A neutral halogen bonding macrocyclic anion receptor based on a pseudocyclopeptide with three 5-iodo-1,2,3-triazole subunits

Abstract

The converging arrangement of iodine atoms along its confined cavity causes a cyclic pseudopeptide with three 5-iodo-1,2,3-triazole subunits to interact with halides, in particular with chloride, in 2.5 vol% water/DMSO.

Halogen Bonding in Solution: Anion Recognition, Templated Self‐Assembly, and Organocatalysis

“…Recently,the Kubik research group also designed amacrocyclic XB-based anion receptor comprising three iodotriazole subunits (Figure 12 B). [58] Ther igid, highly preorganized macrocyclic pseudopeptide 20 showed an impressively high binding affinity for an eutral XB donor (K a (Cl À ) = 1.9 10 3 m À1 in 2.5 %H 2 Oi n[ D 6 ]DMSO at 298 K) as well as Figure 9. Monodentate XB/HB donor systems based on N-succinimide and analogous N-saccharin derivatives.…”

Fluorometric Recognition of Nucleotides within a Water‐Soluble Tetrahedral Capsule

“…We infer that the stability of 1 during anion exchange results from the high density of connections within the structure, wherein each Zn II center is sequestered within a cryptate‐like hexadentate cage, with all cage‐faces bound together into a single dynamic covalent‐ligand framework. The stability of the system is thus derived from the strengths of both coordinative and covalent linkages –…”

Acid‐Regulated Switching of Metal Cation and Anion Guest Binding in Halogen‐Bonding Rotaxanes

“…No appreciable binding was observed for I − and ReO 4 − , which may be due to their inability to fit into the preorganised rotaxane cavity. Given the inherent preference of XB donor host molecules to bind to the heavier and “softer” halides in aqueous solvents due to their greater ease of dehydration, this result is especially notable since it is the first example of an XB rotaxane preferentially binding the most strongly hydrated Cl − in the presence of water, and only the second XB receptor known to display an anti‐Hofmeister binding bias . While rotaxane [ 1 ⋅2 H + ](BF 4 − ) 2 displays stronger Cl − binding compared to [ 2 ⋅H + ]BF 4 − , which is likely to be a consequence of its dicationic character, [ 2 ⋅H + ]BF 4 − displayed rare exclusive Cl − selectivity.…”

“…Importantly,f or [1·2 H + ](BF 4 À ) 2 ,a na nti-Hofmeister binding trend was observedf or the anions tested, with the less strongly hydrated anionsB r À and NO 3 À more weakly boundt han Cl À .N oa ppreciable binding was observed for I À and ReO 4 À ,w hich may be due to their inabilityt of it into the preorganised rotaxanec avity.G iven the inherent preference of XB donor host molecules to bind to the heaviera nd "softer" halidesi na queous solvents due to their greater ease of dehydration, [16,20,42,43] this resulti se speciallyn otable since it is the first example of an XB rotaxane preferentially binding the most strongly hydrated Cl À in the presence of water,a nd only the second XB receptor known to display an anti-Hofmeister binding bias. [44] Hence the observedC l À selectivity for both rotaxanes is likely to result from ac ombination of favourable ammonium HBand XB-chloride interactions together with ap reorganised interlocked binding cavity whichi so fc omplementary shape and size to the halide guest species.…”