A Macrocyclic Tetraether Bolaamphiphile and an Oligoamino α,ο-Dicarboxylate Combine To Form Monolayered, Porous Vesicle Membranes, Which Are Reversibly Sealed by EDTA and Other Bulky Anions

Article abstract of DOI:10.1021/ja00228a037

The hydrophobic tetraether macrocycle 1,20-disulfonyl-4,17,23,36-tetraoxacyclooctatriacontane is obtained in the gram scale from 2,2-dithioethanol and 1,12-dodecanediol.Oxidation or methylation of the sulfur atoms leads to bolaamphiphiles which vesiculate on ultrasonication.These amphiphiles are simple analogues of the membrane constituents of archaebacteria.The vesicles are acid stable and entrap metal ions (Li⁺, Fe²⁺) as well as fluorescent dyes (pyranine, calcein).The dipotassium salt of 2,19-dimethyl-3,6,9,12,15,18-hexaazaeicosanedicarboxylate introduces pores for metal ions into the membrane, but not for the organic dyes.The caionic pores could be closed with water-soluble bulky anions such as camphorsulfonic acid, taurine, and EDTA.The EDTA stopper was extracted from the pore by an excess of Fe(II) ions.Excess of EDTA reclosed the pore.This cycle could be repeated several times.