MACROTRICYCLIC QUATERNARY AMMONIUM-IONS - MEMBRANE CURRENT CAUSED BY FEEBLE FORCES BETWEEN HYDROPHOBIC GROUPS AND BILAYER-MEMBRANES

The H-1 NMR study on the encapsulation of iodide ion by controlled derivatives of macrotricyclic quaternary ammonium ions (RMQA(4+); R=H, CH3, CH3(CH2)(3), C6H5CH2 and C10H7CH2) shows the higher stability of their complexes, having the larger hydrophobic space around their intramolecular cavity, with iodide ion, Here the stability constants were estimated from the H-1 NMR spectra for endocyclic protons, Both benzyl and 2-naphthalenemethyl derivatives can act as ion carriers across phospholipid bilayer membranes, Feeble forces between the increasingly hydrophobic space around their own cavity and the bilayer membrane play an important role in their permeation through the phospholipid bilayer as well as the stability of their encapsulated complex with iodide ion, The selectivity of the benzyl derivative for iodide ion has been confirmed, in the presence of chloride ion, by the drastic and decreasing change in membrane current: its decrease may originate from the change of the apparent valency of 4 to 3 due to the inclusion of I.