Synthesis and characterization of Pd(II)-methyl complexes with N-heterocyclic carbene-amine ligands

A number of palladium(II) complexes with a heteroditopic NHC-amine ligand and their precursor silver(I) carbene complexes have been efficiently prepared and their structural features have been investigated. The heteroditopic coordination of this ligand class was unequivocally shown by NMR-spectroscopy and X-ray crystallographic analysis. The neutral and cationic cis-methyl-palladium(NHC) complexes are not prone to reductive elimination, which is normally a major degenerative pathway for this type of complex. In contrast, under carbon monoxide atmosphere rapid reductive elimination of the acyl-imidazolium salt was observed.