Latest ArticlesVolatile organic compound (VOC) pollution has a serious impact on human and urgently needs to be controlled through the development of new methods and catalytic materials. Compared with traditional thermal catalytic oxidation, the synergistic photothermocatalysis is regarded as a green and environmentally friendly strategy for organic compound pollutant removal, which can promote spontaneous heating of the surface of catalysts to achieve thermal catalytic reaction conditions via harvesting light irradiation. In this paper, a monolithic photothermocatalyst was synthesized through coating graphene oxide (GO) and MnOx in turn on a commercially available melamine sponge, where the GO mainly acted as a photothermal conversion layer to heat the catalytically active MnOx. This monolithic catalyst presented excellent photo-induced activity for formaldehyde elimination under ambient conditions (~90% degradation ratio in 20 min for ~160 ppm initial concentration formaldehyde), and meanwhile possessed a high catalytic durability for multiple cycles. The kinetic study demonstrated that this photothermocatalytic process followed a pseudo-second-order kinetics. Finally, we proposed a possible formaldehyde degradation pathway based on in situ DRIFTS examination.
Three imidazole-modified Ag-polyoxovanadates frameworks (APFs) with a controllable molar ratio of Ag+ to polyoxovanadates (POVs) [Ag(IM)2]2V4O12·2Ag(IM)2 (APF-1), [Ag2(1-eIM)4]2[Ag(1-eIM)2]3·2Ag(1-eIM)2·3(1-HeIM)[V10O28]2 (APF-2) and [Ag(1-pIM)2]3[HV10O28]·2Ag(1-pIM)2·2H2O (APF-3) (IM = imidazole; 1-eIM = 1-ethylimidazole and 1-pIM = 1-propylimidazole) have been successfully achieved by self-assembly of POVs, Ag+ cations, and three different imidazole derivatives. Interestingly, the molar ratios of Ag+ to POVs vary from 4:1, 4.5:1 to 5:1 by changing the vanadium resources and imidazole derivatives. Notably, the coordination environment of Ag+ cations and the structure of POVs in the APFs are also different. Specifically, for APF-1, the four Ag atoms adopt three-coordinated and four-coordinated geometries, respectively, and Ag-imidazole complexes and [V4O12]4− cluster form the one-dimensional polymeric chains. While Ag atoms in APF-2 and APF-3 exhibit two-, four- and five-coordinated geometries for APF-2, four-, five- and six-coordinated geometries for APF-3, respectively. These Ag+ cations and decavanadate clusters are assembled into the 2D supramolecular structure through the Ag-O bonds and Ag…Ag argentophilic interaction. Remarkably, thus-obtained APF-2 can serve as powerful efficient heterogeneous catalyst for construction of CN bond and detoxification of simulant sulfur mustard (yields up to 99%), which enable successful recycling for three cycles with remained catalytic activities and structure stability.
A class of silica anchored Schiff base decorated polyamidoamine (PAMAM) dendrimers were synthesized for removing aqueous Cu(Ⅱ) and Ag(Ⅰ). The adsorption performance was investigated synthetically and the adsorption mechanism was revealed. Results indicate the adsorption capacity depends on dendrimer generation, solution pH, contact time, temperature and initial metal ion concentration. The optimum adsorption pH is 6 for both metal ion. Adsorption kinetic suggests the adsorption can achieve equilibrium at 180 and 150 min for Cu(Ⅱ) and Ag(Ⅰ). The kinetic process is found to be in good agreement with pseudo-second-order model and film diffusion is the rate-controlling step. The adsorption isotherm indicates the adsorption is proceeded by monolayer behavior with chemical mechanism. These adsorbents exhibit competitive adsorption capacity as compared with other reported adsorbents. Theoretical calculation demonstrates the participation of hydroxyl, carbonyl, and amide groups during the adsorption of Cu(Ⅱ), while hydroxyl and amide groups are mainly responsible for capturing Ag(Ⅰ).
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.
