期刊文献+
共找到24篇文章
< 1 2 >
每页显示 20 50 100
A CIDNP STUDY OF THE PHOTOREACTIONS OF METHYLFURANS WITH CHLORANIL 被引量:1
1
作者 Ling jiang CHENG~(1,2) Han Cheng YUAN~3 Er Cheng LI~2 Bao Zhen YAN~3 Jian Hua XU~4 Guang Zhi XU~2 1 Institute of Photographic Chemistry,Chinese Academy Of Sciences,Beijing 100101 2 Institute of Chemistry,Chinese Academy of Sciences,Beijing 100080 3 Department of Applied Chemistry,Beijing Institute of Chemical Technology,Beijing 100029 4 Department of Chemistry,Nanjing University,Nanjing,Jiangsu 210008 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第4期327-330,共4页
The CIDNP observations indicated that photoreaction of methylfurans with chloranil resulted not only furylmethyl hydroxyphenyl ethers via radical pairs but induced furyl radical isomerization to the derivatives of cyc... The CIDNP observations indicated that photoreaction of methylfurans with chloranil resulted not only furylmethyl hydroxyphenyl ethers via radical pairs but induced furyl radical isomerization to the derivatives of cyclopropene,propadiene and pyran. 展开更多
关键词 CIDNP TH A CIDNP STUDY OF THE photoreactions OF METHYLFURANS WITH CHLORANIL
下载PDF
Photochromic fulgides and spirooxazines: mechanism and substituent effect on photoreactions
2
作者 樊美公 明阳福 +4 位作者 于联合 张新宇 孟宪娟 梁永超 杨茁 《Science China Chemistry》 SCIE EI CAS 1996年第2期144-151,共8页
Molecular design, synthesis and photochromic properties of spirooxazines and fulgides are described. In the case of fulgides, the change of the substituents may lead to different photochromic properties and different ... Molecular design, synthesis and photochromic properties of spirooxazines and fulgides are described. In the case of fulgides, the change of the substituents may lead to different photochromic properties and different photoreactions of the kind of compounds. In photochromic process of pyrryl-substituted fulgides, the excited singlet state is the mam species, but the excited triplet state is also involved. However, no excited triplet state has been observed in cyclization of aryl-substituted fulgides. In the case of spirooxazines, the substituents at 2’-position have great effect on the formation of photoproduct and on the mechanism of photoreaction. The increase of steric hindrance of the 2’-position substituent gives rise to the decrease of the quantum yield for the formation of photochromic merocyanine (PMC) and the increase of the relative quantum yield for the charge separated twist intermediate (CT). 展开更多
关键词 PHOTOCHROMISM SPIROOXAZINES FULGIDES photoreaction.
原文传递
Substrate-dependent photoreactivities of BiOBr nanoplates prepared at different pH values 被引量:4
3
作者 艾智慧 王吉玲 张礼知 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第12期2145-2154,共10页
In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1(BOB-1) degr... In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1(BOB-1) degraded salicylic acid more effectively than did those obtained at pH 3(BOB-3),but the order of their photocatalytic activities in rhodamine B(RhB) degradation were reversed. Electrochemical Mott–Schottky and zeta-potential measurements showed that BOB-1 had a more positive valence band and lower surface charge,leading to superior photocatalytic activity in salicylic acid degradation under visible light. However,BOB-3 was more powerful in RhB degradation because larger numbers of superoxide radicals were generated via electron injection from the excited RhB to its more negative conduction band under visible-light irradiation; this was confirmed using active oxygen species measurements and electron spin resonance analysis. This study deepens our understanding of the origins of organic-pollutant-dependent photoreactivities of semiconductors,and will help in designing highly active photocatalysts for environmental remediation. 展开更多
关键词 DEGRADATION Visible light Substrate dependent photoreactivity Bismuth oxybromide nanoplate Rhodamine B Salicylic acid
下载PDF
Photoreaction Behaviors of Two Liquid Crystalline Cinnamoyl Compounds with Different Phase in Solution and Mesomorphic States
4
作者 董晓明 郭金宝 魏杰 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第6期719-725,746,共8页
