Indenyl-functionalised triethylborane adduct of N-heterocyclic carbene: stepwise coordination of indenyl and NHC ligands toward molybdenum fragment.

Indenyl-functionalised BEt(3)-adduct NHCs were prepared by the reaction of imidazolium pro-ligands with LiBEt(3)H. This compound was converted into the indenyl-coordinate molybdenum complex dangling the NHC·BEt(3) moiety as a substituent. The stepwise coordination of NHC afforded a chelate-type mononuclear complex as well as a bimetallic complex.