学科分类
/ 20
398 个结果
  • 简介:ThecrystalstructureofN-(2,3,4,6-tetra-O-acetyl-β-D-gly-cosyl)-thiocarbamicbenzoylhydrazine(C22H27N3O9S)wasdeterminedbyX-raydiffractonmethod.Thehexopyranosylringadoptsachairconformation.Alltheringsubstituentsareintheequatorialpositions.Theacetoxyl-methylgroupisinsynclinalconformation.TheSatomisinsynperiplanarconformationwhilethebenzoylhydrazinemoietyisanti-periplanar.Thethiocarbamicmoietyisalmostcompanarwiththebenzoylhydrazinegroup.Therearetwointramolecularhydrogenbondsandoneintermolecularhydrogenbondforeachmoleculeinthecrystalstructure.Themoleculesformanetworkstructurethroughintermolecularhydrogenbonds.

  • 标签: 晶体结构 N-(2 3 4 6-四-间-乙醚基-β-D-糖基)硫氨基甲酸苯甲酰肼 氢键 构象
  • 简介:Inthispaper,athiol-functionalizednanophotocatalystMPTES/TiO_2wasfirstsynthesizedbyone-potmethodusingP123asatemplate.X-raydiffractionconfirmsthecompleteanatasecrystallineofthiol-functionalizedTiO_2,N_2adsorption-desorptionisothermdemonstratedthatthesematerialspossesshighsurfaceareaandmesoporousstructure.TheresultsofXPSshowthatMPTEShasbeensuccessfullypolymerizedinmesoporousstructuredTiO_2.Thephotodegradationofphenanthrene(PHE)wasinvestigatedundervisiblelightirradiation(λ>420nm)toevaluatethephotocatalyticactivityofthesematerials.BasedtheexperimentresultsofGC-Massanalysis,apossiblemechanismwasproposed.

  • 标签: 纳米复合材料 可见光照射 光催化降解 二氧化钛 功能化 多环芳烃
  • 简介:应用量子化学DVXα方法对钌系氰氯络合物进行了系统的理论计算和解析,确定了相应的稳定几何形态和微观电子结构,为合成、应用和深入研究它们的性能提供了重要的理论依据.

  • 标签: 钌系氰氯络合物 电子结构 DVXα方法
  • 简介:STUDIESONTHESYNTHESISANDREACTIONWITHALKOXIDESOF3-OXO-1,2-BENZOISOTHIAZOLINE--ACETAMIDE1,1-DIOXIDESGuoFengZHAO;HuaZbengYANG(I...

  • 标签:
  • 简介:2,2’-二(1,1’-4-甲基-吡啶)联咪唑(L)、芳香二羧酸与乙酸镉在水热条件下反应得到了配位聚合物[Cd2(L)(p-bdc)2(H2O)2]n(1)和[Cd(L)0.5(m-bdc)]n(2),并用单晶衍射仪定义了其晶体结构.结构分析表明,配合物1结晶属于正交晶系,Ibca空间群,配合物2结晶属于单斜晶系,C2/c空间群,进一步分析表明,所合成的2个化合物都是有扭曲α-Po拓扑的三维网络结构.在室温条件下,配体L和2个配合物均表现出较好的荧光性质.

  • 标签: 晶体结构 联咪唑 羧酸 荧光性质
  • 简介:体外循环后精确控制鱼精蛋白用量对抗肝素,是预防鱼精蛋白中毒性反应的关键环节.由于血液中存在高浓度的亲脂性钾离子(如血液中钾离子的浓度约为5mg/L,血细胞中钾离子的浓度高达150mg/L),而传统的聚阳离子选择性电极膜相中含有阳离子位点,在这种情况下,钾离子很容易进入聚合物膜相而干扰鱼精蛋白阳离子的测定.为了克服血液中钾离子的干扰,开发了肝素活化的聚阴离子选择性电极技术,成功实现了鱼精蛋白聚阳离子的检测,高浓度的钾离子不干扰测定.在最佳条件下,该电极对鱼精蛋白聚阳离子的检出限可达0.1mg·L-1,线性范围为0.5-10mg·L-1.

