Smart Lanthanide Metal-Organic Frameworks with Multicolor Luminescence Switching Induced by the Dynamic Adaptive Antenna Effect of Molecular Rotors.

In this work, dynamic molecular rotors are used to construct smart lanthanide metal-organic frameworks (Ln-MOFs) emitters with adaptive antenna effects for the first time. The movement or distortion of the molecular rotors can be easily regulated by temperature changes, thereby inducing a dynamically changing antenna effect that can automatically match different lanthanide ions, achieving cyclic multicolor luminescence switching behavior and extremely complex multiple encryption anti-counterfeiting technology. In addition, by regulating the doping ratios of Gd(III) and Tb(III) with Eu(III) within the Ln-MOFs, differentiated energy transfer pathways are discovered, and red light emission very close to the BT.2020 color gamut standard is obtained. GdEu-MOF containing only 1% Eu(III) can show bright red luminescence, and in the range of 1-9% Eu(III) content, the characteristic emission intensity of Eu(III) ions and the content show an excellent linear relationship with a slope k as high as 2299. This can be used to identify the content of Eu(III) ions impurities in gadolinium salts from different manufacturers. Eu/Tb-MOF showed highly sensitive and visualized smart photoresponse behaviors to specific antibiotics and amino acids, respectively, with detection limits of 3.2/2.7 nM (tetracycline), 1.7/15.5 nM (oxytetracycline), 0.13/0.97 nM (aspartic acid), and 0.26/1.16 nM (glutamic acid).