高分子材料研究方法 核磁共振與電子順磁共振波譜法課件

Chap3

NMRSpectroscopyandEPRSpectroscopy3.1Introduction3.21HNMRSpectroscopy3.313CNMRSpectroscopy3.4EPRSpectroscopy3.5ApplicationsonPolymersChap3NMRSpectroscopyandEP13.1IntroductionMagnetismandSpinMagneticResonanceNMRSpectroscopyEPRSpectroscopy3.1IntroductionMagnetismand23.1.1MagnetismandSpinMagnetismMovingchargesgeneratemagneticfieldsThemagnetismofmaterialsarerelatedwiththespinofmicroparticles3.1.1MagnetismandSpinMagnet33.1.1MagnetismandSpin3.1.1MagnetismandSpin43.1.2MagneticResonanceMagneticResonance3.1.2MagneticResonanceMagnet53.1.3NMRSpectroscopy3.1.3NMRSpectroscopy63.1.3NMRSpectroscopy3.1.3NMRSpectroscopy73.1.3NMRSpectroscopyRelaxation:excitednucleireturntothelowerenergylevelswithoutradiationSpin-crystalrelaxation:energyexchangedtosurroundingparticles/T1(halflife)Spin-spinrelaxation:energyexchangedwithadjacentnucleus/T2(halflife)3.1.3NMRSpectroscopyRelaxati83.1.4EPRSpectroscopyUnpairedelectrons3.1.4EPRSpectroscopyUnpaired93.21HNMRSpectroscopyChemicalShiftsSpin-SpinCouplingIntegralofAbsorptionPeakElucidationof1HNMRSpectra3.21HNMRSpectroscopyChemica103.2.1ChemicalShifts3.2.1ChemicalShifts113.2.1ChemicalShiftsTheShieldingEffectHeff=H0(1-σ)ν=γHeff/2πHeff:thefieldexperiencedbythenucleus;H0:theexternalfield(ofthespectrometer);σ:thenondimensionalshieldingconstant;ν:thefrequencyatwhichNMRtransitionoccurs;γ:themagnetogyricratio.3.2.1ChemicalShiftsTheShiel123.2.1ChemicalShiftsTheShieldingEffectShielding：Hattachedtoanelectron-donatingsubstituent→adecreaseinHeffDeshielding:Hattachedtoanelectron-withdrawinggroup→anincreaseinHeff3.2.1ChemicalShiftsTheShiel133.2.1ChemicalShiftsChemicalShiftsδ=(νsample-νreference)/νspectrometer×106(ppm)

Normally,tetramethylsilane(TMS)ischosenasthereferenceinnon-aqueousmedia.InTMS,12protonsareallchemicallyequivalentandgiveasinglepeakatanH0higherthanmostotherprotonresonances.3.2.1ChemicalShiftsChemical14高分子材料研究方法核磁共振與電子順磁共振波譜法課件153.2.1ChemicalShiftsChemicalShiftsTherangeofthe1Hchemicalshifts:rathersmall,0-15.H0willnotinfluencethe1Hchemicalshifts3.2.1ChemicalShiftsChemical163.2.1ChemicalShiftsChemicalShiftsFactorsinfluencingchemicalshifts:Theelectronegtivity:Themoreelectronegtivetheatomwhichthecarbonbearingtheprotonisattachedto,themoredeshieldedtheproton.3.2.1ChemicalShiftsChemical173.2.1ChemicalShiftsChemicalShiftsFactorsinfluencingchemicalshifts:Theringcurrentofthedelocalizedelectrons:magneticanisotropyThehydrogenbond:deshieldingThesolventeffect3.2.1ChemicalShiftsChemical18δsimilarlyδsimilarly19δδ203.2.1ChemicalShiftsChemicalShiftsSomeempiricalrules:Formetheneandmethylenegroups:

δ=0.23+ΣσiFor1Hattachedtoalkenes:

δ=5.23+Zgeminal+Ztrans+ZcisForsubstituentbenzenes:

