Tunable Light Emission and Multiresponsive Luminescent Sensitivities in Aqueous Solutions of Two Series of Lanthanide Metal–Organic Frameworks Based on Structurally Related Ligands

Abstract

Two series of lanthanide metal–organic frameworks (Ln-MOFs) from two structurally related flexible carboxylate-based ligands were solvothermally synthesized. H3L2 with additional −CH2− group provides more flexibility and different coordination modes and conformations compared with H3L1. As a result, 2-Ln MOFs are modulated from two-dimensional kgd of 1-Ln to three-dimensional rtl topological frameworks and further achieve enhanced chemical stability. The Eu- and Tb-MOFs exhibit strong fluorescent emission at the solid state because of the antenna effect of the ligands. Interestingly, the emissions can be tuned by simply doping Eu3+ and Tb3+ of different concentrations within the Eu x Tb 1–x MOFs. Notably, 2-Ln MOFs realize nearly white light emission by means of a trichromatic approach (red of Eu­(III), green of Tb­(III), and blue of the H3L2 ligand). Furthermore, 2-Ln MOFs also exhibit water stability and demonstrate high selective and sensitive sensing activities toward Fe­(III) and Cr­(VI) in aqueous solutions. The results further highlight the importance of the ligand flexibility on tuning MOF structures with improved structural stability and ion-sensing properties.

A self‐penetrating and chemically stable zinc (ii)‐organic framework as multi‐responsive chemo‐sensor to detect pesticide and antibiotics in water

“…As we all know, the structural changes, energy and electron transfer are the main reasons that cause the luminescent quenching of LMOFs, according to some reported literature. [ 56–61 ] Thus, we investigated the luminescent quenching mechanism from the above mentioned points. Firstly, the pivotal peak positions of PXRD patterns after sensing of analytes are consistent with those of the original ones, excluding the structural collapse of NUC‐6 (Figure S19).…”

Selective detection of trinitrophenol by a Cd(ii)-based coordination compound

“…The chemistry of such materials is of great interest to synthetic chemists because of their intriguing structural motifs as well as potential applications in areas such as catalysis, magnetism, ion exchange, drug delivery, conductance, photoluminescence and chemical sensing. [4][5][6][7][8][9][10][11][12][13][14][15] In addition to the direct role of the metal ions and organic ligands, there are many more essential conditions, including counter anions, reaction temperatures, solvent media, external stimuli, and pH of the reaction medium, which play crucial roles during compound formation. In addition, there is an eternal relationship among the structure, property and application of the compounds.…”

Self-assembly of a cobalt(II)-based metal–organic framework as an effective water-splitting heterogeneous catalyst for light-driven hydrogen production

“…Metal-organic frameworks (MOFs), as a kind of porous materials, have been the subject of much research, not only owing to their high porosity and the high surface area of the structures which makes them useful for potential applications in gas storage and separation (Lorzing et al, 2019;Wang et al, 2019b), drug delivery (Orellana-Tavra et al, 2020) and molecular recognition (Zhu et al, 2017;Mizutani et al, 2020), but also for the tunability and tailorability of their coordination modes and the numerous possible modifications with functional groups making them useful in catalysis (Zhou et al, 2016;Ji et al, 2019;Song et al, 2019;Feng et al, 2019;Wu et al, 2019), fluorescent sensing (Mi et al, 2019;Yang et al, 2019c;Pratik & Cramer, 2019) and magnetic materials (Lan et al, 2019;Gu et al, 2018;Li et al, 2019). The self-assembly of MOFs with various organic linkers and metal ions or clusters endows these materials with active sites and designable backbones, displaying the combined advantages of homogeneous and heterogeneous properties as catalysts, such as high activity and selectivity on one hand, and recovery and high controllability on the other hand.…”