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81.
Triphenylphosphine‐Mediated Deoxygenative Reduction of CF3SO2Na and Its Application for Trifluoromethylthiolation of Aryl Iodides 下载免费PDF全文
Prof. Yi Yang Long Xu Siqi Yu Dr. Xiaoqiang Liu Yu Zhang Prof. David A. Vicic 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(3):858-863
We report herein a practical method for taming Langlois’ reagent CF3SO2Na to generate CuSCF3 by a triphenylphospine‐mediated deoxygenative reduction process. This chemistry highlights a novel utilization of the inherent CF3S skeleton of Langlois’ reagent as a CF3S feedstock under mild conditions. The CuSCF3 intermediate generated by this protocol can react with a wide array of supporting ligands to furnish several air‐stable [LCu(SCF3)] complexes as valuable trifluoromethylthiolating agents. In addition, the CuSCF3 intermediate can be directly employed for the trifluoromethylthiolation of (hetero)aryl iodides with operational simplicity and atomic efficiency. 相似文献
82.
Rational Design and Application of a Redox‐Active,Photoresponsive, Discrete Metallogelator 下载免费PDF全文
Dr. Rouzbeh Afrasiabi Prof. Dr. Heinz‐Bernhard Kraatz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7695-7700
A photoresponsive discrete metallogelator was rationally designed by incorporating a photochromic azobenzene subunit in the structure of a redox‐active ferrocene–peptide conjugate. The target molecule was purposefully equipped with a dipeptide unit capable of self‐assembly in response to sonication. The designed molecule was shown to undergo supramolecular self‐assembly and achieve organogelation in response to ultrasound, light, heat, and redox signals. The sol–gel phase transition of the designed gelator was found to be sensitive to a plethora of input stimuli, allowing the application of the sol–gel transition behavior in basic logic gate operations. A gel‐based NOT logic gate operation was realized when the redox‐active property of the organogel was examined by using different oxidizing agents. The smart response of the gelator was further exploited in designing XOR operations under oxidizing or non‐oxidizing conditions. 相似文献
83.
Facile synthesis of thermosensitive functional polyaspartamide derivatives by click chemistry 下载免费PDF全文
Guangyan Zhang Yunti Zhang Yanfeng Chu Yingying Ma Renxi Zhuo Xulin Jiang 《Journal of polymer science. Part A, Polymer chemistry》2015,53(10):1296-1303
Biodegradable and thermosensitive polyaspartamide derivatives containing pendant azide groups P(Asp‐Az)X‐HPAs were synthesized from poly(l ‐succinimide) via the ring‐opening reaction with 2‐azidoethylamine (Az) and 5‐hydroxypentylamine (HPA). Then hydrophobic phenethyl (PEA) and imidazole (IMZ) moieties were introduced successfully with very high reaction efficiency above 90% to the side chains of P(Asp‐Az)X‐HPA by click reaction to obtain thermoresponsive polyaspartamide derivatives containing pendant aromatic rings P(Asp‐Az)X‐HPA‐PEAs and the thermo/pH‐responsive polyaspartamide derivatives containing pendant imidazole rings P(Asp‐Az)X‐HPA‐IMZs, respectively. The thermoresponsive behaviors of P(Asp‐Az)X‐HPA‐PEAs and P(Asp‐Az)X‐HPA‐IMZs were confirmed by dynamic light scattering (DLS) and transmittance measurements, and the cloud point can be tuned by designed amounts of azide groups and can be further adjusted by the grafting molar percentage of hydrophobic phenethyl or imidazole moieties to the side chains of P(Asp‐Az)X‐HPA via click chemistry. The pH‐responsive behavior of P(Asp‐Az)X‐HPA‐IMZs can also be tuned. These results indicate that the obtained polyaspartamide‐based functional polymers can be further functionalized with hydrophilic long PEG chain and/or targeted moieties via click chemistry for drug delivery. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1296–1303 相似文献
84.
