Hexaazamacrocyclic Ligands with Long Alkyl Chains as Functional Units in Monomolecular Langmuir – Blodgett Films

Abstract

Properties of three macrocyclic hexaamine derivatives were studied in monolayers as the anion binding or ion channel units. In monolayers at the air-solution interfaces the protonated molecules were found to interact with berchlorate anions in the solution by simple ion-pairing. Interactions with Fe were stronger due to supercomplex formation. In case of hexaamine modified with amide groups additional interactions of Fe with amides induced changes in the structure of the macrocyclic molecule at the air-water interface. The hexaaza macrocyclic ligands studied did not form on their own stable monolayers on electrodes, therefore, two-component monolayers containing α,ω-hydroxythiol and the polyazamacrocyclic ligand were prepared at the air-water interface and transferred onto gold electrode using the mono-layer lifting procedure. This approach allowed to obtain stable coverage of the electrode with the composite monolayer anchored to the gold surface through the thiol groups of hydroxythiol, and with the hydrophilic parts of the hexaazamacrocyclic molecules facing directly the solution, therefore free to interact with the ions present in the solution.