1,3-Dimethyl-4-(diphenylphosphino)imidazolium Triflate: A Functionalized Ionic Liquid with Ambivalent Coordination Capability

Simply using 1-methylimidazole as the starting material, the functionalized ionic liquid 1,3-dimethyl-4-(diphenylphosphino)imidazolium triflate ([3]OTf) has been prepared, from which the corresponding 4-phosphino-substituted N-heterocyclic carbene 4 was generated. The coordination capability of 3 and 4 toward a variety of transition-metal centers has been studied, as well as their electron-donor character through an evaluation of the TEP parameter. 3 behaves as a cationic phosphine ligand, whereas 4 shows a strong preference to coordinate to transition metals through the carbene carbon atom, leading to the obtention of mononuclear complexes with a free phosphine arm which act as metalloligands, allowing for the modular formation of homo- and heterodinuclear transition-metal complexes.