A novel nelnatic liquid crystal compound containing a cinnamoyl moiety (PCPC) and a typically cholesteric liquid crystal cholesteryl cinnamate (CC) were synthesized to explore the mechanism ofcinnamoyl compounds, ... A novel nelnatic liquid crystal compound containing a cinnamoyl moiety (PCPC) and a typically cholesteric liquid crystal cholesteryl cinnamate (CC) were synthesized to explore the mechanism ofcinnamoyl compounds, and the chemical structures of photodimerization were confirmed by Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectral analysis. The photoreaction behaviors of these two cinnamoyl compounds in mesomorphic state and solution were investigated, UV-Vis spectral analysis was used to analyze the photoproduct. The results show that the photochemistry of PCPC in nematic state involves both photodimerization and photoisomerization, while CC shows a complex reaction which can be divided into three parts, and this has enabled us to present new data and interpretations regarding the [2+2] photocycloaddition reaction. Additionally, the results of UV-Vis spectral analysis in solutions strongly suggest that UV-Vis spectral analysis can be used to study the kinetic behaviors of cinnamoyl moiety photoreaction. 展开更多
关键词 Cinnamoyl compound Liquid crystal Photoreaction behavior
下载PDF
PHOTOCHROMIC PROPERTIES OF (E)-DICYCLOPROPYLMETHYLENE-(2,5-DIMETHYL-3-FURYLETHYLIDENE)-SUCCINIC ANHYDRIDE DOPED IN POLYSTYRENE THIN FILMS
5
作者 Abood A.Bahajaj Abdullah M.Asiri 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2008年第4期433-441,共9页
Fulgide 1-E doped in polystyrene polymer films was heated at various annealing temperatures.Upon irradiation with UV light(366 nm),fulgide 1-E undergoes a conrotatory ring closure to the pink colored closed form 1-C.T... Fulgide 1-E doped in polystyrene polymer films was heated at various annealing temperatures.Upon irradiation with UV light(366 nm),fulgide 1-E undergoes a conrotatory ring closure to the pink colored closed form 1-C.The later color was switched back to the original color when the films were irradiated with white light.The kinetics of photocoloration and photobleaching processes were followed spectrophotometrically by monitoring the absorbance of the ring closed product 1-C at itsλ_(max) of 525 nm.The first-... 展开更多
关键词 FULGIDES PHOTOCHROMISM Polymer film Photobleaching Photoreaction kinetics Fatigue resistant
下载PDF
Photosafety testing of dermally-applied chemicals based on photochemical and cassette-dosing pharmacokinetic data
6
作者 Hiroto Ohtake Yukiko Suzuki +2 位作者 Masashi Kato Yoshiki Seto Satomi Onoue 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2016年第1期237-238,共2页
Drug-induced phototoxicity is elicited by exposure of skin and/or eyes to topical or systemic administration of chemicals,followed by exposure to sunlight.For photosafety testing,a new screening strategy,employing in ... Drug-induced phototoxicity is elicited by exposure of skin and/or eyes to topical or systemic administration of chemicals,followed by exposure to sunlight.For photosafety testing,a new screening strategy,employing in vitro photochemical/photobiological and in vivo cassette-dosing pharmacokinetic(PK)studies,was proposed[1,2].The screening system provided reliable phototoxic predictions of tested chemicals at least within the same chemical series;however,the applicability of the proposed strategy is not fully understood. 展开更多
关键词 Photosafety assessment PHOTOTOXICITY PHOTOREACTIVITY Pharmacokinetics
下载PDF
Research on organic matters in the drinking water of Kaschin-Beck disease area
7
作者 Wang Wenhua, Yang Chunlin, Qi Ruiming, Wang Zijian and Peng AnResearch center for Eco-Environmental Sciences.Chinese Academy of Sciences,Beijing 100083,China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1991年第4期35-47,共13页
Organic matters in drinking water of Kaschin-Beck disease areas were extracted. Then analyses and characterization were performed by means of multiply chemical and physical methods. The results did not show the obviou... Organic matters in drinking water of Kaschin-Beck disease areas were extracted. Then analyses and characterization were performed by means of multiply chemical and physical methods. The results did not show the obvious difference in the frame structure of humic substances and the structure of rmcromolecular compounds in the drinking water of disease and non-disease areas, but the difference in the contents of some micromolecular compounds and radicals. The investigation also includes the preliminary research on the photoreaction of drinking water from disease and non-disease areas and the accumulation of natural organic matter in the bone of tested animals. 展开更多
关键词 organic compounds humic substances drinking water Kaschin-Beck disease photoreaction.
