A three-dimensional metal−organic framework (MOF) {[Eu-(L)(H 2 O) 2 ]•DMF} n (1) (H 3 L = 2′-nitro-3,4′,5-biphenyl tricarboxylic acid) was obtained by hydrothermal methods and was characterized in detail.Compound 1 contains [Eu 2 ] binuclear units, and [Eu 2 ] units are further linked by H 3 L, forming a three-dimensional structure. Stability tests suggest that compound 1 exhibits high solvent, pH, and thermal stability. Besides, we also explored the influence of pH values in the luminescence emission of 1 which shows that pH has a negligible effect on the luminescence intensity with the range of pH = 3−11. Importantly, luminescent investigations reveal that 1 can selectively detect aspartic acid or histidine among 14 amino acids with good regenerability in water. Meanwhile, the concentration of aspartic acid can be quantitatively determined. We also discuss the mechanism of luminescence quenching and enhancement in detail. Importantly, this Eu-MOF provides a MOFbased luminescence sensor to detect two amino acids for the first time.

A tetraimidazole-decorating tetraphenylpyrazine has been designed and utilized for the fabrication of a novel metal− organic framework (MOF), denoted as {Mn(Tipp (TippMn, where Tipp = 2,3,5,methyl]phenyl]pyrazine and A = deprotonation of 1,4-naphthalenedicarboxylic acid), through hydrothermal synthesis. Structural analysis reveals that TippMn possesses a 2-fold-interpenetrated 4,8-connected three-dimensional (3D) network with an unprecedented {4 16 •6 12 }{4 4 •6 2 } topology. Fluorescent spectral investigations indicate that TippMn shows discriminative fluorescence when treated by Cr 3+ and Cu 2+ , giving an INHIBIT logical gate performance. Meanwhile, TippMn can be further used as a sensor for MnO 4 − and 2,4,6-trinitrophenol (TNP) by fluorescence quenching. Notably, the sensing processes toward Cu 2+ , Cr 3+ , MnO 4 − , and TNP are labeled with high selectivity and sensitivity, quick response, and good recyclability. It is anticipated that this MOFbased versatile sensor could shed light on the exploration of MOFs for fluorescent sensors, optical switches, etc.

No abstract

Developing metal–organic frameworks (MOFs) as heterogeneous catalysts attracts much attention because their high internal surface areas and open metal sites may facilely improve the catalytic activity. In this study, a copper-cluster-based MOF, denoted as {2Cu(L)(A)·3H2O} n (1, L = bis(4-(4H-1,2,4-triazol-4-yl)phenyl)methane, A = deprotonated 1,4-naphthalenedicarboxylic acid), has been constructed. 1 has a (3,10)-connected three-dimensional (3D) porous network structure with a new topology of {48·624·83}{43}2. Structural analysis reveals that copper ions adopt two coordination modes in the secondary building unit, forming polyhedral copper clusters by Cu–O–Cu bridge bonds. Detailed studies show that 1 can be employed as an efficient heterogeneous catalyst for converting CO2 to cyclic carbonates in 81.0–99.0% yield under 1 atm CO2 and solvent-free conditions. Furthermore, 1 retains good catalytic efficiency after 10 cycles (83.0% conversion). Moreover, 1 exhibits good catalytic performance toward azide–alkyne cycloaddition (AAC) reactions in an aqueous solution with the addition of sodium ascorbate, yielding a series of 1,4-disubstituted 1,2,3-triazoles in high yields (over 99.0%) and presenting recyclable ability.

No abstract