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21.
Fernando R. Díaz Jorge L. Torres M. Angélica Del Valle Jorge H. Vélez J. Christian BernÈde Gastón A. East 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1101-1108
Poly(3,5‐dichloroaniline) was prepared by chemical oxidation in the presence of various sulfonic acids as doping agent, using potassium permanganate as oxidant. 1‐Naphtalene sulfonic acid, 2‐naphatalene sulphonic acid, 1,5‐naphtalene disulfonic acid, and p‐toluenesulfonic acid were the acids of choice. Infrared and UV‐Vis spectroscopy, utilized to characterize the polymers, revealed that the compounds exist in the emeraldine (conductive) oxidation state. The level of doping, conductivity, and morphology were determined as well. The presence of a sulfonic acid produces a morphological change, from granular to microtubule structures, which is responsible for the strong increase in the conductivity of the polymer. 相似文献
22.
Keng Yoon Yeong Mohamed Ashraf Ali Chee Wei Ang Soo Choon Tan Hasnah Osman 《Tetrahedron letters》2014
A facile method to synthesize various 1,2-disubstituted benzimidazoles is developed. It is suggested that formation of a Meisenheimer adduct between the substrate, amine, and solvent aids the N-arylation process. The generality of the protocol is demonstrated by the efficient reactions involving numerous substituents ranging from electron-withdrawing groups to electron-donating groups. 相似文献
23.
Devendra KC Deb Kumar Shah M. Shaheer Akhtar Mira Park Chong Yeal Kim O-Bong Yang Bishweshwar Pant 《Molecules (Basel, Switzerland)》2021,26(11)
This paper numerically explores the possibility of ultrathin layering and high efficiency of graphene as a back surface field (BSF) based on a CdTe solar cell by Personal computer one-dimensional (PC1D) simulation. CdTe solar cells have been characterized and studied by varying the carrier lifetime, doping concentration, thickness, and bandgap of the graphene layer. With simulation results, the highest short-circuit current (Isc = 2.09 A), power conversion efficiency (η = 15%), and quantum efficiency (QE~85%) were achieved at a carrier lifetime of 1 × 103 μs and a doping concentration of 1 × 1017 cm−3 of graphene as a BSF layer-based CdTe solar cell. The thickness of the graphene BSF layer (1 μm) was proven the ultrathin, optimal, and obtainable for the fabrication of high-performance CdTe solar cells, confirming the suitability of graphene material as a BSF. This simulation confirmed that a CdTe solar cell with the proposed graphene as the BSF layer might be highly efficient with optimized parameters for fabrication. 相似文献
24.
Immuno‐Chemotherapeutic Platinum(IV) Prodrugs of Cisplatin as Multimodal Anticancer Agents 下载免费PDF全文
Daniel Yuan Qiang Wong Charmian Hui Fang Yeo Prof. Wee Han Ang 《Angewandte Chemie (International ed. in English)》2014,53(26):6752-6756
There is growing consensus that the clinical therapeutic efficacy of some chemotherapeutic agents depends on their off‐target immune‐modulating effects. Pt anticancer drugs have previously been identified to be potent immunomodulators of both the innate and the adaptive immune system. Nevertheless, there has been little development in the rational design of Pt‐based chemotherapeutic agents to exploit their immune‐activating capabilities. The FPR1/2 formyl peptide receptors are highly expressed in immune cells, as well as in many metastatic cancers. Herein, we report a rationally designed multimodal PtIV prodrug containing a FPR1/2‐targeting peptide that combines chemotherapy with immunotherapy to achieve therapeutic synergy and demonstrate the feasibility of this approach. 相似文献
25.
Yuanjun Chen Shufang Ji Wenming Sun Yongpeng Lei Qichen Wang Ang Li Wenxing Chen Gang Zhou Zedong Zhang Yu Wang Lirong Zheng Qinghua Zhang Lin Gu Xiaodong Han Dingsheng Wang Yadong Li 《Angewandte Chemie (International ed. in English)》2020,59(3):1295-1301
It is highly desirable but challenging to optimize the structure of photocatalysts at the atomic scale to facilitate the separation of electron–hole pairs for enhanced performance. Now, a highly efficient photocatalyst is formed by assembling single Pt atoms on a defective TiO2 support (Pt1/def‐TiO2). Apart from being proton reduction sites, single Pt atoms promote the neighboring TiO2 units to generate surface oxygen vacancies and form a Pt‐O‐Ti3+ atomic interface. Experimental results and density functional theory calculations demonstrate that the Pt‐O‐Ti3+ atomic interface effectively facilitates photogenerated electrons to transfer from Ti3+ defective sites to single Pt atoms, thereby enhancing the separation of electron–hole pairs. This unique structure makes Pt1/def‐TiO2 exhibit a record‐level photocatalytic hydrogen production performance with an unexpectedly high turnover frequency of 51423 h?1, exceeding the Pt nanoparticle supported TiO2 catalyst by a factor of 591. 相似文献
26.
