0000000000713849
AUTHOR
Bianca Sesta
The transport of ions across monoolein bilayers mediated by synthetic macrocyclic carriers
The efficiency as carriers for the alkali and the alkaline earth ions across monoolein bilayers of three macrocyclic compounds has been investigated by conductometric measurements. The results show that although the three compounds have the optimum cavity size for fitting potassium and barium cations, their efficiency in ionic transport is quite different. These discrepancies are rationalized on the basis of the overlap of the water-diazacrown and cation-ligand interactions on the carrier mechanism.
Complexation of the potassium ion by diaza crown compounds in aqueous solutions
The conductance behavior of potassium nitrate in water with and without 1,7,10,16-tetraoxa-4,13-diazacyclooctandecane[2.2] and 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-8.8.8-exacosane[2.2.2] macrocyclic ligands have been studied in order to analyze the complexation behavior of potassium cations in water. The absence of the complexation found in the [2.2] system is discussed in terms of the ligand structural features (presence of hydrogen bond donor and acceptor sites). The ion pair association constant of potassium cryptate as obtained from conductance measurements is also reported and discussed.