δ=7.30-ΣSi3.2.1ChemicalShiftsChemical213.2.2Spin-SpinCouplingTheSpin-SpinCouplingNucleicaninteractwitheachothertocausemutualsplittingoftheotherwisesharpresonancelinesintomultiplets.Thecouplingconstant:thespacingofthemultiplets,whichcharacterizesthestrengthofthecouplingandisexpressedinhertz.3.2.2Spin-SpinCouplingTheSp223.2.2Spin-SpinCouplingTheOriginofSpin-SpinCoupling1Hhas2orientations:Iftheorientationtheadjacentprotonwiththemagneticfield:absorbaslighthigherfrequencyIftheorientationtheadjacentprotonagainstthemagneticfield:absorbaslightlowerfrequency3.2.2Spin-SpinCouplingTheOr23高分子材料研究方法核磁共振與電子順磁共振波譜法課件243.2.2Spin-SpinCouplingTheEquivalenceThechemicalequivalence:Themagneticalequivalence:ThespinsystemTheexpressionofnon-equivalent1H:A,B,…,ZTheexpressionofchemicallyequivalent1H:A’Theexpressionofmagneticallyequivalent1H:AnThestrengthofthespin-spincouplingsystem3.2.2Spin-SpinCouplingTheEq253.2.2Spin-SpinCouplingTheSplittingPatternsThefirst-orderspectraΔν/J≥6ChemicallyandmagneticallyequivalentprotonsdonotcoupletooneanotherCouplingwithtwogroupsofequivalentprotons:thenumberofthemultiplet→n+1rule/therelativeintensitiesofwhicharegivenbyPascal’striangle/thecenterofeachgroupofthemultiplet→δ/J→thedistancebetweenthesplittings3.2.2Spin-SpinCouplingTheSp263.2.2Spin-SpinCouplingTheFirst-orderSpectraCouplingwithseveralgroupsofmagneticallyprotons:thenumberofthemultiplets:(n1+1)(n2+1)…(nN+1)TheSecond-orderSpectraΔν/J<6thenumberofthemultipletusually>n+1rule/therelativeintensities/δ:notatthecenter,butatthecenterofgravity/J:3.2.2Spin-SpinCouplingTheFi273.2.2Spin-SpinCouplingTheCouplingConstantandtheMolecularStructureTheonebond(1J)coupling:13C-1HThetwobond(2J)coupling:thegeminalcoupling,Jisthelargestin1HNMRThethreebond(3J)coupling:thevicinalcoupling,themostcommonin1HNMRThefourorfive(4Jor5J)coupling:thelong-rangecoupling,mainlyoccurinaromaticcompounds3.2.2Spin-SpinCouplingTheCo283.2.3IntegralofAbsorptionPeakTheintegraloftheareaoftheabsorptionpeakgivesthenumberofprotons3.2.3IntegralofAbsorptionP293.2.4Elucidationof

1HNMRSpectraAnalysis1HNMRSpectraConfirmingthenumberofdifferentprotonsaccordingtotheheightoftheintegralcurveDeducingthestructureofthemoleculeinlinewithδ,thenumberofthesplittinglinesandJIfpossible,comparingwiththestandard1HNMRspectraFurtheranalysing1HNMRspectracombinedwiththeotherspectra3.2.4Elucidationof

1HNMRS30高分子材料研究方法核磁共振與電子順磁共振波譜法課件31高分子材料研究方法核磁共振與電子順磁共振波譜法課件323.2.4Elucidationof

1HNMRSpectraMethodsFurtherElucidating1HNMRSpectraHighfield1HNMRspectraShiftreagents:DecoupledspectraThenuclearoverhausterEffectTheexchangingofthedeterium3.2.4Elucidationof

1HNMRS333.313CNMRSpectroscopyComparisonwith1HNMRSpectroscopyProton-decouplingMethods3.313CNMRSpectroscopyCompar343.3.1Comparisonwith

1HNMRSpectraSensitivityLowmagnetogyricratioLownaturalabundanceof13C:Resolutionδ:0-300,largerthanthatof1HNMRby20foldsSomeempiricalrules:3.3.1Comparisonwith

1HNMR353.3.1Comparisonwith

1HNMRSpectraObjects:ThemolecularskeletonFunctionalgroups:C=O,C≡N,quaternarycarbonSpin-SpinCoupling13C-1Hcoupling3.3.1Comparisonwith

