Discrete Heteropolynuclear Yb/Er Assemblies: Switching on Molecular Upconversion Under Mild Conditions.
Jie WangYue JiangJiao-Yang LiuHai-Bing XuYue-Xing ZhangXu PengMohamedally KurmooSeik Weng NgMing-Hua ZengPublished in: Angewandte Chemie (International ed. in English) (2021)
The salts {[Ln2 Ln*(Hhmq)3 (OAc)3 (hfac)2 ]+ [Ln*(hfac)3 (OAc)(MeOH)]- } (Hhmq=2-methanolquinolin-8-oxide, hfac=hexafluoroacetylacetonate; Ln, Ln*=Er, Gd, Yb) feature a discrete heteronuclear cation consisting of two types of lanthanide atoms. The quinolinoxy O-atom serves as a μ2 -bridge to two Ln atoms and as a μ3 -bridge to all three atoms, with metal⋅⋅⋅metal distances being around 3.7 Å. For 1 ([Yb2 Er]+ ), near-infrared downshifted luminescence is switched to competitive upconversion luminescence upon irradiation by a 980 nm laser under an extremely low excitation power (0.288 W cm-2 ) through introduction of fluoride ions. The stability of 1 after addition of fluoride was confirmed by powder X-ray diffraction and multistage mass spectrometry, associated with the 1 H NMR of 6 ([La2 Eu]+ ). More importantly, the at least 20-fold enhancement of the quantum yield in non-deuterated solvents at room temperature under low power densities (2 W cm-2 ) is the highest among the few molecular examples reported.
Keyphrases
- energy transfer
- quantum dots
- room temperature
- ionic liquid
- high resolution
- mass spectrometry
- drinking water
- endoplasmic reticulum
- breast cancer cells
- estrogen receptor
- magnetic resonance
- machine learning
- photodynamic therapy
- magnetic resonance imaging
- molecular dynamics
- high performance liquid chromatography
- solid state
- gas chromatography