Thermosensitive visible-light-excited visible-/NIR-luminescent complexes with lanthanide sensitized by the π-electronic system through intramolecular H-bonding

Autor: Hitomi Ohmagari, Nicolas Marets, Jun Kamata, Mayo Yoneyama, Takumi Miyauchi, Yuta Takahashi, Yukina Yamamoto, Yuto Ogihara, Daisuke Saito, Kenta Goto, Ayumi Ishii, Masako Kato, Miki Hasegawa
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Frontiers in Chemistry, Vol 10 (2022)
Druh dokumentu: article
ISSN: 2296-2646
DOI: 10.3389/fchem.2022.1047960
Popis: Visible-luminescent lanthanide (LnL) complexes with a highly planar tetradentate ligand were successfully developed for a visible-light solid-state excitation system. L was designed by using two 2-hydroxy-3-(2-pyridinyl)-benzaldehyde molecules bridged by ethylenediamine, which was then coordinated to a series of Ln ions (Ln = Nd, Sm, Eu, Gd, Tb, Dy, and Yb). From the measurement of single-crystal X-ray analysis of EuL, two phenolic O atoms and two imine N atoms in L were coordinated to the Eu ion, and each π-electronic system took coplanar with the edged-pyridine moiety through an intramolecular hydrogen bond. The enol group on the phenolic skeleton changed to the keto form, and the pyridine was protonated. Thus, intramolecular proton transfer occurred in L after the complexation. Other complexes take isostructure. The space group is P-1, and the c-axis shrinks with decreasing temperature without a phase transition in EuL. The yellow color caused by the planar structure of L can sensitize ff emission by visible light, and the luminescence color of each complex depends on central Ln ions. Furthermore, a phosphorescence band also appeared at rt with ff emission in LnL. Drastic temperature dependence of luminescence was clarified quantitatively.
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