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31.
Zhaoqi Ye Dr. Yang Zhao Dr. Hongbin Zhang Prof. Yahong Zhang Prof. Yi Tang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6147-6157
For zeolite catalysts, the regulation of active site and pore structure plays an important role in the enhancement of their catalytic performance. In this work, a one-pot and organic template-free co-regulation route is proposed to straightforwardly synthesize basic mesoporous ZSM-5 zeolites with adjustable alkaline-earth metal species. The synthesis pathway combines two decisive strategies: 1) the seed-induced interface assembly growth method and 2) the acidic co-hydrolysis/condensation of aluminosilicate species and alkaline-earth metal (e.g., Mg, Ca, Sr, or Ba) sources. It is interesting that the mesoporous structure was self-evolved through particle-attached seed-interfacial crystallization without the assistance of any template. Meanwhile, the incorporation of alkaline-earth metals species is homogeneous and highly dispersed in the solid products during the whole crystallization process, and finally generate the superior basicity. Catalysis tests of the as-synthesized samples displayed their novel performance in the typical base reaction of Knoevenagel condensation, even for bulky substrates owing to the enhanced diffusion arising from the meso/microporous network. This finding opens new possibilities for facile, cost-effective, and environmentally friendly synthesis of mesoporous high-silica zeolites with tunable acid/base properties, and deepens our understanding of the particle-attached crystallization. 相似文献
32.
33.
Lei Wang Kenan Zhang Yuzhuo Wang Wenbo Li Mingjie Chen Prof. Dr. Junliang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(11):4451-4457
Reported here is a highly efficient Pd/Xiang-Phos catalyzed enantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines in good yields with up to 97 % ee. The sterically bulky and electron-rich (S,Rs)- NMe-X2 ligand is responsible for the excellent reactivities and enantioselectivities. The salient features of this transformation include mild reaction conditions, general substrate scope, good functional-group tolerance, good yields, high enantioselectivities, easy scale-up, and application in the late-stage modification of bioactive compounds. The obtained products can be readily transformed into useful chiral 1,3-aminoalcohols. 相似文献
34.
Weiquan Xu Jin-Yu Chao Dr. Bohan Tang Prof. Zhan-Ting Li Prof. Jiang-Fei Xu Prof. Xi Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(63):e202202200
A supramolecular organic framework-type photocatalyst, named TM-SOF, is constructed by the self-assembly of cucurbit[8]uril and a tetra-arm monomer containing four N, N’-dimethyl 2,5-bis(4-pyridinium)thiazolo[5,4-d]thiazole (MPT) moieties. Benefiting from the multivalent assembly, a photocatalytically active supramolecular MPT dimer can be stably formed in TM-SOF. In addition, TM-SOF exhibits better stability against temperature, substrate, and light irradiation. As a result, TM-SOF shows a significantly improved performance for the photocatalytic aerobic oxidation of aryl boronic acids and thioethers. It is anticipated that this line of research will provide a facile approach for fabricating high-performance supramolecular photocatalysis systems. 相似文献
35.
Fuying Zhang Ming Xu Xianlong Su Wei Yuan Prof. Wei Feng Prof. Qianqian Su Prof. Fuyou Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(2):e202103795
Transcatheter arterial embolization (TAE) is wildly used in clinical treatments. However, the online monitoring of the thrombosis formation is limited due to the challenges of the direct visualization of embolic agents and the real-time monitoring of dynamic blood flow. Thus, we developed a photochemical afterglow implant with strong afterglow intensity and a long lifetime for embolization and imaging. The liquid pre-implant injected into the abdominal aorta of mice was rapidly transformed into a hydrogel in situ to embolize the blood vessel. The vascular embolism position can be observed by the enhanced afterglow of the fixed implant, and the long lifetime of afterglow can also be used to monitor the effect of embolization. This provides an excellent candidate in bio-imaging to avoid the autofluorescence interference from continuous light excitation. The study suggests the potential usefulness of the implant as an embolic agent in TAE and artery imaging during a surgical procedure. 相似文献
36.
Dr. Shang-Bo Yu Dr. Furong Lin Prof. Jia Tian Dr. Yi Liu Prof. Dan-Wei Zhang Prof. Zhan-Ting Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(36):e202200914
Selective preparation of two-dimensional polymers (2DPs) and supramolecular polymers (2DSPs) with defined thickness is crucially important for controlling and maximizing their functions, yet it has remained as a synthetic challenge. In the past decade, several approaches have been developed to allow selective preparation of discrete monolayer 2DPs and 2DSPs. Recently, crystal exfoliation and self-assembly strategies have been employed to successfully prepare bilayer 2DP and 2DSP, which represent the first step towards the controlled “growth” of 2D polymers from the thinnest monolayers to thicker few-layers along the third dimension. This Concept review discusses the concept of accurate synthesis of 2D polymers with defined layers. Advances in this research area will pave the way to rational synthetic strategies for 2D polymers with controlled thickness. 相似文献
37.
In our previous two works, we studied the blow-up and lifespan estimates for damped wave equations with a power nonlinearity of the solution or its derivative, with scattering damping independently. In this work, we are devoted to establishing a similar result for a combined nonlinearity. Comparing to the result of wave equation without damping, one can say that the scattering damping has no influence. 相似文献
38.
The trench on a printed circuit board was reconstructed to fabricate a microfluidic framework that allows low-cost production for small quantities and integration with multifunctional elements. An on-chip electrolyte regulator was thus proposed on this platform to analyze diffusion properties in laminar flow. A numerical model was developed, highlighting the interplay between the electrolyte migration and hydrodynamic properties. Solutions with dissolved sodium chloride were simulated and experimentally tested for the regulation of electrical conductivity under the guidance of the normalized Nernst-Planck equation. The diffusion mechanism and the resulting concentration field were demonstrated in detail. This approach provides a satisfactory manufacturing method and a useful tool for integrated microfluidic systems. 相似文献
39.
Bei-Bei Guo Dr. Yue-Jian Lin Prof. Guo-Xin Jin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(41):9721-9727
Four flexible ligands with different lengths, degrees of flexibility, and steric bulk were synthesized and used to prepare metal-directed assemblies. Interestingly, minor differences among the ligands led to products with dramatically different topologies: a binuclear D -shaped macrocycle, tetranuclear rectangles, and hexanuclear trefoil knots. The interconversion of the trefoil-shaped complexes was also investigated. This contribution introduces a rare ligand-controlled trefoil–rectangle shape transformation in solution. 相似文献
40.
《Tetrahedron》2019,75(33):4556-4560
Morpholino-containing aza-BODIPYs at 3,5-positions were synthesized. The maxima absorption and emission of these dyes locate at the near-infrared region. Aza-BODIPY 1 with the morpholino group as a pH-sensitive functionality could be used to be a pH probe, and the dramatic increase in fluorescence intensity at 675 nm by about 1500 folds. Moreover, the singlet oxygen generation of PS 2 with the dibromo groups at 2,6-positions was more effective than that of the parent dye 1. 相似文献