Latest ArticlesAs a two-dimensional carbon based semiconductor, C3N acts as a promising material in many application areas. However, the basic physical properties such as Raman spectrum properties of C3N is still not clear. In this paper, we clarify the Raman spectrum properties of multilayer C3N. Moreover, the stacking driven Raman spectra change of multilayer C3N is also discussed.
Although fluorobis(phenylsulfonyl)methane (FBSM) and its cyclic analog 2-fluoro-1, 3-benzodithiole-1, 1, 3, 3-tetraoxide (FBDT) possess similar physicochemical properties, Shibata et al. found that FBSM failed to undergo nucleophilic monofluoromethylation of aldehydes regardless of the reaction conditions attempted (using various organic and inorganic bases). However, it was later discovered by Hu et al. that the nucleophilic monofluoromethylation could be accomplished by employing lithium hexamethyldisilazide (LiHMDS) as a base. Herein, we present an in-depth computational investigation into the intriguing effects of reagent structure and bases on the nucleophilic monofluoromethylation of aldehydes. The computations reveal the 1, 4-diazabicyclo[2.2.2]octane (DABCO) catalyzed nucleophilic monofluoromethylation of benzaldehyde with acyclic FBSM is a thermodynamically unfavorable process mainly due to the destabilizing O···O lone pair repulsions in FBSM product, whereas such repulsion could be largely avoided in FBDT product because of its constrained five-membered ring structure. Employing LiHMDS as a base can not only facilitate the nucleophilic monofluoromethylation via Li–O interactions but also render the monofluoromethylation of benzaldehyde with FBSM thermodynamically favored.
The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam. By strategically using the in situ generated Appel's salt or Mitsunobu's zwitterionic adduct as the dehydrating agent, a series of Beckmann rearrangement and following cascade reactions have been developed herein. The protocol allows the conversion of various ketoximes into amide, thioamide, tetrazole and imide products in modular procedures. The generality and tolerance of functionalities of this method have been demonstrated.
Efficient conversion of straw cellulose to chemicals or fuels is an attracting topic today for the utilization of biomass to substitute for fossil resources. The development of catalysts is of vital importance. In this work, a composite catalyst metal-organic frameworks (MOFs) immobilized on three-dimensional reduced graphene oxide (3D-rGO) were synthesized by in situ growth of the MIL-101(Cr) within the 3D-rGO matrix. The supporting of 3D-rGO guaranteed the dispersion and acid site density of MIL-101(Cr). The MIL-101(Cr)@3D-rGO nanocomposite possesses excellent catalytic activity, stability, recyclability and is an idea catalyst for the efficient degradation of straw cellulose into formic acid (FA), acetic acid (AA) and oxalic acid (OA). A maximum FA conversion rates of 95.36% was obtained by using MIL-101(Cr)@3D-rGO(1:1) as catalyst and hydrothermal reaction at mild conditions of 200 ℃ for 1h in alkaline aqueous medium. The MIL-101(Cr)@3D-rGO nanocomposite can be reused with high catalytic activity without any collapse of structure or leaching of chromium.
Targeting RIPK1 is a promising strategy for the treatment or alleviation of acute lung injury (ALI). SZM594, a benzothiazole compound previously developed by our research group, possessed good dual-targeting receptor-interacting protein kinase 1 (RIPK1) and RIPK3 activity and anti-necroptosis activity as well as acceptable in vivo efficacy. In this study, the cyclopropyl moiety of SZM594 was modified based on a structure-based design strategy. The resulting cyclohexanone-containing analogue 41 improved the selectivity toward RIPK1 over RIPK3 and the anti-necroptosis activity was also increased compared with those of SZM594. More importantly, compound 41 could inhibit the tumor necrosis factor-α (TNF-α) expression in lipopolysaccharide (LPS)-induced peritoneal macrophage cell model, and significantly alleviate LPS-induced ALI in a mouse model. This compound could significantly inhibit the expressions of the phosphorylation of RIPK1 and down-stream RIPK3 and mixed lineage kinase domain-like protein (MLKL). Thus, these cyclohexanone-containing benzothiazole analogues represent promising lead structures for the discovery of novel protective agents of ALI.
A facile fabrication strategy is reported to obtain N/O codoped porous carbon nanosheets for purpose of ameliorating the charge transfer and accumulation in the concentrated LiTFSI (lithium bis(trifluoromethane sulfonyl)imide) electrolyte. By tunning the feed ratio of comonomers, the porous nanosheet structure is endowed with a significant ion-adsorption surface area (1630 m2/g) and interconnected hierarchical porosity; meanwhile, high-level N/O dopants (N: 3.58 at%, O: 12.91 at%) increase the effective contact area for electrolyte ions, and further facilitate rapid ion/electron transfer. Benefiting from the advantageous features, carbon nanosheets electrode reveal an enhanced specific capacitance (375 F/g) in three-electrode configuration and the H2SO4-based device yields a high gravimetric energy density of 11.4 Wh/kg. Particularly, the ion-diffusion highways in porous carbon nanosheets contribute to the 2.25 V LiTFSI-based symmetric device with a high energy delivery up to 33.1 Wh/kg. This work offers an inspiring strategy for facile fabrication of carbon nanosheets, and demonstrates their promising application in "water-in-salt" electrolyte-based supercapacitor systems.
