检索结果-南通市图书馆

photo-induced deep aerobic oxidation of alkyl aromatics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2021年第9期64卷 1487-1492页

作者： Chang-Cheng Wang Guo-Xiang Zhang Zhi-Wei Zuo Rong Zeng Dan-Dan Zhai Feng Liu Zhang-Jie Shi Department of Chemistry Fudan UniversityShanghai200438China Department of Chemistry Xi’an Jiaotong UniversityXi’an710049China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryShanghai200032China

Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical ***,the industrial manufacture of benzoic acids and benzene polycarboxylic acids(BPCAs)is mainly based on the deep oxidation of polyalkyl benzene,which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting Me Br and corrosion hazards of production *** this report,photo-induced deep aerobic oxidation of(poly)alkyl benzene to benzene(poly)carboxylic acids was ***_(3) was proved to be an efficient HAT(hydrogen atom transfer)catalyst in the presence of alcohol as both hydrogen and electron ***(O_(2))was found as a sole terminal *** most cases,pure products were easily isolated by simple filtration,implying large-scale implementation *** reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks.

关键词： photo-induced oxidation alkyl aromatics

photo-induced effect in the layered perovskite manganite La_(1.2)Sr_(1.8)Mn_(1.8)Co_(0.2)O_(7)

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2004年第1期47卷 113-120页

作者： ZHANG Ruili1, DAI Jianming1, SONG Wenhai1, MA Yongqing1, YANG Jie1 & SUN Yuping1,2 1. Key Laboratory of Internal Friction and Defects in Solids, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China 2. National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210008, China Correspondence should be addressed to Zhang Ruili (email: rlzhang@***) Received September 1, 2003 Key Laboratory of Internal Friction and Defects in Solids Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China National Laboratory of Solid State Microstructures Nanjing University Nanjing 210008 China

It is helpful to study the photo-induced effect in the perovskite manganites not only for elucidating the mechanism of colossal magnetoresistance (CMR) effect but also for potential applications in technology. The laser-induced effect in the Co doping layered perovskite manganites La1.2Sr1.8Mn1.8Co0.2O7 is studied in this paper and the obtained results are also compared with that gained in the Nd-doping manganites with cubic perovskite structure.

关键词： laser, layered perovskite manganites, photo-induced effect, spin-state.

Contributions of Cs and Rb on Inhibiting photo-induced Phase Segregation and En-hancement Optoelectronic Performances of MA_(1-y)XyPbI_(1.8)Br_(1.2)(X=Cs,Rb)Single Crystals

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2022年第5期41卷 77-84页

作者： Qing Yao Kaiyu Wang Jie Zhang Changqian Li Chenyu Shang Feitong Chen Qi Huang Qiqi Zhao Weiwei Zhang Xiaoyuan Zhan Jianxu Ding College of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China

Introducing inorganic cation into hybrid organic-inorganic perovskites(HOIPs)has attracted great attention because of the enhancement stabilities without sacrificing their excellent optoelectronic ***,we introduce Cs and Rb into MAPbI_(1.8)Br_(1.2)single crystals(SCs)to dig out the mixed cation effect on optoelectronic performances and phase *** Rb and Cs can increase the lattice capacity,which is sufficient to relieve the lattice stress caused by photon energy,thus achieving the purpose of stabilizing the lattice structure and inhibiting migration of halide ions,compared with MAPbI_(1.8)Br_(1.2)*** the other hand,the smaller polarity of Rb and Cs reduces the electron-phonon coupling,thus significantly inhibiting the migration of halide ***,through planar photo-detectors,MA_(0.9)Cs_(0.1)PbI_(1.8)Br_(1.2)-based device behaves much excellent optoelectronic performance(R=0.170 A/W,EQE=51.39%,D^(*)=4.42×10^(12)Jones,on/off ratio:~522).

