Tartrate-based ionic liquids: unified synthesis and characterisation

A convenient and general preparative approach for tartrate-derived organic salts with bulky non-coordinating cations is described. This route is based on neutralisation of tartaric acid with cation hydroxides in aqueous solution. A series of 24 tartrate salts was prepared by systematic variation of the hemi- or bis-tartrate anion and the nature of the organic cation. Chirality of the anion was also explored as a vector for structural modification. Complete characterisation, including X-ray crystallography, was carried out. This comparative study of the physicochemical properties of these salts led to the identification of several informative trends useful for designing proper tartrate-based chiral ionic liquids.