Supramolecolar β-CD base DESs: insights into structural organization

Here we report on our recent studies on a variety of systems, based on the synergy between Cyclodextrins (CD) and (deep) eutectic solvent (DES) media. The well known capability of CDs to capture and progressively release apolar molecules such as aromas or VOCs led to the widespread use of CDs in a variety of fields including food, pharma, pollution containment etc. In this scenario, CD dispersion in fluid media with wide liquid range and low volatility attracts great attention for a wide range of applications. Considering the large relevance of eco-sustainability issues, a proper choice of solvent media where to disperse CDs is highly relevant. We recently reported on binary mixtures of CDs dispersed into either ionic liquids 1 , such as [C2mim][Acetate], or Deep Eutectic Solvents 2 , such as reline, a 1:2 binary mixture of choline chloride and urea. In these works, we highlighted the importance of the nature of the compounds building up the solvents in maintaining CDs in solution, without precipitation. More recently, we explored the new class of solvent media known as Supra-DES, where CDs are no longer playing the role of solutes in a medium, but they rather behave as genuine components of a mixture, which, at the chosen composition, maintains liquid. We reported the structural features of 1:30 DiMeβ-CD and levulinic acid 3 , highlighting the importance of the balance between hydrogen bonding interactions and dispersive ones in stabilizing the liquid medium. Here we will recollect these results and propose new findings related to β-CD and lactic acid Supra-DES.