下载PDF
SOLID STATE PHOTOREACTION OF N-HETERO-CYCLIC COMPOUNDS
8
作者 Ji Ben MENG Wen Guang WANG Yong Mei WANG Hong Gen WANG Department of Chemistry and Central Laboratory,Nankai University Tianjin 300071 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第2期115-118,共4页
Photochemical reactions of 3-methylindole,carbazole,benzimidazole with fused polycyclic aromatic hydrocarbons in solid state were investigated,The structures of 4 new compounds were confirmed by IR,UV,\+1HNNR,MS and e... Photochemical reactions of 3-methylindole,carbazole,benzimidazole with fused polycyclic aromatic hydrocarbons in solid state were investigated,The structures of 4 new compounds were confirmed by IR,UV,\+1HNNR,MS and elemental analysis.The structure of compounds 3.6 was established by X-ray crystallography. 展开更多
关键词 IR SOLID STATE PHOTOREACTION OF N-HETERO-CYCLIC COMPOUNDS PPM KBR
下载PDF
Synthesis and Crystal Structure of Tetraethyl syn-1,5,8,8bβ-Tetrahydrocyclobuta[1,2-b:3,4-b']dipydine-3,4aβ,7,8aβ(4H,4bβH)-tetracarboxylate
9
作者 李荣强 闫凤美 闫红 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第4期409-412,共4页
The synthesis of syn-photodimer from 1,4-dihydropyridine without 4-aryl was studied, and its single crystal was obtained (C22H30N2O8, Mr= 450.48). It crystallizes in monoclinic, space group P21/c with a = 11.937(2... The synthesis of syn-photodimer from 1,4-dihydropyridine without 4-aryl was studied, and its single crystal was obtained (C22H30N2O8, Mr= 450.48). It crystallizes in monoclinic, space group P21/c with a = 11.937(2), b = 20.913(4), c = 9.763(2) A,β = 108.46(3)°, V= 2311.9(8) ,A^3, Z= 4, Dc = 1.294 g/cm^3,/7(000) = 960,μ = 0.099 mm^- 1, R = 0.0640 and wR = 0.1464 for 4077 unique reflections with 1598 observed ones (I 〉 2σ(I). It is shown that the whole molecular structure of the title compound is a twist-boat conformation, and the two double bonds have a trend of potential intramolecular reaction under high-energy irradiation. 展开更多
关键词 1 4-DIHYDROPYRIDINE PHOTOREACTION syn-photodimer crystal structure
下载PDF
Asymmetric Photochemical Reaction of 5-Methylbicyclo[1.1.1]-pentanyl Ketone
10
作者 WANG Xiao-lin ZHANG Ke 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2012年第4期703-706,共4页
The density functional theory(DFT) calculations were performed to investigate a typical Norrish/Yang type II photoreaction of 5-methylbicyclo[1.1.1]-pentanyl ketone.The results reveal the essential correlation betwe... The density functional theory(DFT) calculations were performed to investigate a typical Norrish/Yang type II photoreaction of 5-methylbicyclo[1.1.1]-pentanyl ketone.The results reveal the essential correlation between structures on the one hand and energies,on the other hand,of the reactants,transition states and products based on both singlet ground(S0) and triplet excited(T1) potential energy surfaces.The feasible mechanism indicates that an intramolecular Norrish/Yang cyclization reaction takes place via H-abstraction to obtain the sole chiral cyclobutanol photoproduct.The located crossing point plays an important role in the cyclization process,which permits intersystem crossing(ISC) from T1 to S0 state.The rate-determining step may be to experience ISC between two different potential energy surfaces,requiring sufficient time for electron spin reversion,i.e.,spin multiplicity alteration.These conclusions are further confirmed by the second-order M ller-Plesset perturbation theory(MP2) calculations. 展开更多
关键词 Norrish/Yang type II photoreaction Density functional theory(DFT) Transition state Reaction mechanism Intersystem crossing
下载PDF
基于电子给体-受体复合物的脂肪烃碳氢键多样性转化
11
作者 王泽敏 闫超咸 +4 位作者 刘瑞华 李晓伟 戴佳佳 李祥乾 史大永 《Science Bulletin》 SCIE EI CAS CSCD 2024年第3期345-353,共9页
