Ferrocenylated Chalcogen (Se and Te)-containing N-heterocyclic carbenes: Selenones, silver and palladium complexes

Abstract

New Ferrocenylated Chalcogen (Se and Te)-Containing imidazolium salts have been synthesized. These imidazolium salts have been used as precursors for the synthesis of ferrocenyl-NHC selenones, silver NHC and ionic palladium (II) complexes where the imidazolium ligand act as the cation. For the synthesis of Pd NHC(Se, CNHC) complex from appropriate imidazolium salts, the route of the silver carbene transfer reaction has been adopted and the ligand shows bidentate coordination through (Se, CNHC) atoms. All the compounds have been fully characterized by multinuclear NMR, mass spectrometry and X-ray diffraction. Molecular structures of ferrocenyl chalcogenide imidazolium salts present intra and inter cation/anion interactions. Interestingly, 77Se NMR studies of ionic palladium complexes with ferrocenyl chalcogenide imidazolium cation do not present Se coordination to Palladium in solution. The bond distance between CNHC and selenium atom in both the selenones is similar to other reported imidazolium selenones where this bond has a double bond character.