1HNMR363.3.2Proton-decouplingMethodsBroad-bandDecoupling:Off-resonanceDecouplingSpinTickling3.3.2Proton-decouplingMethod373.4EPRSpectroscopyPrinciplesofEPRSpectroscopyInstrumentationElucidationofEPRSpectraComparisonbetweenEPRSpectroscopyandNMRSpectroscopy3.4EPRSpectroscopyPrinciples383.4.1PrinciplesofEPRSpectroscopyPara-magnetismandAnti-magnetismPara-magnetismmatterswithunpaired(parallellyspinned)electrons,μs

≠0Anti-magnetismmatterswithpaired(anti-parallellyspinned)electrons,μs=03.4.1PrinciplesofEPRSpectr393.4.1PrinciplesofEPRSpectroscopyPara-magnetismandAnti-magnetismPara-magneticmattersMatterswithfreeradicalsMoleculeswithdoubleormultipleunpairedelectronsMoleculeswithtripletelectrons

3.4.1PrinciplesofEPRSpectr403.4.1PrinciplesofEPRSpectroscopyElectronParamagneticResonanceSpinenergystateofelectronsAccordingtothequantummechanics,therepresentstherelationbetweenthespinmomentandspinangularmomentum:μs=-gβS

3.4.1PrinciplesofEPRSpectr413.4.1PrinciplesofEPRSpectroscopyElectronParamagneticResonanceSpinenergystateofelectronsFromtheclassicalelectromagnetictheory,E=-μs·H=-(-gβS)H=gβSHMs=±1/2

3.4.1PrinciplesofEPRSpectr423.4.1PrinciplesofEPRSpectroscopyElectronParamagneticResonanceElectronParamagneticResonance

3.4.1PrinciplesofEPRSpectr433.4.2InstrumentationEPRSpectrometer

3.4.2InstrumentationEPRSpect443.4.2InstrumentationMethodsFrequencyscanningFixingthefield,scanningthefrequencyFieldscanning√Fixingthefrequency,scanningthefieldSeeTable3-133.4.2InstrumentationMethods453.4.2InstrumentationSamplingSamplesGas/liquid/solidSpintrappingandspinlabelingS(theanti-magneticcompound)+R?(highactivity,shortlife)→RS?(stable)S:thespintrap

3.4.2InstrumentationSampling463.4.2InstrumentationSamplingWidelyusedspintrapsNitrosocompounds

NitrosogroupsTertiarycarbonFormingfreeradicalsofnitroxides

3.4.2InstrumentationSampling473.4.2InstrumentationSamplingWidelyusedspintrapsNitroxides

Formingfreeradicalsofnitroxides

3.4.2InstrumentationSampling483.4.3ElucidationofEPRSpectraEPRSpectraHorizontalaxis:thefieldintensityVerticalaxis:Therelativeabsorbance:Thedifferentialoftherelativeabsorbance:3.4.3ElucidationofEPRSpect493.4.3ElucidationofEPRSpectraHyperfineStructure(HFS):interactionsbetweenunpairedelectronsandnucleiDipole-dipoleinteraction:anisotropic3.4.3ElucidationofEPRSpect50高分子材料研究方法核磁共振與電子順磁共振波譜法課件51高分子材料研究方法核磁共振與電子順磁共振波譜法課件52高分子材料研究方法核磁共振與電子順磁共振波譜法課件53高分子材料研究方法核磁共振與電子順磁共振波譜法課件543.4.3ElucidationofEPRSpectraHyperfineStructure(HFS):InteractionofFermicontact:Electronsinsorbitals:isotropicinteractionFreeradicalsinsolutionsHyperfinesplittingconstant(a):2nI+1rule

3.4.3ElucidationofEPRSpect553.4.4ComparisonbetweenEPRSpectroscopyandNMRSpectroscopy3.4.4ComparisonbetweenEPRS563.5ApplicationsonPolymersApplicationsofNMRonPolymersApplicationsofEPRonPolymers3.5ApplicationsonPolymersAp573.5.1ApplicationsofNMRonPolymersIdentification:PolyethylacrylateHa=4.12ppm,Hb=1.21ppmPolyethylpentanoateHa=2.25ppm,Hb=1.11ppm3.5.1ApplicationsofNMRonP583.5.1ApplicationsofNMRonPolymersQuantitativeAnalysisPolybutadienestyrene(PBS)