DNA-based logic gates promote the development of molecular computing and show enormous potential in the fields of nanotechnology and biotechnology. Dumbbell oligonucleotides (DNA) with poly-thymine (poly-T) loops and a nicked random double strand have been demonstrated to be an efficient template for the formation of fluorescent copper nanoclusters (CuNCs) in our previous work. Herein, a new platform technology is presented with which to construct molecular logic gates by employing CuNCs probe as a basic output generator, coupling of functional nucleases as the inputs. Two dumbbell DNAs are used with the difference in stem length (8 bp and 16 bp, respectively). The degradation of DNA templates can be tuned by various nucleic acid enzymes, single-stranded nuclease (S1), double-stranded specific nuclease (DSN), E. coli DNA ligase, exonucleases Ⅰ and Ⅲ. Briefly, S1 can digest both DNA templates, while the cleavage ability of DSN will be resistant by the short stem of SS-DNA (short-stem DNA). Exonuclease Ⅰ and Ⅲ can degrade these two nicked DNA templates, which are inhibited due to the ligation of E. coli DNA ligase. With this novel strategy, a set of logic gates is successfully constructed at the molecular level, including "YES", "PASS 0", "OR", "INHIBIT", which take the advantages of no label, easy operation, fast speed, high efficiency and low cost. Furthermore, S1 nuclease, as the biomarker of numerous carcinogens, is selectively detected in the range of 0.05–50 U/mL with the detection limit of 0.005 U/mL (1 × 10−6 U) based on this platform.
The compost-derived humic substances (HS) can function as electron mediators for promoting hematite bioreduction because of its redox capacity. Humification process can affect redox capacities of compost-derived HS by changing its intrinsic structure. However, the redox properties of compost-derived HS linking with hematite bioreduction during composting still remain unclear. Herein, we investigated the redox capacities of compost-derived HS, and assessed the responses of the redox capacities to the hematite bioreduction. The result showed that compost-derived HS (i.e., humic acids (HA) and fulvic acids (FA)) were able to accept electrons from Shewanella oneidensis MR-1, and the electron accepting capacity was increased during composting. Furthermore, it could be functioned as electron mediators for promoting the hematite bioreduction, achieving 1.19-2.15 times compared with the control experience. Not only the aromatic structures (quinone) but also the non-quinone structures such as nitrogen- and sulfur-containing functional moieties were served as the redox-active functional groups of compost-derived HS. Our work proved that the aromatic functional groups and the heteroatom structures (especially N) were important to the hematite bioreduction. This study highlights the redox-active properties of compost-derived HS and its impact on the microbial reduction of iron mineral. Redox capacity of compost-derived HS might mitigate the environmental risk of contaminants when the composting production was added into the contaminated soils as low-cost repair materials
We predicted two stable two-dimensional materials of carbon and bismuth elements, namely BiC and Bi2C monolayers. The stabilities of two monolayers were examined by cohesive energy, Born criteria, first-principle MD simulations and phonon spectra, respectively. By including the spin-orbit coupling effects, the BiC monolayer is a metal and the Bi2C monolayer possesses a narrow direct (indirect) band gap of 0.403 (0.126) eV under the HSE06 (GGA-PBE) functional. For the adsorption of CO2 molecules, the BiC and Bi2C monolayers have three stable adsorption sites C2, T3 and T4 with the adsorption energies as -0.57, -0.51 and -0.81 eV, and the activation ability on the adsorption as T4 > T3 > C2. These consequences make the BiC and Bi2C monolayers to be promising adsorbents to capture CO2 gas, the Bi2C monolayer to be well photovoltaics and optoelectronics material, and the BiC monolayer to be ideal battery and electronics materials, respectively.
Droplet-based microfluidic technology can be utilized as a microreactor to prepare novel functional monodisperse microcapsules. In this study, a droplet-based microfluidic chip with surface modification, which allowed the one-step preparation of double emulsion microcapsules. An O/W/O double emulsion using polyethylene (glycol) diacrylate (PEGDA) solution as the intermediate water phase was prepared by regulating the hydrophilicity and hydrophobicity of the chip surface, with PEGDA microcapsules prepared using UV polymerization. And then anti-tumor drug paclitaxel and neurotoxin 6-OHDA were encapsulated in microcapsules for drug and toxicology evaluation, respectively. Compared to controls, drug-loaded microcapsules caused a significant increase in the death rate of PC12 cells. This indicates that the obtained drug-loaded microcapsules could be used in drug evaluation and potentially in drug screening and delivery.
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