Toward transmembrane anionophores based on rigid bis(choloyl) conjugates: reversal of the ion selectivity by appended polyamines

Abstract

A bis(polyamine)-appending rigid linker-tethered bis(choloyl) conjugate was synthesized as a potent anionophore with high selectivity for iodide over the other monoanionic ions.

Synthesis, Anion Recognition, and Transmembrane Anionophoric Activity of Tripodal Diaminocholoyl Conjugates

“…However, the above pH discharge experiments do not provide any clear evidence for cation- or anion-selective transport. Under the conditions of pH discharge, any of these four mechanisms, that is, H + /cation antiport, OH – /anion antiport, H + /anion symport and OH – /cation symport, would equally cause pH change in the internal of the vesicles. ,− The chloride-selective transport by compounds 1 and 2 was confirmed by measuring their chloride efflux activity with chloride-ion-selective electrode. − Thus, a series of EYPC vesicles loaded with NaCl was prepared and added to an external isotonic NaNO 3 solution. After a DMSO solution of compound 1 or 2 of increasing concentrations was added, the efflux of chloride anions out of the liposomes was immediately monitored by the electrode for a period of 300 s. The final reading of the electrode that was used to calibrate the 100% release of chloride anions was obtained by the addition of 5 wt % aqueous Triton X-100 solution.…”

“…The experimental protocols previously described by us and others − were adopted to prepare the liposomes and examine the chloride efflux and pH discharge activity of compounds 1 – 3 .…”

Membrane active cationic cholic acid-based molecular umbrellas

“…Their systems composed of two steroid moieties functionalized with amino, guanidino or squaramide groups, were able to promote chloride transmembrane transport via a cation/anion symport process. [20][21][22] Our group has extensively studied imidazolium 23,24 and benzimidazolium 25,26 cations in the transport of chloride across phospholipid membranes and demonstrated the antibacterial applications of these anion transporters. However, other anions possess a key role in mammalian physiology.…”