Two Series of Solvent-Dependent Lanthanide Coordination Polymers Demonstrating Tunable Luminescence and Catalysis Properties

Two series of lanthanide-organic frameworks with the formulas [Ln(BTATB)(DMF)(2)(H2O)]center dot DMF center dot 2H(2)O (Ln = La (1a), Eu (2a), Tb (3a), Er (4a)) and [Ln(BTATB)(H2O)(2)]center dot 2DMA center dot 4H(2)O (Ln = Er (1b), Yb (2b), Lu (3b)), respectively, were solvothermally synthesized from 4,4',4 ''-(benzene-1,3,5-triyltris(azanediyl))tribenzoate (H(3)BTATB) and Ln(NO3)(3) under DMF or DMA media and characterized by thermogravimetric analyses, IR spectroscopy, X-ray powder diffraction, and single crystal X-ray diffraction. X-ray single-crystal diffraction analyses for these complexes revealed that series A features an interesting 2D interdigitated layer architecture with (6,3) topology. Series B exhibits a 2D bilayer structure. The luminescence properties were studied, and the results showed that complex 3a displayed strong fluorescent emission in the visible region, where the emission intensities of 3a are enhanced upon the addition of Zn2+, demonstrating Zn2+-modulated fluorescence. Yb(III) complex 2b emits typical near-infrared luminescence (983 nm) in DMF (lambda(ex) = 315 nm). The Knoevenagel condensation reaction (benzaldehyde and malononitrile or ethyl cyanoacetate in acetonitrile) was studied using 3a and 2b as catalysts. The results showed that the conversion rates of reactions catalyzed by 3a increased to 99 and 42%, respectively, whereas the reactions catalyzed by 2b exhibited lower conversion rates.