Supramolecular lanthanide metallogels rapidly formed at room temperature and their thermally stable luminescence behavior

Luminescent supramolecular metallogels based on the coordinating interaction of lanthanide ions and Fmoc-L-phenylalanine were prepared at room temperature within several seconds. The prepared metallogels exhibited strong characteristic luminescent behavior of lanthanide ions. The formation mechanism of metallogels was investigated by scanning electron microscopy, 1H NMR, FT-IR as well as UV–Vis spectroscopy. The results indicated that the formation mechanism involved the synergistic effect between lanthanide metal-ligand coordination, π-π stacking and hydrogen bonding. The prepared metallogels showed excellent thermally stable luminescence, which may be attributed to their thermally stable structure. Additionally, the reversible “on-off” luminescence effect could be achieved by alternately titrating NaOH and HCl into the metallogels. Therefore, the metallogels could be potentially used as sensors and luminescent materials.