This critical review focuses on the development of anion sensors, being either fluorescent and/or colorimetric, based on the use of the 1,8-naphthalimide structure; a highly versatile building unit that absorbs and emits at long wavelengths. The review commences with a short description of the most commonly used design principles employed in chemosensors, followed by a discussion on the photophysical properties of the 4-amino-1,8-naphthalimide structure which has been most commonly employed in both cation and anion sensing to date. This is followed by a review of the current state of the art in naphthalimide-based anion sensing, where systems using ureas, thioureas and amides as hydrogen-bonding receptors, as well as charged receptors have been used for anion sensing in both organic and aqueous solutions, or within various polymeric networks, such as hydrogels. The review concludes with some current and future perspectives including the use of the naphthalimides for sensing small biomolecules, such as amino acids, as well as probes for incorporation and binding to proteins; and for the recognition/sensing of polyanions such as DNA, and their potential use as novel therapeutic and diagnostic agents (95 references).

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Colorimetric and fluorescent anion sensors: an overview of recent developments in the use of 1,8-naphthalimide-based chemosensors

Applications of Supramolecular Anion Recognition

The present critical review outlines the close relationship and mutual interplay between molecular recognition, active site considerations in enzyme catalysis involving anions, and organocatalysis utilizing explicit hydrogen bonding. These interconnections are generally not made although, as we demonstrate, they are quite apparent as exemplified with pertinent examples in the field of (thio)urea organocatalysis. Indeed, the concepts of anion binding or binding with negatively (partially) charged heteroatoms is key for designing new organocatalytic transformations. Utilizing anions through recognition with hydrogen-bonding organocatalysts is still in its infancy but bears great potential. In turn, the discovery and mechanistic elucidation of such reactions is likely to improve the understanding of enzyme active sites (108 references).

(Thio)urea organocatalysis—What can be learnt from anion recognition?

Detection Ying Zhou,†,‡ Jun Feng Zhang, and Juyoung Yoon*,† †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea ‡Key Laboratory of Medicinal Chemistry for Natural Resource, School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, P. R. China

Fluorescence and colorimetric chemosensors for fluoride-ion detection.

Recent Advances in Supramolecular Analytical Chemistry Using Optical Sensing.

The influence of anions on tautomerism in benzimidazole containing anion receptors has been studied via a variety of techniques in both solution and the solid state. The results show that hydrogen bonding interactions between the receptors and guests have a significant effect of the nature of the tautomer present. The compounds show a preference for complexation of lactate over pyruvate.

Benzimidazole-based anion receptors exhibiting selectivity for lactate over pyruvate.

A series of tren-based amide or urea linked tris-indole anion receptors have been synthesised and their anion complexation properties studied in DMSO-d 6/water mixtures.

Tris-(2-aminoethyl)amine-based tripodal trisindolylureas: new receptors for sulphate

https://pubs.rsc.org/en/content/articlepdf/2020/CC/D0CC03612A

A quantitative assay to study the lipid selectivity of membrane-associated systems using solution NMR

Herein, we present the synthesis of a thymine nucleobase-appended ‘frustrated’ monomer, which exhibits self-association in DMSO solutions through the formation of hydrogen bonds. This self-association process has been explored in both competitive DMSO solutions and the solid state, using a combination of NMR and single crystal X-ray diffraction techniques. The self-associative equilibria within the solution state are balanced in such a way that the hydrogen bond donating and accepting thymine residue present within the monomeric structure is free to coordinate further guest species such as the complimentary DNA base adenine. The adenine simulants, 2-aminopyridine and 2,6-diaminopyridine have been used to explore the potential of these self-associated structures towards the coordination of complimentary DNA base pairs.

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'Frustrated' hydrogen bonded self-associated systems as templates towards DNA incorporated nanostructure formation

Bis(thio)urea receptors (1–4) based on 1,2-bisaminocyclohexane are shown to function as transmembrane anion antiporters. The results show that cis-receptors have a greater propensity for anion transport than analogous trans-receptors. Stability constants using 1H NMR techniques highlight the significance of stereoisomerism on anion binding in solution, as cis-receptors bind anions more strongly than trans-receptors.

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Jennifer R. Hiscock

Papers

Benzimidazole-based anion receptors exhibiting selectivity for lactate over pyruvate.

Tris-(2-aminoethyl)amine-based tripodal trisindolylureas: new receptors for sulphate

A quantitative assay to study the lipid selectivity of membrane-associated systems using solution NMR

'Frustrated' hydrogen bonded self-associated systems as templates towards DNA incorporated nanostructure formation

The influence of stereochemistry on anion binding and transport