简介:用密度泛函理论,在B3LYP/6-311++G**计算水平下分别对尿嘧啶所有的气相、液相、过渡态和质子转移异构体的结构进行全优化,获得它们在气相和水相中的几何结构和电子结构,PCM反应场溶剂模型用于水相计算.结果显示:在气相和水相中,水参与反应降低了互变异构质子迁移的反应活化能,对互变异构质子迁移的反应起到催化作用,但是没有改变各异构体的稳定性顺序.同时研究了尿嘧啶各烯醇式水助质子互变异构的反应机理,提出了尿嘧啶各烯醇式互变异构质子迁移的反应为平面六元环的过渡态结构.探讨了溶剂化效应对互变异构体的几何结构、能量、电荷分布以及互变异构反应活化能的影响等.
简介:Wehavesuccessfullysynthesized1-(2′-Phenyl)cycloproply1-2,3-epoxypropan-1-ol3,whichwillbeappliedtothekineticsstudyofoxiranylcarbinylradical.
简介:多代替的dihydrofurans是为自然产品和药品的合成的珍贵中介。可观的注意集中于发展有效并且为他们的准备的regioselective方法。把K2CO3用作一个底,与fur-2-oylmethyltriphenylarsonium溴化物1的反应和乙醇2-acetyl-3-arylacrylate2在在房间温度的tetrahydrofuran,我们发现一个有效协议被完成综合trans-3-aryl-4-carbethoxy-2,3-dihydro-2-fur-2-oyl-5-methylfurans3在有高stereoselectivity的好产量。化合物3的结构被红外,1HNMR,MS和HRMS证实。为3的形成的机制被建议。
简介:Treatmentof4-amino-3-(1-aryl-5-methyl-1,2,3-triazol-4-yl)-5-mercapto-1,2,4-triazoles/2-amino-5-(1-aryl-5-methyl-1,2,3-triazole-4-yl)-1,3,4-thiadiazoleswithbenzaldehyde,acetoneandω-bromoacetophenonewastestedandcompared.ThetitlecompoundsSchiffbases,amides,imidazolo[2,1-b]-1,3,4-thiadiazolesand7H-s-triazolo[3,4-b]-1,3,4-thiadiazineshavebeenconfirmedbyelementalanalyses,^1HNMR,IRandMSspectra.AllthecompoundshavealsobeenscreenedfortheirantibacterialactivitiesagainstB.subtilis,S.aureusandE.coli.
简介:Thioglycolicacid(TGA)-stabilizedCdTenanocrystals(NCs)werepreparedwithsodiumtelluriteastelluriumsource,whichavoidsthecumbersomeprocessesassociatedwithH2TeorNaHTesources.FluorescentCdTe/SiO2compositesweresynthesizedbyasol-gelmethodwithouttheexchangeofsurfaceligands.ThephasestructureofCdTeNCswasinvestigatedbyX-raydiffractometry.Forcomparison,somecharacterizationsweredoneforboththeCdTeNCsandthecomposites.CdTeNCsandCdTe/SiO2compositeswerecharacterizedwithTEM,digitalcameraandfluorescencespectrophotometer.ThestabilityofCdTeNCsandthecompositeswereinvestigatedinphosphate-bufferedsaline(PBS)bufferandthefluorescentpropertiesofthecompositeswerediscussedindetail.
简介:ThephotodegradationreactionrateofCHCl3inTiO2particulatesuspensionwasimperovedsignificantlybyHCl-treatment.TheeffectofHCl-treatmentonthephotocatalyticactivityofTiO2wasstrdiedinaPECcellbyusingIntensity-ModulatedPhotocurrentSpectroscopy(IMPS).ThemagntudeofphotocurrentresponseandthecharacteristicfrequenciesoftheupperandlowersemicirclesinthecomplexplaneofIMPSresponsewereanalyzed,andtheccathodicandanodicreactionprocessesofphotogeneratedholesandelectronswerediscussed.Theincreasesinthecathodicandanodicphotocurrentresponseandinthetimeconstantsofbothcathodicandanodicreactionprocessesofphotogeneratedholesandelectronswerediscussed.TheincreasesinthecathodicandanodicphotocurrentresponseandinthetimeconstantsofbothcathodicandanodicreactionprocessesindicatethatHCl-treatmentleadstotheimprovementofthephotocatalyticactivityofTiO2andachangeofthephotocatalytickineticmechanism.
