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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.

简介：IntroductionGuillain-Barresyndrome(GBS)isconsideredtobeanautoimmunedisorderofperipheralnervoussystem’.Thebalanceofsympatheticnervesandparasympatheticnervesisdisturbed,whichleadstocompleteparalysisi’2’3.Moslpatientsshowthetypicalsymptomsafterbeinginfe...

简介：AF-5wassynthesizedthroughaconvergentmethod.ThekeystepwastheRobinsonannulationusingakeyintermediatepentylvinylketone.

简介：Tris)(η5-cyclopentadienyl-μ-carbonyl-iron)-μ3-nitrosylclusterwasobtainedfromthereactionofcyclopentadienyldicarbonylirondimerwithnitrogenmonoxideinxylene.Theclusterwascharacterizedbyelementalanalyses,IR,MSand1HNMR.Thecrystalstructureof[(η5-C5H5)(μ-CO)Fe]3(μ3-NO).C4H8OwasdeterminedbyX-raydiffractionanalysis.ItcrystallizesintheorthorhombicspacegroupPnma,a=9.053(2),6=10.545(2),c=22.525(4)A,V=2150.3(7)A3,Z=4,Dc=1.68g.cm-3;structuresolutionandrefinementbasedon1141reflectionswithI>3.0(I)(MoKa,A=0.71073A)convergedatR=0.0540.Theinfraredabsorptionbandat1325cm-1oftheμ3-NOinthecluster,whichisredshifted,showsthatμ3-NOisactivated.

简介：(-)-(5R,6S)-6-Acetoxyhexadecan-5-olide1,anaturalmosquitoattractantpheromone,wassynthesizedfromreadilyavailablealdehyde2andcyclopentanone3usingL-proline-catalyzedasymmetricaldolreactionasthekeystep.

简介：TwonewcoenzymeB12analogues,2’,5’-dideoxycytidylcobalamin(2a)and2’,5’-dide-oxyuridinylcobalamin(2b),andtwoothers,2’,5’-dideoxyadenosylcobalamin(2c),and5’-deoxy-thymidylcobalamin(2d)werepreparedbyanimprovedmethod.AllthefouranalogueswereinvestigatedbyUV-visand2D1HNMRspectroscopy.Thecomparisonsanddiscussionabouttheirspectroscopicpropertiesweredone.

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.

简介：根据Ａｆ－Ａｇ自由基加聚反应的数量分布函数，导出凝胶点附近的渐进分布函数和高分子矩的表示式．进一步应用标度变换，得到了描述溶胶－凝胶相变的广义标度律，从而揭示了Ａｆ－Ａｇ自由基加聚的固化反应是一个相变过程．

简介：(±)-5,5'-Dihydroxy-7,7'-dimethoxy-8,8'-biflavone((±)-l)wasresolvedintoitsopti-callypureformsviatheformationandrecrystallizationofits(2R)-and(2S)-l-(4-toluenesulfonyl)proly-late,andthemethylatedderivativesof(+)-and(-)-lwerealsoprepared.Theabsoluteconfigurationsofallthese8,8'-biflavoneshavebeenconfirmedbytheirCDspectra.

简介：Reactionsofthe6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrilederivative1withα-halo-carbonylcompoundsgavetheortho-substitutedintermediates2a-cwhichwereconvertedintofuro[2,3-b]thiopyrano[4,3-d]pyridines3a-cbyfusionofafuranmoietyunderbasicconditions.Furthercyclizationof3a-cledtoafusionofapyrimidinering,yieldingthetetracyclicproducts6,7and8.Inaddition,condensationof6withvariousaromaticaldehydesaffordedthecorrespondingimines9a,b.Mannichreactionof7gaveproducts10a,b.

简介：Fourteennew1-acyl-5-arylbiuretsweresynthesizedbythereactionofarylureaswithacylisocynantes.Thelatterwasobtainedfromacylchlorideandleadcyanateindichloromethane,usingpyridineascatalyst.Thestructuresofcompounds3a-nwereconfirmedbyIR,1HNMRandMSspectra.

