二维核磁共振谱原理.pptx

2D核磁共振谱 1 2 2020 3 20 3 2020 3 20 4 2020 3 20 5 2020 3 20 6 2020 3 20 7 2020 3 20 COSY HypotheticalCoupling 8 2020 3 20 COSY 1H 1HCoupling 9 2020 3 20 10 2020 3 20 Coupling networks canbetracedout asshowninthefigurebelow COSYSpectrumofCodeine 11 2020 3 20 TableofCOSYcorrelations COSYSpectrumofCodeine 12 2020 3 20 13 2020 3 20 14 2020 3 20 15 2020 3 20 WhatYouSeeInaNOESY 16 2020 3 20 突出表现NOE效应的NOESY谱 17 2020 3 20 18 2020 3 20 NOESY 19 2020 3 20 NOESYSpectrumofCodeine Thesampleis3 3mgofcodeinein 65mlCDCl3AcontourplotoftheNOESYspectrumisshownbelow Aswithallhomonuclear2Dplots thediagonalconsistsofintensepeaksthatmatchthenormalspectrum asdoprojectionsontoeachaxis Theinterestinginformationiscontainedinthe cross peaks whichappearatthecoordinatesof2protonswhichhaveanNOEcorrelation Forsmallmolecules theNOEisnegative ExchangepeakshavetheoppositesignfromNOEpeaks makingthemeasytoidentify Thewaterpeakat1 5ppmexchangeswiththeOHat2 9ppm shownhereinred Thespectrumisphasedwiththelargediagonalpeaksinverted showninredhere sotheNOEcross peaksarepositive 20 2020 3 20 Expansionoftheupfieldregion 8 7 127 18 18 3 5 105 11 16 18 9 10 17 17 10 1611 18 16 14 18 18 13 18 16 14 1713 14 17 17 13 17 17 17 17 NOESYSpectrumofCodeine 21 2020 3 20 TableofNOEs indicatesthemoreupfieldofgeminalCH2protons Inadditiontoconfirmingassignments theNOESYspectrumallowsstereospecificassignmentsofmethyleneHs The3cross peaksindicatedinredontheplotbelowdistinguishbetweenthe3CH2pairs 5 18 16 1718 13 NOESYSpectrumofCodeine 22 2020 3 20 23 2020 3 20 24 2020 3 20 2DC H相关谱 C HCOSY 25 2020 3 20 2D远程C HCOSY 26 2020 3 20 HeteronuclearMultipleQuantumCoherence HMQC andHeteronuclearMultipleBondCoherence HMBC 2 DinverseH Ccorrelationtechniquesthatallowforthedeterminationofcarbon orotherheteroatom tohydrogenconnectivity GradientHMBC gHMBC improvestheacquiredspectrabysignificantlyreducingunwantedsignalartifacts HMQCisselectivefordirectC HcouplingHMBCwillgivelongerrangecouplings 2 4bondcoupling HMQCandHMBC 27 2020 3 20 HMQC trans ethyl2 butenoate 28 2020 3 20 HMQC HeteronuclearMultiple QuantumCoherenceExperiment 29 2020 3 20 C 9 H C 9 H HMQC HeteronuclearMultiple QuantumCoherenceExperiment 30 2020 3 20 HMQC 1 BondCHCorrelation ofCodeine 31 2020 3 20 Thisisa2Dexperimentusedtocorrelate orconnect 1Hand13Cpeaksforatomsseparatedbymultiplebonds usually2or3 Thecoordinatesofeachpeakseeninthecontourplotarethe1Hand13Cchemicalshifts Thisisextremelyusefulformakingassignmentsandmappingoutcovalentstructure TheinformationobtainedisanextensionofthatobtainedfromanHMQCspectrum butismorecomplicatedtoanalyze LikeHMQC thisisan inversedetection experiment andispossibleonlyonnewermodelspectrometers AcornNMR snewJEOLEclipse 400isequippedtoperforminverseexperiments andusesZ gradientsforimprovedspectralquality ThetimerequiredforanHMBCdependsontheamountofmaterial butismuchgreaterthanforHMQC andcantakefromanhourtoovernight HMBC Multiple BondCHCorrelation ofCodeine 32 2020 3 20 Peaksoccuratcoordinatesinthe2dimensionscorrespondingtothechemicalshiftsofacarbonandprotonsseparatedby usually 2or3bonds Theexperimentisoptimizedforcouplingsof 8Hz Smallercouplingsareobserved buttheirintensitiesarereduced Comparetothespectrumobtainedwhentheexperimentisoptimizedfor4Hz Theexperimentisdesignedtosuppress1 bondcorrelations butafewareobservedinmostspectra Inconcentratedsamplesofconjugatedsystems 4 bondcorrelationscanbeobserved ThereisnowaytoknowhowmanybondsseparateanHandCwhenapeakisobserved soanalysisisaprocessofattemptingtoassignallobservedpeaks testingforconsistencyandcheckingtobesurenoneoftheassignmentswouldrequireimplausibleorimpossiblecouplings Becauseofthelargenumberofpeaksobserved analysisrequiresseveralexpandedplots Inthiscase thespectrumhasbeendividedinto4sections eachofwhichisdiscussedbelow HMBC Multiple BondCHCorrelation ofCodeine 33 2020 3 20 HMBC Multiple BondCHCorrelation ofCodeine 34 2020 3 20 Thediscussionbelowusesthenumberingsystemshownatright Thenumberswereassignedtopeaksinthe1D13Cspectrum startingdownfield movingupfield andnumberingeachsequentially ThisgeneratesauniqueidentifierforeachCarbon evenbeforeknowinganyassignments HMBC Multiple BondCHCorrelation ofCodeine C9 H C3 H C5 H 1 2 3 4 5 6 35 2020 3 20 C9 H C3 H C5 H 17 HMBC Multiple BondCHCorrelation ofCodeine 36 2020 3 20 More1Dand2D SepctraforCodeine 37 2020 3 20 1D1Hand13CNMRSpectraofCodeine C18H21NO3 MW 299 4DataacquiredonaJEOLEclipse 400spectrometer 1Hspectrum C3 H C5 H C10 H C7 H C8 H C9 H C12 H3 C11 H C16 H C18 H C18 H C17 H C14 H C3 H C5 H C9 H C3 H C5 H 38 2020 3 20 13Cspectra18mgsample 1 3hrsacquisitiontime 1 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 18 1D1Hand13CNMRSpectraofCodeine 39 2020 3 20 PeakAssignmentsforCodeine 40 2020 3 20 Bothexperimentsareusedtoidentify multiplicity quaternary CH CH2orCH3 ofpeaksina13Cspectrum Usually DEPTispreferredbecausemuchlesstimeisrequired ForDEPT 1Hmagnetizationisgeneratedfirst thentransferredto13C This polarizationtransfer enhancessensitivity Also theexperimentrepetitionrateisdependentonrelaxationof1H ratherthan13C soashorterdelayisneeded DEPTalsocandistinguishbetweenCHandCH3 u