  • 标签: 离子通量 离子选择性电极 鱼精蛋白 肝素
  • 简介:Asimpleandefficientmethodhasbeendeveloped;benzil/benzoinundergoessmoothcondensationwithvarioussubstitutedaldehydeandammoniumacetateinthepresenceofpotassiumdihydrogenphosphate(KH_2PO_4)undermildreactionconditionstoaffordthecorrespondingtrisubstitutedimidazoleinexcellentyields.Themethodforsynthesisofproduct,thereactionmixturewasrefluxinethanolfor40-90min.Thepresentmethodissimple,efficient,andcost-effective.

  • 标签: 钾 dihydrogen 磷酸盐(KH2PO4 ) 2 4 5-Triaryl-1H 鈥搃m idazole BENZIL 安息香 铵醋酸盐
  • 简介:ThreeC2-symmetric(10R,11R)-diethylsubstituteddibenzosuberane(DBS)-basedheliceneswithvaryingstericandconjugationdemandsoftheirbottomfragmentsweresynthesized.Onlythehelicene-7a[withthebottompartderivedfromtetralonewasfoundphoto-switchableinreasonabletimescale.Photoisomerizationofthediastereomericallypure(10R,11R,P)-helicene(7a)at280nmledtovirtuallyexclusiveformationoftheoppositeMform-diastereomer7a′(7a′/7a=99.6/0.4).Thepreferentialreturnof7a′to7acanbeeffecteduponirradiationat254nm(7a′/7a=3G/67)orthermallyat1307a′/7a=0/100).Thephoto-inducedswitchingprocessamountstoa133%differenceind.e.(from99.2%to-34%).TheconcomitantchangeofhelicenechiralitybetweenthesetwodiastereomericphotostationarystatesaugurswellfortheirpotentialapplicationasanopticalswitchinLCmaterials.Toourknowledge,oursystemservesasthebestchirochromicopticalswitchascomparedtotheexamplespossessingsimilarphotochromicproperties.

  • 标签:
  • 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:Basedonthestructure-activityrelationshipsofRGD-containingpeptides,aseriesof1,3-dihydro-l,3-dioxo-2H-isoindolederivativesweresynthesized.Allofthemwerefirstreported.Theirstructureswereconfirmedbyspectraldataandelementalanalysis.Theirabilitytoinhibitangiogenesiswereevaluatedinthechickembryochorioallantoicmembraneassayat-10^-5mol/L.Compounds5band5edisplayedobviouslyantiangiogenicactivity.

  • 标签: 合成 血管基因 1 3-二氢-l 3-二氧-2H-异吲哚衍生物 侯选基因 RGD时序
  • 简介:Aunanoparticles(AuNPs)wereelectrodepositedatthehighlyorderedanataseTiO2nanotubearray(TiO2NA)electrodeundersonicating,andtheAuNP-TiO2NAsensorwascharacterizedbyscanningelectronmicroscope(SEM),X-rayphotoelectronspectroscopy(XPS),X-raydiffraction(XRD).ThephotoelectrochemicalexperimentsindicatetheAuNP-TiO2NAsensorhaslowerphotoelectro-resistance,higherphotoelectrocatalyticalactivityandstabilitythanthatofpureTiO2NAsensorunderthesameconditions.Theas-preparedsensorcanbeusedforthedeterminationofchemicaloxygendemand(COD)inrealsamples,andtheobtainedresultsarecomparablewellwiththoseofbystandardK2Cr2O7method.Themethodproposedissimple,fast,costeffective,andenvironmentallyfriendly.

  • 标签: TiO2NA AuNP ELECTRODEPOSITION COD PHOTOELECTROCHEMICAL CATALYSIS
  • 简介:采用自洽场离散变分Xa(SCC-DV-Xa)方法对纯V2O5及夹层V2O5的能带结构、态密度、键强度、电子集居数等进行了研究.结果表明,Li+引入V2O2层间的最佳位置是在双键氧之下(或之上),且靠近层的中心位置,此时它与周围原子间的作用力非常微弱,并且材料的导电性增强,使夹层复合材料Li+注入/脱出具有很好的可逆性和较好的光学性质.