The ability to selectively introduce diverse functionality onto hydrocarbons is of substantial value in the synthesis of both small molecules and pharmaceuticals.In this endeavour,as a photocatalyst-and metalfree proc... The ability to selectively introduce diverse functionality onto hydrocarbons is of substantial value in the synthesis of both small molecules and pharmaceuticals.In this endeavour,as a photocatalyst-and metalfree process,the electron donor–acceptor(EDA)strategy has not been well explored.Here we report an approach to aliphatic carbon-hydrogen bond diversification through an EDA complex constituted by HCl and S^(IV)=O groups.As an efficient hydrogen atom transfer(HAT)reagent,chlorine radical can be produced via a proton-coupled electron transfer process in this system.Based on this unusual path,a photopromoted versatile aliphatic C–H functionalization is developed without photo-and metal-catalysts,including thiolation,arylation,alkynylation,and allylation.This conversion has concise and ambient reaction conditions,good functional group tolerance,and substrate diversity,and provides an alternative solution for the high value-added utilization of bulk light alkanes. 展开更多
关键词 PHOTOREACTION Electron donor-acceptor Aliphatic C-H functionalization Chlorine radicals Gaseous alkanes
原文传递
Photoinduced difunctionalization with bifunctional reagents containing N-heteroaryl moieties 被引量:2
12
作者 Wooseok Lee Inyoung Park Sungwoo Hong 《Science China Chemistry》 SCIE EI CAS CSCD 2023年第6期1688-1700,共13页
Bifunctional reagents that serve as dual coupling partners with an activating species have emerged as valuable synthetic tools in organic chemistry.They allow for the development of diverse reaction modes with enhance... Bifunctional reagents that serve as dual coupling partners with an activating species have emerged as valuable synthetic tools in organic chemistry.They allow for the development of diverse reaction modes with enhanced efficiency and structural variability,which is in high demand for atom-economic and sustainable synthesis.Among them,bifunctional reagents containing Nheteroaryl groups have received much attention due to their ability to introduce privileged N-heteroaryl moieties into complex molecules that are otherwise challenging to access.Furthermore,these reagents have been employed under visible-light conditions to achieve various synthetic applications,enabling difunctionalization of alkenes,alkynes,and[1.1.1]propellanes under mild reaction conditions,providing access to highly functionalized N-heteroarenes.In this review,we provide an overview of the recent achievements and applications of photoinduced difunctionalization using bifunctional reagents containing N-heteroaryl groups.We systematically categorize the representative contributions in the field based on bifunctional reagents and their reactivity patterns.This review aims to highlight the potential of these reagents as powerful synthetic tools for sustainable and diverse synthesis. 展开更多
关键词 bifunctional reagents N-heteroarylation PHOTOREACTION difunctionalization radical reaction
原文传递
Type I Photoreaction and Photoinduced Ferroptosis by a Ru(II)Complex to Overcome Tumor Hypoxia in Photodynamic Therapy 被引量:2
13
作者 Fen Qi Hao Yuan +4 位作者 Yuncong Chen Xin-Xin Peng Yanping Wu Weijiang He Zijian Guo 《CCS Chemistry》 CSCD 2023年第7期1583-1591,共9页
