二维核磁共振谱原理.ppt

2D核磁共振谱 COSY HypotheticalCoupling COSY 1H 1HCoupling Coupling networks canbetracedout asshowninthefigurebelow COSYSpectrumofCodeine TableofCOSYcorrelations COSYSpectrumofCodeine WhatYouSeeInaNOESY 突出表现NOE效应的NOESY谱 NOESY NOESYSpectrumofCodeine Thesampleis3 3mgofcodeinein 65mlCDCl3AcontourplotoftheNOESYspectrumisshownbelow Aswithallhomonuclear2Dplots thediagonalconsistsofintensepeaksthatmatchthenormalspectrum asdoprojectionsontoeachaxis Theinterestinginformationiscontainedinthe cross peaks whichappearatthecoordinatesof2protonswhichhaveanNOEcorrelation Forsmallmolecules theNOEisnegative ExchangepeakshavetheoppositesignfromNOEpeaks makingthemeasytoidentify Thewaterpeakat1 5ppmexchangeswiththeOHat2 9ppm shownhereinred Thespectrumisphasedwiththelargediagonalpeaksinverted showninredhere sotheNOEcross peaksarepositive 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 TableofNOEs indicatesthemoreupfieldofgeminalCH2protons Inadditiontoconfirmingassignments theNOESYspectrumallowsstereospecificassignmentsofmethyleneHs The3cross peaksindicatedinredontheplotbelowdistinguishbetweenthe3CH2pairs 5 18 16 1718 13 NOESYSpectrumofCodeine 2DC H相关谱 C HCOSY 2D远程C HCOSY HeteronuclearMultipleQuantumCoherence HMQC andHeteronuclearMultipleBondCoherence HMBC 2 DinverseH Ccorrelationtechniquesthatallowforthedeterminationofcarbon orotherheteroatom tohydrogenconnectivity GradientHMBC gHMBC improvestheacquiredspectrabysignificantlyreducingunwantedsignalartifacts HMQCisselectivefordirectC HcouplingHMBCwillgivelongerrangecouplings 2 4bondcoupling HMQCandHMBC HMQC trans ethyl2 butenoate HMQC HeteronuclearMultiple QuantumCoherenceExperiment C 9 H C 9 H HMQC HeteronuclearMultiple QuantumCoherenceExperiment HMQC 1 BondCHCorrelation ofCodeine 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 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 HMBC Multiple BondCHCorrelation ofCodeine Thediscussionbelowusesthenumberingsystemshownatright Thenumberswereassignedtopeaksinthe1D13Cspectrum startingdownfield movingupfield andnumberingeachsequentially ThisgeneratesauniqueidentifierforeachCarbon evenbeforeknowinganyassignments HMBC Multiple BondCHCorrelation ofCodeine C9 H C3 H C5 H 1 2 3 4 5 6 C9 H C3 H C5 H 17 HMBC Multiple BondCHCorrelation ofCodeine More1Dand2D SepctraforCodeine 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 13Cspectra18mgsample 1 3hrsacquisitiontime 1 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 18 1D1Hand13CNMRSpectraofCodeine PeakAssignmentsforCodeine Bothexperimentsareusedtoidentify multiplicity quaternary CH CH2orCH3 ofpeaksina13Cspectrum Usually DEPTispreferredbecausemuchlesstimeisrequired ForDEPT 1Hmagnetizationisgeneratedfirst thentransferredto13C This polarizationtransfer enhancessensitivity Also theexperimentrepetitionrateisdependentonrelaxationof1H ratherthan13C soashorterdelayisneeded DEPTalsocandistinguishbetwe