δC=CH=5ppm,δC6H=7ppmthenumberofstyreneunit:A/5athenumberofbutadieneunit:3.5.1ApplicationsofNMRonP593.5.1ApplicationsofNMRonPolymersTacticity3.5.1ApplicationsofNMRonP60高分子材料研究方法核磁共振與電子順磁共振波譜法課件613.5.1ApplicationsofNMRonPolymersStructuresinCopolymers3.5.1ApplicationsofNMRonP62高分子材料研究方法核磁共振與電子順磁共振波譜法課件633.5.1ApplicationsofNMRonPolymersMolecularMovement:spin-spinrelaxationtimeSolidNMR3.5.1ApplicationsofNMRonP643.5.2ApplicationsofEPRonPolymersFreeRadicalsinInitiatingSystemsROOH-para-N,N-dimethylbenzylaminesystemMNPheptacoset3.5.2ApplicationsofEPRonP653.5.2ApplicationsofEPRonPolymersFreeRadicalsinInitiatingSystemsAmmoniumpersulfate(APS)-cycloaminesystemMNPheptacoset3.5.2ApplicationsofEPRonP663.5.2ApplicationsofEPRonPolymersDynamicsofPolymerizationDecompositionofinitiatorsChaininitiationChainterminationChainpropagation3.5.2ApplicationsofEPRonP673.5.2ApplicationsofEPRonPolymersChainStructureHead-headstructureinPVCMNPnonet3.5.2ApplicationsofEPRonP683.5.2ApplicationsofEPRonPolymersChainStructureHead-tailstructureinPVCMNPhexet3.5.2ApplicationsofEPRonP69Chap3

NMRSpectroscopyandEPRSpectroscopy3.1Introduction3.21HNMRSpectroscopy3.313CNMRSpectroscopy3.4EPRSpectroscopy3.5ApplicationsonPolymersChap3NMRSpectroscopyandEP703.1IntroductionMagnetismandSpinMagneticResonanceNMRSpectroscopyEPRSpectroscopy3.1IntroductionMagnetismand713.1.1MagnetismandSpinMagnetismMovingchargesgeneratemagneticfieldsThemagnetismofmaterialsarerelatedwiththespinofmicroparticles3.1.1MagnetismandSpinMagnet723.1.1MagnetismandSpin3.1.1MagnetismandSpin733.1.2MagneticResonanceMagneticResonance3.1.2MagneticResonanceMagnet743.1.3NMRSpectroscopy3.1.3NMRSpectroscopy753.1.3NMRSpectroscopy3.1.3NMRSpectroscopy763.1.3NMRSpectroscopyRelaxation:excitednucleireturntothelowerenergylevelswithoutradiationSpin-crystalrelaxation:energyexchangedtosurroundingparticles/T1(halflife)Spin-spinrelaxation:energyexchangedwithadjacentnucleus/T2(halflife)3.1.3NMRSpectroscopyRelaxati773.1.4EPRSpectroscopyUnpairedelectrons3.1.4EPRSpectroscopyUnpaired783.21HNMRSpectroscopyChemicalShiftsSpin-SpinCouplingIntegralofAbsorptionPeakElucidationof1HNMRSpectra3.21HNMRSpectroscopyChemica793.2.1ChemicalShifts3.2.1ChemicalShifts803.2.1ChemicalShiftsTheShieldingEffectHeff=H0(1-σ)ν=γHeff/2πHeff:thefieldexperiencedbythenucleus;H0:theexternalfield(ofthespectrometer);σ:thenondimensionalshieldingconstant;ν:thefrequencyatwhichNMRtransitionoccurs;γ:themagnetogyricratio.3.2.1ChemicalShiftsTheShiel813.2.1ChemicalShiftsTheShieldingEffectShielding：Hattachedtoanelectron-donatingsubstituent→adecreaseinHeffDeshielding:Hattachedtoanelectron-withdrawinggroup→anincreaseinHeff3.2.1ChemicalShiftsTheShiel823.2.1ChemicalShiftsChemicalShiftsδ=(νsample-νreference)/νspectrometer×106(ppm)

