A Pyrene-Based N‑Heterocyclic Carbene: Study of Its Coordination Chemistry and Stereoelectronic Properties

A new
pyrene-N-heterocyclic carbene ligand has been obtained and
coordinated to rhodium and iridium, affording the corresponding [MCl­(NHC)­(COD)]
and [MCl­(NHC)­(CO)2] complexes (M = Ir, Rh). The presence
of the pyrene backbone allows the introduction of a η6-bonded [RuCp]+ fragment and facilitates the formation
of the corresponding heterometallic complexes of Rh/Ru and Ir/Ru.
The stereoelectronic properties of the new ligand have been studied
by means of IR spectroscopy and cyclic voltammetry and demonstrate
that the introduction of the [RuCp]+ fragment results in
the reduction of the electron-donating power of the ligand.