Combined study of anion recognition by a carbazole-based neutral tripodal receptor in a competitive environment

Abstract

Anion recognition studies have been carried out on a series of neutral synthetic receptors in which carbazole-2-carboxamide has been used as building block. Different ligands which include one to three carbazole units in their structure have been prepared. Binding experiments have been performed under competitive conditions in DMSO and DMSO-water solutions. The tripodal receptor offered a better host-guest association due to the synergistic effect of a well arranged set of hydrogen bonds. A selective response towards the biologically important pyrophosphate anion has been achieved. This selectivity is enhanced when studies are carried out with an increasing water content, which gets as high as 20% (v/v) in NMR experiments. The significance of this result lies in the use of a neutral receptor which exclusively interacts with the anionic guest through hydrogen bonding. The influence of multiple equilibria in the studied system has been analysed. Several techniques ((1)H NMR, (31)P NMR, mass spectrometry, diffusion-NMR, ITC, absorption and emission spectroscopy) have been employed to get a better understanding of the different processes taking place in solution for the evaluated receptors.

Carbazole–azine based fluorescence ‘off–on’ sensor for selective detection of Cu2+ and its live cell imaging

“…Carbazole and its derivatives possess highly conjugated systems, engage in active ICT and are used as electron‐donating chromophores . Carbazole compounds are promising candidates for electroluminescent and photorefractive devices because of their electron‐donating and hole‐transporting properties, and their remarkable application as fluorescent sensors . In the bis‐azine type ligand, the electron density is located on the [C=N−N=C] moiety.…”

“…[59][60][61][62][63] Carbazole compounds are promising candidates for electroluminescent and photorefractive devices because of their electron-donating and hole-transporting properties, and their remarkable application as fluorescent sensors. [64][65][66][67][68][69][70][71][72][73][74][75][76] In the bis-azine type ligand, the electron density is located on the [C=N−N=C] moiety. Binding NMR, Nuclear magnetic resonance spectroscopy; PBS, Phosphate-buffered saline; TDDFT, Time-dependent density functional theory; UV, Ultraviolet; Vis, Visible of metal ions to the ligand affects the electron density and thus influences the fluorescence of the ligand.…”

Preorganized Fluorescent Receptor for the Preferential Binding of the Glutarate Anion

“…In continuation of our ongoing studies on the synthesis and anion binding of new families of carbazole and carbazolocarbazole derivatives, we herein focus our attention on developing a convenient synthetic entry to carbazolo[1,2‐ a ]carbazole 5 . This compound has not only an arch‐shaped geometry with two pyrrole rings adequately oriented towards the center of the binding cavity but also two additional arms that each contain an amide functionality.…”

Binding studies and anion-selective electrodes with neutral isophthalamide-based receptors

“…[14][15][16][17] Interestingly, the easy derivatisation of the plain isophthalamide core has rendered many examples which illustrate how slight structural alterations can have a remarkable inuence in the binding ability of the receptor. [18][19][20] In this regard, our interest in the design of pyrrole-based receptors [21][22][23][24][25] has led us to combine the isophthalamide fragment with pyrrole units which can contribute to expand and enhance the original binding cavity.…”