  • 标签: PEO 夹层复合材料 掺杂位置 电子结构 五氧化二钒 锂离子
  • 简介:基于C,B,N和Ga与H原子间的L-J势函数,系统计算了H2处于(n,n,)(n=8,10,12)单壁C,BN和GaN纳米管内部及外部不同处的势能.根据势能变化曲线,分析了3种纳米管氢物理吸附能力的差异,给出了H2在3种纳米管外部的势能表达式.研究结果表明:3种纳米管内部的氢吸附力均分别高于管外;随着纳米管直径的增加,各纳米管管内的氢吸附力均略有下降,而管外变化不明显;GaN,BN和C纳米管依次具有更好的储氢能力.

  • 标签: 纳米管 H2 势能 储氢
  • 简介:采用油的酸的一条简单solvothermal途径被开发了与不同形状准备锐钛矿TiO2nanocrystals,它被从0~0.5mmol增加NaF的数量从nanorods调节到nano椭圆体,并且光乐队差距因此从3.47eV减少了到3.29eV。不管多么当氟化物被改变到NH4F,结果的TiO2nanocrystals拥有了一个锐钛矿阶段,但是由小尺寸的nanocrystals组成并且nanorods,和乐队差距被增加到3.53eV。X光检查光电子光谱学(XPS)结果与NaF的增加的数量说明了氟的符号内容的增加为形状和光乐队的变化的报道能TiO2nanocrystals豁开。而且,氟的符号内容的缺席引起了形状的更少的变化,产品的光乐队差距的增加面对NH4F。这结果可以提供另一个方法与氟化物的帮助改变形状和金属氧化物nanocrystals的乐队差距。

  • 标签: 锐钛矿 TiO 2 氟化物 合成 光乐队差距 Solvothermal 途径
  • 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:Toinvestigatethetreatmenteffectof2-seleniumbridgedβ-cyclodextrin(2-SeCD),aGPXmimic,onthestrokeofstroke-pronespontaneouslyhypertensiverats(SHRSP),fifty-twoSHRSPof8-weekoldwererandomlydividedintofourgroupsA,B,CandcontrolgroupD.TheratsofgroupsA,B,CandDweregiven1.0%-1.5%NaClmassfractionasdrinkingfluid.Afteronsetofstroke,groupsA,BandCweregivenorally16.05,160.5and1605mg*kg-1*day-1of2-SeCD,respectively,andgroupDwasgivenwaterfor2weeks.Theclinicalscoreofstroke,systolicbloodpressure(SBP),survivaltimeofratswererecordedandthehistopathologicexaminationsoftheirbrainandcarotidarteryweremadeafterdecapitation.Theclinicalscoresofstrokeaftertreatmentwith160.5mg*kg-1*day-1(GroupB)and1605mg*kg-1*day-1(GroupC)of2-SeCDare2.55±0.98and1.98±0.79,respectively,thoseareobviouslylowerthanthatofgroupD(3.41±0.83,p<0.01).ThesurvivaldaysingroupB(10.0±8.6)andgroupC(14.4±7.9)arelongerthanthatforgroupD(4.7±2.9,p<0.01).TheelectronmicroscopestudyshowedthattheendotheliumofcarotidarterywasneartonormalingroupBandgroupC,whileitwasseriouslyinjuredincontrolgroupDandmildlyinjuredingroupA.2-SeCDmayeffectivelybeusedtotreatthestrokeforSHRSP.

  • 标签: 2-硒跨接β-环式糊精 谷胱甘肽过氧化物酶 酶模拟 高血压
  • 简介:Carbonylationofallylhalidescatalyzedbypoly(N-vinyl-2-pyrro-lidone)anchoredpalladiumcatalystaffordsβ,r-butonicacidunderatmo-sphericpressureandatroomtemperature.Theactivityandefficiencyofthecatalystaremuchhigherthanthoseofthereportedcatalystsforthisreaction.

  • 标签: ALLYL palladium CATALYZED VINYL halide carbonyl