Photodynamic therapy(PDT)usually shows limited efficacy in solid tumors since traditional PDT is O_(2)^(-)dependent while solid tumors are inherently hypoxic.In addition,hypoxic tumor cells possess antiapoptotic pathw... Photodynamic therapy(PDT)usually shows limited efficacy in solid tumors since traditional PDT is O_(2)^(-)dependent while solid tumors are inherently hypoxic.In addition,hypoxic tumor cells possess antiapoptotic pathways that resist PDT-induced apoptosis.Therefore,developing photosensitizers(PSs)that show low O_(2)^(-)dependency and can induce nonapoptotic cell death pathways is critically needed.Herein,a series of Ru(II)polypyridine complex-based PSs,RuNMe,RuH,and RuCN,were synthesized,and their applications against hypoxic tumor cells through PDT were investigated.All three complexes showthe ability to generate the superoxide anion radical(·O_(2)^(-)),which is the type I photoreaction and less O_(2)^(-)dependent.RuNMe shows the best PDT performance against MCF-7 cells and three-dimensional multicellular spheroids,due to its higher cellular uptake and more reactive oxygen species generation.More importantly,RuNMe-incubated MCF-7 cells show photoinduced ferroptosis as evidenced by glutathione peroxidase 4 downregulation and lipid peroxide accumulation.This work not only develops a novel ferroptosis-inducing Ru(II)complex with the type I PDT process but also offers an effective strategy to solve tumor hypoxia in PDT. 展开更多
关键词 ferroptosis photodynamic therapy O2-independent type I photoreaction superoxide anion radical(·O_(2)^(-))
原文传递
Assessing the utility of dissolved organic matter photoreactivity as a predictor of in situ methylmercury concentration 被引量:1
14
作者 Sara J.Klapstein Susan E.Ziegler +1 位作者 David A.Risk Nelson J.O'Driscoll 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第6期160-168,共9页
Methylmercury(MeHg) bioaccumulation is a growing concern in ecosystems worldwide. The absorption of solar radiation by dissolved organic matter(DOM) and other photoreactive ligands can convert MeHg into less toxic... Methylmercury(MeHg) bioaccumulation is a growing concern in ecosystems worldwide. The absorption of solar radiation by dissolved organic matter(DOM) and other photoreactive ligands can convert MeHg into less toxic forms of mercury through photodemethylation. In this study, spectral changes and photoreactivity of DOM were measured to assess the potential to control photoreactions and predict in situ MeHg concentration. Water samples collected from a series of lakes in southwestern Nova Scotia in June, August, and September were exposed to controlled ultraviolet-A(UV-A) radiation for up to 24 hr. Dissolved organic matter photoreactivity, measured as the loss of absorbance at 350 nm at constant UV-A irradiation, was positively dependent on the initial DOM concentration in lake waters(r^2=0.94). This relationship was consistent over time with both DOM concentration and photoreactivity increasing from summer into fall across lakes. Lake in situ MeHg concentration was positively correlated with DOM concentration and likely catchment transport in June(r = 0.77) but not the other sampling months. Despite a consistent seasonal variation in both DOM and Fe, and their respective correlations with MeHg, no discernable seasonal trend in MeHg was observed. However, a 3-year dataset from the 6 study lakes revealed a positive correlation between DOM concentration and both Fe(r = 0.91) and MeHg concentrations(r = 0.51) suggesting a more dominant landscape mobility control on MeHg.The DOM-MeHg relationships observed in these lakes highlights the need to examine DOM photoreactivity controls on MeHg transport and availability in natural waters particularly given future climate perturbations. 展开更多
关键词 METHYLMERCURY Dissolved organic carbon photoreactions Kejimkujik National Park Freshwater lakes
原文传递
Absolute Asymmetric Synthesis Using A Cocrystal Approach
15
