nmr-eng1952年诺贝尔物理学奖FelixBloch珀

NuclearMagneticResonanceanditsApplicationsin Averyimportanttechniquewidelyusedinbiology,chemistry,clinical/diagnosis,geology,materialogy,Features:fast,ultra-highresolution,non-damagetechniqueRelatedNobel1952 物理学奖：布洛赫(FelixBloch 珀赛(EdwardPurcell)因发展了核磁精密测量的新方法及由此所作的发现—核 布洛赫(FelixBloch 珀赛尔(Edward 核磁波谱学方面的杰出贡献。一.脉冲傅利叶变换核磁谱二.二维核磁谱三.核磁成像: :科学家库尔特·.维特里希“forhisdevelopmentofnuclearmagneticresonancespectroscopyfordeterminingthethree-dimensionalstructureofbiologicalmacromoleculesin他将获得2002 化学奖另一半的奖金Ifoneknowsallthemeasurementsofahouseonecandrawathree-dimensionalpictureofthathouse.Inthesameway,bymeasuringavastnumberofshortdistancesinaprotein,itispossibletocreateathree-dimensionalpictureofthatprotein.2003 医学奖 科学家保罗·劳特布尔Lauterbur)和英国科学家彼得·曼斯菲尔德(PeterMansfield用核 层析“拍摄”的脑截面图MRIisusedforimagingofallorgansintheNMR基本核 （NuclearMagneticResonance，简写为是一种研究原子核在核外磁场中能级及其跃迁的波谱（用具磁 件;（）在强磁的激下，一具某些磁性的原子核的能量可裂2个或2以上能级;如果此外一能其好于分相则该核就可能吸能称为 吸低能态跃迁到高能态，所吸能量数量相当频率范围0.10H的磁于线波围简频）。因此核 就是研究磁性原子核对射频能的吸收BasicPrincipalofNMR:SpinOnlynucleiwithspinnumber(I)0canelectromagneticEvenatomicmass&numberI=0(12C,Evenatomicmass&oddnumberI=whole (14N,2H,OddatomicmassI=halfinteger(1H,13C,15N,Thespinstatesofthenucleus(m) m=I,(I-1),(I-2),…,-Properly,miscalledthemagneticquantumAAZΙ例奇偶偶零1H13C15N29Si12C16O12S偶奇整2H14NBasicFor1H,13C,15N,31P(biologicallyrelevantnucleiwithIm=m=1/2,-Thismeansthatonlytwostates(energylevels)canbetakenbythesenuclei.=Ih/ Anotherimportantparameter=Ih/histhePlanckisthegyromagneticratio(磁旋比)anditonthenatureofeachE=-E=-hBo/E=hBo/BasicEnergyDeviationbetweenαspinandβspin:Eh0Aincidentphotonwhichexcitestheαspintoβspinwithfrequency:=Bo/当电磁波的能量符合下式

E

高能自低能自选进动核便与辐射光子相互（），体系吸收能量，核磁。

必须注意：在无外加磁场时，核能级是简并的，各状态的能量实现核 的方BasicB2ThereB2FixB0,varyBB

,varyB(MagneticChemicalReason:differencein‘Beffective’onthesa butwithdifferen ectronenvironmentFor1H,TMS(tetramethylsilane)wasusedasaHTMSHsample TMS 核 磁能级之间的跃迁

探示波

射频磁

射发生NNN

S扫描发生

同时，把时样品线圈所发的变化（核磁磁场的作用是自旋体系的磁发

振吸收信号）交 Solid-stateNMRinHeterogeneousCatalysisFewHeterogeneousCatalystsaresolidSolid-stateNMRandSolutionDipolarAnisotropicinteraction(nucleiinfixedLowBroadMagicAngleSpinning(MASCross-polarizationcombinedwithMAS(CP-Homogeneous (HPD)Multi-pulsehigh-resolutiontechniquesforquadrupolarnuclei(multiquantumresonance(MQMAS)，doubleresonancelikeREDOR,etc)魔角旋转 相互作用减小，达到了窄化谱线的目的。魔角旋转技术就是通过样品旋转来达到减小相互作用的，当样品高速旋转时β与θ的差别就会平均掉r魔角机械旋转的原理 动态双旋)－样品绕两个动态双旋)－样品绕两个轴高速旋-quantum(MQ)MAS－high uadrupolarMASandPeaksarebetterresolvedandApplicationofMASCompositionandstructureofzeoliteLewisandBrønstedacidChemicalstateandcatalyticpropertyofthemolecularabsorbedinnanoporesThestereo-structureofthestructure-directingagentinthezeoliteporesandthegrowthmechanismofzeoliteReactionmechanismincatalysis分子筛骨架的组成和结B酸和L酸位的性质机理(5)催化反应机理Structureofporous1.129SiMAS–Chemicalshiftdependsonthestructureofzeolite,especiallythebondangleofSi(nAl)(n=0~4)andCrystallinityandhydrolysisextentaffectthelineExample:低硅分子高硅分NMRspectraweredifferentbetweenhigh低硅分子高硅分HighSi/AlSi(0Al)HighNarrowQ4/Q3/Q2LowSi/AlBroadpeakExample:Mesoporous

VVolumeadsorb/c3g-0

dv/dlog(w)9dv/dlog(w)6 ng60

NH3-NH3- Al-SBA-15焙烧及水热处理后的结构2727AlWSBETChem.Mater.2007,19, 27AlMASBroadOnlyexcitationbetween(+1/2\-1/2)canbeIdentifythecoordinationofAlatoms,e.g.,4-foldcoordination(tetrahedron)or6-foldcoordination(octahedron)Y型分子Y型分子筛在不同脱铝条件下的27AlMASNMR胶体晶的干胶转 多级孔结构MFI分子Basedonthecrystallizationofsilicacolloids 500 100Intensity(a.Intensity(a.Transmission(a.dcbaabcd

