Search

Lanthanide metal–organic frameworks (Ln-MOFs) have excellent optical properties and structural diversity, providing a unique platform for the development of fluorescent sensing and optical materials. In the work described herein, a series of isostructural 3D Ln-MOFs [Ln(L)(H2O)]·2H2O (Ln = Eu (1), Gd (2), Tb (3), H3L = 3,3′,3″-[1,3,5-benzenetriyltris(carbonylimino)]tris-benzoate) are fabricated under solvothermal conditions. The good thermal, water, and acid–base stabilities of 3are prerequisites for fluorescent sensing applications. 3can be used as a ratiometric broad-spectrum fluorescent sensor for toluenediamines (TDAs) in real urine with the advantages of visualization, ultrasensitivity, and selectivity. Interestingly, a smartphone-assisted intelligent sensing platform manifests promising results for the detection of TDAs, providing a chance for further development of portable diagnostic tools. In addition, by tuning the ratios of Eu3+/Tb3+and Eu3+/Gd3+/Tb3+, nine bimetallic-doped EuxTb1–x(x= 0.10–0.90, 4–12) and one trimetallic-doped Gd0.95Tb0.015Eu0.035(13) were obtained. 4–12exhibit a gradient of luminescent colors from yellow-green to pink with different ratios of Eu3+and Tb3+ions. Meanwhile, the trimetallic-doped Gd0.95Tb0.015Eu0.035(13) shows near-white-light emission with a quantum yield of 8.76%. Interestingly, the inks made with 1–13are invisible under ambient light but show visual color-tunable luminescence under a 254 nm UV lamp, which may facilitate their anti-counterfeiting applications.

A cyanide-bridged FeIII2CoIIdouble zigzag chain, {[FeIII(bipy)(CN)4]2CoII(btab)2}n[bipy=2,2′-bipyridine, btab=4,4′-(1,3-phenylene)-bis-4H-1,2,4-triazole] (1), was obtained with tetracyanometalate precursors and CoIIions. The chains were further linked by the ditopic btab ligands to a layer. Magnetic property studies demonstrate that 1shows both metamagnetism with a critical field Hc=400 Oe and single-chain magnet behavior.