Yulin Yang

3d–4f Metal–Organic Framework with Dual Luminescent Centers That Efficiently Discriminates the Isomer and Homologues of Small Organic Molecules

A 3d-4f luminescent metal-organic framework (MOF), [Tb2(Cu8I8)(C12H8NO2)6(H2O)4]·5C4H8O2 (4), and three analogues {[La2(Cu8I8)(C12H8NO2)6(C4H8O2)2(H2O)2]·3C4H8O2·2H2O (1), [Ce2(Cu8I8)(C12H8NO2)6(H2O)4]·5C4H8O2 (2), and [Eu2(Cu8I8)(C12H8NO2)6(H2O)4]·5C4H8O2 (3)}, were self-assembled from copper(I) halide clusters and lanthanide metal ions with an organic linker [3-(pyridin-4-yl)benzoic acid] under solvothermal conditions. Compound 4 with high quantum yield (Φ = 68%) exhibits reversible luminescence behavior, accompanying the removal and recovery of guest molecules (1,4-dioxane). Because of the unique porous structure and dual luminescent centers of compound 4, it can efficiently differentiate benzene series with different sizes and provide readouts in corresponding optical signals. Furthermore, it also can unambiguously discriminate the isomers, homologues, and other small molecules with similar structural motifs from one another. The luminescent color of the MOF sensor in different guest solvents has obvious changes that can be clearly distinguished by the naked eye. This multicolor luminescence originates from emissions of the dual luminescent centers, and the emissions have shifted, enhanced, weakened, or quenched to different degrees.

Reversible photoluminescence switching behavior and luminescence thermochromism of copper(I) halide cluster coordination polymers

Two novel coordination polymers [Cu3I4(C16H32N4)]·ClO4 (1) and [Cu6I6Br2(C16H32N4)(CH3CN)2] (2) (C16H32N4·2Br− = 4-Aza-1-azoniabicyclo-[2.2.2]octane, 1,1′-(1,4-butanediyl)bis-dibromide) have been synthesized under solvothermal conditions. At room temperature, compounds 1 (Φ = 46.2%) and 2 (Φ = 26.62%) show strong photoluminescence in solid state. At low temperature, compound 1 displays obvious thermochromic luminescence while compound 2 has no obvious change which can be observed by naked eye. However, compound 2 displays a interesting phenomenon. The luminescence of compound 2 is reversible when the coordinated CH3CN molecules in structure are removed by heat and recovered from acetonitrile solvent.

Synthesis, structures and luminescence properties of 3d–4f heterometallic–organic frameworks (HMOFs) constructed from different copper halide clusters

Four novel 3d–4f heterometallic–organic frameworks (HMOFs), namely [Gd2(Cu2I2)(C6H4NO2)6(C3H7NO)(H2O)]·(C3H7NO) (1), [Gd2(Cu4I4)(C6H4NO2)6(C3H7NO)2] (2), [Gd2(Cu6I6)(C12H8NO2)6(C2H6O)2(H2O)2] (3) and [Gd2(Cu8I8)(C12H8NO2)6(H2O)4]·5(C4H8O2) (4), have been solvothermally synthesized and characterized. The four compounds incorporate Cu2I2, Cu4I4, Cu6I6 and Cu8I8 clusters in three-dimensional frameworks, respectively, and the influence of Ln3+ ions, copper halide clusters and ligands on the construction of the structures has been analyzed. The four compounds display four different emission colours. Interestingly, compound 3 responds to external mechanical force. After grinding, the fluorescence has been obviously quenched. Compound 4 displays a reversible luminescence behavior, accompanying the removal and recovery of the guest molecules in the channel.