Metal-organic frameworks are a class of attractive materials for fluorescent sensing. Improvement of hydrolytic stability, sensitivity, and selectivity of function is the key to advance application of fluorescent MOFs in aqueous media. In this work, two stable MOFs, [ZrO(OH)(HO)(L)] (BUT-14) and [ZrO(OH)(HO)(L)] (BUT-15), were designed and synthesized for the detection of metal ions in water. Two new ligands utilized for construction of the MOFs, namely, 5',5‴-bis(4-carboxyphenyl)-[1,1':3',1″:4″,1‴:3‴,1''''-quinquephenyl]-4,4''''-dicarboxylate (L) and 4,4',4″,4‴-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl))tetrabenzoate (L), are structurally similar with the only difference being that the latter is functionalized by pyridine N atoms. The two MOFs are isostructural with a sqc-a topological framework structure, and highly porous with the Brunauer-Emmett-Teller (BET) surface areas of 3595 and 3590 m g, respectively. Interestingly, they show intense fluorescence in water, which can be solely quenched by trace amounts of Fe ions. The detection limits toward the Fe ions were calculated to be 212 and 16 ppb, respectively. The efficient fluorescent quenching effect is attributed to the photoinduced electron transfer between Fe ions and the ligands in these MOFs. Moreover, the introduced pyridine N donors in the ligand of BUT-15 additionally donate their lone-pair electrons to the Fe ions, leading to significantly enhanced detection ability. It is also demonstrated that BUT-15 exhibits an uncompromised performance for the detection of Fe ions in a simulated biological system.

In this work a rigid asymmetrical tricarboxylate ligand p-terphenyl-3,4″,5-tricarboxylic acid (H3L) has been employed, and a unique heterometallic alkaline earth-lanthanide microporous luminescent metal-organic framework (MOF) {[Ba3La0.5(μ3-L)2.5(H2O)3(DMF)]·(3DMF)}n (1·3DMF) (DMF = dimethylformamide) has been isolated under solvothermal conditions. Single-crystal X-ray structural analysis demonstrates that 2D inorganic Ba-O-La connectivity can be observed in 1, which are further bridged via rigid terphenyl backbones of L(3-), forming a unique I(2)O(1)-type microporous luminescent framework. A 1D microporous channel with dimensionality of 9.151(3) Å × 10.098(1) Å can be observed along the crystallographic a axis. PXRD patterns have been investigated indicating pure phases of 1. The luminescence explorations demonstrated that 1 exhibits highly selective and sensitive sensing for Al(3+) over other cations with high quenching efficiency Ksv value of 1.445 × 10(4) L·mol(-1) and low detection limit (1.11 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive sensing for MnO4(-) over other anions with quenching efficiency Ksv = 7.73 × 10(3) L·mol(-1) and low detection limit (0.28 μM (S/N = 3)). It is noted that, when different concentrations of MnO4(-) solutions (0.5 to 100 μM) were dropped into the suspension of 1, the bright blue luminescence of the suspension observed under UV light can gradually change into pink color, indicating visually luminescent sensing, which makes the detection process of MnO4(-) more convenient in practical. The result also reveals that 1 represents the first example of bifunctional heterometallic alkaline earth-lanthanide MOF-based luminescent probes for selectively detecting Al(3+) and MnO4(-) in the water solutions.

X-ray detectors with high performance, durability, and flexibility detectors are required for a wide range of applications in several fields, such as medical treatment (imaging, diagnostic radiology, etc.), nondestructive testing (radioscopic inspections, radiography testing, etc.), security and defense (luggage/body scanning systems, paper mail, etc.), nuclear and radiation industries (nuclear power plants, research reactors, users of nuclear gauges, etc.), and scientific research and development. [1]-[9] Thereof, indirect X-ray detectors are widely used for ordinary flat panel X-ray detection, among which scintillator is the most important factor affecting the detection performance. [10][11][12][13][14] Currently, the ideal scintillator should meet the following basic conditions: (i) good stopping power and excellent radiation absorption, [15]-[18] (ii) high photoluminescence (PL) with large Stokes shift and radioluminescence (RL) intensity, (iii) nontoxicity with environmentally stable, [19] (iv) easily manufactured and extendable to large-area flexible applications. [20,21] Among all, inorganic copper (I)-based metal halide semiconductors meeting all the above requirements are considered as promising candidates. In particular, zero-dimensional (0D) cesium copper chloride, Cs 3 Cu 2 Cl 5 , shows excellent photoelectric performance in ultraviolet photodetectors. [22] With isolated [Cu 2 Cl 5 ] 3dimers and Cs + ions, Cs 3 Cu 2 Cl 5 is expected to exhibit intriguing optical properties mainly derived from self-trapped excitons (STEs). Different from the narrow and rapid emission of free excitons and inter-band recombination, the emission of STEs is featured with broad spectra and large Stokes shifts. Generally, the STEs emission that occurs in Cs 3 Cu 2 Cl 5 originates from structural deformation of [Cu 2 Cl 5 ] 3− dimers. [23] At the time of photoexcitation, the Cu-Cl bonds elongate (shrink) on the equatorial plane but shrink (elongate) in the axial direction, which in turn causes the local structure change from a high symmetry to a low symmetry configuration.To further improve its photophysical characteristics, the diversified structural optimization in Cs 3 Cu 2 Cl 5 could offer deeper insights and more controlling knobs on STEs emission. Zero-dimensionalCs 3 Cu 2 Cl 5 exhibits intriguing optical properties, which can meet the basic requirements of ideal scintillator application. Here, green emitter Cs 3 Cu 2 Cl 5 nanosheets are successfully synthesized, and by doping with 2% potassium (K + ), their photoluminescence quantum yield (70.23% to 81.39%), radioluminescence intensity, and stability are improved. Further experimental and theoretical studies point out that: (1) K + brings the neighboring [Cu 2 Cl 5 ] 3− dimers groups closer, leading to lattice shrinkage and lower lattice constants; (2) such compact crystal structure results in stronger exciton-photon coupling and reduced phonon-electron coupling strength, which is beneficial to form self-trapped excitons and enhanced luminescence; (3) lower lattice ...