Shane M. Hickey Shani K. Tripcony Rui Li Richard J. Williams 《Supramolecular chemistry》2015,27(5-6):425-435
Using the rigid norbornane scaffold, a series of low-molecular-weight organogelators has been synthesised and evaluated. Three separate compounds (16, 19 and 20) were identified as organogelators in three aromatic organic solvents (PhMe, anisole and o-xylene). The formation of fibrillar assemblies at nanometre level was confirmed using atomic force microscopy and transmission electron microscopy. 相似文献
85.
Fluorinated Musk Fragrances: The CF2 Group as a Conformational Bias Influencing the Odour of Civetone and (R)‐Muscone 下载免费PDF全文
Dr. Ricardo Callejo Dr. Michael J. Corr Mingyan Yang Prof. Mingan Wang Dr. David B. Cordes Prof. Alexandra M. Z. Slawin Prof. David O'Hagan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8137-8151
The difluoromethylene (CF2) group has a strong tendency to adopt corner over edge locations in aliphatic macrocycles. In this study, the CF2 group has been introduced into musk relevant macrocyclic ketones. Nine civetone and five muscone analogues have been prepared by synthesis for structure and odour comparisons. X‐ray studies indeed show that the CF2 groups influence ring structure and they give some insight into the preferred ring conformations, triggering a musk odour as determined in a professional perfumery environment. The historical conformational model of Bersuker and co‐workers for musk fragrance generally holds, and structures that become distorted from this consensus, by the particular placement of the CF2 groups, lose their musk fragrance and become less pleasant. 相似文献
86.
TBAI‐Catalyzed/Water‐Assisted Double C−S Bond Formations: An Efficient Approach to Sulfides through Metal‐Free Three‐Component Reactions 下载免费PDF全文
Xue‐Qiang Chu Prof. Dr. Xiao‐Ping Xu Prof. Dr. Shun‐Jun Ji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14181-14185
An aqueous catalytic method for double C?S bond formations that involves alcohol derivatives, organic halides, and sodium thiosulfate has been developed. A diverse range of functionalized sulfides, including pharmaceutical and biological derivatives, can be obtained in an efficient and eco‐friendly manner under air. The mechanistic studies revealed that this tetrabutylammonium‐iodide‐catalyzed/water‐assisted reaction generated a mercaptan species as the key intermediate. 相似文献
87.
This article discussed "teaching-practice-test" teaching mode with teaching practical experience and content matching.Results showed that this mode highlighted the proportion of practice and problem-solving in the process of learning; improved students' ability to solve problems using professional and disciplinary knowledge; changed learning styles from cramming way to autonomous learning step by step and trained students' creativity. 相似文献
88.
Close‐Packed Two‐Dimensional Silver Nanoparticle Arrays: Quadrupolar and Dipolar Surface Plasmon Resonance Coupling 下载免费PDF全文
Sukang Yun Soonchang Hong Jesus A. I. Acapulco Jr. Ho Young Jang Songyi Ham Kyungeun Lee Prof. Seong Kyu Kim Prof. Sungho Park 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6165-6172
Silver nanoparticles (NPs) ranging in size from 40 to 100 nm were prepared in high yield by using an improved seed‐mediated method. The homogeneous Ag NPs were used as building blocks for 2D assembled Ag NP arrays by using an oil/water interface. A close‐packed 2D array of Ag NPs was fabricated by using packing molecules (3‐mercaptopropyltrimethoxysilane) to control the interparticle spacing. The homogeneous 2D Ag NP array exhibited a strong quadrupolar cooperative plasmon mode resonance and a dipolar red‐shift relative to individual Ag NPs suspended in solution. A well‐arranged 2D Ag NP array was embedded in polydimethylsiloxane film and, with biaxial stretching to control the interparticle distance, concomitant variations of the quadrupolar and dipolar couplings were observed. As the interparticle distance increased, the intensity of the quadrupolar cooperative plasmon mode resonance decreased and dipolar coupling completely disappeared. The local electric field of the 2D Ag NP array was calculated by using finite difference time domain simulation and qualitatively showed agreement with the experimental measurements. 相似文献
89.
