Metal–organic frameworks (MOFs) based on group 3 and 4 metals are considered as the most promising MOFs for varying practical applications including water adsorption, carbon conversion, and ...biomedical applications. The relatively strong coordination bonds and versatile coordination modes within these MOFs endow the framework with high chemical stability, diverse structures and topologies, and interesting properties and functions. Herein, the significant progress made on this series of MOFs since 2018 is summarized and an update on the current status and future trends on the structural design of robust MOFs with high connectivity is provided. Cluster chemistry involving Y, lanthanides (Ln, from La to Lu), actinides (An, from Ac to Lr), Ti, and Zr is initially introduced. This is followed by a review of recently developed MOFs based on group 3 and 4 metals with their structures discussed based on the types of inorganic or organic building blocks. The novel properties and arising applications of these MOFs in catalysis, adsorption and separation, delivery, and sensing are highlighted. Overall, this review is expected to provide a timely summary on MOFs based on group 3 and 4 metals, which shall guide the future discovery and development of stable and functional MOFs for practical applications.
Metal–organic frameworks (MOFs) based on group 3 and 4 metals with high chemical stability, structural diversity, and various interesting properties are reviewed. Cluster and framework chemistry of group 3 and 4 metals are expected to provide a timely summary on MOF development, which shall guide the discovery and development of stable and functional MOFs for practical applications.
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Sufficient pore size, appropriate stability, and hierarchical porosity are three prerequisites for open frameworks designed for drug delivery, enzyme immobilization, and catalysis involving large ...molecules. Herein, we report a powerful and general strategy, linker thermolysis, to construct ultrastable hierarchically porous metal–organic frameworks (HP-MOFs) with tunable pore size distribution. Linker instability, usually an undesirable trait of MOFs, was exploited to create mesopores by generating crystal defects throughout a microporous MOF crystal via thermolysis. The crystallinity and stability of HP-MOFs remain after thermolabile linkers are selectively removed from multivariate metal–organic frameworks (MTV-MOFs) through a decarboxylation process. A domain-based linker spatial distribution was found to be critical for creating hierarchical pores inside MTV-MOFs. Furthermore, linker thermolysis promotes the formation of ultrasmall metal oxide nanoparticles immobilized in an open framework that exhibits high catalytic activity for Lewis acid-catalyzed reactions. Most importantly, this work provides fresh insights into the connection between linker apportionment and vacancy distribution, which may shed light on probing the disordered linker apportionment in multivariate systems, a long-standing challenge in the study of MTV-MOFs.
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By anchoring triazole units onto its skeleton, the luminescent sensing properties of a terbium(iii) metal-organic framework could be efficiently improved, including not only an expansion of the scale ...of analytes such as Fe3+, anions and nitroaromatic molecules, but also enhanced selectivity and sensitivity.
Ultrafine face‐centered cubic (fcc) ruthenium nanoclusters (NCs) are of great interest due to their super high catalytic activity. However, it is extremely difficult to prepare ≈1 nm fcc ruthenium ...NCs with high energy atoms due to their easy aggregation. Herein, the nucleation process of ruthenium centers by confined pyrolysis of a multivariate metal–organic framework to isolate ultrafine fcc NCs (from single atom to 1.33 nm) via in situ formed stabilizers is unveiled. Systematic investigations demonstrate that preferential nucleation of Ru single atoms to fcc clusters in the initial nucleation represents a key step and makes it possible to separate ultrafine fcc Ru NCs with in situ formed N‐doped porous carbon. A record high turnover frequency of 1300.53 min−1 for methanolysis of ammonia borane is achieved by 1.33 nm NCs. This work suggests a new strategy to prepare ultrafine metal NCs by instantly capturing structure‐specific crystal nuclei with in situ formed stabilizers.
The nucleation process of Ru centers is unveiled by confined pyrolysis of a multivariate metal–organic framework. The preferential nucleation of Ru single atoms to face‐centered cubic clusters in the initial nucleation suggests a new strategy to prepare ultrafine metal nanoclusters (from single atom to 1.33 nm) by instantly capturing structure‐specific crystal nuclei with in situ formed stabilizers.
