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91.
Marcin Bielawski Joel Malmgren Leticia M Pardo Ylva Wikmark Berit Olofsson 《ChemistryOpen》2014,3(1):19-22
An efficient one-pot synthesis of N-heteroaryl iodonium triflates from the corresponding N-heteroaryl iodide and arene has been developed. The reaction conditions resemble our previous one-pot syntheses, with suitable modifications to allow N-heteroaryl groups. The reaction time is only 30 min, and no anion exchange is required. The obtained iodonium salts were isolated in a protonated form, these salts can either be employed directly in applications or be deprotonated prior to use. The aryl groups were chosen to induce chemoselective transfer of the heteroaryl moiety to various nucleophiles. The reactivity and chemoselectivity of these iodonium salts were demonstrated by selectively introducing a pyridyl moiety onto both oxygen and carbon nucleophiles in good yields. 相似文献
92.
设计了“铁盐和亚铁盐”的单元教学,以“探究硫酸亚铁的性质”和“线路板腐蚀液的研究”为核心任务,把铁盐与亚铁盐的性质、Fe2+和Fe3+的相互转化等核心知识贯穿其中,建立从物质类别、元素价态视角研究物质性质及转化的思路方法,促进多维度化学学科核心素养的融合发展。经过多轮次教学改进,结合教学实践过程及其教学效果抽提出“注重应用无机物的认识模型,重点把握研究物质性质的角度和思路”“抓住典型活动,培养学生的关键能力”“设计开放性任务,通过有效的师生对话进行诊断,外显问题解决思路”等教学策略。 相似文献
93.
Dr. Andrey Belyaev Prof. Pi-Tai Chou Prof. Igor O. Koshevoy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):537-552
Tunable electron-accepting properties of the cationic phosphorus center, its geometry and unique preparative chemistry that allows combining this unit with diversity of π-conjugated motifs, define the appealing photophysical and electrochemical characteristics of organophosphorus ionic chromophores. This Minireview summarizes the achievements in the synthesis of the π-extended molecules functionalized with P-cationic fragments, modulation of their properties by means of structural modification, and emphasizes the important effect of cation-anion interactions, which can drastically change physical behavior of these two-component systems. 相似文献
94.
《Journal of Saudi Chemical Society》2014,18(5):387-391
Three crosslinked polymers were prepared via condensation polymerization between triethanolamine and glycerol [(25:75%), (50:50%) and (0:100%) (G:TEA)] with maleic anhydride which produced polymers I, II and III consequently. All the prepared polymers were doped with metal salts (CuCl2, NiCl2 and FeCl2). D.C. conductivity was measured in the temperature range of (298–373 K), the result showed that the electrical conductivity increased several orders of magnitude with increasing temperature, the activation energy decreased with increasing conductivity. A.C. measurement is used to calculate the dielectric constant for the polymers in both pure and doped state. 相似文献
95.
Calcite Microneedle Arrays Produced by Inorganic Ion‐Assisted Anisotropic Dissolution of Bulk Calcite Crystal 下载免费PDF全文
Xia Long Ruijie Meng Weike Wu Prof. Yurong Ma Prof. Dong Yang Prof. Limin Qi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(15):4264-4272
Besides studies on the mineralization process, research on the demineralization of minerals provides another way to understand the crystallization mechanism of biominerals and fabricate crystals with complicated morphologies. The formation of ordered arrays of c‐axis‐oriented calcite microneedles with a tri‐symmetric structure and lengths of more than 20 μm was realized on a large scale for the first time through anisotropic dissolution of calcite substrates in undersaturated aqueous solution in the presence of ammonium salts. The lengths and the aspect ratios of the calcite microneedles can be tuned by simply changing the concentrations of the ammonium salts and the dissolution time. The shape of the transverse cross sections of the calcite microneedles obtained in the presence of NH4Cl and NH4Ac is almost regularly triangular. The tri‐symmetric transverse cross‐section geometry of the calcite microneedles could be attributed to the tri‐symmetric feature of rhombohedral calcite atomic structures, the synergetic interactions between electrostatic interaction of ammonium ions and dangling surface carbonate groups, and the ion incorporation of halide ions. 相似文献
96.
Exploring the Synthesis of a New Group of Chiral Ammonium Salts with Specific Configurations at the Stereogenic Nitrogen Centers 下载免费PDF全文
Dr. Prisca K. Eckert Christopher Golz Dr. Patrick Degen Cornelia Werner Prof. Dr. Heinz Rehage Prof. Dr. Carsten Strohmann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3268-3272
A group of new chiral dications with a fixed, specific configuration at the stereogenic nitrogen center was created. Stereoselective synthesis and recrystallization give the diastereomerically and enantiomerically pure dications, including a chiral amphiphile with surface‐active properties. 相似文献
97.
Marcel Hartmann Prof. Dr. Armido Studer 《Angewandte Chemie (International ed. in English)》2014,53(31):8180-8183
Radical carboiodination of various aryl amines is reported. Aryl diazonium salts, generated in situ from the corresponding aryl amines, are reacted with Bu4NI to provide the corresponding aryl radicals which undergo 5‐exo or 6‐exo cyclization. Iodine abstraction eventually affords the carboiodinated products in good to excellent yields. If TEMPO is added, the cascade provides the cyclized carboaminoxylation products. Running the reaction in the presence of PhTeTePh affords the phenyltellurated cyclized products. 相似文献
98.
Takahito Kasahara Young Jin Jang Léanne Racicot Dimitrios Panagopoulos Dr. Steven H. Liang Prof. Dr. Marco A. Ciufolini 《Angewandte Chemie (International ed. in English)》2014,53(36):9637-9639
A metathesis reaction occurs when a diaryliodonium triflate is heated with an aryl iodide, resulting in the formation of a new diaryliodonium triflate. 相似文献
99.
A new approach to the synthesis of 5,5'-dinitro-3,3'-azo-1H-1,2,4-triazole ( 3 ) starting from 3,6-dihydrazinyl-1,2,4,5-tetrazine (DHT) was discovered. Nitrogen-rich energetic salts of 3 were synthesized in high yields. It is unusual that all the salts were less thermally stable than the neutral compound 3 . Of all the compounds, the decomposition temperature of 217 °C, as well as being insensitive towards impact and friction, which suggests potential application as an environmentally friendly nitrogen-rich energetic material. 相似文献
100.
在常压、无溶剂、120℃条件下,考察了14种碱金属无机酸盐(MA,M=Li^+,Na^+,K^+)催化正辛硫醇与碳酸乙烯酯的S-羟乙基化反应性能。普遍的规律是:在阴离子A相同的情况下,钾盐的催化活性高于相应的钠盐,而锂盐无催化活性。在各种无机酸钾盐中,如果共轭酸酸性越强,则相应的钾盐的催化活性越低。为探究钾盐催化剂活化-SH的机理的普适性,以K_3PO_4为催化剂,考察了在不同反应温度下,6种不同结构的硫醇与碳酸乙烯酯的β-羟乙基化反应催化活性,得出规律是硫醇的酸性越强,其反应活性越高,S-H键越容易解离。该反应无溶剂参与,硫醇与碳酸乙烯酯的物质的量之比接近理论量,产物β-羟乙基硫醚的选择性>99%,产物中无卤素盐副产物生成,易于分离。 相似文献