A novel luminescent microporous lanthanide metal-organic framework (Ln-MOF) based on a urea-containing ligand has been successfully assembled. Structural analysis revealed that the framework features two types of 1D channels, with urea N-H bonds projecting into the pores. Luminescence studies have revealed that the Ln-MOF exhibits high sensitivity, good selectivity, and a fast luminescence quenching response towards Fe , Cr anions, and picric acid. In particular, in the detection of Cr O and picric acid, the Ln-MOF can be simply and quickly regenerated, thus exhibiting excellent recyclability. To the best of our knowledge, this is the first example of a multi-responsive luminescent Ln-MOF sensor for Fe , Cr anions, and picric acid based on a urea derivative. This Ln-MOF may potentially be used as a multi-responsive regenerable luminescent sensor for the quantitative detection of toxic and harmful substances.

From the perspective of efficient and economical utilization of materials, it is very meaningful to achieve multifunctional performance in its assembly process, and this is also the future development trend of metal–organic framework (MOF) materials. As an important type of intermolecular interaction, hydrogen bonding is widely used in supramolecular self-assembly, molecular recognition, and catalytic organic reactions. Following the hydrogen bond functionalization construction strategy, we introduced urea–hydrogen bonding sites into the ligands and then introduced functionalized ligands into the MOF frameworks, which efficiently realized the construction of multifunctional lanthanide MOFs. Structural analysis indicated that the MOF consists of 2D layers with parallelogram holes and stacking into 3D frameworks through the N–H···O hydrogen bonding interactions. Interestingly, a functionalization ligand in the MOF frameworks plays three different roles: support, recognition, and both support and recognition. Thanks to the pores rich in urea sites and the excellent luminescent properties of lanthanide ions, the MOF can be used as a regenerable luminescent sensor for the efficient detection of picric acid. Moreover, two fluorescent dyes, such as perylene and fluorescein, can be encapsulated into the functionalized pores and show excellent dual-emitting performance, which proved that we have successfully adjusted the luminescent properties of Ln-MOF by introducing guest luminescent molecules. More importantly, the hydrogen bond functionalization construction strategy will provide some experimental reference for the construction of multifunctional MOF materials.

A novel "turn-on" phosphorescent chemodosimeter based on a cyclometalated Ir(III) complex has been designed and synthesized, which displays high selectivity and sensitivity toward Hg(2+) in aqueous media with a broad pH range of 4-10. Furthermore, by time-resolved photoluminescence techniques, some interferences from the short-lived background fluorescence can be eliminated effectively and the signal-to-noise ratio of the emission detection can be improved distinctly by using the chemodosimeter. Finally, the chemodosimeter can be used to monitor Hg(2+) effectively in living cells by confocal luminescence imaging.

A series of unique homochiral lanthanide tetranuclear quadruple-stranded helicates have been self-assembled controllably by using the intrinsic advantages of chiral bridging ligands, (S)-H L and (R)-H L, and lanthanide ions with high coordination numbers. The self-assembly process of these chiral helicates not only ensures the structural stability and quadruple-stranded feature of lanthanide cluster in the solid state and solution, but also achieves effective transfer and amplification of the chirality code from the ligand to a higher supramolecular level. Moreover, through using optical rotation, circular dichroism spectra analysis, and luminescence measurements, we demonstrate that these chiral lanthanide helicates could serve as sensitive and multi-responsive sensors to recognize and detect F anions based on the change of chiral signal and NIR luminescence simultaneously, which represents a meaningful exploration for developing functional lanthanide-based polynuclear clusters.

Mimicking nature seems to be one of the smartest strategies to design novel catalysts for CO2 conversion under mild conditions.