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.
Polyoxometalate (POM)-based metal-organic framework (MOF) materials contain POM units and generally generate MOF materials with open networks. POM-based MOF materials, which utilize the advantages of ...both POMs and MOFs, have received increasing attention, and much effort has been devoted to their preparation and relevant applications over the past few decades. They have good prospects in catalysis owing to the electronic and physical properties of POMs that are tunable by varying constituent elements. In this review, we present recent developments in porous POM-based MOF materials, including their classification, synthesis strategies, and applications, especially in the field of catalysis.
POM-based MOF materials, which combine the advantages of both POMs and MOFs, have received increasing attention. In this review, we present the recent developments in porous POM-based MOF materials for the first time, including their classification, synthesis strategies and applications, especially in the field of catalysis.
A 9,10‐dihydro‐9‐oxa‐10 phosphophenanthrene‐10‐oxide based derivative tris‐(3‐dopo‐propyl)‐triazine trione (TAD) is applied to polyethylene terephthalate (PET). The melting and blending process of ...the composite is carried out through twin screws. The flame retardancy, thermostability, and mechanical property have elevated with slight load agent. The limiting oxygen index (LOI), vertical burning test (UL 94), and cone calorimeter test are proceeded to sustain the flame retardancy of PET/TAD‐x. The 30.2% LOI value and UL 94V‐1 rating will be attained with 5 wt% load, the peak of heat release rate show 33.4% decrease, concurrently. The thermogravimetric analysis is performed to characterized the constancy of flame retardant composites during the heating process. Relevant evidence express that TAD provided appreciable assistance in improving carbon‐forming capacity and postponing initial decomposition temperature. The Raman spectra, TG‐Fourier transform infrared, Hot‐Stage FTIR are used to explain the connection about the optimization of performance and the alteration of products in pyrolyzing or after pyrolyzation. In addition, the mechanical properties are supported via tensile and impact test. This study confirms TAD has great potential competitiveness in future halogen‐free flame retardant applications as viable and environmentally friendly to polyester material.
Amorphous Ni sulfoselenide on the surface of Ni(OH)2 nanoplate that is supported by nickel foam is synthesized, which demonstrates high activity and durability for hydrogen evolution reaction (HER) ...and urea oxidation reaction (UOR) in alkaline media. As for HER, the introduction of sulfur in Ni sulfoselenide not only increases the electrochemical active area, but also improves the water adsorption ability and provides an optimal adsorption site for hydrogen atom. As for UOR, the in-situ formed amorphous oxyhydroxide is believed as the real active species. The electrolyzer assembled by Ni sulfoselenide electrodes shows a low voltage of 1.47 at 10 mA cm−2 in 1 M KOH + 0.5 M urea, which is much lower than that required for overall water splitting. The present work demonstrates an effective bifunctional electrode for HER and UOR that can be used to produce hydrogen and remove pollutant (urea) in water at the same time.
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•Amorphous Ni sulfoselenide, selenide and sulfide are synthesized.•Ni sulfoselenide presents high activity and durability for HER and UOR.•Sulfur plays a crucial role in improving the HER activity of Ni sulfoselenide.•In-situ formed amorphous Ni oxyhydroxide is the active species for UOR.
Disrupting the balance between self-renewal and differentiation of hematopoietic stem cells (HSCs) leads to bone marrow failure or hematologic malignancy. However, how HSCs sustain their quiescent ...state and avoid type I interferon (IFN)-mediated exhaustion remains elusive. Here we defined a circular RNA that we named cia-cGAS that was highly expressed in the nucleus of long-term (LT)-HSCs. Cia-cGAS deficiency in mice caused elevated expression of type I IFNs in bone marrow and led to decreased numbers of dormant LT-HSCs. Under homeostatic conditions, cia-cGAS bound DNA sensor cGAS in the nucleus to block its synthase activity, thereby protecting dormant LT-HSCs from cGAS-mediated exhaustion. Moreover, cia-cGAS harbored a stronger binding affinity to cGAS than self-DNA did and consequently suppressed cGAS-mediated production of type I IFNs in LT-HSCs. Our findings reveal a mechanism by which cia-cGAS inhibits nuclear cGAS by blocking its enzymatic activity and preventing cGAS from recognizing self-DNA to maintain host homeostasis.
