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Under solvothermal conditions, an imidazole derivative 4,4' -bis(2-methyl-1H-imidazol-1-yl)-1, 1 '-biphenyl (4,4'-BMIB), 2,5-dimethoxyterephthalic acid (H2DTA) and Zn(ll) ion were used to construct a metal-organic framework (MOF) with fluorescent properties, namely [Zn(DTA)(4,4'-BMIB) ]„(MOF 1). It was characterized by X-Ray single crystal diffraction, X-Ray powder diffraction, infrared spectroscopy and thermogravimetric analysis. The results showed that MOF 1 was a four connected frame structure with topological symbol (63- 103). In addition, MOF 1 has good fluorescence and can realize highly sensitive and selective fluorescence quenching detection of iron ions in aqueous solution. [ABSTRACT FROM AUTHOR]

Under solvothermal conditions, an imidazole derivative 4, 4' -bis (2-methyl-1H-imidazol-1-yl) - 1, 1'-biphenyl (4, 4'-BMIB), 2, 5-dimethoxyterephthalic acid (H2DTA) and Zn (II)ion were used to construct a metal-organic framework (MOF) with fluorescent properties, namely [Zn (DTA) (4, 4'-BMIB)]n(MOF 1). It was characterized by X-Ray single crystal diffraction, X-Ray powder diffraction, infrared spectroscopy and thermogravimetric analysis. The results showed that MOF 1 was a four connected frame structure with topological symbol (6³⋅10³). In addition, MOF 1 has good fluorescence and can realize highly sensitive and selective fluorescence quenching detection of iron ions in aqueous solution. [ABSTRACT FROM AUTHOR]

Computational screening was employed to calculate the enantioseparation capabilities of 45 functionalized homochiral metal–organic frameworks (FHMOFs), and machine learning (ML) and molecular fingerprint (MF) techniques were used to find new FHMOFs with high performance. With increasing temperature, the enantioselectivities for (R,S)‐1,3‐dimethyl‐1,2‐propadiene are improved. The "glove effect" in the chiral pockets was proposed to explain the correlations between the steric effect of functional groups and performance of FHMOFs. Moreover, the neighborhood component analysis and RDKit/MACCS MFs show the highest predictive effect on enantioselectivities among the four ML classification algorithms with nine MFs that were tested. Based on the importance of MF, 85 new FHMOFs were designed, and a newly designed FHMOF, NO2‐NHOH‐FHMOF, with high similarity to the optimal MFs achieved improved chiral separation performance, with enantioselectivities of 85%. The design principles and new chiral pockets obtained by ML and MFs could facilitate the development of new materials for chiral separation. [ABSTRACT FROM AUTHOR]

Atmospheric water harvesting by strong adsorbents is a feasible method of solving the shortage of water resources, especially for arid regions. In this study, a machine learning (ML)-assisted high-throughput computational screening is employed to calculate the capture of H2O from N2 and O2 for 6013 computation-ready, experimental metal-organic frameworks (CoRE-MOFs) and 137,953 hypothetical MOFs (hMOFs). Through the univariate analysis of MOF structure-performance relationships, Qst is shown to be a key descriptor. Moreover, three ML algorithms (random forest, gradient boosted regression trees, and neighbor component analysis (NCA)) are applied to hunt for the complicated interrelation between six descriptors and performance. After the optimizing strategy of grid search and five-fold cross-validation is performed, three ML can effectively build the predictive model for CoRE-MOFs, and the accuracy R2 of NCA can reach 0.97. In addition, based on the relative importance of the descriptors by ML, it can be quantitatively concluded that the Qst is dominant in governing the capture of H2O. Besides, the NCA model trained by 6013 CoRE-MOFs can predict the selectivity of hMOFs with a R2 of 0.86, which is more universal than other models. Finally, 10 CoRE-MOFs and 10 hMOFs with high performance are identified. The computational screening and prediction of ML could provide guidance and inspiration for the development of materials for water harvesting in the atmosphere. [ABSTRACT FROM AUTHOR]

[Display omitted] • The optimal performance range of 2D MOF membrane had more accurate than 3D MOFMs. • Extreme gradient boosting had accuracy regression effort in MOF membrane. • PLD was a key descriptor for Kr/Xe by univariate analysis and machine learning. • Molecular fingerprint analyzed MOF membrane separation mechanisms for Kr/Xe. • Three design strategies were proposed to boost MOF membrane performance for Kr/Xe. Separation of Xe and Kr is extremely important in several applications, such as spent nuclear fuel reprocessing. In this work, high-throughput computational screening (HTCS) was used to simulate the dynamic behavior of Kr/Xe separation for 6013 computation-ready, experimental metal–organic framework membranes (CoRE-MOFMs). First, the structure–performance relationships of the metal–organic framework membranes (MOFMs) for Kr/Xe separation were analyzed by univariate analysis. Then, five machine learning (ML) algorithms (random forest, decision tree, support vector machine, k-nearest neighbors and extreme gradient boosting) were employed for classification and regression of permeability and permselectivity. Besides, the excellent bits of linkers were determined by molecular fingerprints (MFs), and the excellent nodes and separation mechanisms were also discussed. Finally, three design strategies were proposed to boost the Kr/Xe separation performance of MOFMs. Combining HTCS, ML and MF, we provide a new direction for designing high-performance MOFMs for Kr/Xe separation. [ABSTRACT FROM AUTHOR]

