Recently, the Ming-Hua Zeng team from the School of Chemistry and Chemical Engineering (School of Carbon Neutrality Future Technology) at Shantou University made new progress in the research field of "Coordination Cluster Assembly and Application". The related research findings were published under the title "Discrete Heteropolynuclear Yb/Er Assemblies: Switching on Molecular Upconversion Under Mild Conditions" in the top journal "Angewandte Chemie International Edition" (impact factor 17.6) in the field of inorganic chemistry.

Authors:

Jie Wang, Yue Jiang, Jiao-Yang Liu, Hai-Bing Xu*, Yue-Xing Zhang, Xu Peng, Mohamedally Kurmoo, Seik Weng Ng, Ming-Hua Zeng*

Paper information:

Angew. Chem. Int. Ed. 2021, 60, 22368-22375.

Paper link:

https://doi.org/10.1002/anie.202107637

English abstract of the paper:

The salts {[Ln₂Ln*(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 ([Yb²Er]⁺), 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 ¹H NMR of 6 ([La²Eu]⁺). 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.