作者 H.Koshima 《复旦学报(自然科学版)》 CAS CSCD 北大核心 2007年第5期570-,共1页
1 Results Absolute asymmetric synthesis by means of solid-state reaction of chiral crystals self-assembled from achiral molecules is an attractive and promising methodology for asymmetric synthesis because it is not n... 1 Results Absolute asymmetric synthesis by means of solid-state reaction of chiral crystals self-assembled from achiral molecules is an attractive and promising methodology for asymmetric synthesis because it is not necessary to employ any external chiral source like a chiral catalyst.In order to design reliably absolute asymmetric syntheses in the solid state,it is inevitable to prepare and predict the formation of chiral crystals from achiral compounds.We have prepared a number of chiral cocrystals co... 展开更多
关键词 absolute asymmetric synthesis achiral molecules chiral crystallization COCRYSTALS photoreactions
原文传递
Rational design of a visible-light photochromic diarylethene:a simple strategy by extending conjugation with electron donating groups 被引量:2
16
作者 Shanliang Tang Fengling Song +2 位作者 Meiheng Lu Keli Han Xiaojun Peng 《Science China Chemistry》 SCIE EI CAS CSCD 2019年第4期451-459,共9页
Photochromic diarylethenes have been widely used in many fields. However, their cyclization process must be induced by UV light. In this article, a simple strategy is developed by extending π-conjugation with electro... Photochromic diarylethenes have been widely used in many fields. However, their cyclization process must be induced by UV light. In this article, a simple strategy is developed by extending π-conjugation with electron donating groups. The modified dirylethene derivative can photocyclolize under 405-nm light with a good photochromic efficiency. Meanwhile, its absorption and moderate fluorescence can be switched effectively in both directions by visible lights(405 and 520 nm, respectively) in different solutions and in living cells. We believe that this simple method will become a versatile strategy for developing various dirylethylenes with visible-light photochromism. 展开更多
关键词 diarylethylenes VISIBLE-LIGHT PHOTOCHROMISM PHOTOREACTION quantum yield fluorescence PHOTOSWITCHING
原文传递
Photochemical Studies on 5-Methylbicyclo[1.1.1]pentane Derivatives: p-Orbital Overlap Controlled Enantioselectivity 被引量:1
17
作者 马满玲 杨超 +3 位作者 李冰 邵玉田 赵国磊 夏吾炯 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2012年第1期91-95,共5页
The first example of the p-orbital overlap controlled enantioselectivity of Norrish type II photocyclization reaction was described. Irradiation of 5-methyl bicyclo[l. 1.1 ]pentanyl ketone with UV in the solid state a... The first example of the p-orbital overlap controlled enantioselectivity of Norrish type II photocyclization reaction was described. Irradiation of 5-methyl bicyclo[l. 1.1 ]pentanyl ketone with UV in the solid state as well as in the acetonitrile solution afforded the Norrish/Yang photocyclization compound as the sole product. Solid-state asymmetric photochemical studies using ionic chiral auxiliary technique led to the enantioselectivity as high as 60%. The results were rationalized by Xray single crystal structure. 展开更多
关键词 ENANTIOSELECTIVITY porbital overlap solid state Norrish type 11 photoreaction ionic chiral auxiliary
原文传递
Synthesis and Properties of Degradable Copolymers Com- posed of Poly(E-caprolactone) and 3,4-Dihydroxycinnamic Acid 被引量:1
18
作者 李继航 施冬健 +3 位作者 徐华青 胡娜 东为富 陈明清 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2012年第10期2445-2452,共8页