A brilliantly stable and luminescent Zn 5 -cluster-based metal-organic framework, namely {[Z n 5 (bci) 4 (OH) 2 (SO 4) 2 ]·4H 2 O} (MOF 1), was successfully constructed by zwitterionic ligand H 2 bciCl (1,3-bis(4-carboxybenzyl)-1H-imidazol-3-ium chloride) in solvothermal condition. MOF 1 which crystallized in tetragonal crystal system P4 1 2 1 2 space group with 8-connected bcu body-centered-cubic topology exhibits excellent organic solvent stability, water stability, and pH stability. As a new fluorescence sensor, MOF 1 can selectively, sensitively, rapidly and recyclably detect tetracycline (TCY) antibiotic in aqueous solution through fluorescence quenching effect with a low detection limit of 0.083 μM. Additionally, as a fluorescent detection material with potential practical application value, MOF 1 is able to detect TCY in chicken, egg and fish samples with excellent recovery rates. The reasonable fluorescent detection mechanism has been confirmed, which may be a combination of fluorescence resonance energy transfer (FRET) and photoelectron electron transfer (PET). A brilliantly stable and luminescent Zn 5 -cluster-based metal-organic framework, namely {[Z n 5 (bci) 4 (OH) 2 (SO 4) 2 ]·4H 2 O} (MOF 1), was successfully constructed by zwitterionic ligand H 2 bciCl (1,3-bis(4-carboxybenzyl)-1H-imidazol-3-ium chloride) in solvothermal condition. MOF 1 which crystallized in tetragonal crystal system P4 1 2 1 2 space group with 8-connected bcu body-centered-cubic topology exhibits excellent organic solvent stability, water stability, and pH stability. As a new fluorescence sensor, MOF 1 can selectively, sensitively, rapidly and recyclably detect tetracycline (TCY) antibiotic in aqueous solution through fluorescence quenching effect with a low detection limit of 0.083 μM. Additionally, as a fluorescent detection material with potential practical application value, MOF 1 is able to detect TCY in chicken, egg and fish samples with excellent recovery rates. The reasonable fluorescent detection mechanism has been confirmed, which may be a combination of fluorescence resonance energy transfer (FRET) and photoelectron electron transfer (PET). [Display omitted] [ABSTRACT FROM AUTHOR]

