Structure and properties of the (α-PicH)3[RhCl6] salt containing 2-methylpyridinium cations

Abstract

The organic-inorganic hybrid salt consisting of 2-methylpyridinium cation (α-picoline, α-Pic) and hexachlororhodate(III) anion (α-PicH)3[RhCl6] was prepared in high yield. The compound was characterized using a variety of spectral techniques (UV–Vis, IR, Raman, XAFS) and its crystal structure was determined by X-ray single crystal diffraction. The system of strong NH…Cl hydrogen bonds is observed in the structure between organic cations and complex anions resulting in the formation of oppositely charged conglomerates {(α-PicH)4[RhCl6]}+ and {(α-PicH)2[RhCl6]}−. The chemical processes taking place during the thermal decomposition of the salt in He and H2/He atmospheres were studied, and the products of these transformations were identified. The unique thermal stability of [RhCl6]3− anions in an α-PicHCl ionic liquid and a range of temperature up to 250 °C was demonstrated using UV–Vis absorption spectroscopy.