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Utilization of a proper metal–organic framework (MOF) template has recently attracted significant attention for the fabrication of high-performance supercapacitor electrodes; however, limited ...attention has been paid to the process of preparation of an excellent MOF template used to derive the anticipated electrode materials. Herein, a two-fold interpenetrating MOF with a microporous structure and multi-components, such as nickel, phosphorus, nitrogen, oxygen, and carbon, in the final framework was successfully constructed. The pristine sample could be directly utilized as a supercapacitor electrode material, which exhibited the moderate electrochemical capacitance of 979.8 F g −1 at the current density of 1 A g −1 . Using the simple treatment of one-step pyrolysis under a nitrogen atmosphere at different annealing temperatures (500 °C, 600 °C, 700 °C, and 800 °C), rare hierarchical Ni/P/N/C composites, denoted as Ni/P/N/C-500, Ni/P/N/C-600, Ni/P/N/C-700, and Ni/P/N/C-800, were derived from the parent MOF. The anticipated multi-components Ni, P, N, and O were uniformly incorporated into the carbon materials, which resulted in an excellent synergistic effect to improve the electrochemical energy storage performance. The morphologies and components of these derivatives were characterized via SEM, XPS, and XRD, indicating the uniform distribution of different components in the hybrid structures. The maximum specific capacitance for the Ni/P/N/C-500 electrode reached 2887.87 F g −1 at the current density of 1 A g −1 , which was superior to that of other hierarchical composites and established a new benchmark in the related field. The combination of several advantages, such as high surface area, even distribution, and ultra-high content of Ni/P/N/C components, in these derivatives ensured their high-performance in energy storage. The presented results fully demonstrate the unique advantage of utilizing the pre-designed MOFs as a template to prepare hybrid materials used as potential electrode-active materials in supercapacitors and provide an efficient route to fabricate superior-performance energy-storage devices.
Chromium metal–organic frameworks (MOFs) are well-known for their stable porous frameworks, which are not fully explored due to the difficulty encountered in the synthesis process. In order to ...investigate the possibilities of Cr-MOFs as separation materials towards C2 guest molecules, a novel iron MOF was constructed, which could serve as the scaffold to fabricate Cr-MOFs via post-synthetic metalation. The corresponding gas adsorption properties of the two iso-structural MOFs had been systematically investigated, illustrating the potential separation ability of Cr-MOF with respect to CO2/C2H2 and C2H2/C2H4. Furthermore, the real and feasible behaviors of gas separation for Cr-MOF had been verified by dynamic breakthrough experiments. Compared to the iso-structural Fe-MOF, the fabricated Cr-MOF not only improved the chemical stability, but also enhanced the separation efficiency of the C2 gas molecules. The systematic investigation clearly manifests the important role of chromium ions towards the separation of gas molecules and provides other insights into fabricating MOF-based separation materials.
The field of metal-organic framework (MOF)-based biomimetic catalysts has achieved great progress but is still in its infancy. The systematic investigation of the tailored construction of MOF-based ...biomimetic catalysts is required for further development. Herein, two iron-based MOFs, namely, (Fe
3
O)
2
(H
2
O)
4
(HCOO)(L)
2
n
(HUST-5: H
6
L = hexakis(4-formylphenoxy) cyclotriphosphazene; HUST = Huazhong University of Science and Technology) and (Fe
3
O)(H
2
O)
3
(L)
n
(HUST-7) have been fabricated through the assembly of different iron clusters and hexa-carboxylate ligand under the control of the added acid species. The two MOFs exhibit distinct secondary building units (SBUs) and topological structures, which could be used as biomimetic catalysts for the systematic comparisons of structural characteristics and the catalytic activity. Both MOFs possess catalytic activity similar to that of natural peroxidases towards the catalysis of the oxidation of a variety of substrates. Significantly, HUST-5 and HUST-7 can effectively catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H
2
O
2
accompanied by significant colorimetric biosensing. With same compositions, different catalytic performances were obtained due to differences in the porous structures and characteristics of SBUs in two Fe-MOFs, which was also validated by theoretical calculation results. Furthermore, the phenomenon of colorimetric biosensing could be significantly suppressed by the addition of ascorbic acid (AA) during the oxidation process of TMB. It was observed from these findings that a facile colorimetric biosensing platform for detecting H
2
O
2
and ascorbic acid has been successfully explored. Therefore, this work provides another unique perspective for the tailor-made preparation of stable MOF-based peroxidase mimics with excellent catalytic performance and colorimetric biosensing.
