配合物。 新络合物的合成、结构和性质在相关的单、双和非环金属化铱(III)化合物的背景下进行了讨论。