Three-Coordinate Iron(II) N-Heterocyclic Carbene Alkyl Complexes

Abstract

Mononuclear alkyl N-heterocyclic carbene complexes of the type Fe(NHC)R2, NHC = SIPri, IPri, R = CH2SiMe3, CH2C6H5, were prepared by the alkylation of “FeCl2(THF)1.5” with one equivalent per Fe of MgR2, in the presence of the NHC. Alkylation with 0.5 equiv of MgR2 under carefully controlled conditions gave Fe(NHC)(CH2SiMe3)Cl, NHC = SIPri, IPri. Magnetic and computational studies and structural determination by X-ray diffraction reveal three-coordinate high-spin (S = 2) alkyl complexes.