Nickel-containing di-charged imidazolium ligand with high crystalline organization. Interception and characterization of a transient carbene/cation species

New nickel-containing di-charged imidazolium-based molten salt (2) was prepared by treatment of nickel chloride with bis-(2-(3-methylimidazolium-1-yl)ethyl)ether dichloride (1) in good yield. This compound has been fully characterized by elemental analysis, polarized optical microscopy (POM), differential scanning calorimetry (DSC), powder and single-crystal X-ray diffraction, and electrospray mass spectrometry. X-ray diffraction studies of 2 revealed a quite interesting 3D organization whereas cations and anions each arrange in individual chains, which are themselves connected in an extended, columnar-type network. Furthermore the presence of [NiCl4]2− unit in compound 2 induces a 3D crystalline arrangement much higher than that observed for compound 1. The ESI(+)-MS studies show the same set of fragments detected for both compound 1 and 2 displaying similar losses including the presence of a di-charged molecule. The fragmentation of nickel-containing compound 2 gave a very high intense cation–carbene ion of m/z 235, suggesting an additional stabilization by the presence of [NiCl4]2− unit in the structure of 2 related to the low intensity signal found for 1 in the same m/z.