Deep eutectic solvents: A structural point of view on the role of the cation

Use of ammonium salts or binary mixtures derived from amino acids, glycine betaine, choline and indole-3-butyric acid as plant regulators

“…36,37 However, the melting point of the synthesized binary mixtures depends on the components as well as the type and strength of the intervening hydrogen bonds. 38 Note that IBA combined with amino acids has a signicantly higher thermal stability than the acid form of IBA. By comparison, the thermal stability of IBA combined with choline or glycine betaine is considerably less enhanced.…”

What a difference a methyl group makes – probing choline–urea molecular interactions through urea structure modification

“…Another ab initio study, performed by Wagle and colleagues, 23 proposes that the melting points of three cholinium chloride based DES correlate with the bond order of the choliniumÁ Á Áchloride interaction but not with the bond order of the HBDÁ Á Áchloride contacts. Migliorati and colleagues 29 compared eutectic mixtures based on urea and either cholinium chloride or butyltrimethylammonium chloride, finding that while the ureaÁ Á Áchloride interaction is relatively favoured in the latter this does not translate into a more pronounced melting point depression. It is then clear that the contribution of the HBDÁ Á Áanion interaction to the melting point depression remains controversial.…”

Connecting chloride solvation with hydration in deep eutectic systems

“…A recurrent finding is that the anion, usually chloride, plays a primary role by defining the H-bond network. [7][8][9][10][11][12][13][14] In the archetypal DES ChCl:urea, the local structure sees chloride in constant H-bond flux with choline and urea, at the centre of a local cluster. The cation and HBD have different bonding affinities and short-range diffusion dynamics.…”