Dinuclear Rhodium(I)– N ‐Heterocyclic Carbene Complexes as Alkyne Hydropyridonation Catalysts

A series of new Rh I – N ‐Heterocyclic carbene dinuclear complexes of type [Rh( µ ‐Cl)( η 2 ‐coe)(NHC)] 2 , containing IPr BIAN , IPr Cl , and IPr* ligands, has been prepared. The crystal structure of the IPr Cl functionalized rhodium–dinuclear complex reveals an intermolecular Cl···Cl halogen bond. The chlorido‐bridges can be cleaved by pyridine to afford the corresponding mononuclear derivatives RhCl( η 2 ‐coe)(NHC)(py). These complexes are efficient alkyne hydropyridonation catalysts, with the IMes complex exhibiting the highest reactivity within the series.