Normally,tetramethylsilane(TMS)ischosenasthereferenceinnon-aqueousmedia.InTMS,12protonsareallchemicallyequivalentandgiveasinglepeakatanH0higherthanmostotherprotonresonances.3.2.1ChemicalShiftsChemical83高分子材料研究方法核磁共振與電子順磁共振波譜法課件843.2.1ChemicalShiftsChemicalShiftsTherangeofthe1Hchemicalshifts:rathersmall,0-15.H0willnotinfluencethe1Hchemicalshifts3.2.1ChemicalShiftsChemical853.2.1ChemicalShiftsChemicalShiftsFactorsinfluencingchemicalshifts:Theelectronegtivity:Themoreelectronegtivetheatomwhichthecarbonbearingtheprotonisattachedto,themoredeshieldedtheproton.3.2.1ChemicalShiftsChemical863.2.1ChemicalShiftsChemicalShiftsFactorsinfluencingchemicalshifts:Theringcurrentofthedelocalizedelectrons:magneticanisotropyThehydrogenbond:deshieldingThesolventeffect3.2.1ChemicalShiftsChemical87δsimilarlyδsimilarly88δδ893.2.1ChemicalShiftsChemicalShiftsSomeempiricalrules:Formetheneandmethylenegroups:

δ=0.23+ΣσiFor1Hattachedtoalkenes:

δ=5.23+Zgeminal+Ztrans+ZcisForsubstituentbenzenes:

δ=7.30-ΣSi3.2.1ChemicalShiftsChemical903.2.2Spin-SpinCouplingTheSpin-SpinCouplingNucleicaninteractwitheachothertocausemutualsplittingoftheotherwisesharpresonancelinesintomultiplets.Thecouplingconstant:thespacingofthemultiplets,whichcharacterizesthestrengthofthecouplingandisexpressedinhertz.3.2.2Spin-SpinCouplingTheSp913.2.2Spin-SpinCouplingTheOriginofSpin-SpinCoupling1Hhas2orientations:Iftheorientationtheadjacentprotonwiththemagneticfield:absorbaslighthigherfrequencyIftheorientationtheadjacentprotonagainstthemagneticfield:absorbaslightlowerfrequency3.2.2Spin-SpinCouplingTheOr92高分子材料研究方法核磁共振與電子順磁共振波譜法課件933.2.2Spin-SpinCouplingTheEquivalenceThechemicalequivalence:Themagneticalequivalence:ThespinsystemTheexpressionofnon-equivalent1H:A,B,…,ZTheexpressionofchemicallyequivalent1H:A’Theexpressionofmagneticallyequivalent1H:AnThestrengthofthespin-spincouplingsystem3.2.2Spin-SpinCouplingTheEq943.2.2Spin-SpinCouplingTheSplittingPatternsThefirst-orderspectraΔν/J≥6ChemicallyandmagneticallyequivalentprotonsdonotcoupletooneanotherCouplingwithtwogroupsofequivalentprotons:thenumberofthemultiplet→n+1rule/therelativeintensitiesofwhicharegivenbyPascal’striangle/thecenterofeachgroupofthemultiplet→δ/J→thedistancebetweenthesplittings3.2.2Spin-SpinCouplingTheSp953.2.2Spin-SpinCouplingTheFirst-orderSpectraCouplingwithseveralgroupsofmagneticallyprotons:thenumberofthemultiplets:(n1+1)(n2+1)…(nN+1)TheSecond-orderSpectraΔν/J<6thenumberofthemultipletusually>n+1rule/therelativeintensities/δ:notatthecenter,butatthecenterofgravity/J:3.2.2Spin-SpinCouplingTheFi963.2.2Spin-SpinCouplingTheCouplingConstantandtheMolecularStructureTheonebond(1J)coupling:13C-1HThetwobond(2J)coupling:thegeminalcoupling,Jisthelargestin1HNMRThethreebond(3J)coupling:thevicinalcoupling,themostcommonin1HNMRThefourorfive(4Jor5J)coupling:thelong-rangecoupling,mainlyoccurinaromaticcompounds3.2.2Spin-SpinCouplingTheCo973.2.3IntegralofAbsorptionPeakTheintegraloftheareaoftheabsorptionpeakgivesthenumberofprotons3.2.3IntegralofAbsorptionP983.2.4Elucidationof