Synthesis,Properties, and Redox Behavior of 1,1,4,4‐Tetracyano‐2‐ferrocenyl‐1,3‐butadienes Connected by Aryl,Biaryl, and Teraryl Spacers 下载免费PDF全文
Dr. Taku Shoji Akifumi Maruyama Chisa Yaku Natsumi Kamata Prof. Dr. Shunji Ito Dr. Tetsuo Okujima Prof. Dr. Kozo Toyota 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):402-409
Aryl‐substituted 1,1,4,4‐tetracyano‐1,3‐butadienes (FcTCBDs) and bis(1,1,4,4‐tetracyanobutadiene)s (bis‐FcTCBDs), possessing a ferrocenyl group on each terminal, were prepared by the reaction of a variety of alkynes with tetracyanoethylene (TCNE) in a [2+2] cycloaddition reaction, followed by retro‐electrocyclization of the initially formed [2+2] cycloadducts (i.e., cyclobutene derivatives). The characteristic intramolecular charge transfer (ICT) between the donor (ferrocene) and acceptor (TCBD) moieties were investigated by using UV/Vis spectroscopy. The redox behaviors of FcTCBDs and bis‐FcTCBDs were examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed their properties of multi‐electron transfer depending on the number of ferrocene and TCBD moieties. Moreover, significant color changes were observed by visible spectroscopy under the electrochemical reduction conditions. 相似文献
90.
Partial substitution of cations and anions in perovskite-type materials is a powerful way to tune the desired properties. The systematic variation of the cations size, the partial exchange of O2− for N3− and their effect on the size of the optical band gap and the thermal stability was investigated here. The anionic substitution resulted in the formation of the orthorhombic perovskite-type oxynitrides Mg0.25Ca0.65Y0.1Ti(O,N)3, Ca1-xYxZr(O,N)3, and Sr1–xLaxZr(O,N)3. A two-step synthesis protocol was applied: i) (nano-crystalline) oxide precursors were synthesized by a Pechini method followed by ii) ammonolysis in flowing NH3 at T = 773 K (Ti) and T = 1273 K (Zr), respectively. High-temperature synthesis of such oxide precursors by solid–state reaction generally resulted in phase separation of the different A-site cations. Changes of the crystal structures were investigated by Rietveld refinements of the powder XRD data, thermal stability by DSC/TG measurements in oxygen atmosphere, oxygen and nitrogen contents by O/N analysis using hot gas extraction technique, and optical band gaps by photoluminescence spectroscopy. By moving from Mg0.25Ca0.65Y0.1Ti(O,N)3 via Ca1–xYxZr(O,N)3 to Sr1–xLaxZr(O,N)3, the degree of tilting of the octahedral network is reduced, as observed by an increase in the B–X–B angles caused by the simultaneously increasing effective ionic radius of the A-site cation(s). In general, increasing substitution levels on the A-site (Y3+ and La3+) are accompanied by an enhanced replacement of O2− by N3−. In all three systems, this anionic substitution resulted in a reduction of the optical band gap by approximately 1 eV (Ti) and up to 2.1 eV (Zr) compared to the respective oxides. For Mg0.25Ca0.65Y0.1Ti(O,N)3 an optical band gap of 2.2 eV was observed, appropriate for a solar water splitting photocatalyst. The Zr-based oxynitrides required a by a factor of 2 higher nitrogen contents to significantly reduce the optical band gap and the measured values of 2.9 eV–3.2 eV are larger compared to the Ti-based oxynitride. Bulk thermal stability was revealed up to T = 881 K. In general, the thermal stability decreased with increasing substitution levels due to an increasing deviation from the ideal anionic composition as demonstrated by O/N analysis. 相似文献