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263 个结果
  • 简介:ELECTRON TRANSFER BETWEEN Eu+ AND Ce+ IN SrMgF4 MATRIXELECTRONTRANSFERBETWEENEu+ANDCe+INSrMgF4MATRIX¥YingWU;Ch...

  • 标签:
  • 简介:NaphtholgreenBwasused,forthefirsttime,asanewmediatorinanamperometricglucosebiosensor.Itisagoodmediator,promotingelectrontransferfromglucoseoxidasetographiteelectrode.Thebiosensorshowshighsensitivitytoglucoseatlowpotentialwithresponsetimeof30seconds.Thelinearrangeisfrom1.5to18μmol/Lglucosewithdetectionlimitof0.5μmol/Lglucose.

  • 标签: 萘酚绿B 介体 葡糖氧化酶 生物传感器
  • 简介:Copolymerizationofstyrene(St)andisoprene(IP)wascarriedoutwithacatalystsystemcomposeaofanhydrouslanthanidechloridehexamethylphosphoramidecomplex(LnCl3·HMPA)andaluminumorganiccompound(AOC).Amongthecatalystsexamined,catalystNdCl3·HMPA/AI(i-Bu)3showedahighactivityinthecopolymerizationundercertainconditionsgivingcopolymers(5%—15%Stcontent)withhighcis-1,4microstructureinIPunits(>95%).TheeffectsofHMPA/Ndmolarratio,Al/Ndmolarratio,monomer/Ndmolarratio,Stfeedratio,andthereactiontimeoncopolymerizationwereexaminedwiththiscatalyticsystem.Theobtainedcopolymerswerecharacterizedby^1Hand^13CNMRspectroscopiesandgel-permeationchromatography(GPC).

  • 标签: 异戊二烯 苯乙烯 氯化镧 共聚反应 六甲基磷酰胺 铝有机化合物
  • 简介:MHP(CH3OOH)和EHP(CH3CH2OOH)的电离精力被方法根据在6-311+G*基础的Koopmans定理设置了的光谱学(足)测量和两个Gaussian-2(G2)计算和Hartree-Fock(HF)第一次铺平的HeI光电子决定了。MHP和EHP的PE系列的任务和描述被G2和HF计算也支持。MHP和EHP的第一个电离精力分别地是9.87和9.65eV。在空气的EHP的更高的溶解度被归因于他们的更低的电离精力价值。

  • 标签: 电光子分光光谱 量子计算 甲基过氧化氢 乙基过氧化氢 哈特里-福克法
  • 简介:二新自然杂环的混合物bretschneiderazinesA(2)和B(3)的灵巧的合成,从Bretschneiderasinensis的茎的一篇摘录孤立,被报导。我们作为关键步骤与硫和光气由指导lithiation和顺序的处理采用了benzamide的环合反应。所有新混合物充分借助于红外,1HNMR,13CNMR,和HRMS被描绘了。

  • 标签: 杂环化合物 全合成 简便合成 环化反应 红外特征 新化合物
  • 简介:Layereddoublehydroxides(LDHs)withhydrotalcite-typestructurecontainingFe3+,Al3+andMg2+werepreparedbymeansofacoprecipitationmethod.Theproductswerecharacterizedbyelementanalysis,X-raypowderdiffractionandtransmissionelectronmicroscopy.Itwasfoundthatevenifthemolarratioofn(Fe+Al)/n(Fe+Al+Mg)>0.33,yetapurehydrotalcite-likecompound(HTlc)phasewasgainedwhenn(Fe)/n(Al+Mg+Fe)≤0.30andn(Al)/n(Al+Mg+Fe)≤0.30;theAl(OH)3phaseappearedintheproductswhenn(Al)/n(Al+Mg+Fe)>0.30;andanamorphousphaseemergedwhenn(Fe)/n(Al+Mg+Fe)>0.33.TheseresultsshowthatthereisnoconcentrationsuperpositioneffectbetweenFe3+andAl3+onthecrystallinestateoftheproducedsamples.Inourpreviouswork,theconcentrationsuperpositioneffectbetweenZn2+andMg2+inthesynthesisofZn-Mg-Al-LDHswasfound.ForthepreparedFe-Al-Mg-LDHssamples,thevalueoflatticeparameteraisbetween0.30-0.32nm;andthevalueoflatticeparametercisbetween2.30-2.47nm,thebasalspacingisintherangeof0.76-0.83nm.Whentheratioofn(Fe)/n(Al)isaconstant,thevaluesofaandcincreasewiththeincreaseoftheMg2+contentoftheproducedsamples.Themeanparticlesizeandthemeancrystalgrainweredeterminedbyvirtueofaparticle-sizeinstrument,XRD-ScherrerformulaandTEMmethod,respectively.

