Investigation of the Supramolecular Assembly of Luminescent Lanthanide Nanoparticles Surface Functionalized by p‐Sulfonato‐Calix[4]arenes with Charged Aromatic Compounds

• Published in: European journal of inorganic chemistry 2021-09, Vol.2021 (36), p.3761-3770
• Main Authors: Cheignon, Clémence, Heurté, Margaux, Knighton, Richard C., Kassir, Ali A., Lecointre, Alexandre, Nonat, Aline, Boos, Anne, Christine, Câline, Asfari, Zouhair, Charbonnière, Loïc J.
• Format: Article
• Language: English
• Subjects: Calixarenes; Chemical Sciences; FRET; Lanthanides; Nanoparticles; Photoluminescence
• 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. p‐Sulfonato‐sulfoxo‐calix[4]arenes were shown to strongly bind to the surface of Tb doped LaF3 nanoparticles, providing an excellent antenna effect for Tb emission. In the presence of some aromatic charged compounds, a strong interaction of the aromatic compounds into the cavity of the surface anchored calixarenes is observed, with a surprising enhancement of the association as compared to the free calixarene in solution.