Triazine Poly(carboxylic acid) Metal-Organic Frameworks and the Fluorescent Response with Lead Oxygen Clusters: [Pb7(COO)12X2] by Halogen Tuning (X = Cl, Br, or I)

Cage Bismuth Metal-Organic Framework Materials Based on a Flexible Triazine-Polycarboxylic Acid: Subgram Synthesis, Application for Sensing, and White Light Tuning

Bismuth-based metal-organic frameworks (MOFs) have always attracted the attention of many researchers. Here, we first report a crystalline Bi-MOF (Bi-TDPAT) based on a flexible triazine-polycarboxylic linker 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine (H₆TDPAT) and bismuth nitrate; its crystallite quality is adequately good and the diffraction data can be collected directly by single crystal X-ray diffraction rather than 3D electron diffraction. The structure of Bi-TDPAT belongs to a novel topology type btt. Notably, the synthesis scale of Bi-TDPAT can be expanded, and sub-gram synthesis can be realized. At the same time, we synthesized a microcrystalline material Bi-TATAB utilizing 2,4,6-tris(4-carboxylphenylamino)-1,3,5-triazine (H₃TATAB). The structures of the two materials were characterized by several microanalysis tools. Considering that Bi-TDPAT is a blue light-emitting material with a broad emission peak, we prepared a white light emitting composite material Eu/Tb@Bi-TDPAT by encapsulating Eu(III)/Tb(III) in Bi-TDPAT. In addition, the fluorescence sensing functions of Bi-TDPAT and Bi-TATAB were explored. The results showed that they could detect and recognize various nitrophenols, and the optimal limit of detection is as low as 0.21 μM, which can be reused even after five cycles. Energy competitive absorption (CA) and photo-induced electron transfer are the main sensing mechanisms. By comparing and analyzing the properties of these two bismuth-based crystalline materials, we believe that this work also provides inspiration for the synthesis and development of bismuth-based MOF in the future.

Three Pbx(COO)y Cluster Frameworks Based on a Flexible Triazinetricarboxylic Acid Ligand: Syntheses, Structures, and Fluorescent Sensing Application for Nitrophenols

Three new metal-organic frameworks (MOFs), namely, [Pb₇(TTPCA)₄Cl₂]·3H₂O (1), [Pb₇(TTPCA)₄(DMA)₂(HCOO)₂]·H₂O (2), and [Pb₄(TTPCA)₃]·3DMF·2H₂O·H₃O (3), were synthesized by the H₃TTPCA ligand [H₃TTPCA = 1,1',1″-(1,3,5-triazine-2,4,6-triyl)-tripiperidine-4-carboxylic acid], with lead(II) nitrate under solvothermal conditions. They were characterized by CHN analysis, IR spectroscopy, UV-vis spectroscopy, and single-crystal and powder X-ray diffraction. In addition, their thermogravimetric analysis and fluorescence properties were studied. Compounds 1-3 were 3D MOF structures with different Pb_x(COO)_y clusters: ([Pb₇(COO)₁₂Cl₂]), ([Pb₇(COO)₁₂]), and [Pb₈(COO)₁₈]. Fluorescence detection of compounds 1-3 shows that they can act as excellent sensors of nitrophenols with a low limit of detection and a high quenching constant.

Ln-MOFs with window-shaped channels based on triazine tricarboxylic acid as a linker for the highly efficient capture of cationic dyes and iodine

Seven isostructural complexes were synthesized under solvothermal condition by the 4,4′,4′′ ((1,3,5-triazine-2,4,6-triyl)tri(azanediyl))tribenzoic acid and rare earth metal ions. It is found that 1 exhibits the adsorption capacity of 758.72 mg g⁻¹ to iodine.

Effects of transition metal cations and temperature on the luminescence of a 3-cyano-4-dicyanomethylene-5-oxo-4,5-dihydro-1H-pyrrole-2-olate anion

The luminescence intensity of a 3-cyano-4-dicyanomethylene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate anion (HA−) drops to zero upon complexation with transition metal cations, and reversibly drops by 6–7 times upon heating from 27 up to 123 °C.

Conductive MOFs with Photophysical Properties: Applications and Thin-Film Fabrication

Metal-organic frameworks (MOFs) are a class of hybrid materials with many promising applications. In recent years, lots of investigations have been oriented toward applications of MOFs in electronic and photoelectronic devices. While many high-quality reviews have focused on synthesis and mechanisms of electrically conductive MOFs, few of them focus on their photophysical properties. Herein, we provide an in-depth review on photoconductive and photoluminescent properties of conductive MOFs together with their corresponding applications in solar cells, luminescent sensing, light emitting, and so forth. For integration of MOFs with practical devices, recent advances in fabrication of photoactive MOF thin films are also summarized.

A novel cadmium metal–organic framework-based multiresponsive fluorescent sensor demonstrating outstanding sensitivities and selectivities for detecting NB, Fe3+ ions and Cr2O72− anions

A Cd(ii) metal–organic framework (MOF) [Cd₃(L)(NTB)₂(DMA)₂]·2DMA was solvothermal prepared in the presence of ligand L (L = (E)-4,4′-(ethene-1,2-diyl)bis[(N-pyridin-3-yl)benzamide]) and ligand H₃NTB (H₃NTB = 4,4′,4′′-nitrilotribenzoic acid).