Coordination Geometrical Effect on Ligand-to-Metal Charge Transfer-Dependent Energy Transfer Processes of Luminescent Eu(III) Complexes
| Autor: | Tomoko Akama, Tetsuya Taketsugu, Masato Kobayashi, Pedro Paulo Ferreira da Rosa, Shiori Miyazaki, Koji Fushimi, Yasuchika Hasegawa, Yuichi Kitagawa, Ken Onda, Kiyoshi Miyata, Haruna Sakamoto |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Square antiprismatic molecular geometry
Luminescence 010304 chemical physics Chemistry Ligand chemistry.chemical_element 010402 general chemistry 01 natural sciences LMCT 0104 chemical sciences Ion chemistry.chemical_compound Crystallography Europium β-diketonate Coordination geometry 0103 physical sciences Pyridine Physical and Theoretical Chemistry Ground state HOMO/LUMO |
| Zdroj: | Journal of physical chemistry A. 125(1):209-217 |
| ISSN: | 1089-5639 |
| Popis: | Photophysical properties of europium (Eu(III)) complexes are affected by ligand-to-metal charge transfer (LMCT) states. Two luminescent Eu(III) complexes with three tetramethylheptadionates (tmh) and pyridine (py), [Eu(tmh)(3)(py)(1)] (seven-coordinated monocapped-octahedral structure) and [Eu(tmh)(3)(py)(2)] (eight-coordinated square antiprismatic structure), were synthesized for geometrical-induced LMCT level control. Distances between Eu(III) and oxygen atoms of tmh ligands were estimated using single-crystal X-ray analyses. The contribution percentages of pi-4f mixing in HOMO and LUMO at the optimized structure in the ground state were calculated using DFT (LC-BLYP). The Eu-O distances and their pi-4f mixed orbitals affect the energy level of LMCT states in Eu(III) complexes. The LMCT energy level of an eight-coordinated Eu(III) complex was higher than that of a seven-coordinated Eu(III) complex. The energy transfer processes between LMCT and Eu(III) ion were investigated using temperature-dependent and time-resolved emission lifetime measurements of D-5(0) -> F-7(J) transitions of Eu(III) ions. In this study, the LMCT-dependent energy transfer processes of seven- and eight-coordinated Eu(III) complexes are demonstrated for the first time. |
| Databáze: | OpenAIRE |
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