Two MOFs exhibit distinct secondary building units (SBUs) and topological structures, which could be used as biomimetic catalysts for the systematic comparisons of structural characteristics and the catalytic activity.
In a two-phase heat transfer device, achieving a high capillarity of the wick while reducing flow resistance within a limited space becomes the key to improving the heat dissipation performance. As a ...commonly used wick structure, mesh is widely employed because of its high permeability. However, achieving the desired capillary performance often requires multiple layers to be superimposed to ensure an adequate capillary, resulting in an increased thickness of the wick. In this study, an ultra-thin biomimetic copper forest structural modification of copper mesh was performed using an electrochemical deposition to solve the contradiction between the permeability and the capillary. The experiments were conducted on a copper mesh to investigate the effects of various conditions on their morphology and capillary performance. The results indicate that the capillary performance of the modified copper mesh improves with a longer deposition time. The capillary pressure drops can reach up to 1400 Pa when using ethanol as the working fluid. Furthermore, the modified copper mesh demonstrates a capillary performance value (ΔPc·K) of 8.44 × 10−8 N, which is 1.7 times higher than that of the unmodified samples. Notably, this enhanced performance is achieved with a thickness of only 142 μm. The capillary limit can reach up to 45 W when the modified copper mesh is only 180 μm. Microscopic flow analysis reveals that the copper forest modified structure maintains the original high permeability of the copper mesh while providing a greater capillary force, thereby enhancing the overall flow characteristics.
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The systemic immune-inflammation index, a new index based on platelets, neutrophils and lymphocytes, has been shown to be associated with outcomes of patients with venous sinus thrombosis and cancer. ...However, its application in acute ischemic stroke has rarely been reported. Therefore, we examined the relationship between systemic immune-inflammation index levels at hospital admission and the outcomes of patients 3 months after onset, and plotted a nomogram to predict the probability of adverse outcomes in patients with acute ischemic stroke.
We retrospectively analyzed a total of 208 patients with acute ischemic stroke who were admitted between January 2020 and December 2020, and recorded the modified Rankin score 3 months later. A modified Rankin score ≥ 3 was defined as an adverse outcome. Age, sex, NIHSS score, SII, hypertension and coronary heart disease were included in the binary logistic regression, and the nomogram was plotted with a regression equation.
Receiver operating characteristic (ROC) curve analysis indicated that the best cutoff value of the systemic immune-inflammation index was 802.8, with a sensitivity of 70.9% and specificity of 58.2% (area under the curve: 0.657, 95% confidence interval: 0.572-0.742). The nomogram had a C index of 0.802. The average error of the calibration curves of the training set and the validation set was 0.021 and 0.034, respectively.
The systemic immune-inflammation index is associated with short-term adverse outcomes in patients with acute ischemic stroke, and the nomograms can predict the risk of adverse outcomes in patients with acute ischemic stroke.
Multivariate (MTV) hierarchical metal–organic frameworks (MOFs), which contain multiple regions arranged in ordered structures, show promise for applications such as gas separation, size-selective ...catalysis, and controlled drug delivery. However, the complexity of these hierarchical MOFs is limited by a lack of control during framework assembly. Herein, we report the controlled generation of hierarchical MOF-on-MOF structural formation under the guidance of two design principles, surface functionalization and retrosynthetic techniques for stability control. Accordingly, the tunability of spatial distributions, compositions, and crystal sizes has been achieved in these hierarchical systems. The resulting MOF-on-MOF hierarchical structures represent a unique crystalline porous material which contains a controllable distribution of functional groups and metal clusters that are associated together within a framework composite. This general synthetic approach not only expands the scope and tunability of the traditional MTV strategy to multicomponent materials, but also offers a facile route to introduce variants and sequences to sophisticated three-dimensional hierarchical and cooperative systems. As a proof of concept, the photothermal effects of a porphyrinic core-MOF are exploited to trigger the controlled guest release from a shell-MOF with high guest capacity, highlighting the integrated cooperative behaviors in multivariate hierarchical systems.
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