1HNMRSpectraAnalysis1HNMRSpectraConfirmingthenumberofdifferentprotonsaccordingtotheheightoftheintegralcurveDeducingthestructureofthemoleculeinlinewithδ,thenumberofthesplittinglinesandJIfpossible,comparingwiththestandard1HNMRspectraFurtheranalysing1HNMRspectracombinedwiththeotherspectra3.2.4Elucidationof

1HNMRS99高分子材料研究方法核磁共振與電子順磁共振波譜法課件100高分子材料研究方法核磁共振與電子順磁共振波譜法課件1013.2.4Elucidationof

1HNMRSpectraMethodsFurtherElucidating1HNMRSpectraHighfield1HNMRspectraShiftreagents:DecoupledspectraThenuclearoverhausterEffectTheexchangingofthedeterium3.2.4Elucidationof

1HNMRS1023.313CNMRSpectroscopyComparisonwith1HNMRSpectroscopyProton-decouplingMethods3.313CNMRSpectroscopyCompar1033.3.1Comparisonwith

1HNMRSpectraSensitivityLowmagnetogyricratioLownaturalabundanceof13C:Resolutionδ:0-300,largerthanthatof1HNMRby20foldsSomeempiricalrules:3.3.1Comparisonwith

1HNMR1043.3.1Comparisonwith

1HNMRSpectraObjects:ThemolecularskeletonFunctionalgroups:C=O,C≡N,quaternarycarbonSpin-SpinCoupling13C-1Hcoupling3.3.1Comparisonwith

1HNMR1053.3.2Proton-decouplingMethodsBroad-bandDecoupling:Off-resonanceDecouplingSpinTickling3.3.2Proton-decouplingMethod1063.4EPRSpectroscopyPrinciplesofEPRSpectroscopyInstrumentationElucidationofEPRSpectraComparisonbetweenEPRSpectroscopyandNMRSpectroscopy3.4EPRSpectroscopyPrinciples1073.4.1PrinciplesofEPRSpectroscopyPara-magnetismandAnti-magnetismPara-magnetismmatterswithunpaired(parallellyspinned)electrons,μs

≠0Anti-magnetismmatterswithpaired(anti-parallellyspinned)electrons,μs=03.4.1PrinciplesofEPRSpectr1083.4.1PrinciplesofEPRSpectroscopyPara-magnetismandAnti-magnetismPara-magneticmattersMatterswithfreeradicalsMoleculeswithdoubleormultipleunpairedelectronsMoleculeswithtripletelectrons

3.4.1PrinciplesofEPRSpectr1093.4.1PrinciplesofEPRSpectroscopyElectronParamagneticResonanceSpinenergystateofelectronsAccordingtothequantummechanics,therepresentstherelationbetweenthespinmomentandspinangularmomentum:μs=-gβS

3.4.1PrinciplesofEPRSpectr1103.4.1PrinciplesofEPRSpectroscopyElectronParamagneticResonanceSpinenergystateofelectronsFromtheclassicalelectromagnetictheory,E=-μs·H=-(-gβS)H=gβSHMs=±1/2

3.4.1PrinciplesofEPRSpectr1113.4.1PrinciplesofEPRSpectroscopyElectronParamagneticResonanceElectronParamagneticResonance

3.4.1PrinciplesofEPRSpectr1123.4.2InstrumentationEPRSpectrometer

3.4.2InstrumentationEPRSpect1133.4.2InstrumentationMethodsFrequencyscanningFixingthefield,scanningthefrequencyFieldscanning√Fixingthefrequency,scanningthefieldSeeTable3-133.4.2InstrumentationMethods1143.4.2InstrumentationSamplingSamplesGas/liquid/solidSpintrappingandspinlabelingS(theanti-magneticcompound)+R?(highactivity,shortlife)→RS?(stable)S:thespintrap

3.4.2InstrumentationSampling1153.4.2InstrumentationSamplingWidelyusedspintrapsNitrosocompounds

NitrosogroupsTertiarycarbonFormingfreeradicalsofnitroxides

3.4.2InstrumentationSampling1163.4.2InstrumentationSamplingWidelyusedspintrapsNitroxides

Formingfreeradicalsofnitroxides

3.4.2InstrumentationSampling1173.4.3ElucidationofEPRSpectraEPRSpectraHorizontalaxis:thefieldintensityVerticalaxis:Therelativeabsorbance:Thedifferentialoftherelativeabsorbance:3.4.3Elucid