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.
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.
简介:STUDIESONTHESYNTHESISANDREACTIONWITHALKOXIDESOF3-OXO-1,2-BENZOISOTHIAZOLINE-2-ACETAMIDE1,1-DIOXIDESGuoFengZHAO;HuaZbengYANG(I...
简介:Asimpleandefficientmethodhasbeendeveloped;benzil/benzoinundergoessmoothcondensationwithvarioussubstitutedaldehydeandammoniumacetateinthepresenceofpotassiumdihydrogenphosphate(KH_2PO_4)undermildreactionconditionstoaffordthecorrespondingtrisubstitutedimidazoleinexcellentyields.Themethodforsynthesisofproduct,thereactionmixturewasrefluxinethanolfor40-90min.Thepresentmethodissimple,efficient,andcost-effective.
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.
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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.
简介:Basedonthestructure-activityrelationshipsofRGD-containingpeptides,aseriesof1,3-dihydro-l,3-dioxo-2H-isoindolederivativesweresynthesized.Allofthemwerefirstreported.Theirstructureswereconfirmedbyspectraldataandelementalanalysis.Theirabilitytoinhibitangiogenesiswereevaluatedinthechickembryochorioallantoicmembraneassayat-10^-5mol/L.Compounds5band5edisplayedobviouslyantiangiogenicactivity.
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.
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。
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.
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.
简介:Carbonylationofallylhalidescatalyzedbypoly(N-vinyl-2-pyrro-lidone)anchoredpalladiumcatalystaffordsβ,r-butonicacidunderatmo-sphericpressureandatroomtemperature.Theactivityandefficiencyofthecatalystaremuchhigherthanthoseofthereportedcatalystsforthisreaction.