We present a facile route towards a dual single‐atom nanozyme composed of Zn and Mo, which utilizes the non‐covalent nano‐assembly of polyoxometalates, supramolecular coordination complexes as the ...metal‐atom precursor, and a macroscopic amphiphilic aerogel as the supporting substrate. The dual single‐atoms of Zn and Mo have a high content (1.5 and 7.3 wt%, respectively) and exhibit a synergistic effect and a peroxidase‐like activity. The Zn/Mo site was identified as the main active center by X‐ray absorption fine structure spectroscopy and density functional theory calculation. The detection of versatile analytes, including intracellular H2O2, glucose in serum, cholesterol, and ascorbic acid in commercial beverages was achieved. The nanozyme has an outstanding stability and maintained its performance after one year's storage. This study develops a new peroxidase‐like nanozyme and provides a robust synthetic strategy for single‐atom catalysts by utilizing an aerogel as a facile substrate that is capable of stabilizing various metal atoms.
A new synthesis strategy for a dual single‐atom nanozyme has been developed by using a macroscopic polymer aerogel as the supporting substrate and supramolecular coordination complexes/polyoxometalates as the metal precursor. The nanozyme with high catalytic activity and super‐long stability has been applied in the detection of various analytes including intracellular H2O2, glucose in serum, cholesterol, and ascorbic acid in commercial beverages.
Controlling gas sorption by simple pore modification is important in molecular recognition and industrial separation processes. In particular, it is challenging to realize the inverse selectivity, ...which reduces the adsorption of a high‐affinity gas and increases the adsorption of a low‐affinity gas. Herein, an “opposite action” strategy is demonstrated for boosting CO2/C2H2 selectivity in porous coordination polymers (PCPs). A precise steric design of channel pores using an amino group as an additional interacting site enabled the synergetic increase in CO2 adsorption while suppressing the C2H2 adsorption. Based on this strategy, two new ultramicroporous PCP physisorbents that are isostructural were synthesised. They exhibited the highest CO2 uptake and CO2/C2H2 volume uptake ratio at 298 K. Origin of this specific selectivity was verified by detailed density functional theory calculations. The breakthrough separation performances with remarkable stability and recyclability of both the PCPs render them relevant materials for C2H2 purification from CO2/C2H2 mixtures.
Boosting inverse CO2/C2H2 selectivity is achieved through precise steric design of amino groups in the pore surface to provide enhanced CO2–framework interactions and suppressed C2H2 adsorption. The obtained two new porous coordination polymers (PCPs) exhibit high CO2 uptake and strong separation performance for one‐step C2H2 purification at room temperature, which can be considered as new physisorbents with this specific inverse selectivity.
Single‐ligand‐based electronically conductive porous coordination polymers/metal–organic frameworks (EC‐PCPs/MOFs) fail to meet the requirements of numerous electronic applications owing to their ...limited tunability in terms of both conductivity and topology. In this study, a new 2D π‐conjugated EC‐MOF containing copper units with mixed trigonal ligands was developed: Cu3(HHTP)(THQ) (HHTP=2,3,6,7,10,11‐hexahydrotriphenylene, THQ=tetrahydroxy‐1,4‐quinone). The modulated conductivity (σ≈2.53×10−5 S cm−1 with an activation energy of 0.30 eV) and high porosity (ca. 441.2 m2 g−1) of the Cu3(HHTP)(THQ) semiconductive nanowires provided an appropriate resistance baseline and highly accessible areas for the development of an excellent chemiresistive gas sensor.
Makes sense: As two ligands offer more opportunity than one to tune MOF conductivity and topology, a 2D π‐conjugated copper‐based electronically conductive MOF with two different trigonal organic ligands was developed (see structure). The semiconductivity and high porosity of the resulting nanowires provided a low conductivity baseline and highly accessible surface areas, thus resulting in excellent room‐temperature chemiresistive sensing properties.
