简介:NewrareearthvanadatesYSrQ-xCaxV3O9-y(x=0.0,0.67,1.0,1.33and2.0)havebeensynthesizedbyanewsimplemethod.X-raypowderdiffractionresultsshowthattheyaremono-phase.Theybelongtoorthorhombicstructureandtheirlatticeconstantsarecalculated.TheresultsofweightgainsinTGcurvesshowthatthelowervalentvanadiumisoxidizedtohighervalentstateathighertemperature.Theoxygencontentsofnewcompoundsarecalculatedfromtheweightgains.BothV3+andV4+coexistinYSr2-xCaxV3O9-y.Thesecompoundsexhibitlowelectricresistivityatroomtemperature.
简介:标题化合物(C30H35N3)以4-甲基苯甲醛、环十二酮和3-甲基-1-苯基-1H-吡唑-5-胺,在三氟乙酸和醋酸的作用下,经微波辐射合成得到.其结构通过单晶X射线衍射法确定,晶体属单斜晶系,空间群P21/c,相对分子质量Mr=437.61,晶胞参数a=1.08926(11)nm,b=2.1927(2)nm,c=1.04954(14)nm,V=2.4641(5)nm3,Z=4,晶胞密度Dc=1.180g/m3,吸收系数μ=0.069mm-1,单胞中电子的数目F(000)=944.晶体结构用直接法解出,经全矩阵最小二乘法对原子参数进行修正,最终的偏离因子为R=0.0468,ωR=0.0905.在晶体结构中新形成的吡啶环为共平面结构.
简介:Theabinitiomolecularorbitalmethodisemployedtostudytheenantioselectivereductionofacetophenonewithboranecatalyzedbythiszolidino[3,4-c]oxazaborolidine.Computationresultshowsthatthecontrollingstepforthereductionisthedecompositionofthecatalyst-alkoxyboraneadductandthereductionleadstoS-alcohols.ThetransitionatateofthehydridetransferfromtheboranemoietytothecarbonylcarbonofacetophenoneisatwistedchairstructurewithaB(2)-N(3)-BBH3-HBH3-CCo-OCO6-memberedring.
简介:SYNTHESISOF3-ARYL-1(2H,4H)ACRIDONESANDTHEIRDERIVATIVES¥RongYIN;GuangFanHAN;YuTianLI(DepartmentofMedicalLaboratory,JilinMediea...
简介:Theimportantintermediateforsynthesesofvariousanti-HIVnucleosideanalogues,methyl2,3-dideoxy-3-fluoro-6-O-(p-methylbenzoyl)-a-D-ribofuranoside,wassynthesizedstartingfrom2-deoxy-D-ribosein5stepswithanoverallyieldof24%.Thisstrategycanbealsousedforsynthesizingotheranalogueswithvarioussubstitutionsat3-Cposition.
简介:Thenanomaterialsoftenexhibitveryinterestingelectrical,optical,magnetic,andchemicalproperties,whichcannotbeachievedbytheirbulkcounterparts[1-7].Thedevelopmentofuniformnanometersizedparticleshasbeenintensivelypursuedbecauseoftheirtechnologicalandfundamentalscientificimportance[8-15].Itissignificantthatnanostructuredmaterialscanbecontrollablyassembledintotherequiredgeometryontosubstrates,becomingthebasisofthenextgenerationofcomponentsanddevices[16-31].Thedevelopmentofnewmethodsandstrategiesfororganizingthenanoparticlebasicbuildingblocksintothedesiredstructuresisrequired.Superlatticesmadefromthesebuildingblocksgiveustheopportunitytostudynotonlythepropertiesoftheindividualbuildingblocks,butalsocollectiveeffects.Thesuperparamagneticironoxidenanocrystals(NCs)havebeenusedinthefieldsofbio-medicine,ferrofluids,refrigerationsystem,catalysis,particularlyinmagneticresonanceimaging,tissueengineering,anddrugdeliveryapplications[32-42].