A simple thermodynamic model for rationalizing the formation of self-assembled multimetallic edifices: application to...

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Lanthanide Chemistry

Background:

• Lanthanide complexes with multidentate ligands are crucial for developing novel materials.
• Understanding the self-assembly and stability of these complexes is key to their application.
• Helical structures in metal complexes offer unique properties and potential applications.

Purpose of the Study:

• To synthesize and characterize novel lanthanide complexes with a bis-tridentate ligand (L2).
• To investigate the formation and stability of different lanthanide complex stoichiometries.
• To develop a thermodynamic model for predicting the formation of heterobimetallic helicates.

Main Methods:

• Reaction of bis-tridentate ligand L2 with lanthanide triflate salts (Ln = La-Lu).
• Spectroscopic characterization including crystal-field independent NMR methods.
• Thermodynamic modeling using free energy principles and intermetallic interactions.

Main Results:

• Successful formation of three stable lanthanide complexes: [Ln(L2)(3)](3+), [Ln(2)(L2)(3)](6+), and [Ln(2)(L2)(2)](6+).
• Crystal structure of [Tb(2)(L2)(3)](6+) validated the helical structure observed in solution.
• A thermodynamic model accurately predicted experimental constants and allowed for molecular programming.

Conclusions:

• The study successfully synthesized and characterized novel lanthanide helicates.
• A robust thermodynamic model was developed for predicting complex formation and stability.
• The findings enable the rational design and molecular programming of extended lanthanide structures.