The activity of nanomaterials (NMs) in catalytically scavenging superoxide anions mimics that of superoxide dismutase (SOD). Although dozens of NMs have been demonstrated to possess such activity, ...the underlying principles are unclear, hindering the discovery of NMs as the novel SOD mimics. In this work, we use density functional theory calculations to study the thermodynamics and kinetics of the catalytic processes, and we develop two principles, namely, an energy level principle and an adsorption energy principle, for the activity. The first principle quantitatively describes the role of the intermediate frontier molecular orbital in transferring electrons for catalysis. The second one quantitatively describes the competition between the desired catalytic reaction and undesired side reactions. The ability of the principles to predict the SOD-like activities of metal-organic frameworks were verified by experiments. Both principles can be easily implemented in computer programs to computationally screen NMs with the intrinsic SOD-like activity.
Design of the gas-diffusion process in a porous material is challenging because a contracted pore aperture is a prerequisite, whereas the channel traffic of guest molecules is regulated by the ...flexible and dynamic motions of nanochannels. Here, we present the rational design of a diffusion-regulatory system in a porous coordination polymer (PCP) in which flip-flop molecular motions within the framework structure provide kinetic gate functions that enable efficient gas separation and storage. The PCP shows substantial temperature-responsive adsorption in which the adsorbate molecules are differentiated by each gate-admission temperature, facilitating kinetics-based gas separations of oxygen/argon and ethylene/ethane with high selectivities of ~350 and ~75, respectively. Additionally, we demonstrate the long-lasting physical encapsulation of ethylene at ambient conditions, owing to strongly impeded diffusion in distinctive nanochannels.
A large number of SARS-related coronaviruses (SARSr-CoV) have been detected in horseshoe bats since 2005 in different areas of China. However, these bat SARSr-CoVs show sequence differences from SARS ...coronavirus (SARS-CoV) in different genes (S, ORF8, ORF3, etc) and are considered unlikely to represent the direct progenitor of SARS-CoV. Herein, we report the findings of our 5-year surveillance of SARSr-CoVs in a cave inhabited by multiple species of horseshoe bats in Yunnan Province, China. The full-length genomes of 11 newly discovered SARSr-CoV strains, together with our previous findings, reveals that the SARSr-CoVs circulating in this single location are highly diverse in the S gene, ORF3 and ORF8. Importantly, strains with high genetic similarity to SARS-CoV in the hypervariable N-terminal domain (NTD) and receptor-binding domain (RBD) of the S1 gene, the ORF3 and ORF8 region, respectively, were all discovered in this cave. In addition, we report the first discovery of bat SARSr-CoVs highly similar to human SARS-CoV in ORF3b and in the split ORF8a and 8b. Moreover, SARSr-CoV strains from this cave were more closely related to SARS-CoV in the non-structural protein genes ORF1a and 1b compared with those detected elsewhere. Recombination analysis shows evidence of frequent recombination events within the S gene and around the ORF8 between these SARSr-CoVs. We hypothesize that the direct progenitor of SARS-CoV may have originated after sequential recombination events between the precursors of these SARSr-CoVs. Cell entry studies demonstrated that three newly identified SARSr-CoVs with different S protein sequences are all able to use human ACE2 as the receptor, further exhibiting the close relationship between strains in this cave and SARS-CoV. This work provides new insights into the origin and evolution of SARS-CoV and highlights the necessity of preparedness for future emergence of SARS-like diseases.
Direct structural information of confined CO
in a micropore is important for elucidating its specific binding or activation mechanism. However, weak gas-binding ability and/or poor sample ...crystallinity after guest exchange hindered the development of efficient materials for CO
incorporation, activation and conversion. Here, we present a dynamic porous coordination polymer (PCP) material with local flexibility, in which the propeller-like ligands rotate to permit CO
trapping. This process can be characterized by X-ray structural analysis. Owing to its high affinity towards CO
and the confinement effect, the PCP exhibits high catalytic activity, rapid transformation dynamics, even high size selectivity to different substrates. Together with an excellent stability with turnover numbers (TON) of up to 39,000 per Zn
cluster of catalyst after 10 cycles for CO
cycloaddition to form value-added cyclic carbonates, these results demonstrate that such distinctive structure is responsible for visual CO
capture and size-selective conversion.