Oxygen ligation is envisioned to provide a stable and distinctive coordination environment to the strongly oxophilic rare-earth metals. However, the well-defined dialkyl complexes bearing oxyanion ancillary ligand had been rarely addressed for the instability of the complexes and the shortage of easily available ligands. Herein, we report the synthesis of phosphate ligated dialkyl yttrium complexes (PYR2) featuring a high stability and a tunable ligand. Treated with the borate reagent, the phosphate yttrium complex displays high activity and selectivity in the catalytic cis-1, 4-polymerization of isoprene (up to 96.5%). Furthermore, using AlMe3 as an additive, the stereoselectivity switches to trans-1, 4-polymerization (up to 92.0%).
Lung cancer is the most common malignancy in the world, with a high mortality rate. Nevertheless, therapies to act effectively against lung cancer remain elusive. So far, chemotherapy is still the frontline treatment of lung cancer. Doxorubicin (DOX) is a broad-spectrum anti-tumor drug. However, DOX often has serious side effects and causes multi-drug resistance, which greatly limits its clinical application. In this work, biodegradable methoxy poly(ethylene glycol)-poly(lactic acid) (MPEG-PLA) and cyclo(Arg-Gly-Asp-d-Phe-Lys) (cRGD) polypeptide modified PEG-PLA (cRGD-PEG-PLA) copolymers were used for the co-delivery of curcumin (CUR) and DOX (CUR-DOX/cRGD-M). The particle size of the self-assembled drug-loaded nanomicelle approximately was 27.4 nm and the zeta potential was −2.7 mV. Interestingly, CUR can enhance the uptake of DOX by Lewis lung carcinoma (LL/2) cells. The experimental results in vivo and in vitro showed that CUR-DOX/cRGD-M combination therapy could promote apoptosis of lung cancer cells, and conspicuously inhibit the tumor growth. Our data indicate that CUR-DOX/cRGD-M will be biodegradable and sustainable, which may have potential clinical application value in the treatment of lung cancer.
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
Lewis base-catalyzed annulations of allenoates have been one of the most powerful synthetic strategies for the synthesis of various valuable cycles, especially in the preparation of biologically active natural products and pharmaceuticals. Generally, the effective Lewis bases mainly include tertiary phosphine, NHC and tertiary amine catalysts, among those catalysis, tertiary amine Lewis bases have proven to be effective catalysts for a range of synthetic transformations. In the past decades, tremendous progress involving tertiary amines-promoted cycloaddition of allenoates has been made in the chemoselective construction of valuable motifs. This review describes a comprehensive and updated summary of tertiary amine Lewis base-promoted annulation reactions of allenoates. Diverse reactivities, chemoselectivties and detailed reaction mechanisms will be highlighted in this review.
Covalent organic frameworks (COFs), as a novel class of functional polymers, exhibit versatile applications due to their crystalline porous structures and conjugated skeletons. However, synthesis of COFs with high crystallinity still faces great challenges, especially for scale-up preparation. Herein we report a two-step solvothermal process to improve crystallinity of COFs. The first step focuses on polycondensation of monomers with no need for optimizing crystallization conditions. In the second step, appropriate solvothermal conditions are used to facilitate crystallization of the COFs through defects correction and structural repairing. Furthermore, this strategy could also be applicable to scale-up synthesis of high quality COFs, which lays a foundation for their practical applications.
Aggregation-induced emission enhancement and aggregation-induced chirality inversion are two individual phenomena for the enantiomerically pure organic dyes in the aggregates. Herein we reported for the first time that these two interesting phenomena could be observed simultaneously in the aggregated states of enantiomerically pure S/R-1, 1′-binaphthol annulated perylene diimides, in which two perylene diimides moieties were bridged by S/R-1, 1′-binaphthol (BINOL) at the bay positions. Owing to the rotatable C2 axes between two naphthol annulated perylene diimides moieties, both of them display intrinsic behaviors of aggregation-induced emission enhancements. At the same time, due to the steric hindrances in the imide and methoxy positions, the neighboring two π-systems of these two unique polycyclic aromatic imides in poor solvents are preferable to adopt a cross-stacking mode and thus form helical X-aggregates of opposite chirality (M/P) with chirality inversion characteristics in their circular dichroism and circularly polarized luminescence spectroscopic studies.
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