Directing cation-cation interactions in thiamine compounds: Analysis of a series of organic salts based on vitamin B1

A series of ionic compounds based on the dicationic vitamin B1 structure have been synthesized and characterized. A set of perfluoroalkyl-based anions, each with a distinct structure, were paired with the cations and the solid-state structures of the salts were analyzed via single-crystal X-ray diffraction. Phase transitions and thermal stability of the compounds were examined via dynamic scanning calorimetry and thermogravimetric analysis. It was found that the salt of the cyclical anion, 1,3-disulfonylhexafluoropropyleneimide [NCyF]⁻, exhibited higher thermal stability while displaying comparable phase transition temperatures as compared to the linear anionic congeners. The cations within the [NCyF]⁻ compound were found to interact as paired dimers, a form which is not observed in the other ionic species. Hirshfeld surface analyses supplemented with computational studies of the compounds is used to rationalize and evaluate the distinct properties of the compounds arising from changes in anion geometry.