Catalytic and Photoluminescence Properties of the First‐ and Second‐Sphere Coordination of Lanthanide Complexes
Year: 2025
Type: article
Abstract: The efficient binding of receptors L k ( L k = L5 ‐ L8 ) to [Eu(hfac) 3 ] (H‐hfac = 1,1,1,5,5,5‐hexafluoropentane‐2,4‐dione) allows (i) to gather the basic unit‐containing tridentate ligands L k and the acidic unit‐bearing bidentate hfac − co‐ligands into a stable single molecular [ L k Eu(hfac) 3 ] adduct working as a catalyst for Michael C─C bond formations, (ii) to enhance the acidity of the N‐H units connected to the benzimidazole side arms of the bound ligands L5 and L7 , and (iii) to reorganize their geometries into cis ‐ cis conformation for activating Michael substrates 1 and 2 through H‐bonding interactions on the second‐sphere coordination to provide the target product 3 (up to 92% yield). A maximum enantiomeric excess of 21% could be achieved due to the long distance between the chiral sources and the catalytic sites in the europium complexes. Stepwise distortions from planarity of the terdentate L k ligands in the yttrium complexes [ L k Y(hfac) 3 ] ( L k = L2 , L3 , and L5 ‐ L10 ) can be tuned by addition of specific substituent into the benzimidazole side arms, thus realizing some control over their dual fluorescence and phosphorescence emission properties. All [ L k Eu(hfac) 3 ] ( L k = L2 , L3 , and L5 ‐ L10 ) complexes display europium‐centered photoluminescence properties induced by the antenna effect and modulated by the specific design of the light‐harvesting aromatic ligand located in the first coordination sphere.
Source: Chemistry - A European Journal
Institution: University of Geneva
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,640
OpenAlex ID: W4414929535