Sulfonamide carbazole receptors for anion recognition

Abstract

Carbazole-based receptors functionalized with two sulfonamide groups have been synthesized and their properties as anion receptors have been evaluated. The receptor with bis(trifluoromethyl)aniline groups has shown a very high affinity for halide ions, especially remarkable as only two hydrogen bonds are formed in the complexes. (1)H NMR and fluorescence titrations have been carried out and binding constants up to 7.9 × 10(6) M(-1) have been reached. X-ray structures have been obtained and a modelling study has shown the possible reasons for the large affinity of these compounds for halide anions.

Anion Recognition with Hydrogen‐Bonding Cyclodiphosphazanes

“…Many hydrogen‐bonding motifs used in organocatalysis have also proven to be effective as components of synthetic anion receptors or vice versa 1. These motifs include, for example, (thio)urea,2 sulfonamide,3 phosphorus (tri)amide,4 silanediol,5 triphenol6 and squaramide motifs 7. Consequently, synthetic strategies have emerged that highly effectively employ hydrogen‐bonding motifs in (asymmetric) anion‐binding catalysis 8.…”

Carbazole-Based Colorimetric Anion Sensors

“…Subsequent reduction yields either 1,8-diamino-3,6-dichlorocarbazole ( 8 ) [ 22 ] or 1,8-diaminocarbazole ( 9 ) [ 28 ], depending upon the reagents and conditions. These two diamines have already been used for the synthesis of various anion receptors, including amides, thioamides, sulfonamides, and ureas [ 17 , 18 , 20 , 26 ]. Additionally, our group has used them also for the synthesis of model receptors 1 and 2 ( Scheme 1 ) [ 19 , 22 ].…”

“…It combines several attractive features, such as the presence of a strong carbazole chromophore and fluorophore directly coupled with anion binding sites, a strong hydrogen bond donor (i.e., carbazole NH), a rigid skeleton that facilitates the preorganization of auxiliary hydrogen bond donors and the ease of synthesis and derivatization. Diaminocarbazole-based receptors show particularly high affinity towards oxyanions (carboxylates, phosphates, and sulfates) [ 3 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ] and some of them are also very active anion transporters [ 22 , 25 , 26 ].…”

Boron based fluoride anion receptors: Electrochemical and sensory applications

“…Whereas LiF is essentially insoluble in the nonaqueous electrolyte solvents such as dimethyl ether (DME) and carbonate based solvents, in the presence of anion receptors LiF is relatively highly soluble, and typically 1 M solutions of LiF in dimethyl ether could be obtained so that high lithium ion conductivities could be achieved in lithium ion batteries. 1, 3, 4 Whereas there are reltively highly selective colorimetric fluoride anion receptors based on Bronsted acid-base reactions or hydrogen bonding interactions as in the case of urea-, [12][13][14][15] indole-, 16 pyrrole-, 17, 18 carbazole-, 19 thiourea-20 and calixarene-based 21-24 anion receptors ( Figure 2), the boron-based anion receptors have superior electrochemical and thermal stabilities, and thereby are compatible with the state of the art carbonate-based nonaqueous electrolytes (E ox >4.5 V vs Li/Li + ). 25 The borate-and boroxine-based fluoride anion receptors are readily accessible from the corresponding relatively inexpensive boric acid derivatives.…”