Anion-controlled foldamers

Abstract

This tutorial review provides a summary of anion-mediated folding of linear and cyclic oligomers as well as anion-responsive behaviours of related polymeric architectures. Anions have emerged as a significant focus of the supramolecular community and here we review their impact on directing the secondary structures of synthetic oligomers and polymers while modulating physical properties e.g. molecular recognition. Oligomers and polymers responsive to anionic guests are typically constructed with hydrogen bond donors complementary to the target anions. Anion binding within the cavities leads to folding and helical wrapping of linear and cyclic oligomers as well as control over macromolecular properties of polymers. This review covers the impact of anion binding on guiding the secondary structures of single-stranded folded oligomers (foldamers) and cyclic oligomers (macrocycles), and on modulating the physical properties of select polymer architectures.

Anion binding induced conformational changes exploited for recognition, sensing and pseudorotaxane disassembly

“…1,2 For example, anion-controlled foldamers are oligomeric receptors which fold to encapsulate anionic guest species, excluding the surrounding solvent, [3][4][5] whilst induced-fit anion sensors can exhibit effective sensing behaviour, with selectivity arising from key geometrical differences in the receptor-anion complexes. [6][7][8][9][10] Planar, π-delocalised groups, such as pyrene, have the propensity to form excited state dimers, excimers, 11,12 with the extent of formation dependent on the ability of the groups to overlap.…”

Comparative Study of the Mechanical Unfolding Pathways of α- and β-Peptides

“…[1][2][3][4][5][6] Among the large variety of different categories of foldamers the β-peptides are one of the most studied systems. [7][8][9][10][11][12][13][14][15] These peptides are ideal candidates for drug design and peptidomimetic applications, because of their versatility and significantly higher metabolic stability in comparison to natural peptides.…”

Stereodivergent Anion Binding Catalysis with Molecular Motors

“…5 D), which results in an electropositive C−H capable of engaging in hydrogen bonding with negatively charged species . In the case of aryl triazole oligomers that cannot adopt a planar conformation, this interaction translates into a helical supramolecular arrangement in the presence of, among others, chloride anions . Based on this concept, chiral oligotriazoles bearing a trans ‐1,2‐cyclohexanediamine backbone have been developed and their utility in asymmetric anion binding catalysis has been elegantly illustrated for the dearomatization of a variety of heterocycles .…”