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•Cia-cGAS deficiency leads to elevated type I IFNs in LT-HSCs•Cia-cGAS binds to cGAS and inactivates the enzymatic activity of cGAS in LT-HSCs•Cia-cGAS protects dormant HSCs from cGAS-mediated exhaustion•Cia-cGAS is a potent suppressor of cGAS-mediated recognition and autoimmune response
Disrupting the balance between self-renewal and differentiation of HSCs leads to severe pathologic consequences. Xia et al. identify a circular RNA cia-cGAS that is highly expressed in the nucleus of LT-HSCs. Under homeostatic conditions, cia-cGAS binds DNA sensor cGAS to block its synthase activity, protecting dormant LT-HSCs from cGAS-mediated exhaustion.
Water shortages have become a major problem facing the world today. Membrane separation technology is commonly used in water treatment applications. The development of new materials for water ...treatment can reduce the energy required for water treatment, reduce cost, and improve efficiency. The unique structure and properties of graphene and silica make them attractive materials for preparation of nanofiltration membranes for water treatment. We have successfully prepared a graphene oxide/silica (GO/SiO
2
) hybrid composite materials by in situ hydrolysis, using tetraethyl orthosilicate (TEOS) as a silicon source in an alkaline environment. The chemistry and structure of these materials are characterized by TEM, FTIR, Raman, and XPS of GO and the GO/SiO
2
composite. BET porosimetry reveals that the total pore volume of the composite is 2.84 cm
3
g
−1
, the specific surface area is 2897 m
2
g
−1
, and the average pore diameter is 3.97 nm. We prepared GO membranes and GO/SiO
2
composite membranes by vacuum suction filtration. The morphology of the membrane was observed by FESEM and AFM. The composite membrane has a larger surface roughness (
R
ms
= 9.39). We also tested the thermal stability by TGA, and hydrophilicity by water contact angle measurements. The water permeance of the composite membrane is up to 229.15 L m
−2
h
−1
bar
−1
, and the rejection of the rhodamine B dye molecules is as high as 99%. The GO/SiO
2
hybrid composite membrane has good hydrophilicity and thermal stability, high water permeance and rejection, and can be developed as a high-performance material for water treatment.
Single metal atom isolated in nitrogen‐doped carbon materials (MNC) are effective electrocatalysts for oxygen reduction reaction (ORR), which produces H2O2 or H2O via 2‐electron or 4‐electron ...process. However, most of MNC catalysts can only present high selectivity for one product, and the selectivity is usually regulated by complicated structure design. Herein, a carbon black‐supported CoNC catalyst (CB@CoNC) is synthesized. Tunable 2‐electron/4‐electron behavior is realized on CB@Co‐N‐C by utilizing its H2O2 yield dependence on electrolyte pH and catalyst loading. In acidic media with low catalyst loading, CB@CoNC presents excellent mass activity and high selectivity for H2O2 production. In flow cell with gas diffusion electrode, a H2O2 production rate of 5.04 mol h−1 g−1 is achieved by CB@CoNC on electrolyte circulation mode, and a long‐term H2O2 production of 200 h is demonstrated on electrolyte non‐circulation mode. Meanwhile, CB@CoNC exhibits a dominant 4‐electron ORR pathway with high activity and durability in pH neutral media with high catalyst loading. The microbial fuel cell using CB@CoNC as the cathode catalyst shows a peak power density close to that of benchmark Pt/C catalyst.
