Synthesis and anion binding properties of 1,8-disulfonamidocarbazole dipyrromethane Schiff-base macrocycle & its amine analogue

Synthesis and Anion Binding Properties of a Novel 1,8-dipyrrolecarbazole Schiff-base

“…[9,12] On the other hand, the examples of carbazole Schiff-base anion receptors are very rare in the literature. [13] Although various anion receptors containing a carbazole or a pyrrole are known, to the best of our knowledge, the receptor which is composed of those structural subunits combined in a single molecule and attached to each other by the imine nitrogen has not been reported yet. The incorporation of the rigid imine double bond would lead to a more rigid receptor which could participate in hydrogen bonding with its two pyrrole moieties, thus improving the receptor binding and/or selectivity towards anions.…”

Carbazole sulfonamide-based macrocyclic receptors capable of selective complexation of fluoride ion

“…As shown in Scheme 1 , macrocycles 1 and 2 were facilely synthesized by condensation of carbazole-1,8-disulfonyl chloride 3 22,23 with the appropriate diamines in dry CH 2 Cl 2 using TEA as a catalyst, giving reasonable yields of 30% and 25%, respectively. Both macrocycles were fully characterized by 1 H NMR, 13 C NMR, and HRMS (high resolution mass spectrometry) techniques.…”

“… 21 In 2016, we synthesized 1,8-disulfonamidocarbazole-dipyrromethane Schiff-base macrocycle & its reduced derivative and evaluated their anion binding properties by UV-vis and 1 H NMR titration methods. 22 The results indicated that two macrocyclic receptors exhibited strong binding interactions ( K a > 10 4 M −1 ) with fluoride, acetate and dihydrogen phosphate ions over other anions in the highly competitive DMSO medium, but both macrocycles were poorly selective among these three anions.…”

Two carbazole disulfonamide-diamide macrocycles with semi-flexible meta-xylyl linkages for anion recognition

“…On the other hand, the skeleton of carbazole-1,8-disulfonamides has unique advantages as an ideal molecular platform for developing anion receptors, 16,[19][20][21][22][23] based on the following reasons: firstly, carbazole NH itself and its two adjacent sulfonamide NHs can easily work together to facilitate anion binding via three convergent N-H hydrogen bond donors. Secondly, compared with the most-commonly used amide group, its analogous sulfonamide group has a more acidic NH proton and is thus a better hydrogen bond donor.…”

“…24,25 Thirdly, it is easy to introduce various functional groups into the carbazole backbone for tuning its anion binding properties. 26 As part of our continuing interest in the development of carbazole 1,8-sulfonamide-based anion receptors/sensors, 16,[20][21][22] we have recently synthesized two carbazole disulfonamidediamide macrocyclic receptors with rigid meta-phenylene spacers and have studied their anion binding properties in DMSO-d 6 solution. 27 The experimental results revealed that it was difficult to leverage all the available NH groups in the macrocycles to complex the examined anions (except for spherical Cl À ), probably due to the existing structural rigidity of these macrocycles.…”