Gitlina Anastasia Yu, Fadaei-Tirani Farzaneh, Severin Kay
Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
Dalton Trans. 2023 Feb 28;52(9):2833-2837. doi: 10.1039/d2dt04039e.
The isomerization of iridium(III) complexes with metalated N-heterocyclic carbene (NHC) ligands was studied. The isomers of complexes with 1-phenyl-3-methylbenzimidazolin-2-ylidene or 1-phenyl-3-benzylbenzimidazolin-2-ylidene ligands are transformed cleanly into the isomers when solutions of the complexes are treated with first HNTf and then NEt. The transformation can be accomplished within a few minutes and the side product (NEtH)(NTf) is easy to separate. Spectroscopic and structural analyses indicate that the isomerization proceeds by protonation of the carbene ligand at the metalated phenyl group, accompanied by a → rearrangement of the carbene donors. An iridium complex with a 1-phenyl-1,2,4-triazolo[4,3-]phenanthridine-based carbene ligand could not be isomerized under similar conditions, most likely because of its reduced conformational flexibility.
研究了含金属化N-杂环卡宾（NHC）配体的铱（III）配合物的异构化反应。当用HNTf处理配合物溶液，然后再用NEt处理时，含1-苯基-3-甲基苯并咪唑-2-亚基或1-苯基-3-苄基苯并咪唑-2-亚基配体的配合物异构体能够顺利地转化为相应异构体。该转化过程可在几分钟内完成，且副产物（NEtH）（NTf）易于分离。光谱和结构分析表明，异构化反应是通过卡宾配体在金属化苯基处的质子化进行的，同时伴随着卡宾供体的σ→π重排。在类似条件下，含1-苯基-1,2,4-三唑并[4,3-b]菲啶基卡宾配体的铱配合物无法异构化，这很可能是由于其构象灵活性降低所致。
