The interaction of an amphiphile crown ether with divalent metal ions. An electrochemical, Langmuir film, and molecular modeling study

Highlights: • A new amphiphilic crown ether forms complexes with Cu(II), Zn(II) and Ni(II). • The crown ether ligand differentiates between the metal ions in water. • The selectivity of complexation might be adjusted by solvent engineering. -- Abstract: A new crown ether bearing two hydrophobic lateral chains was synthesized and its complexation properties toward divalent metal ions were studied experimentally and theoretically in water and in non-aqueous environment. Electrochemistry and Langmuir film technique were used to evaluate the stability of complexes formed by the ligand with Cu(II), Zn(II) or Ni(II). Molecular modeling allowed unveiling the structure of the complexes. The results obtained show that all three cations form complexes with the crown ether. However, the stability of the complexes is different depending on the cation and on the environment in which they are formed. This observation suggests that cation complexation can be controlled by adjusting solvent properties; it can be useful in view of possible technological and/or medical applications.