Combinatorial design of multimeric chelating peptoids for selective metal coordination. Issue 28 (12th June 2019)

• Record Type: Journal Article
• Authors: Ricano, Abel; Captain, Ilya; Carter, Korey P.; Nell, Bryan P.; Deblonde, Gauthier J.-P.; Abergel, Rebecca J.
• Is Part Of: Chemical science. Volume 10:Issue 28(2019)
• Page Start: 6834
• Page End: 6843
• Publication Date: 2019-06-12
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9sc01068h
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : The combinatorial synthesis of a new library of tetrameric peptoid ligands is introduced, enabling coordination and characterization of f-block metals. Abstract : Current methods for metal chelation are generally based on multidentate organic ligands, which are generated through cumbersome multistep synthetic processes that lack flexibility for systematically varying metal-binding motifs. Octadentate ligands incorporating hydroxypyridinone or catecholamide binding moieties onto a spermine scaffold are known to display some of the highest affinities towards f-elements. Enhancing binding affinity for specific lanthanide or actinide ions however, necessitates ligand architectures that allow for modular and high throughput synthesis. Here we introduce a high-throughput combinatorial library of 16 tetrameric N -substituted glycine oligomers (peptoids) containing hydroxypyridinone or catecholamide chelating units linked via an ethylenediamine bridge and, for comparison, we also synthesized the corresponding mixed ligands derived from the spermine scaffold: 3, 4, 3-LI(1, 2-HOPO)2 (CAM)2 and 3, 4, 3-LI(CAM)2 (1, 2-HOPO)2 . Coordination-based luminescence studies were carried out with Eu 3+ and Tb 3+ to begin probing the properties of the new ligand architecture and revealed higher sensitization efficiency with the spermine scaffold as well as different spectroscopic features among the structural peptoid isomers. Solution thermodynamic properties of selected ligands revealed different coordination properties between the spermine and peptoid analogues with Eu 3+ stability constants log β 110 ranging from 28.88 ± 3.45 to 43.97 ± 0.49. The general synthetic strategy presented here paves the way for precision design of new specific and versatile ligands, with a variety of applications tailored towards the use of f-elements, including separations, optical device optimization, and pharmaceutical development.