An Unusually Static, Sterically Hindered Silver Bis(N-heterocyclic carbene) Complex and Its Use in Transmetalation

A dimeric silver complex of the bulky bis(N-heterocyclic carbene) ligand 1,1‘-dimesityl-3,3‘-methylenediimidazol-2,2‘-diylidene exhibits a surprisingly static
structure in solution, due to a favorable chelate ring conformation, yet serves as a convenient transmetalation reagent for the formation of a new κ2-bis(NHC) rhodium(I)
complex. The latter complex demonstrates a strong influence of N-substituent steric bulk on the bis(NHC) binding
mode.

以大位阻双(N-杂环卡宾（bis(N-heterocyclic carbene, NHC)）配体1,1'-双(均三甲苯基)-3,3'-亚甲基二咪唑-2,2'-二亚基形成的二聚体银配合物，因有利的螯合环构象在溶液中展现出出人意料的静态稳定结构；该配合物同时可作为便捷的转金属化试剂，用于制备新型κ²-双(NHC)铑(I)配合物。后一种配合物表明，N取代基的空间位阻对双(NHC)的配位模式具有显著影响。