2

Wavenumber(cm-

0

Relativepressure

abcabcdabcdAmountAmountadsorbed0

Standardadsorbtion

MS--MS-MFI-MS-MFI-MS-MFI-27AlMASNMRspectra:a:Si/Al=20;b:Si/Al=10;c:Si/Al=5.O+NH2 OO+NH2 OOOOSO3SCOGrafting ababccSolidstate29SiNMRand13Cmesoporoussilicas

-CH=CH-mesoporous

Vinyl--CH=CH-mesoporous------- ---

------2--------

-------- ------------O-Si-O---

------

Bicontinous

Solidstate

-Si-

*

2

6 6

212a)10%APTES,b)10%GPS,c)10%MPTMS,d)ande)10%TEVS2AcidPropertiesinSurfaceacidityisveryimportantin1HMASNMR,averypowerfultechniqueforBrønstedacid ethedrawbackofFT-IR:different–OHgroupsinband3200~3400cm-1UseprobemoleculartodetecttheLewisacidsites((CH3)3P、15N-Py、13CO,etc)31P，15N，13CMASNMR,1HMASNMRdirectcharacterizationmethodforLowresolution；cannotgiveLewisacidbasemolecularasaprobeforacidsitesinCO－－LewissitesCH3COCH3－－Brønstedsites

Onlyonebasicgroup

labeledamines（pyridine、n-butylamine,organophosphorous（TMP、BrønstedorLewisacid1.1HMASNMRcharacterizetheOHNormally,-OHonzeolitesurfacecanbeidentified-0.5~0.5ppm:OHonoutersurfaceofzeoliteornon-frameOHinteractedwithmetalions(MOH); Defectsor(SiOH)end2.8~3.6ppm：non-frame(AlOH)whichconnectedwithframeatomandhydro-bondedwithsurroundingO3.6~4.3ppm:OHinhuge-cageofzeoliteorbridgedSiOHAlin4.6~5.2ppm:bridged(SiOHAl)in5.2~7.0ppm:bridged(SiOHAl)inHZSM-5orHBwhichisinteractedwithframeatoms2.2.DetermineacidTheacidstrengthcanbedetectedbymolecularprobemethod.Forinstance,strongbase,2Hlabeledpyridinecanbeusedtodiscriminatetheacidornon-acid–OHsites,whileweakbasewasusedtoidentifytheacidsiteswithdifferentstrength.Afterabsorptionofprobemolecular,differentgroupsshowdifferentchemicalshift.Thenfromthechemicalshift,thestrengthofacidcouldbedetected.beforeandafterabsorptiontocalculateBacidstrength。Alsoitcanbeusedcalculatethenon-framealuminumnumberinouter2.3.ToprobetheL-acidsitesin15Nlabeledpyridineorammonia15NMASNMRorCP/MAStoidentifytheB-acidorL-acid=205ppm,B-acid=260ppm,L-acid=290~300ppm,OHofweak=315ppm,liquidTrimethylphosphorous(TMP)31PMAS=-1~-3ppm,B-acidsites,[(CH3)3P-H+]=-32~-60ppm,L-acid=-68ppm,physicalabsorbedTMPB-acidsitescanbecalculated,butL-acidsitescan3、SurfaceAbsorptiononSurfacespeciesisveryimportantforthemechanism,whichisdirectlyrelatedtotransientNMR→Absorbedmolecularstates→129Xeasaprobemolecular:powerfultoolsforzeoliteandporousmaterials。1.ChemicalstateofabsorbedCH3OH→Howdid C-CbondHowabouttheinteractionbetweenmethanoland---------13CMASNMR13CMASNMRspectraofabsorbedonSAPO-520ºC,δ=50ppm,150C,onemorepeakfrommethylether250C10mins,broadpeakindicatessolid-stateNMRspectrum,anewpeakascribedto(CH3OSi)appears.(CH3OSi)isanintermediateforthisreaction13CMASNMR是研究吸附甲醇与分甲醇吸附在SAPO-5上的13CMASNMR谱。20Cº时在50ppm出现一 峰;当加热到150Cº保持10min测试时,37%的甲醇转化成二甲醚(b谱,峰形较窄,表明分子仍然有很大运动性;进一步加热到C持n后(),峰,典型的,,还出现一个新峰,其化 移与二甲醚相近,归属为与骨架相连的甲氧基(CHOi,是一个强键的反应中间物;继续加热到0C,甲醇转化成烯烃和烷烃的混合物,谱线又变窄产物的流动性增强。检测果显了从个弱键甲醇分子到一个强键的反应中间物最后又生成了弱键的碳氢产物。上明,13CMSNMR究筛的反应中间物和探索反应机理提供十分重要和明确的 。3.2.Scheme1.SchematicRepresentationofStepwiseGenerationofMesoporesMicroporesinSBA-15byTreatment(i)ConcentratedH2SO4at95°Candii)SubsequentCalcinationat200°C。Caftertreatmentwith60wt%H2SO4Caftertreatmentwith60wt%H2SO4(b)synthesizedSBA-15(a)andofthesamesubsequentsubsequent calcination at5In-situMASveryimportantmethodforthestudyofreactionAnexample:AlkylationofbenzenebypropeneonHZSM-11Afterpro