• A new luminescent Cd(II) metal-organic framework with mixed-ligands was synthesized and analyzed. • It shows high sensitivity for detecting Chloramphenicol. • It can as a promising fluorescence probe to detect Chloramphenicol in milk and honey. A new and water-stable metal-organic framework, [Cd 2 (L) 2 (tmd)]·3H 2 O (MOF 1), was successfully synthesized by mixed ligands of H 2 L and tmd under solvothermal condition (H 2 L= 5-acetamidoisophthalic acid, tmd= 4,4-trimethylenedipyridine). Single-crystal X-ray diffraction shows that the structural unit of MOF 1 is a tetranuclear [Cd 4 (L) 6 ] primary building unit. Fluorescence sensing experiments revealed that MOF 1 exhibited selectivity and sensitivity detection of Chloramphenicol (CHL) antibiotic in aqueous solutions. The fluorescence quenching effect showed that MOF 1 had a very low detection limit for CHL (LOD= 0.11 μM). More importantly, MOF 1 can be used as a new fluorescence sensor for the detection of CHL in milk and honey samples with very good recoveries of 98.2-103.0 % and 97.0-98.9 %, respectively. Furthermore, the internal filtration effect (IFE) and photoelectron electron transfer (PET) may be responsible for the fluorescence quenching efficiency. A new and water-stable metal-organic framework, [Cd 2 (L) 2 (tmd)]·3H 2 O (MOF 1), was successfully synthesized by mixed ligands of H 2 L and tmd under solvothermal condition (H 2 L= 5-acetamidoisophthalic acid, tmd= 4,4-trimethylenedipyridine). Single-crystal X-ray diffraction shows that the structural unit of MOF 1 is a tetranuclear [Cd 4 (L) 6 ] primary building unit. Fluorescence sensing experiments revealed that MOF 1 exhibited selectivity and sensitivity detection of Chloramphenicol (CHL) antibiotic in aqueous solutions. The fluorescence quenching effect showed that MOF 1 had a very low detection limit for CHL (LOD= 0.11 μM). More importantly, MOF 1 can be used as a new fluorescence sensor for the detection of CHL in milk and honey samples with very good recoveries of 98.2-103.0 % and 97.0-98.9 %, respectively. Furthermore, the internal filtration effect (IFE) and photoelectron electron transfer (PET) may be responsible for the fluorescence quenching efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new luminescent Cd(Ⅱ) metal-organic framework with mixed-ligand has been obtained and characterized. • It exhibits detection of nitrofurazone and nitrofurantoin with high selectivity and recyclability with low limit of detection. • It can be applied as the first potential luminescent sensing material for nitrofurazone and nitrofurantoin in milk and honey. A new and water-stable Cd (II) metal-organic framework, namely [Cd(mba)(bpdb) 0.5 ] (MOF 1), was successfully designed and synthesized by a mixed ligand of H 2 mba and bpdb under solvothermal condition (bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, H 2 mba = 4-(carboxymethyl)benzoic acid). Single crystal X-ray structural analysis suggests that MOF 1 crystallized in the monoclinic system with the P2 1 /c space group and exhibits a 3D framework based on the infinite [CdO 5 N] chain. Fluorescence sensing experiments show that MOF 1 can be used as a fluorescence sensor to selectively, sensitively and quickly detect Nitrofurazone (NFZ) and Nitrofurantoin (NFT) antibiotics with very low detection limits of 0.116 μM and 0.123 μM, respectively. More importantly, MOF 1 was able to detect the NFT and NFZ antibiotics in milk and honey samples with good recovery rates. Additionally, the possible fluorescent quenching reasons for NFZ and NFT antibiotics were mainly caused by the fluorescence resonance energy transfer (FRET) and photoelectron electron transfer (PET) mechanism. A new and water-stable Cd (II) metal-organic framework, namely [Cd(mba)(bpdb) 0.5 ] (MOF 1), was successfully designed and synthesized by a mixed ligand of H 2 mba and bpdb under solvothermal condition (bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, H 2 mba = 4-(carboxymethyl)benzoic acid). Single crystal X-ray structural analysis suggests that MOF 1 crystallized in the monoclinic system with the P2 1 /c space group and exhibits a 3D framework based on the infinite [CdO 5 N] chain. Fluorescence sensing experiments show that MOF 1 can be used as a fluorescence sensor to selectively, sensitively and quickly detect Nitrofurazone (NFZ) and Nitrofurantoin (NFT) antibiotics with very low detection limits of 0.116 μM and 0.123 μM, respectively. More importantly, MOF 1 was able to detect the NFT and NFZ antibiotics in milk and honey samples with good recovery rates. Additionally, the possible fluorescent quenching reasons for NFZ and NFT antibiotics were mainly caused by the fluorescence resonance energy transfer (FRET) and photoelectron electron transfer (PET) mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • In silico screening was performed for the dynamic adsorption of O 2 and N 2. • K O2 and the metal type of the MOFs were critical factors for O 2 /N 2 separation. • Transition-metal-based MOFs were more conducive to the selective adsorption of O 2 over N 2. • Three strategies are proposed to design MOFs for O 2 /N 2 separation. It remains a great challenge to separate O 2 from N 2 at room temperature. Pressure swing adsorption (PSA) technology is a potential candidate, and the development of high-efficiency adsorbents for O 2 /N 2 separation at room temperature has attracted a great deal of interest. In this work, machine learning (ML)-assisted high-throughput computational screening (HTCS) techniques were performed to screen the dynamic adsorption of O 2 and N 2 in 6,013 computation-ready experimental metal–organic frameworks (CoRE-MOFs) , including the competitive adsorption of O 2 and the diffusion of pure N 2 and O 2 , to identify the best materials for O 2 /N 2 separation. First, based on HTCS, we established the relationships between the structural/energetic descriptors with the performance indicators. Three machine learning (ML) algorithms were then applied to predict the performance indicators of MOFs. In addition, the relative importance of the structural/energetic descriptors and metal center type in MOFs toward the separation performance was evaluated, indicating that the metal center type of MOFs is a key factor for the separation of O 2 /N 2. Transition metal elements were determined to have highest importance by ML. Moreover, the 13 best MOFs were identified for the dynamic adsorption of O 2 from the air. Finally, three types of design strategies could significantly improve the performance of MOFs, such as regulating the topology and alternating the metal node and organic linker. The combination of HTCS, ML, and design strategies from bottom to top provide powerful microscopic insights for the development of MOF adsorbents for the separation of O 2 at room temperature. [ABSTRACT FROM AUTHOR]