A Pyrene-Based N-Heterocyclic Carbene: Studyof Its Coordination Chemistry and Stereoelectronic Properties.

A newpyrene-N-heterocyclic carbene ligand has been obtained andcoordinated to rhodium and iridium, affording the corresponding [MCl(NHC)(COD)]and [MCl(NHC)(CO)2] complexes (M = Ir, Rh). The presenceof the pyrene backbone allows the introduction of a η6-bonded [RuCp]+fragment and facilitates the formationof the corresponding heterometallic complexes of Rh/Ru and Ir/Ru.The stereoelectronic properties of the new ligand have been studiedby means of IR spectroscopy and cyclic voltammetry and demonstratethat the introduction of the [RuCp]+fragment results inthe reduction of the electron-donating power of the ligand. [ABSTRACT FROM AUTHOR]