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941.
Phosphorus tailings and fly ash both are solid wastes and do harm to the environment. Here, they were added into thermoplastic polyurethane (TPU) matrices together with intumescent flame retardants (IFR), and the synergistic effects between IFR and phosphorus tailings or fly ash for improving the flame retardancy of TPU were investigated. The cone calorimeter test (CCT) results indicated that adding phosphorus tailings or fly ash substitute for part of IFR could obtain a better flame retardant effect. The peak heart release rate (PHRR) of TPU/25 wt% IFR composites exhibited a reduction of 77% than that of neat TPU, and the total smoke production presented a reduction of 16%. However, the PHRR value and total smoke production of the sample TPU/20 wt% IFR/5 wt% phosphorus tailings were reduced by 91% and 57%, respectively, compared to that of neat TPU. The dense char promoted by the presence of IFR and phosphorus tailings or fly ash delayed the diffusion of volatile pyrolysis products and transmission of heat and oxygen to the underlying material. Therefore, a certain amount of phosphorus tailings or fly ash can be used as synergistic agents with IFR to enhance the fire safety of TPU materials. From another aspect, it also provides a promising way for recycling use of phosphorus tailings and fly ash. 相似文献
942.
Yu‐Jin Kong Zhi‐Ping Yan Si Li Hui‐Fang Su Kai Li You‐Xuan Zheng Shuang‐Quan Zang 《Angewandte Chemie (International ed. in English)》2020,59(13):5336-5340
A pair of propeller‐like chiral trinuclear CuI clusters ( R/S‐Cu3 ) with unique photoinduced fluorescence enhancement were prepared. R/S‐Cu3 showed intense variable luminescence after UV light irradiation, which was attributed to the stepwise oxidation of ligand in the clusters. It exhibited typical aggregation‐induced emission (AIE) (αAIE=17.3). Mechanism studies showed that metal cluster‐centered (MCC) and triplet metal‐to‐ligand charge‐transfer (3MLCT) processes are the origin of the luminescence; the processes are regulated by a restriction of intramolecular motions mechanism in a different state. The chiral structure and AIE feature endow R/S‐Cu3 with remarkable circularly polarized luminescence (glum=2×10?2) in the aggregated state. It shows good capability for producing reactive oxygen species. This work enriches the kinds of atomically precise AIE clusters, gains insight into their luminescence mechanism, and offers the prospect of application in multifunctional materials. 相似文献
943.
The Mechanism of the Magnetodielectric Response in a Molecule‐Based Trinuclear Iron Cluster Material
Dong Li Xuan Wang Hai‐Xia Zhao Yan‐Ping Ren Gui‐Lin Zhuang La‐Sheng Long Lan‐Sun Zheng 《Angewandte Chemie (International ed. in English)》2020,59(34):14409-14413
Magnetodielectric response mechanisms are critical for the rational design and synthesis of molecule‐based magnetodielectric materials. Herein, the magnetodielectric response was investigated in the molecule‐based material [Fe3O(CH3COO)6(py)3](py) ( 1 ). Its magnetodielectric coefficient (MD) is ?2.8 % for phase transition III and ?4.1 % for phase transition I. Study of the mechanism of the magnetodielectric response in 1 reveals that its magnetodielectric response at phase transition I is induced by the charge‐frustration of the trinuclear iron cluster, while that at phase transition III is attributed to the spin‐frustration of the trinuclear iron cluster, providing a new route for the design of magnetodielectric materials. 相似文献
944.
Nguyen Tien Cong Huynh Thi Xuan Trang Pham Duc Dung Tran Hoang Phuong Vu Quoc Trung Nguyen Dang Dat Dang Thi Tuyet Anh Nguyen Van Tuyen Luc Van Meervelt 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(9):874-882
Five 2‐aroyl‐5‐bromobenzo[b]furan‐3‐ol compounds (two of which are new) and four new 2‐aroyl‐5‐iodobenzo[b]furan‐3‐ol compounds were synthesized starting from salicylic acid. The compounds were characterized by mass spectrometry and 1H NMR and 13C NMR spectroscopy. Single‐crystal X‐ray diffraction studies of four compounds, namely, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐fluorophenyl)methanone, C15H8BrFO3, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐chlorophenyl)methanone, C15H8BrClO3, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐bromophenyl)methanone, C15H8Br2O3, and (4‐bromophenyl)(3‐hydroxy‐5‐iodobenzofuran‐2‐yl)methanone, C15H8BrIO3, were also carried out. The compounds were tested for their in vitro cytotoxicity on the four human cancer cell lines KB, Hep‐G2, Lu‐1 and MCF7. Six compounds show good inhibiting abilities on Hep‐G2 cells, with IC50 values of 1.39–8.03 µM. 相似文献
945.