Photoreactive and degradable hyperbranched (HB) copolymers with various 3,4-dihydroxycinnamic acid (DHCA) compositions, poly(e-caprolactone)-co-poly(3,4-dihydroxycinnamic acid) (PCL-co-PDHCA), were ob- taine... Photoreactive and degradable hyperbranched (HB) copolymers with various 3,4-dihydroxycinnamic acid (DHCA) compositions, poly(e-caprolactone)-co-poly(3,4-dihydroxycinnamic acid) (PCL-co-PDHCA), were ob- tained by thermal melt-polycondensation of PCL and DHCA. The HB structures and the branching degree (BD) of the PCL-co-PDHCA copolymers were confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The melting points (Tm) of the PCL-co-PDHCA copolymers changed depending on the PCL and DHCA composition by differential scanning calorimetry (DSC) measurements. Wide angle X-ray dif- fraction (WXRD) analysis showed semi-crystalline of the PCL and PCL-co-PDHCA polymers. The PCL-co-PDHCA copolymers showed good photoreactivities and fluorescent properties. Crosslinking of the cin- namoyl groups in the copolymers caused by UV irradiation affected the thermal stability and wettability slightly. Moreover, the hydrolysis experiments revealed that copolyrners are facile degradable. 展开更多
关键词 DEGRADABILITY hyperbranched structure PHOTOREACTIVITY
原文传递
Chemical effects of size quantization of CdS nanoparticles
19
作者 陈德文 王素华 《Science China Chemistry》 SCIE EI CAS 1996年第6期645-653,共9页
The behaviour of photoreaction occurring on the superfine duster interface of semiconductor CdS has been studied. The results indicated that the size quantization effect of semiconductor nanoparticles was obviously re... The behaviour of photoreaction occurring on the superfine duster interface of semiconductor CdS has been studied. The results indicated that the size quantization effect of semiconductor nanoparticles was obviously reflected not only in their physical properties, but also in the interfacial photocatalysis reactions initiated by superfine nanopartides. This means that the direction and mechanisms in photoreactions of the compounds adsorbed on the surface of nanopartides could vary with the alteration of particle size because the redox potential values of semiconductor particles could be changed with the variation of particle size. Doubtlessly, this effect could play an important role in controlling the interfacial reaction mechanisms and raising the selectivity to photoreaction paths. 展开更多
关键词 nanoparticles CADMIUM SULFIDE SIZE QUANTIZATION effect ESR photoreaction.
原文传递
ELECTRON PARAMAGNETIC RESONANCE STUDIES OF SINGLE CRYSTAL SODIUM HEXAMOLYBDOCHROMATE (Ⅲ)Cr^(3+)/Na_3(AlMo_6O_(24)H_6)·8H_2O
20
作者 游效曾 陈颉 +1 位作者 韩世莹 眭云霞 《Science China Chemistry》 SCIE EI CAS 1991年第2期129-134,共6页
An X-band EPR study on a Na_3(CrMo_6O_(24)H_6)·8H_2O single crystal diluted by its isomor-phic compound Na_3(AlMo_6O_(24)H_6)·8H_2O at room temperature is reported. Using the least squares-fitting method to ... An X-band EPR study on a Na_3(CrMo_6O_(24)H_6)·8H_2O single crystal diluted by its isomor-phic compound Na_3(AlMo_6O_(24)H_6)·8H_2O at room temperature is reported. Using the least squares-fitting method to simulate the EPR data for principal planes, the Hamiltonian parameterswere obtained. The principal values of the g tensors are g_(ZZ) = 1.904, g_(XX)= 1.973, g_(YY)=1.933. The zero field splitting tensor parameters are D = 0.275 cm^(-1), E = 0.05 cm^(-1). The fielddependence of Cr^(3+) energy levels with field at different angles from the principal axes whenthe field is along the principal planes is calculated based on these experimental parameters.The isofrequency plots of calculated field vs. angle are also shown. They agree well with theexperimental results. 展开更多
关键词 electron PARAMAGNETIC resonance PHOTOREACTION POLYOXOMOLYBDATES zero field SPLITTING
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部