A carbon black supported single‐atom CoNC catalyst for oxygen reduction reaction with tunable 2‐electron/4‐electron behavior is synthesized, which shows excellent activity and production rate for H2O2 generation in acidic media at low catalyst loading, while high 4‐electron performance in neutral media at high catalyst loading.
The incorporation of large π-conjugated ligands into metal–organic frameworks (MOFs) can introduce intriguing photophysical and electrochemical properties into the framework. However, these effects ...are often hindered by the strong π–π interaction and the low solubility of the arylated ligands. Herein, we report the synthesis of a porous zirconium-based MOF, Zr6(μ3-O)4(μ3-OH)4(OH)6(H2O)6(HCHC) (PCN-136, HCHC = hexakis(4-carboxyphenyl)hexabenzocoronene), which is composed of a hexacarboxylate linker with a π-conjugated hexabenzocoronene moiety. Direct assembly of the Zr4+ metal centers and the HCHC ligands was unsuccessful due to the low solubility and the unfavorable conformation of the arylated HCHC ligand. Therefore, PCN-136 was obtained from aromatization-driven postsynthetic annulation of the hexaphenylbenzene fragment in a preformed framework (pbz-MOF-1) to avoid π–π stacking. This postsynthetic modification was done through a single-crystal-to-single-crystal transformation and was clearly observable utilizing single -crystal X-ray crystallography. The formation of large π-conjugated systems on the organic linker dramatically enhanced the photoresponsive properties of PCN-136. With isolated hexabenzocoronene moieties as photosensitizers and Zr–oxo clusters as catalytic sites, PCN-136 was employed as an inherent photocatalytic system for CO2 reduction under visible-light irradiation, which showed increased activity compared with pbz-MOF-1.
Two novel polyoxometalate (POM)-based metal–organic frameworks (MOFs), TBA3ε-PMoV 8MoVI 4O36(OH)4Zn4BTB4/3·xGuest (NENU-500, BTB = benzene tribenzoate, TBA+ = tetrabutylammonium ion) and TBA3ε-PMoV ...8MoVI 4O37(OH)3Zn4BPT (NENU-501, BPT = 1,1′-biphenyl-3,4′,5-tricarboxylate), were isolated. In these compounds, the POM fragments serving as nodes were directly connected with organic ligands giving rise to three-dimensional (3D) open frameworks. The two anionic frameworks were balanced by TBA+ ions residing inside the open channels. They exhibit not only good stability in air but also tolerance to acidic and basic media. Furthermore, they were employed as electrocatalysts for the hydrogen evolution reaction (HER) owing to the combination of the redox activity of a POM unit and the porosity of a MOF. Meanwhile, the HER activities of ε(trim) 4/3 , NENU-5, and HKUST-1 were also studied for comparison. Remarkably, as a 3D hydrogen-evolving cathode operating in acidic electrolytes, NENU-500 exhibits the highest activity among all MOF materials. It shows an onset overpotential of 180 mV and a Tafel slope of 96 mV·dec–1, and the catalytic current density can approach 10 mA·cm–2 at an overpotential of 237 mV. Moreover, NENU-500 and NENU-501 maintain their electrocatalytic activities after 2000 cycles.
miRNAs are a family of approximately 22-nuleotide-long noncoding RNAs involved in the formation and progress of tumors. Since traditional methods for the detection of miRNAs expression have many ...disadvantages, we developed a simple method called polyA RT PCR. With this method, we detected a series of miRNAs and found that mir-126 is one of the miRNAs underexpressed in breast cancer cells. Flow cytometry analysis showed that mir-126 inhibited cell cycle progression from G1/G0 to S. Further studies revealed that mir-126 targeted IRS-1 at the translation level. Knocking down of
IRS-1 suppresses cell growth in HEK293 and breast cancer cell MCF-7, which recapitulates the effects of mir-126. In conclusion, we developed a simple method for high-throughput screening of miRNAs and found that mir-126, a cell growth suppressor, targets
IRS-1.
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