The ~1HNMR Spectra of Binary Mixtures of Molten 2-Methylpyridinium Chloride and μ-Hydrogenbis(2-Methylpyridinium) Iodide

摘要

The ~1HNMR spectra of binary solutions of molten 2-methylpyridinium chloride (2mepyrCl) and μ-hydrogenbis(2-methylpyridinium) iodide (μ-I) were measured as a function of composition over the entire composition range and as a function of temperature between 95 °C and 145 °C. In addition, the phase diagram for the binary mixture was constructed using differential scanning calorimetry. The chemical shift of the nitrogenic proton, δ_(N-H), in the pure 2-mepyrCl showed a barely discernible increase over the entire temperature range, indicating a slight deshielding. On the other hand, δ_(N-H), for the pure μ-I exhibited a strong temperature dependence, decreasing as the temperature increased, indicating that the proton was becoming more shielded or less acidic. In the binary mixtures, the temperature dependence of δ_(N-H) at constant composition was again barely discernible until a mole fraction of μ-I greater than 0.5 was reached after which the temperature dependence of δ_(N-H), showed an approximately linear dependence on the mole fraction of μ-I, the larger the mole fraction, the greater the temperature dependence and the smaller δ_(N-H), The phase diagram indicated the existence of a congruently melting compound with a 1:1 stoichiometry and a unique X-ray diffraction powder pattern confirmed the existence of this compound. A possible structure of this compound is suggested and its relationship to the melt's structure is suggested.