Combinatorial design of multimeric chelating peptoids for selective metal coordination

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Current metal chelation methods rely on complex organic ligands, limiting systematic modification of metal-binding properties.
• Octadentate ligands with hydroxypyridinone or catecholamide moieties on spermine scaffolds show high affinity for f-elements.
• Developing modular and high-throughput synthetic strategies is crucial for enhancing binding affinity to specific lanthanide and actinide ions.

Purpose of the Study:

• To introduce a high-throughput combinatorial library of peptoid ligands for f-element chelation.
• To compare the properties of new peptoid ligands with existing spermine-based ligands.
• To investigate the potential of these ligands in applications such as separations and pharmaceutical development.

Main Methods:

• Synthesized a library of 16 tetrameric N-substituted glycine oligomers (peptoids) with hydroxypyridinone or catecholamide chelating units.
• Prepared control ligands based on the spermine scaffold: 3,4,3-LI(1,2-HOPO)2(CAM)2 and 3,4,3-LI(CAM)2(1,2-HOPO)2.
• Conducted coordination-based luminescence studies with Eu3+ and Tb3+ and solution thermodynamic measurements.

Main Results:

• Peptoid ligands were successfully synthesized, offering a modular approach to ligand design.
• Spermine scaffold ligands exhibited higher sensitization efficiency in luminescence studies with Eu3+ and Tb3+.
• Stability constants (log β110) for Eu3+ ranged from 28.88 ± 3.45 to 43.97 ± 0.49, indicating strong metal-ligand interactions.

Conclusions:

• The presented synthetic strategy enables the precision design of specific and versatile ligands for f-elements.
• The new peptoid architecture offers a flexible platform for tailoring ligand properties.
• These ligands have potential applications in f-element separations, optical devices, and pharmaceutical development.