Size Selectivity in Heterolanthanide Molecular Complexes with a Ditopic Ligand

Area of Science:

• Coordination Chemistry
• Lanthanide Chemistry
• Materials Science

Background:

• The similar reactivity of lanthanides complicates the design of ordered hetero-lanthanide compounds.
• Lanthanide complexes often form statistically populated polynuclear structures.

Purpose of the Study:

• To achieve site selectivity in hetero-lanthanide tetranuclear complexes.
• To investigate the factors governing ion selectivity in lanthanide coordination compounds.
• To develop a rational design strategy for ordered lanthanide complexes.

Main Methods:

• Sequential room temperature synthesis of lanthanide complexes.
• Single crystal X-ray diffraction for structural determination.
• Solid-state structural and magnetic studies.
• Solution studies using 19F NMR and photoluminescence (PL).

Main Results:

• Successfully synthesized Y2La2, Dy2La2, and Eu2La2 tetranuclear complexes with a ditopic pyterpyNO ligand.
• X-ray diffraction revealed isostructural complexes with distinct CN8 and CN9 metal coordination sites.
• High ion selectivity (91% for Y2La2) was observed, correlating with ionic radii differences.
• Selectivity was maintained regardless of synthetic route, including self-assembly.

Conclusions:

• The ditopic pyterpyNO ligand enables site selectivity in hetero-lanthanide tetranuclear complexes.
• Ion selectivity is influenced by ionic radii differences but not exclusively governed by electrostatic interactions.
• This study provides a pathway for the rational design of complex, ordered lanthanide materials.