关键词： perovskite single crystal photo-induced phase segregation mixed A-cation optoelectronic performances

Metal-free photo-induced radical C-P and C-S bond formation for the synthesis of 2-phosphoryl benzothiazoles

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第5期31卷 1313-1316页

作者： Wenchao Yang Bing Li Mingming Zhang Shuang Wang Yigang Ji Sa Dong Jianguo Feng Shuzhong Yuan Guangling College and Institute of Pesticide of School of Horticulture and Plant Protection Yangzhou UniversityYangzhou 225009China Jiangsu Key Laboratory of Biofuctional Molecules Department of Life Sciences and ChemistryJiangsu Second Normal UniversityNanjing 210013China

We reveal here a visible-light promoted phosphorylation of 2-isocyanoaryl thioethers for the first time with concomita nt C(sp3)-S bond cleavage and imidoyl C-S fo ***,this method features the use of 3 mol%organic dye Rose Bengal as the photocatalyst without external transition-metal or peroxide oxidants,and provides a novel and environmentally friendly approach for the preparation of a variety of 2-phosphoryl benzothiazoles in moderate to good yields.

关键词： Phosphorylation photo-induced Isocyanides Radical cascade reaction H-Phosphorus oxides

Investigation on the photo-induced de-oxygenation process of myoglobin in aqueous solution by use of fluorescence spectroscopy

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2008年第5期51卷 414-419页

作者： MA JunYan ZHENG XueFang TANG Qian MA Jing GAO DaBin HU JiHan Liaoning Key Lab of Bio-organic Chemistry Dalian University Dalian 116622China College of Bioengineering Dalian UniversityDalian 116622China

A photo-induced de-oxygenation process of myoglobin (Mb) in aqueous solution was investigated by use of fluorescence spectroscopy. The spectra are characterized by the fluorescence intensity declining gradually after each scan,and the decay of fluorescence intensity being significant in each scan,which is assigned to the release of oxygen from the opening of the heme-pockets induced by illumination. More illumination will cause more release of oxygen; if the temperature of an Mb solution is increased when it is illuminated,the rate of de-oxygenation will be higher. It was found that ligand-oxygen in Fe-porphyrin could be removed from Mb by nitrogen. This indicates that the interac-tion between oxy-Mb and other different gases can be tested by the method of fluorescence spectros-copy. In addition,fluorescence spectroscopy can be employed to probe the energy transfer between Fe-porphyrin and tryptophan or tyrosine in Mb molecules.

关键词： fluorescence spectroscopy myoglobin photo-induced de-oxygenation

photo-induced Thermally Stimulated Depolarization Current (TSDC) in Natural and Synthetic Alexandrite (BeAl₂O₄:Cr³⁺)

在线全文

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2016年第12期7卷 881-894页

作者： Neilo Marcos Trindade Ana Regina Blak Elisabeth Mateus Yoshimura Luis Vicente de Andrade Scalvi Rosa Maria Fernandes Scalvi Sã o Paulo Federal Institute S&atilde o Paulo Brazil Institute of Physics University of S&atilde o Paulo S&atilde o Paulo Brazil Department of Physics S&atilde o Paulo State University Bauru Brazil

The investigation of electrical properties in alexandrite (BeAl2O4:Cr3+) in synthetic and natural forms is presented in this paper. Alexandrite is a rare and precious mineral that changes color according to the light incident on it. In the synthetic form, it is used technologically as an active laser medium. The electrical characterization was obtained using the Thermally Stimulated Depolarization Current (TSDC) technique, an interesting tool to study the behavior of impurities in insulators. Alexandrite presented the electric dipole relaxation phenomenon, both in natural and in synthetic samples. It was possible to observe TSDC bands for the synthetic sample at around 170 K, and at around 175 K for the natural sample. Besides, photo-induced TSDC measurements were performed through the excitement of the samples by using a continuous wave argon laser. In addition, photoluminescence measurements were performed to verify in advance whether the laser light would be absorbed by the sample, and in order to complement the photo-induced TSDC measurements analysis. The results of photo-induced TSDC experiments have contributed to the understanding of the TSDC bands behavior: the results obtained with the technique suggest that there is an effective participation of Cr3+ ions in the formation of TSDC bands because they were more intense when the sample was exposed to the argon laser beam.