Shekhar KC Roshan K. Dhungana Namrata Khanal Ramesh Giri 《Angewandte Chemie (International ed. in English)》2020,59(21):8047-8051
We report a Ni‐catalyzed regioselective α‐carbonylalkylarylation of vinylarenes with α‐halocarbonyl compounds and arylzinc reagents. The reaction works with primary, secondary, and tertiary α‐halocarbonyl molecules, and electronically varied arylzinc reagents. The reaction generates γ,γ‐diarylcarbonyl derivatives with α‐secondary, tertiary, and quaternary carbon centers. The products can be readily converted to aryltetralones, including a precursor to Zoloft, an antidepressant drug. 相似文献
27.
Nate W. J. Ang Joo C. A. Oliveira Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2020,59(31):12842-12847
The chemical use of CO2 as an inexpensive, nontoxic C1 synthon is of utmost topical interest in the context of carbon capture and utilization (CCU). We present the merger of cobalt catalysis and electrochemical synthesis for mild catalytic carboxylations of allylic chlorides with CO2. Styrylacetic acid derivatives were obtained with moderate to good yields and good functional group tolerance. The thus‐obtained products are useful as versatile synthons of γ‐arylbutyrolactones. Cyclic voltammetry and in operando kinetic analysis were performed to provide mechanistic insights into the electrocatalytic carboxylation with CO2. 相似文献
28.
29.
纤维素溶剂研究进展 总被引:12,自引:0,他引:12
概述了纤维素溶剂的重要研究进展,主要包括N-甲基吗啉-N-氧化物(NMMO)在85℃以上高温可破坏纤维素分子间氢键,导致溶解;氯化锂/二甲基乙酰胺(LiCl/DMAc)在100℃以上可溶解纤维素;1-丁基-3-甲基咪唑盐酸盐([BMIM]Cl)和1-烯丙基-3-甲基咪唑盐酸盐([AMIM]Cl)离子液体,含强氢键受体Cl-离子,通过它们与纤维素羟基作用而引起溶解.氨基甲酸酯体系则是通过尿素与纤维素在100℃以上反应转变为纤维素氨基甲酸酯,然后再溶解于NaOH水溶液中;氢氧化钠/水体系,只能溶解结晶度和聚合度较低的纤维素;NaOH/尿素、NaOH/硫脲和LiOH/尿素水溶液体系,它们预冷至-5~-12℃后可迅速溶解纤维素.主要是通过低温产生小分子和大分子间新的氢键网络结构,导致纤维素分子内和分子间氢键的破坏而溶解,同时尿素或者硫脲作为包合物客体阻止纤维素分子自聚集使纤维素溶液较稳定.低温溶解技术不仅突破了加热溶解的传统方法,而且可推进化学"绿色化"进程.共引用参考文献50篇. 相似文献
30.
Szandra Klátyik Eszter Takács Mária Mörtl Angéla Földi Zsuzsa Trábert Éva Ács 《International journal of environmental analytical chemistry》2017,97(10):901-921
Dissipation of the herbicide active ingredient glyphosate was investigated in natural waters. To assess combined effects, glyphosate was applied in its pure form (glyphosate isopropylammonium salt) and in preparation Roundup Classic® formulated with polyethoxylated tallowamines (POEA). Standing and running surface water samples originated from Lake Balaton and River Danube between early May and mid-June of 2015. The kinetics of dissipation of glyphosate, measured by high-performance liquid chromatography combined with UV-VIS absorbance detection or tandem mass spectrometry, was investigated under laboratory conditions in aquaria with or without the presence of biofilms. The quantity and the biofilm structure of algal biomass were determined by in vivo fluorimetry and scanning electron microscopy. The presence of POEA affected the dissipation of glyphosate, and dissipation profiles differed in the investigated natural waters. Significantly higher initial concentrations of glyphosate were measured in River Danube for treatment with formulated glyphosate (101.4 ± 6.2 µg L?1), than with glyphosate alone (79.9 ± 6.6 µg L?1), and dissipation to a residual level (57.6 ± 1.4 µg L?1) consequently took longer (approximately by 1 day). Degradation of glyphosate from the initial level (91.24 ± 5.9 µg L?1) in Lake Balaton was not detected. Phytotoxic effects of glyphosate, particularly if enhanced by a formulant on algal biomass, were observed. Thus, 5–18% and 11–33% of algal biomass reduction was determined in River Danube upon treatments with glyphosate and Roundup Classic®, respectively. Corresponding biomass decreases in Lake Balaton were 1.3–13% and 9–14%, respectively, accompanied by an overall decay in the algal biofilms. In River Danube, treatments resulted in the occurrence of 1.4–5.8% of green algae in the algal biomass in 28 days, while green algae were not detected in the untreated control. The results indicate that glyphosate is capable of modifying the structure of the algal community and to induce increased secretion of extracellular polymeric substances matrix in the biofilms assessed. 相似文献