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.

This critical review covers advances in anion complexation in the year 2010. The review covers both organic and inorganic systems and also highlights the applications to which anion receptors can be applied such as sensing, anion transport, control of molecular motion and gelation (179 references).

Anion receptor chemistry: highlights from 2010

Perturbations in cellular chloride concentrations can affect cellular pH, autophagy and lead to the onset of apoptosis. With this in mind synthetic ion transporters have been used to disturb cellular ion homeostasis and thereby induce cell death; however, it is not clear whether synthetic ion transporters can also be used to disrupt autophagy. Here we show that squaramide-based ion transporters enhance the transport of chloride anions in liposomal models and promote sodium chloride influx into the cytosol. Liposomal and cellular transport activity of the squaramides is shown to correlate with cell death activity, which is attributed to caspase-dependent apoptosis. One ion transporter was also shown to cause additional changes in the lysosomal pH which leads to impairment of lysosomal enzyme activity and disruption of autophagic processes. This disruption is independent of the initiation of apoptosis by the ion transporter. This study provides the first experimental evidence that synthetic ion transporters can disrupt both autophagy and induce apoptosis.

/pdf/a-synthetic-ion-transporter-that-disrupts-autophagy-and-uc17a5rrhh.pdf

A synthetic ion transporter that disrupts autophagy and induces apoptosis by perturbing cellular chloride concentrations

1,3-Diindolylureas and thioureas have been synthesised and their anion complexation properties in solution studied. Whilst diindolylthioureas showed only moderate afinities and selectivities, diindolyureas show remarkably high affinity for dihydrogen phosphate in solution for an acyclic, neural receptor in water/[D-6]DMSO mixtures. These easy-to-make compounds adopt relatively planar conformations in the solid-state and are able to donate four hydrogen bonds and yet not fill the coordination sphere of carbonate or phosphate, allowing two or three receptors to bind to each anion in the solid-state.

Jennifer R. Hiscock

Papers

Anion receptor chemistry: highlights from 2010

A synthetic ion transporter that disrupts autophagy and induces apoptosis by perturbing cellular chloride concentrations

1,3-Diindolylureas and 1,3-Diindolylthioureas: Anion Complexation Studies in Solution and the Solid State

1,3-Diindolylureas: high affinity dihydrogen phosphate receptors

1,2,3-triazole-strapped calix[4]pyrrole: a new membrane transporter for chloride.