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991.
Three solvent‐dependent chiral copper(II) compounds, {[Cu2(bzgluO)2(H2O)2]·4H2O}n ( 1 ), {[Cu2(bzgluO)2(DMSO)2]·H2O}n ( 2 ) and [Cu2(bzgluO)2(DMF)2]n ( 3 ) (H2bzgluO=N‐benzoyl‐L‐glutamic acid) have been synthesized under ambient temperature conditions and characterized by elemental analysis, IR spectra, UV spectra, thermogravimetric analysis, powder X‐ray diffraction (PXRD) and single‐crystal X‐ray diffraction. Compounds 1 and 2 both crystallize in the orthorhombic space group P212121. Compound 3 crystallizes in the tetragonal space group P43. Compound 1 exhibits a ladder‐like 1D chain structure, which is extended by hydrogen‐bonding interactions to form a 3D supramolecular network. Compounds 2 and 3 both give a diamond‐like 3D structure. Besides, there are hydrogen‐bonding interactions in 2 . The structural difference indicates that the solvent system plays a crucial role in modulating structures of coordination compounds. Circular dichroism (CD) and the magnetic properties of the compounds have also been investigated. 相似文献
992.
Highly Contorted 1,2,5‐Thiadiazole‐Fused Aromatics for Solution‐Processed Field‐Effect Transistors: Synthesis and Properties 下载免费PDF全文
Xin Shi Shuli Liu Chunming Liu Yueming Hu Saihua Shi Dr. Nina Fu Dr. Baomin Zhao Prof. Dr. Zhaohui Wang Prof. Dr. Wei Huang 《化学:亚洲杂志》2016,11(15):2188-2200
A straightforward strategy has been used to construct 1,2,5‐thiadiazole‐fused 12‐ring π systems through twofold Stille coupling and subsequent cyclodehydrogenation by utilizing the building blocks of naphthodithiophene and 5,6‐substituted benzo[b]‐2,1,3‐thiadidazole. Molecules 1 a and 1 b , which exhibit highly contorted π surfaces, show a butterfly‐shaped conformation according to DFT calculations. Within the molecules, a plane‐to‐plane angle of 44.8° was found. UV/Vis absorption, thermogravimetric analysis, differential scanning calorimetry, and cyclic voltammetry (CV) were used to study their physical properties. Strong intermolecular interactions of the nonplanar molecules were also observed by concentration‐dependent 1H NMR spectroscopy measurements and thin‐film XRD characterization. The low‐lying LUMO and high‐lying HOMO levels of the molecules are ?3.73 and ?5.48 eV, respectively, as estimated from CV measurements; this indicates their potential as semiconducting materials for solution‐processed organic field‐effect transistors (OFETS). A field‐effect hole mobility of up to 0.035 cm2 V?1 s?1, a threshold voltage of 6.98 V, and a current on/off ratio of 8.65×105 in air for 1 a have been demonstrated with the top‐contact bottom‐gate field‐effect transistor device structures; this represents an important step toward the solution‐processed OFET application of contorted aromatics. 相似文献
993.
A Surfactant‐Encapsulating Polyoxometalate Nanowire Assembly as a New Carrier for Nanoscale Noble‐Metal Catalysts 下载免费PDF全文
Dr. Wen‐Zhe Zhou Dr. Xiao‐Jia Feng Dr. Hua‐Qiao Tan Dr. Hong‐Fei Shi Dr. Yong‐Hui Wang Shan Gao Prof. Yang‐Guang Li 《化学:亚洲杂志》2016,11(21):3107-3112
The loading of noble‐metal nanoparticles (NMNPs) onto various carriers to obtain stable and highly efficient catalysts is currently an important strategy in the development of noble metal (NM)‐based catalytic reactions and their applications. We herein report a nanowire supramolecular assembly constructed from the surfactant‐encapsulating polyoxometalates (SEPs) CTAB‐PW12, which can act as new carriers for NMNPs. In this case, the Ag NPs are loaded onto the SEP nanowire assembly with a narrow size distribution from 5 to 20 nm in diameter; the average size is approximately 10 nm. The Ag NPs on the nanowire assemblies are well stabilized and the over agglomeration of Ag NPs is avoided owing to the existence of well‐arranged polyoxometalate (POM) units in the SEP assembly and the hydrophobic surfactant on the surface of the nanowire assembly. Furthermore, the loading amount of the Ag NPs can be adjusted by controlling the concentration of the AgNO3 aqueous solution. The resultant Ag/CTAB‐PW12 composite materials exhibit high activity and good stability for the catalytic reduction of 4‐nitrophenol (4‐NP) with NaBH4 in isopropanol/H2O solution. The NMNPs‐loaded SEP nanoassembly may represent a new composite catalyst system for application in NM‐based catalysis. 相似文献
994.
