X-Ray single-crystal diffraction has been the most straightforward and important technique in structural determination of crystalline materials for understanding their structure-property ...relationships. This powerful tool can be used to directly visualize the precise and detailed structural information of porous coordination polymers or metal-organic frameworks at different states, which are unique for their flexible host frameworks compared with conventional adsorbents. With a series of selected recent examples, this review gives a brief overview of single-crystal X-ray diffraction studies and single-crystal to single-crystal transformations of porous coordination polymers under various chemical and physical stimuli such as solvent and gas sorption/desorption/exchange, chemical reaction and temperature change.
Considering their unique roles in organic synthesis, and pharmaceutical and agrochemical applications, the development of fluoroalkylation, cyclization, and indole oxidative cleavage are important ...topics. Herein, an unprecedented electrochemical tri‐ and difluoromethylation/cyclization/indole oxidative cleavage process occurring in an undivided cell is presented. The protocol employs a readily prepared Langlois reagent as the fluoroalkyl source, affording a series of tri‐ or difluoromethylated 2‐(2‐acetylphenyl)isoquinoline‐1,3‐diones in good yields with excellent stereoselectivity. It is worth noting that this new methodology merges the fluoroalkylation/cyclization of N‐substituted acrylamide alkenes with the oxidative cleavage of an indole C(2)=C(3) bond under external oxidant‐free conditions.
Tri‐ and difluoromethylation/cyclization/indole oxidative cleavage: An unprecedented electrochemical tri‐ and difluoromethylation/cyclization/indole oxidative cleavage process has been established in an undivided cell. The protocol employs a readily prepared Langlois reagent as the fluoroalkyl source, affording a series of tri‐ or difluoromethylated 2‐(2‐acetylphenyl)isoquinoline‐1,3‐diones in good yields with excellent stereoselectivity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We describe the application of S−H bond insertion reactions of aryl diazoacetates with cysteine residues that enabled metal‐free, S−H functionalization under visible‐light conditions. Moreover, this ...process could be intensified by a continuous‐flow photomicroreactor on the acceleration of the reaction (6.5 min residence time). The batch and flow protocols described were applied to obtain a wide range of functionalized cysteine derivatives and cysteine‐containing dipeptides, thus providing a straightforward and general platform for their functionalizations in mild conditions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
An efficient photoredox‐catalyzed halo‐trifluoromethylation reaction of 1,7‐enynes has been developed under mild conditions. This photocatalytic protocol provides an efficient and functional strategy ...leading to CF3− and halogen‐containing 3,4‐dihydroquinolin‐2(1H)‐ones from a wide range of 1,7‐enynes through two different radical pathways. The reaction mechanism was proposed based on the control experiments.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Topology, an important branch of mathematics, is an ideal theoretical tool to describe topological states and phase transitions. Many topological concepts have found their physical entities in real ...or reciprocal spaces identified by topological invariants, which are usually defined on orientable surfaces, such as torus and sphere. It is natural to investigate the possible physical realization of more intriguing non-orientable surfaces. Herein, we show that the set of spin-induced ferroelectric polarizations in cubic perovskite oxides AMn
Cr
O
(A = La and Tb) reside on the topological Roman surface-a non-orientable two-dimensional manifold formed by sewing a Möbius strip edge to that of a disc. The induced polarization may travel in a loop along the non-orientable Möbius strip or orientable disc, depending on the spin evolution as controlled by an external magnetic field. Experimentally, the periodicity of polarization can be the same or twice that of the rotating magnetic field, which is consistent with the orientability of the disc and the Möbius strip, respectively. This path-dependent topological magnetoelectric effect presents a way to detect the global geometry of a surface and deepens our understanding of topology in both mathematics and physics.
Comprehensive Summary
A three‐component reaction of 1,3‐enynes and cyclobutanone oxime esters in the presence of aryl boronic acids or organozinc reagents via the photoredox/copper or ...photoredox/nickel catalysis has been established. This redox‐neutral 1,4‐cyanoalkylarylation reaction has demonstrated mild condition, high catalytic reactivity and wide functional group compatibility, allowing access to a variety of functionalized tetra‐substituted allene derivatives with high chemo‐ and regioselectivity. Moreover, using photocatalytic continuous flow technique to promote this process would result in increased yields (70% in flow vs. 61% in batch), reduced reaction times (7 min in flow vs. 6 h in batch), and easy scale‐up (upgrade to gram scale), showcasing its potential as a synthetic platform.
