Investigation of the Supramolecular Assembly of Luminescent Lanthanide Nanoparticles Surface Functionalized by p‐Sulfonato‐Calixarenes with Charged Aromatic Compounds

• Published in: European journal of inorganic chemistry Vol. 2021; no. 36; pp. 3761 - 3770
• Main Authors: Cheignon, Clémence, Heurté, Margaux, Knighton, Richard C, Kassir, Ali A, Lecointre, Alexandre, Nonat, Aline, Boos, Anne, Câline Christine, Asfari, Zouhair, Charbonnière, Loïc J
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-09-2021
• Subjects: Affinity; Aromatic compounds; Calixarenes; Energy transfer; Excitation; Inorganic chemistry; Luminescence; Luminescence quenching; Nanoparticles; Paraquat; Rhodamine 6G
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202100546

The surface coordination of p‐sulfonato‐ (C[4]), p‐sulfonatothia‐ (SC[4]) and p‐sulfonato‐sulfoxocalix[4]arene (SO2C[4]) on La0.9Tb0.1F3 nanoparticles (TbNP) was investigated by UV‐Vis absorption and luminescence spectroscopies. SO2C[4] displayed the strongest affinity towards the NPs and a significant antenna effect leading to observation of the characteristic Tb emission bands upon calixarene excitation. NPs decorated by a shell of SO2C[4] were prepared and the interaction with rhodamine 6G (R6G) was studied. The progressive addition of R6G resulted in a strong Tb to R6G energy transfer process, as revealed by a long lived emission of R6G upon SO2C[4] excitation. The FRET efficiency was almost quantitative (87–90 %), pointing to an average distance of 28 to 32 Å between the R6G and the Tb emitting centres of the NP. An association of one R6G per SO2C[4] was deduced with a very strong apparent affinity (K=2.5×107 M−1) in water. Similar interactions were observed with paraquat, resulting in TbNP luminescence quenching. In both cases, an unexpected increase of the association constant of the cation with SO2C[4] was observed when SO2C[4] is anchored at the surface of the NP.