N,P‐Codoped Carbon Networks as Efficient Metal‐free Bifunctional Catalysts for Oxygen Reduction and Hydrogen Evolution Reactions 下载免费PDF全文
Dr. Jintao Zhang Prof. Liangti Qu Prof. Gaoquan Shi Jiangyong Liu Prof. Jianfeng Chen Prof. Liming Dai 《Angewandte Chemie (International ed. in English)》2016,55(6):2230-2234
The high cost and scarcity of noble metal catalysts, such as Pt, have hindered the hydrogen production from electrochemical water splitting, the oxygen reduction in fuel cells and batteries. Herein, we developed a simple template‐free approach to three‐dimensional porous carbon networks codoped with nitrogen and phosphorus by pyrolysis of a supermolecular aggregate of self‐assembled melamine, phytic acid, and graphene oxide (MPSA/GO). The pyrolyzed MPSA/GO acted as the first metal‐free bifunctional catalyst with high activities for both oxygen reduction and hydrogen evolution. Zn–air batteries with the pyrolyzed MPSA/GO air electrode showed a high peak power density (310 W g?1) and an excellent durability. Thus, the pyrolyzed MPSA/GO is a promising bifunctional catalyst for renewable energy technologies, particularly regenerative fuel cells. 相似文献
995.
Transfer of Two‐Dimensional Oligonucleotide Patterns onto Stereocontrolled Plasmonic Nanostructures through DNA‐Origami‐Based Nanoimprinting Lithography 下载免费PDF全文
Yinan Zhang Prof. Jie Chao Prof. Huajie Liu Fei Wang Prof. Shao Su Bing Liu Prof. Lan Zhang Dr. Jiye Shi Prof. Lihua Wang Prof. Wei Huang Prof. Lianhui Wang Prof. Chunhai Fan 《Angewandte Chemie (International ed. in English)》2016,55(28):8036-8040
The precise functionalization of self‐assembled nanostructures with spatial and stereocontrol is a major objective of nanotechnology and holds great promise for many applications. Herein, the nanoscale addressability of DNA origami was exploited to develop a precise copy‐machine‐like platform that can transfer two‐dimensional oligonucleotide patterns onto the surface of gold nanoparticles (AuNPs) through a deliberately designed toehold‐initiated DNA displacement reaction. This strategy of DNA‐origami‐based nanoimprinting lithography (DONIL) demonstrates high precision in controlling the valence and valence angles of AuNPs. These DNA‐decorated AuNPs act as precursors in the construction of discrete AuNP clusters with desired chirality. 相似文献
996.
Size Fractionation of Two‐Dimensional Sub‐Nanometer Thin Manganese Dioxide Crystals towards Superior Urea Electrocatalytic Conversion 下载免费PDF全文
Dr. Sheng Chen Dr. Jingjing Duan Anthony Vasileff Prof. Shi Zhang Qiao 《Angewandte Chemie (International ed. in English)》2016,55(11):3804-3808
A universal technique has been proposed to sort two‐dimensional (2D) sub‐nanometer thin crystals (manganese dioxide MnO2 and molybdenum disulfide MoS2) according to their lateral dimensions. This technique is based on tuning the zeta potential of their aqueous dispersions which induces the selective sedimentation of large‐sized 2D crystals and leaves the small‐sized counterparts in suspension. The electrocatalytic properties of as‐obtained 2D ultrathin crystals are strongly dependent on their lateral size. As a proof‐of‐concept study, the small‐sized MnO2 nanocrystals were tested as the electrocatalysts for the urea‐oxidation reaction (UOR), which showed outstanding performance in both half reaction and full electrolytic cell. A mechanism study reveals the enhanced performance is associated with the remarkable structural properties of MnO2 including ultrathin (ca. 0.95 nm), laterally small‐sized (50–200 nm), and highly exposed active centers. 相似文献
997.
Nickel‐Catalyzed Decarbonylative Borylation of Amides: Evidence for Acyl C−N Bond Activation 下载免费PDF全文
Jiefeng Hu Dr. Yue Zhao Jingjing Liu Yemin Zhang Prof. Dr. Zhuangzhi Shi 《Angewandte Chemie (International ed. in English)》2016,55(30):8718-8722
A nickel/N‐heterocyclic carbene catalytic system has been established for decarbonylative borylation of amides with B2nep2 by C?N bond activation. This transformation shows good functional‐group compatibility and can serve as a powerful synthetic tool for late‐stage borylation of amide groups in complex compounds. More importantly, as a key intermediate, the structure of an acyl nickel complex was first confirmed by X‐ray analysis. Furthermore, the decarbonylative process was also observed. These findings confirm the key mechanistic features of the acyl C?N bond activation process. 相似文献
998.
