A Belted Monofacial Ionophore Featuring High Selectivity for Lithium Ion Complexation

Area of Science:

• Supramolecular chemistry
• Organic chemistry
• Coordination chemistry

Background:

• The cis,cis-trispiro ether 1 exhibits a preferred equatorial conformation in both solid and solution states.
• Understanding the binding behavior of macrocyclic ethers with metal ions is crucial in host-guest chemistry.

Purpose of the Study:

• To investigate the binding affinity and complexation behavior of cis,cis-trispiro ether 1 with lithium ions.
• To characterize the stoichiometry and structural evolution of lithium complexes formed with the trispiro ether.

Main Methods:

• Spectroscopic analysis to monitor complex formation.
• Crystallography to determine the structure of the resulting complexes.
• Titration experiments to study the binding stoichiometry.

Main Results:

• The cis,cis-trispiro ether 1 demonstrates strong binding with lithium ions.
• An initial 2:1 (ether:Li+) sandwich complex (2) is formed.
• Progressive addition of lithium perchlorate (LiClO4) leads to the transformation into a 1:1 (ether:Li+) complex (3).

Conclusions:

• The trispiro ether 1 acts as an effective ligand for lithium ions.
• The stoichiometry of the complex is dependent on the concentration of lithium ions.
• The conformational flexibility of the ether allows for adaptable coordination with lithium.