Construction of fluorescence active MOFs with symmetrical and conformationally rigid N-2-aryl-triazole ligands

A novel fluorescent molecule based on 1,2,3-triazole for determination of palladium (II) and hydrazine hydrate in aqueous system

In recent years, hydrazine hydrate has been widely used in various fields as fuel and chemical raw materials, etc. However, hydrazine hydrate is also a potential threat to living body and natural environment. The effective method is urgently needed to detect hydrazine hydrate in our living environment. Secondly, as a precious metal, palladium has attracted more and more attention because of its excellent properties in industrial manufacturing and chemical catalysis. However, its potential danger is also slowly approaching, so it is necessary to find an excellent way to detect palladium, too. Herein, a fluorescent molecule, 4,4',4'',4'''-(1,4-phenylenebis(2H-1,2,3-triazole-2,4,5-triyl)) tetrabenzoic acid (NAT), was synthesized. Firstly, NAT has very high selectivity and sensitivity for determination of Pd²⁺, because Pd²⁺ can coordinate well with carboxyl oxygen of NAT. The detection performance of Pd²⁺ is that the linear range is from 0.06 to 4.50 μM and the detection limit is 16.4 nM. Furthermore, the chelate (NAT-Pd²⁺) can continue to be used for quantitative determination of hydrazine hydrate with a linear range of 0.05-6.00 μM and the detection limit is 19.1 nM. The interaction time of NAT-Pd²⁺ and hydrazine hydrate is about 10 min. Of course, it also has good selectivity and strong anti-interference ability for many common metal ions, anions and amine like compounds. At last, the ability of NAT to quantitatively detect Pd²⁺ and hydrazine hydrate in actual samples has also been verified and the results are very satisfactory.

Construction of Stable Helical Metal-Organic Frameworks with a Conformationally Rigid "Concave Ligand"

A helical metal-organic framework was prepared by using a conformationally rigid tetratopic benzoic acid ligand with binding units pointing toward each other (concave ligand). To avoid the obvious intramolecular interactions between binding units, matching spacing groups were applied to introduce atropic repulsion, thereby allowing the formation of extended frameworks for the first time. With this new ligand design, a helical-shaped MOF with significantly improved air and moisture stability was successfully prepared, thus providing a new strategy for ligand design toward porous material constructions.