简介:2-Oxoderivativesofglycosides,called2-ketoglycosidesorglycoside2-uloses,arebiologicallyimportantincarbohydratemetabolismandareveryusefulinsynthesisofbranched-chainsugarsandaminosugars.Verylittleisknownoftheirchemistrybecauseofthehighsusceptibilityofthesecompoundstodegradationinsolution,andinparticulartheirinstabilitytobase.Thusitisimportanttostudythereactivitiesof2-ketoglycosides.Inapreviouspaper,wereportedthetransformationof2-ketoglycosidesinpyridinesolution.Duringthetransformationof2-and3-ketoglycosides,ademethoxylationreactionoftheenolintermediatewasshowntotakeplacesimultaneouslywitheliminationtogivehex-1-enopyran-3-ulose.
简介:Thecomplexes(PhCH2)2Sn(MBT)2(2)and(PhCH2)3Sn(MBT)(3)(HMBT:2-mercaptobenzothiazole)havebeensynthesizedandcharacterizedbyelementalanalyses,andIR,^1H,^13C,^119SnN-MRspectrometriesandX-raydiffraction.Studiesonthecrystalstructuresof2and3showthatHMBTactsasbidentateligandthroughchelationofNandSatoms.Complex2containsasix-coordinatetinatomwiththeaxialangleC(15)-Sn(1)-C(22)129.6(2)°.Andthetinenvironmentofcomplex3isadistortedcis-trigonalbipyramidwithC(8)-Sn(1)-N(1)158.80°.
简介:hePhotocatalyticcharacterizationofTiO2supportedonactivecarbonwasinvestigatedforphotocatalyticdecompositionofdichloroaceticacid.ItwasfoundthatTiO2/ACexhibitedahigherphotocatalyticactivitythanpureTiO2.ThereasonisthatactivecarbonactingaspowerfuladsorbentsupportsmakeshighconcentrationenvironmentsoforganicpollutantmoleculesaroundTiO2particles.
简介:N酰--hydroxy-4-phenyl-oxazolidinethiones能被处理很快在高收益变换成他们的乙醇thiol酉旨与在0è的EtSH
简介:Inthiswork,acidfunctionalizedmulti-wallcarbonnanotubes(MWCNTs)weremodifiedwithimidazolium-basedionicliquids.Theselectiveoxidationofvariousalcoholswithhydrogenperoxidecatalyzedby[PZnMo_2W_9O_(39)]~(5-),ZnPOM,supportedonionicliquids-modifiedwithMWCNTs,MWCNTAPIB,isreported.Thiscatalyst[ZnPOM@APIB-MWCNT],wascharacterizedbyX-raydiffraction,scanningelectronmicroscopy(SEM)andFT-IRspectroscopicmethods.Thisheterogeneouscatalystexhibitedhighstabilityandreusabilityintheoxidationreactionwithoutlossofitscatalyticperformance.
简介:TwonewintercalationcompoundsFe0.90PS3(phen)0.41(1)(phenstandsfor1,10-phenanthrolineincludingapartof1,10-phenanthrolineH+)andFe0.83PS3(bipy)0.34(2)(bipystandsfor2,2’-bipyridineH+)weresynthesizedbythereactionofthelayeredFePS,with1,10-phenanthrolineor2,2’-bipyridineinthepresenceofaniliniumchloride.Theywerecharacterizedbyelementalanalyses,powderX-raydiffraction(XRD),infraredspectroscopy.Thelatticespacingoftheintercalatewasexpandedby0.90nmforFe0.90PS3(phen)0.41and0.57nmforFe0.83PS3(bipy)0.34withrespecttothepristineFePS3,indicatingthattheringplaneoftheguestsisperpendiculartothelayerofthehost.TheUV-visabsorptionspectraofthefiltrateinpreparationoftheintercalatesindicatethat1,10-phenanthrolineor2,2’-bipyridinealsoactsasacomplexingagenttoremoveintralamellarFe2+ionsintothesolutionduringintercalation.Themagneticpropertiesof1and2werestudied.
简介:Anumberofnaphthalenedonorcompoundsthatpossessanadamantanaminebindingmoietyandan(OCH2CH2)n(nn1,2,3,4,6,8)spacerweresynthesized.Thefluorescencequenchingbetweenthesedonorsubstratesandmono-6-O-p-nitrobenzoyl-β-cyclodextrin(pNBCD)andmono-6-O-m-nitrobenzoyl-β-cyclodextrin(mNBCD)wasstudiedindetail.Itwasfoundthatveryefficientfluorescencequenchingcouldoccurinthesesupramolecularsystems.Thisquenchingwasattributedtothephotoinducedelectrontransferinsidethesupramolecularassemblybetweenthenaphthalenedonorsandcyclodextrinacceptors.DetailedStern-VolmerconstantsweremeasuredandtheywerepartitionedintodynamicStern-Volmerquenchingconstantsandstaticbindingconstants.Itwasdemonstratedthatthebindingconstantsbetweenallthenaphthalenecompoundsandcyclodextrinsarethesameastheypossessthesamebindingsite,i.e.,adamantanamine.