New metal aminocarbene-substituted cyclopentadienyliron half sandwich complexes

Some new half sandwich cyclopentadienyl aminocarbene complexes were prepared by treatment of the corresponding alkoxycarbene complexes with primary and secondary amines, including enantiopure chiral aminoalcohols and amines with acetyl, phosphine, alkene, and alkyne functionalities, all of which proved to be compatible with the substrates. In two cases the complexes were crystallographically characterized indicating that the metal–carbon double bond is – in contrast to some alkoxycarbene analogues – not in conjugation with the cyclopentadienyl π-system in the solid state. Some of the complexes were characterized by cyclic voltammetry showing similar behavior as the corresponding alkoxycarbene complexes. The complexes are the first examples of half sandwich complexes with a cyclopentadienyl-aminocarbene ligand system.