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：以恒电位法在pH=9．0碱性水溶液中碳纤维簇电极上镀单层锌，在含有组氨酸和电解氧化锌镀层下原位合成了锌-组氨酸-羟基络合物修饰碳纤维电极，模拟了生物酶识别痕量的硫氢酸根离子，优化了电极制备的条件。建立了开路电位测定硫氢酸根离子的方法，在中性水溶液中，该电极以开路电位变化响应注入溶液中的硫离子浓度，并可用能斯特方程描述开路电位变化的规律。方法的最低检出限为1．0×10μmol／L，检测范围为1．0×10～1．0×10-18mol／L，相对标准偏差为3．5％。对实际样品中硫氢酸根离子检测结果为1．12×10-13mol／L，加标回收率为109．2％。研制的电化学传感器具有响应快速，灵敏度高，检出限低，检测范围宽，仪器简单方便等特点。

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简介：5-Amino-1,10-phenanthrolineandthreetypesofnew5-substituted1,10-phenanthrolinederivativesbydifferentalkylamides,phen-NHCOR[phen=1,10-phenanthrolineR=CH=CH2;(CH2)nBr,n=1,3-5(CH2)nCH3,n=9--14],weresynthesized.Theywerecharacterizedbymeansofelementalanalyses,infraredspectroscopy,protonnuclearmagneticresonancespectroscopy,andmassspectroscopy.Thesenewcompoundsareimportantligandsortheactivematerialsofruthenium(Ⅱ)electrochemiluminescent(ECL)sensors.

简介：ThecatalyticactivityofFe/ZSM-5fortheselectivereductionofNOtoN2withmethaneinthepresenceofexcessO2wasstudied.Fe/ZSM-5catalystswithvariousFeloadingswerepreparedbyimpregnationmethod.ItiswellknownthatmethaneisinactivewhenFe/ZSM-5asthecatalystfortheselectivecatalyticreduction(SCR)ofNOwithmethane.However,thispapershowsthatwhenthecontentofFewasabout0.5%,Fe/ZSM-5showedhighercatalyticactivityandselectivityofmethane,andputforwardmeasurableactivationforCH4isanimportantfactorforthereactionofremovalofNOxwithCH4.

简介：Sulfonylureaherbicideshavebeenwidelyusedbecauseoftheirlowapplicationrates,goodcropselectivitiesandlowmammaliantoxicities.However,somesulfonylureasmightpersistunfavourablyintheenvironmentwithresidualproblems.Inordertolookforecologicallysaferandenvironmentallybenignsulfonylureas,andonkeepingthepyrimidineringbeingmonosubstituted,15novelC5-monosubstitutedbenzenesulfonylureacompoundsweresynthesized.Thestructuresofallthecompoundssynthesizedwereconfirmedbyelementalanalysisand1HNMR.PreliminaryherbicidalactivitiesofthesenewsulfonylureacompoundsweredeterminedbyALSscreening(invitro)andpotbioassayexperiments(invivo).TheherbicidalresultsshowthatsomenovelsulfonylureasarecomparabletocommercialForamsulfuronandMonosulfuron.

简介：Newmethodsfordehydrogenationofsteroidal2,5（10）-dieneswith2,3-dichloro-5,6-dicyano-1,4-benzoquinone（DDQ）orpyridiniumhydrobromideperbromide（PHP,Py·HBr·Br2）toaromaticAringsteroidinquantitativeyieldinshorttimearedescribed.

简介：Thesupramolecularinclusioncompoundofβ-cyclodextrin(β-CD,host)with(η5-cyclopentadienyl)tricarbonylmanganese[MnCp(CO)3,guest]wasobtainedinacrystallinestate.Thehost-guestcompoundisthermallystableanddonotliberatetheguestonheatingat100$invacuum.Itwascharacteriedbyelementalanalysis,1HNMR,differentialscanningthermal(DSC)analysisandTLC.ContinueousvariationplotbyNMRmethodshowsthatβ-CDformed1:1inclusioncompoundwithMnCp(CO)3.Onthebasisof1HNMRspectraandthemodelbuildingwithCoreyPaulingKoltum(CPK)models,themostprobableinclusionmodeisproposed.