RESUMEN
We have prepared novel divalent ionic liquids (ILs) based on the bis(trifluoromethylsulfonyl)imide anion where two charged imidazolium groups in the cations are either directly bound to each other or linked by a single atom. We assessed the influence of the side-chain functionality and divalency on their physical properties and on the thermodynamics of mixing. The results indicate that shortening the spacer of a divalent IL reduces its thermal stability and increases its viscosity. Mixtures of divalent and monovalent ILs show small but significant deviations from ideality upon mixing. These deviations appear to depend primarily on the (mis)match of the nature and length of the cation side-chain. The non-ideality imposed by mixing ILs with different side-chains appears to be enhanced by the increase in formal charge of the cations in the mixture.
RESUMEN
Supported chiral ionic liquids (SILs) were prepared choosing the starting material for the ionic liquid part from the enantiopure stock of the chiral pool (monoterpenoids and an amino acid) and the sporopollenin as an environmentally friendly support. Sporopollenins are microcapsules with naturally well-defined sizes and shapes that can be obtained from pollen grains after removal of the internal cytoplasm and the second shell layer. As thermally stable organic biocompatible structures, sporopollenins have attracted increasing interest in recent years for several applications. Herein, bio-based ILs were anchored onto the surface of sporopollenins obtained from the pollen of Populus deltoides, selected as a model pollen grain. These new structures, which present an external positively charged shell, were characterized by physico-chemical techniques (ATR-FTIR, TGA, SEM, EDX, and solid-state 13C NMR). A metathesis reaction was also performed on selected bio-based IL modified sporopollenins, demonstrating the possibility to switch the surface properties by exploiting well-known IL chemistry.