  • 标签: 羟化物 水滑石结构 LDHS 元素分析 摩尔比
  • 简介:采用密度泛函B3LYP/6-311G(d,p)方法对CH3F与C2H3的反应体系进行了理论研究,获得了反应的势能面信息及可能的微观机理.在QCISD(T)/6-311++G(d,p)水平上精确计算了各反应物种的单点能.结果表明,除抽提氢反应外,标题反应还存在抽提氟(R1)、消氟化氢(R2)、消氢(R3)和自由基形成(R4)四类反应.在QCISD(T)/6-311++G(d,p)//B3LYP/6-311G(d,p)水平上,R1,R2,R3和R4反应的能垒分别是163.9,152.2,209.8和224.2kJ·mol-1,相应反应能为-56.6,-164.3,-2.7和-156.0kJ·mol-1,所有反应均放热,为热力学允许的反应.

  • 标签: CH3F C2H3 反应机理 过渡态 消氟化氢反应
  • 简介:8,8′-Dibromo-6,6′,7,7′-tetramethoxy-5,5′-diisopropyl-3,3′-oxydimethylenedinaphtho[2,1-b:2′,1′-d]furan,C32H30Br2O;M.W.=670;triclinic;spacegroupP1;a=8.896(2),b=10.216(1),c=10.423(1)A,α=108.48(1),β=119.36(1),γ=99.26(1);V=723.5A3;Z=1,Dcal.=1.479g.cm-3.MoKα=28.11cm-1,F(000)=326,T=293K.Thestructurewassolvedbydirectmethodandfull-matrixleast-squaresrefinementconvergedatR=0.034for2377observedreflections.Theoxygenatominseven-memberedringexistsinadisorderedarrangement.Bothbisnaphthaleneandoxygen-containingfive-memberedringhaveplanarconformationswithdihedralangle6°,showingmarkedaromaticfeature.

  • 标签: FURAN derivative dibromo-6 6 TRICLINIC membered planar
  • 简介:用Co2(CO)8与CH3CSNH2反应制得产物Ⅰ,又用Na2Fe(CO)4与Ⅰ反应制得产物Ⅱ(Ⅰ:Co3(μ3-S)(CO)7(CH3CSNH),Ⅱ:Co2Fe(μ3-S)(CO)7(CH3CSNH).通过元素分析。IR、UV、1HNMR、MS表征并用X射线衍射法测得Ⅱ的单晶结构.该簇合物属三斜晶系、PT空间群,晶胞参数:a=0.9203(1),b=1.1296(2),c=1.1425(2)nm;α=116.40°(2),β=101.92°(2),γ=92.58°(1);z=2,V=1.2162nm3,Dc=1.698cm3,μ=21.89cm-1.结构分析表明,Co2FeS构三角锥分子骨架,所有CO均为端基配体,S1为面桥基配体,CH3CSNH为双齿配体,与Co、Fe形成五元环结构.

  • 标签: 簇合物 三角锥分子骨架 硫代乙酰胺
  • 简介:采用直接动力学的方法,对多通道反应体系Br+CH3S(O)CH3进行了理论研究.在BH&H-LYP/6-311G(2d,2p)水平下获得了优化几何构型、频率及最小能量路径(MEP),能量信息的进一步确认在MC-QCISD(单点)水平下完成.利用正则变分过渡态理论,结合小曲率隧道效应校正(CVT/SCT)方法计算了该反应的两个可行的反应通道在200K~2000K温度范围内的速率常数.在整个反应区间内,生成HBr的反应通道与生成CHa的反应通道存在着竞争,前者是主反应通道,后者是次反应通道.变分效应和小曲率隧道效应对反应速率常数的计算影响都很小.理论计算得到的两个反应通道的反应速率常数与实验值符合得很好.

  • 标签: 直接动力学方法 速率常数 小曲率隧道效应 正则变分过渡态理论
  • 简介:路易斯底能从CF3SiMe3和包含羰基的混合物催化-trifluoromethyl酒精的形成。-trifluoromethyl白酒能也被用来处于基本条件支持合成,这被发现。

  • 标签: 有机合成 有机化学 催化反应
  • 简介:Synthesisofinorganicnanostructureswithspecificsizeandwelldefinedmorphologieshasattractedconsiderableattentionduetotheirsuperiorelectrical,optical,magnetic,andchemical

  • 标签: 纳米结构 FE2O3 合成 笼状 自由 三维
  • 简介:利用Gaussian-94计算程序中的B3LYP方法,在6-311+G(2d)6d基组下,对Si5,Si5H3,Si5H6,Si5Li3和Si5Na3原子簇的几何结构进行优化和频率计算.结果表明,Si5原子簇中最稳定的具有D3h对称性的结构中,位于同一平面上的3个Si原子确实具有剩余的成键能力,可以与3个H,Li,Na原子和6个H原子形成稳定的化合物.研究还发现,虽然H,Li和Na都属同一主族,但它们与Si5原子簇中Si原子的键连方式却不同,而且它们的加入,对Si5原子簇的'三角双锥'结构也有不同的影响.

