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2.B.63.  The Diamidocarbazole Substituted Anion Transporter (DSAT) Family 

Maslowska-Jarzyna et al. 2021 established 1,8-diamidocarbazoles as a versatile platform for the development of active chloride carriers. They investigated the influence of various electron-withdrawing substituents in positions 3 and 6 of the carbazole core on the chloride transport activity of these anionophores. Using a lucigenin assay and large unilamellar vesicles as models, the 3,6-dicyano- and 3,6-dinitro- substituted receptors were found to be highly active and perfectly deliverable chloride transporters, with EC50,270s value as low as 22 nM for Cl-/NO3 - exchange. Mechanistic studies revealed that diamidocarbazoles form 1:1 complexes with chloride in lipid bilayers and facilitate chloride/nitrate exchange by carrier mechanism. Furthermore, owing to its increased acidity, the 3,6-dinitro- substituted receptor acts as a pH-switchable transporter, with physiologically relevant apparent pKa of 6.4.