We reported a three‐component reaction of 1,3‐enynes and cyclobutanone oxime esters in the presence of aryl boronic acids or organozinc reagents via the photoredox/copper or photoredox/nickel catalysis, providing a variety of functionalized tetra‐substituted allenes with high chemo‐ and regioselectivities. Moreover, using photocatalytic continuous flow technique to promote this process would result in increased yields (70% in flow vs. 61% in batch), reduced reaction times (7 min in flow vs. 6 h in batch), and easy scale‐up (up to gram scale).
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A photoinduced 1,4-heteroaryl migration from a carbon center to a nitrogen center accompanied by a cyanoalkylacylation of heterocyclic-substituted azidyl homoallylic alcohols and cycloketone oxime ...esters has been described. This simple and powerful protocol merged the dual C-C bond cleavage with C-N bond formation, providing an efficient and environmentally safe approach to a variety of synthetically useful cyanoalkyl-containing
β
-enamino ketones with outstanding selectivity and commendable functional group compatibility. Moreover, the application of microflow technique enhanced these reactions compared with the equivalent batch reaction, significantly reducing the reaction times to 5-9.3 min and broadening the substrate scope to more than 35 successful substrates.
We have reported a photocatalyzed C-C bond cleavage/C-N bond formation cyanoalkylacylation reaction through the remote
C
-center to
N
-center heteroaryl migration under mild conditions using the microflow technique.
Xiyanping (XYP) is a Chinese herbal medicine used in the clinic to treat respiratory infection and pneumonia. Recent evidence identified XYP as a potential inhibitor of severe acute respiratory ...syndrome coronavirus 2, implying XYP as a possible treatment for the coronavirus disease 2019 (COVID‐19). Here, we conducted a prospective, multicenter, open‐label and randomized controlled trial to evaluate the safety and effectiveness of XYP injection in patients with mild to moderate COVID‐19. We consecutively recruited 130 COVID‐19 patients with mild to moderate symptoms from five study sites, and randomized them in 1:1 ratio to receive XYP injection in combination with standard therapy or receive standard supportive therapy alone. We found that XYP injection significantly reduced the time to cough relief, fever resolution and virus clearance. Less patients receiving XYP injection experienced disease progression to the severe stage during the treatment process. No severe adverse events were reported during the study. Taken together, XYP injection is safe and effective in improving the recovery of patients with mild to moderate COVID‐19. However, further studies are warranted to evaluate the efficacy of XYP in an expanded cohort comprising COVID‐19 patients at different disease stages.
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In this study, we incorporated 2,3-dialdehyde nanocrystalline cellulose (DANC) into chitosan as a reinforcing agent and manufactured biodegradable films with enhanced gas barrier properties. DANC ...generated via periodate oxidation of cellulose nanocrystal (CNC) was blended at various concentrations with chitosan, and bionanocomposite films were prepared via casting and characterized systematically. The results showed that DANC developed Schiff based bond with chitosan that improved its properties significantly. The addition of DANC dramatically improved the gas barrier performance of the composite film, with water vapor permeability (WVP) value decreasing from 62.94 g·mm·m
·atm
·day
to 27.97 g·mm·m
·atm
·day
and oxygen permeability (OP) value decreasing from 0.14 cm
·mm·m
·day
·atm
to 0.026 cm
·mm·m
·day
·atm
. Meanwhile, the maximum decomposition temperature (Td
) of the film increased from 286 °C to 354 °C, and the tensile strength of the film was increased from 23.60 MPa to 41.12 MPa when incorporating 25 wt.% of DANC. In addition, the chitosan/DANC (75/25, wt/wt) films exhibited superior thermal stability, gas barrier, and mechanical strength compared to the chitosan/CNC (75/25, wt/wt) film. These results confirm that the DANC and chitosan induced films with improved gas barrier, mechanical, and thermal properties for possible use in film packaging.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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