AbstractTwo new β-carboline alkaloids, aspergillspins A-B (1–2), three new quinolone alkaloids, aspergillspins C-E (3–5), and two new isocoumarins, aspergillspins F-G (6–7), together with four known alkaloids were isolated from the marine gorgonian-derived fungus Aspergillus sp. SCSIO 41501. Their structures were identified by spectroscopic analysis, and the absolute configurations of several chiral carbons in 2 and 3 were further established by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. Their cytotoxic and antibacterial activities were also evaluated. 相似文献
946.
Xuan Mu Yu Wang Chengchen Guo Yamin Li Shengjie Ling Wenwen Huang Peggy Cebe Huan‐Hsuan Hsu Fabio De Ferrari Xiaocheng Jiang Qiaobing Xu Alessandra Balduini Fiorenzo G. Omenetto David L. Kaplan 《Macromolecular bioscience》2020,20(1)
Hierarchical molecular assembly is a fundamental strategy for manufacturing protein structures in nature. However, to translate this natural strategy into advanced digital manufacturing like three‐dimensional (3D) printing remains a technical challenge. This work presents a 3D printing technique with silk fibroin to address this challenge, by rationally designing an aqueous salt bath capable of directing the hierarchical assembly of the protein molecules. This technique, conducted under aqueous and ambient conditions, results in 3D proteinaceous architectures characterized by intrinsic biocompatibility/biodegradability and robust mechanical features. The versatility of this method is shown in a diversity of 3D shapes and a range of functional components integrated into the 3D prints. The manufacturing capability is exemplified by the single‐step construction of perfusable microfluidic chips which eliminates the use of supporting or sacrificial materials. The 3D shaping capability of the protein material can benefit a multitude of biomedical devices, from drug delivery to surgical implants to tissue scaffolds. This work also provides insights into the recapitulation of solvent‐directed hierarchical molecular assembly for artificial manufacturing. 相似文献
947.
948.
Catalytic Asymmetric Synthesis of [2,3]‐Fused Indoline Heterocycles through Inverse‐Electron‐Demand Aza‐Diels–Alder Reaction of Indoles with Azoalkenes 下载免费PDF全文
Min‐Chao Tong Xuan Chen Jun Li Rong Huang Haiyan Tao Prof. Dr. Chun‐Jiang Wang 《Angewandte Chemie (International ed. in English)》2014,53(18):4680-4684
An unprecedented catalytic asymmetric inverse‐electron‐demand aza‐Diels–Alder reaction of indoles with in situ formed azoalkenes is reported. A diverse set of [2,3]‐fused indoline heterocycles were achieved in generally good yields (up to 97 %) with high regioselectivity and diastereoselectivity (>20:1 d.r.), and with excellent enantioselectivity (up to 99 % ee). 相似文献
949.
Wen Ai Xueyan Yang Yunxiang Wu Xuan Wang Prof. Yuanchao Li Dr. Yaxi Yang Dr. Bing Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17653-17657
A RhIII‐catalyzed procedure for the C7‐selective C?H alkylation of various indolines with α‐diazo compounds at room temperature is reported. The advantages of this process are: 1) simple, mild, and pH‐neutral reaction conditions, 2) broad substrate scope, 3) complete regioselectivity, 4) no need for an external oxidant, and 5) N2 as the sole byproduct. Furthermore, alkylation and bis‐alkylation of carbazoles at the C1 and C8 positions have also been developed. More significantly, for the first time, a successful IrIII‐catalyzed intermolecular insertion of arene C?H bonds into α‐diazo compounds is reported. 相似文献
950.
The Relationship between DNA Sequences and Oligonucleotide‐Templated Silver Nanoclusters and Their Fluorescence Properties 下载免费PDF全文
Ye Teng Xuan Yang Lei Han Prof. Erkang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):1111-1115
A novel approach was developed to study the relationship between DNA sequences and DNA‐templated silver nanoclusters (DNA‐Ag NCs) in detail by using an ordinary DNA strand as an example. Three kinds of Ag NCs are formed by using the DNA strand as a scaffold. By dividing the DNA template into several parts according to their different affinities to Ag+, it was found that the fluorescence properties of DNA‐Ag NCs are related to not only the sequences but also to the position of different parts in the template, which provides a more efficient approach to obtain DNA‐Ag NCs with required photoluminescence properties and may ultimately contribute to the targeted synthesis of DNA‐Ag NCs. 相似文献