The next generation of C2-symmetric ligands: A di-N-heterocyclic carbene (NHC) ligand and the synthesis and X-ray characterization of mono- and dinuclear rhodium(I) and iridium(I) complexes

A new C-2-symmetric chelating di-N-heterocyclic carbene (NHC) ligand is reported. The stable free di-carbene (+/-)[DEAM-BY] (3) forms upon treating the imidazolium salt(+/-)[DEAM-BI][OTf](2) (2) with potassium bis-trimethylsilylamide (where DEAM-BY=trans-9,10-dihydro-9,10-ethanoanthracene-11,12-bis(1-benzyl)imidaz-2-ylidene and DEAM-BI = trans-9,10-dihydro-9,10-ethanoanthracene-11,12-bis(1-benzyl)imidazolium). Metalation reactions of 2 with [Rh(COD)Cl](2) and [Ir(COD)Cl](2) are carried out under mild conditions to produce either mono- or bimetallic complexes. Each compound is characterized by NMR spectroscopy, combustion analysis, and single-crystal X-ray crystallography. Published by Elsevier Ltd.