关键词： Alexandrite Chrysoberyl Thermally Stimulated Depolarization Current (TSDC) photoluminescence photo-induced

photo-induced Tandem Cyclizations of 3-Iodofalvones with Electron Rich Five-member Heteroarenes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photo-Induced Tandem Cyclizations of 3-Iodofalvones with Ele...

Oxidant and transition-metal-free photo-induced direct oxidative annulation of 1-aryl-2-（furan/thiophe-2-yl）butane-1,3-diones

第十五届全国光化学学术讨论会

作者：杨谦王锐韩杰李晨晨王涛张尊听 School of Chemistry and Chemical Engineering Shaanxi Normal University

Flavones are a class of natural product which could be found in many plants. They have various biological activities, including antioxidant, anti-tumor, anti-proliferative, anti-inflammatory activities and have been used in the treatment of cancer, cardiovascular disease, neurodegenerative disorders, etc. Flavones are also an important scaffold for medicinal chemistry and versatile building blocks for the construction of various heteroaromatics. Vinyl radicals were generated from 3-iodoflavones under a mercury lamp and occurred tandem cyclizations with fused heterocyclic aromatics system entailing two consecutive C-C bond formations to synthesis benzo[e]chromeno[2,3-g]indol-13（1H）-one derivatives. The reaction worked smoothly in acetonitrile without any additives such as transition metal, ligand andoxidant giving rise to a broad variety of novel polycyclic xanthone frame works in good yields under mild and environmentally reaction conditions. The described methodology provided a rapid access to polycyclic xanthones with excellent regio-selectivity under the mild, environmental friendly condition without the requirement of any catalyst or additives.

关键词： photo-induced Tandem Cyclizations Benzo[e]chromeno[2,3-g] indol-13(1H)-ones fused heterocyclic aromatics system

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Oxidant and transition-metal-free photo-induced direct oxida...

Tune of thermally and photo-induced electron transfer in Fe-Co cyanometallates

第十五届全国光化学学术讨论会

作者：张瑾张曦王涛姚新波王平荆思思梁勇张尊听 School of Chemistry and Chemical Engineering Shaanxi Normal University

A few photo-induced dehydrogenative reaction have been reported, most of them need for oxidant or transition metal. Our group has been focused on the synthesis of various heteroaromatics via the photochemical reactions. Herein, we would like to report the photocyclization of 1-aryl-2-（furan/thiophe-2-yl）butane-1,3-diones and ethyl-3-aryl-2-（furan-2-yl）-3-oxo-propanoates, which underwent an keto-enol tautomerism, affording various highly functionalized heteroaromatics by the elimination of a hydrogen molecule from intermediate A. The functionalized and polyheterocyclic compounds were synthesized via the direct oxidative annulation（UV irradiation） of 1-aryl-2-（furan/thiophe-2-yl）butane-1,3-diones and ethyl-3-aryl-2-（furan-2-yl）-3-oxo-propanoates in the EtOH solution. Notable feature of our strategy include a) mild reaction conditions, b) easy work-up, and c) NO requirement of any catalysts and oxidants. Meanwhile, the fluorescence properties of compounds were determined. The phenomenon of excited-state intramolecular proton transfer（ESIPT） was observed for both 1-（5-hydroxynaphtho[2,1-b]furan-4-yl）ethanone and 1-（5-hydroxyfuran/thieno/pyrrolo[3,2-e]benzofuran-4-yl） ethanone analogues. Meanwhile, ethyl-5-hydroxynaphtho [2,1-b]furan-4-carboxylate observed with a significant enhancement of the fluorescence quantum efficiencies in the EtOH solution.

关键词： photo-induced Oxidative Annulation Polyheterocyclic ESIPT

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Tune of thermally and photo-induced electron transfer in Fe-...