Three modes of interactions between anions and phenolic macrocycles: a comparative study

Abdurakhmanova, E. R.; Cmoch, Piotr; Szumna, Agnieszka

doi:10.1039/d2ob00880g

Cited by 8 publications

(1 citation statement)

References 56 publications

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“…Nevertheless, the Dalcanale group noticed weak interactions of large anions (PF6 -) with acetal CH groups in the upper rim, 34 and some of us found weak but non-negligible interactions of anions with 7 via aromatic CH groups in the lower rim. 35 The latter observation was particularly surprising because resorcinols are classic electron-rich aromatic rings that have not been previously considered capable of CHanion interactions. Intrigued by this observation we aimed to rationally enhance anion binding via the aromatic CH groups at the lower rim of resorcin [4]arenes, and for this purpose, we designed receptors 1-4 (Fig.…”

Section: Design and Theoretical Calculationsmentioning

confidence: 99%

Supramolecular umpolung: converting electron-rich resorcin[4]arenes into potent CH-bonding anion receptors and transporters

Abdurakhmanova,

Mondal,

Jędrzejewska

et al. 2023

Preprint

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CH-hydrogen bonding anion receptors constitute an emerging class of anion sensors and transporters which, owing to their proteolytic and pH resistance, have great potential for biological applications. However, CH groups, being weak hydrogen bond donors, require additional enhancement of their binding properties. In this work, we demonstrate a new enhancement strategy that relies on the generation of large dipole moments by a combination of electron-donating and electron-withdrawing substituents. More specifically, the substitution of electron-rich resorcin[4]arenes with electron-withdrawing nitro groups in the upper rim induces a dipole moment of 15.8 D and concentrates electrostatic potential at the lower rim, leading to strong CH···anion binding at this remote site. As a result, tetranitroresorcin[4]arenes, available in just two synthetic steps, acquire high affinities towards halides (Ka(Cl-) = 1.36 × 105 M-1 in THF), remarkable tolerance to water, and selective chloride transport activity (EC50 = 0.012 mol%). A pivotal role of the seemingly innocent alkyl chains surrounding the binding site in making the receptors resistant to competitive aqueous/organic solvent mixtures and enabling anion transport is also demonstrated.

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Section: Design and Theoretical Calculationsmentioning

confidence: 99%