简介:Poly(aryleneetherdiketone)swerepreparedbythearomaticnucleophilicdisplacementreactionof4,4’-difluorobenzilwithdifferentbisphenolsinthepresenceofan-hydrouspotassiumcarbonateindiphenylsulfoneatelevatedtemperature.Thepolymersobtainedhadinherentviscosityof0.51~0.63dL/g,andexhibitedglasstransitiontemper-aturerangingfrom136~217℃mainlydependingonthebisphenolsusedinthepolymersynthesis.Thermogravimetryofthesepolymersshowedexcellentthermalstability,indi-catingthat10%weightlossesofthepolymerswereobservedintherangeabove428℃and438℃inairandnitrogen,respectively.ThemechanicalpropertiesofthesepolymerswerealsodescribedandthepermeabilityoffivepolymersforH2,O2andN2wasdeterminedat30℃.
简介:Baker'syeastmediatedreductionofopticallyactivediketoneisdescribed.Thetwoketogroupsareefficientlydifferentiatedandtheeevalueoftherecoveredmaterialisconsiderablyraised.Itaffordshighlyopticallyactivekeyintermediatesefficientlyforthesynthesisofnaturalpolyhydroxylatedagarofuranproducts.
简介:Noveltetranuclearcoppercomplexes,Cu4(OH)2(ClO4)3(HA).H2O(1)andCu4(ClO4)5(H3B).3H2O(2),weresynthesizedbyreacting1,5-bis(1'-phenyl-3'-methyl-5'-pyrazolone-4')-1,5--pentanedionewith1,3-propanediamineand2-hydroxyl-1,3-propanediamineinthepresenceofatemplatereagentcopperion,New[2+2]typeopencyclicmultidentateligandsarealsoobtainedfromthereaction(H4A)andH6Bstandfornewcompoundsfrom1,3-propanediamineand2-hydroxyl-1,3-propanediamine,respectively),TheyeachcontainfiveC=O,threeC=NandoneNH2group[s,Thecomplexeswerecharacterizedbyelementalanalyses,conductivity,FR-i.r.electronicspectraandextendedX-rayabsorptionfinestructure(EXAFS),Copperionsin(1)arebasicallyfourcoordinatewithtetragonalgeometry.TheaveragecoordinationbonddistancesofCu-NandCu-Oare1.91Aand2.05A.In(2).copperionsareprimarilyfivecoordinatewithsquare-basedpyramidalgeometry.TheaveragecoordinationbonddistancesofCu-NandCu-Oare1.93Aand2.08A.Fourcopperatomsinmoleculesmaybearrangedtetragonally.Boththeligandfieldandthecoordinationbondsincomplex(1)arestrongerthanthosein(2).Investigationsonvariabletemperaturesusceptibilitiesshowthatsomeantiferromagneticexchangeinteractionexistinthecomplexes,Theplotsofx-1versusTobeytheCurie-Weisslawonlyatlowtemperature.Preliminaryresultsofabioassayindicatethatthetwocomplexeshavesomeantitumouractivityinvitro.
简介:Anewtypeofβ-diketonebasedsidechainliquidcrystallinepolysiloxanes(DKLCP)withdifferentlengthofflexiblespacersandendgroupshavebeensynthesizedbyhydrosilationreaction.Thisisliquidcrystalpolymers(LCP)usingcoordinatingβ-diketoneligandasmesogens.ThephasebehaviourofDKLCPpolymerswasstudiedbydifferentialscanningcalorimetryandpolarizingmicroscopy.X-raydiffractioninvestigationsdemonstratedthatthepolysiloxaneswithsufficientlylongflexiblespacersweresmecticliquidcrystalpolymers,whilethosewithmuchshorterspacerswerenematicones.
简介:Anewtypeofpalladiumchelateofβ-diketone-basedsidechainliquidcrystalpolysiloxane(Pd-DKLCP)hasbeensynthesizedbychelationreactionofpalladiumdichloridewithpolymericligand,β-diketonepolysiloxane(DKLCP),usingTHFassolventatR.T..ThePd-chelationresultsingreatlyincreasingthephasetransitiontemperatureTKandtheenthalpychange△HKfromcrystaltoliquidcrystalstateandmakingthetemperaturerangeofLCstate△T(△T=TCl-TK)widened.AllthesechelatesPd-DKLCP’sdonotshowTCluntildecompositionat205℃.ItisnoteworthythatthePd-chelationcanexertmorepositiveeffectonthemesomorphicbehaviourofthepolymerligandthanthecounterpartCu-DKLCPdoes.Itisprobableduetothebiggersizeofdisc-likemesogenformedfromβ-diketoneandPd+2ionwith4dorbital.