Extraction and isolation of lithospermic acid B from Salvia miltiorrhiza Bunge using aqueous two‐phase extraction followed by high‐performance liquid chromatography 下载免费PDF全文
Yong Xue Guo Chang Zhi Shi Lei Zhang Lin Lv Yue Yong Zhang 《Journal of separation science》2016,39(18):3624-3630
A rapid and effective method integrating separation and purification of lithospermic acid B from Salvia miltiorrhiza Bunge was developed by combining an aqueous two‐phase system extraction with preparative chromatography. An aqueous two‐phase system of n‐butyl alcohol/KH2PO4 was chosen from seven systems. The influence of parameters including concentration of KH2PO4, n‐butyl alcohol concentration, pH, and the ratio of an aqueous two‐phase system to crude extract were investigated using a single factor design. Response surface methodology was subsequently used to find the optimal compositions of an aqueous two‐phase system. Keeping a solvent‐to‐solid ratio of 10, the final optimized composition of an aqueous two‐phase system was 39.1% w/w n‐butyl alcohol and 22.6% w/w KH2PO4. Under these conditions a recovery yield of 99.8% and a high partition coefficient of 310.4 were obtained. In a pilot‐scale experiment using optimized conditions, 18.79 g of lithospermic acid B with a purity of 70.5% and in a yield of 99.8% was separated from 0.5 kg of crude extract. Subsequently, 9.94 g lithospermic acid B with a purity of 99.3% and recovery yield of 70.3% was obtained with a preparative chromatographic process, and the two‐step total recovery was 70.1%. 相似文献
999.
Determination and removal of sulfonamides and quinolones from environmental water samples using magnetic adsorbents 下载免费PDF全文
Hao Wu Yating Shi Xiaozhen Guo Shuangli Zhao Juanli Du Hongping Jia Lina He Liming Du 《Journal of separation science》2016,39(22):4398-4407
In this study, the magnetic materials known as polymerized ionic liquid@3‐(trimethoxysilyl)propyl methacrylate@Fe3O4 nanoparticles were synthesized and utilized as potential adsorbents. First, these nanoparticles were applied to the analysis of sulfonamides and quinolones present in different water samples using magnetic solid phase extraction and high‐performance liquid chromatography. Under optimized conditions, the developed method showed excellent detection sensitivity, with limits of detection (S/N = 3) and quantification limits (S/N = 10) within 0.2–1.0 and 0.8–3.4 μg/L, respectively. The spiked recoveries of the SAs and QNs in environmental water samples ranged from 83.5 to 103.0%, with RSDs of less than 4.5%. In addition, the adsorbents effectively removed sulfamethoxazole and ofloxacin present in existing aquatic environments. The adsorption kinetics and isotherms of sulfamethoxazole and ofloxacin on the magnetic adsorbents were studied to assess removal performance. The results indicate that the adsorption process follows a pseudo‐second‐order mechanism, which reveals that the sorption mechanism is the rate‐limiting step and produces high qmax values (sulfamethoxazole = 70.35 mg/g and ofloxacin = 48.95 mg/g), thus demonstrating the enormous adsorption capacity of these magnetic adsorbents. 相似文献
1000.
Antibacterial poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) fibrous membranes containing quaternary ammonium salts 下载免费PDF全文
Xiaoyan Fan Maoli Yin Zhiming Jiang Nengyu Pan Xuehong Ren Tung‐Shi Huang 《先进技术聚合物》2016,27(12):1617-1624
In this study, antimicrobial membranes based on biodegradable material poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) [P(3HB‐4HB)] and quaternary ammonium salts (QASs) by two methods have been performed. Three QASs with varied alkyl chain lengths have been synthesized successfully and characterized by 1H nuclear magnetic resonance and Fourier transform infrared. The synthesized QASs were blended with P(3HB‐4HB) and electrospun into composite fibrous membranes or casted into conventional membranes. Electrospun fibrous membranes with large surface areas are a superior type of antimicrobial biomaterials, and they exhibit preferable properties than solution casting membranes. Specifically, electrospun fibrous membranes are tougher and can inactivate both Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli O157:H7 in a contact time of 30 min, whereas the solution casting membranes cannot. The length of alkyl chain in the quaternary ammonium groups on the modified P(3HB‐4HB) membranes is able to influence the antimicrobial activity. This type of antimicrobial material may have potential applications in biomaterial field. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献