  • 标签: Si5H3 Si5H6 Si5Li3 Si5Na3 硅原子簇 结构
  • 简介:AbinitiomolecularorbitalcalculationsofdoublynegativechargedB16H162-(D2)andneutralB16H16(Td)havebeendoneattheHF/6-31Glevel.TheyarepredictedtobechemicallyandkineticallystablebyvibrationalanalysesontheirrespectiveenergyhypersurfaceoftheHF/6-31Glevel.ThegeometricalstructureofthespeciesB16H1622-(D2)wasdiscussed.

  • 标签: Closo BORON hydrides ab INITIO MOLECULAR
  • 简介:TwopossiblereactionmechanismsofVS~+(~3∑~-,~1Γ)withCOinthegasphasehavebeenstudiedbyusingB3LYP/TZVPandCCSD(T)/6-311+G(3dr,3pd)methods:theO/Sexchangereaction(VS~++CO→VO~++CS)andtheS-transferreaction(VS~++CO→V~++COS).Thetworeactionsproceedviatwo-stepandone-stepmechanism,respectively.ThebarriersofthetripletandsingletPESsare30.6and50.9kcal/mol,respectively,forO/Sexchangereactionand7.3and50.2kcal/mol,respectively,fortheS-transferreaction.Theresultsindicatethatthetripletgroundstatereactionismorefavorable,andtheS-transferreactionismorefavorablethantheO/Sexchangereaction,whichisingoodagreementwiththeexperimentalobservation.

  • 标签: 钒元素 铅矿 硫化物 理论研究
  • 简介:FurfuralinaqueoussolutionwastreatedbyUV/O3method.Theresultsshowthattheremovalrateoffurfuralisseverelyenhancedandthesynergismphenomenonappearswhenultravioletandozonearepresenttogether.TheinfluencesofexperimentalparameterssuchaspH,theintensityoflightandthenegative-positiveionsonfurfuraldegradationwereinvestigated.Theresultsindicatethatfurfural(300mg/L)isalmostcompletelydegradedafter3hundertheoptimumconditions.TheintermediateinthefurfuraldegradationwascharacterizedbyGC-MSandIRspectrumandthedegradationmechanismoffurfuralbyUV/O3technologywasproposed.

  • 标签: 全降解 糠醛 技术 协同作用 实验参数 光照强度
  • 简介:Thetitlecompounds5a-5cwerepreparedviathereactionofmethyl2-perfluoroal-kynoates(4)withmethyl5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate(3),whichwasobtainedfromthereactionofmethylpropynate(2)withacetylmethylenetriphenylphosphorane(1)at-5-0℃.IntramoleculareliminationofPh3POtookplacewhencompound5washeatedinaqueousmethanolat115-120℃insealedtube,yieldingdimethyl2-trifluoromethyl-4-methylisophthalate(6a)from5aandmethyl5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate(6b)from5b,respectively.Thestructuresofcompounds5,6aand6bwereconfirmedbyIR,MS,1HNMR,19FNMRand13CNMRspectroscopyandelementalanalyses.Rectionmechanismsfortheformationofcompounds5,6aand6bwereproposed.

  • 标签: Phosphorane polysubstituted ARENE INTRAMOLECULAR CYCLIZATION
  • 简介:Erbium,Ytterbium-codopedZrO2nanoparticles(ZrO2∶Er3+,Yb3+)werepreparedbythesol-emulsion-geltechnique.Thepurposeofthepresentstudyistheapplicationofupconversionphosphorinthebiologicallabel.Inordertomakeoutthemechanismofupconversionunder980nmexcitationthe488nmpumpwasused.Theinfluenceoftemperatureonthecrystallitephasewasstudied.TheresultsconfirmtheupconvertedmechanisminZrO2∶Er3+,Yb3+nanocrystalsisduetoanenergytransferupconversion(ETU).

  • 标签: 二氧化锆 能量上转换作用 作用机理 铒离子 镱离子 掺杂