Targeted synthesis of kagome (kgm) topologic 2D covalent organic frameworks remains challenging, presumably due to the severe dependence on building units and synthetic conditions. Herein, two ...isomeric “two‐in‐one” monomers with different lengths of substituted arms based on naphthalene core (p‐Naph and m‐Naph) are elaborately designed and utilized for the defined synthesis of isomeric kgm Naph‐COFs. The two isomeric frameworks exhibit splendid crystallinity and showcase the same chemical composition and topologic structure with, however, different pore channels. Interestingly, C60 is able to uniformly be encapsulated into the triangle channels of m‐Naph‐COF via in situ incorporation method, while not the isomeric p‐Naph‐COF, likely due to the different pore structures of the two isomeric COFs. The resulting stable C60@m‐Naph‐COF composite exhibits much higher photoconductivity than the m‐Naph‐COF owing to charge transfer between the conjugated skeletons and C60 guests.
Targeted synthesis of two isomeric naphthalene‐based covalent organic frameworks with Kagome topology is realized by rational design of isomeric “two‐in‐one” monomers with different length of substituents. The specific pore structures of the two isomeric frameworks result in a significant difference in spatial immobilization of C60 guests. Incorporation of C60 into m‐Naph‐COF increases the photoconductivity of m‐Naph‐COF, presumably due to the enhanced charge transfer effect.
(Deuterium‐labeled) CF2H‐ and CFH2‐moieties are of high interest in drug discovery. The high demand for the incorporation of these fluoroalkyl moieties into molecular structures has witnessed ...significant synthetic progress, particularly in the (deutero)hydrodefluorination of CF3‐containing compounds. However, the controllable replacement of fluorine atoms while maintaining high chemoselectivity remains challenging. Herein, we describe the development of a selective (deutero)hydrodefluorination reaction via electrolysis. The reaction exhibits a remarkable chemoselectivity control, which is enabled by the addition of different organoboron sources. The procedure is operationally simple and scalable, and provides access in one step to high‐value building blocks for application in medicinal chemistry. Furthermore, density functional theory (DFT) calculations have been carried out to investigate the reaction mechanism and to rationalize the chemoselectivity observed.
We herein reported an electrochemical selective (deutero)hydrodefluorination reaction of trifluoroacetamides. The reaction which exhibits a remarkable chemoselectivity control and delivers (deuterium‐labeled) CF2H‐ and CFH2‐products in good yields with high level of deuterium incorporation, respectively, is enabled by the addition of different organoboron sources and (deuterated)water as the deuterium or hydrogen source.
Prussian blue (PB) has emerged as a promising cathode material in aqueous batteries. It possesses two distinct redox centers, and the potassium ions (K+) are unevenly distributed throughout the ...compound, adding complexity to the interpretation of the K+ insertion/de-insertion kinetic mechanism. Traditional ensemble-averaged measurements are limited in uncovering the precise kinetic information of the PB particles, as the results are influenced by the construction of the porous composite electrode and the redox behavior from different particles. In this study, the electrochemical processes of individual PB particles were investigated using nano-impact electrochemistry. By varying the potentials, different types of transient current signals were obtained that revealed the kinetic mechanism of each oxidation/reduction reaction in combination with theoretical simulation. Additionally, a partially contradictory conclusion between single-particle analysis and the ensemble-averaged measurement was discussed. These findings contribute to a better understanding of the electrochemical processes of cathode materials with multiple redox centers, which facilitates the development of effective strategies to optimize these materials.
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