NMR Spectroscopy Explained: Simplified Theory, Applications and Examples for Organic Chemistry and Structural Biology

685 Pages·2007·13.26 MB·English

by  Neil E. Jacobsen

NMR SPECTROSCOPY EXPLAINED

NMR SPECTROSCOPY
EXPLAINED
Simplified Theory, Applications and
Examples for Organic Chemistry
and Structural Biology
Neil E. Jacobsen, Ph.D.
University of Arizona
Copyright©2007byJohnWiley&Sons,Inc.Allrightsreserved
PublishedbyJohnWiley&Sons,Inc.,Hoboken,NewJersey
PublishedsimultaneouslyinCanada
Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmittedinanyformorbyany
means,electronic,mechanical,photocopying,recording,scanning,orotherwise,exceptaspermittedunder
Section107or108ofthe1976UnitedStatesCopyrightAct,withouteitherthepriorwrittenpermissionofthe
Publisher,orauthorizationthroughpaymentoftheappropriateper-copyfeetotheCopyrightClearanceCenter,
Inc.,222RosewoodDrive,Danvers,MA01923,[phone],fax[phone],oronthewebat
www.copyright.com.RequeststothePublisherforpermissionshouldbeaddressedtothePermissions
Department,JohnWiley&Sons,Inc.,111RiverStreet,Hoboken,NJ07030,[phone],fax(201)
748-6008,oronlineathttp://www.wiley.com/go/permission.
LimitofLiability/DisclaimerofWarranty:Whilethepublisherandauthorhaveusedtheirbesteffortsin
preparingthisbook,theymakenorepresentationsorwarrantieswithrespecttotheaccuracyorcompletenessof
thecontentsofthisbookandspecificallydisclaimanyimpliedwarrantiesofmerchantabilityorfitnessfora
particularpurpose.Nowarrantymaybecreatedorextendedbysalesrepresentativesorwrittensalesmaterials.
Theadviceandstrategiescontainedhereinmaynotbesuitableforyoursituation.Youshouldconsultwitha
professionalwhereappropriate.Neitherthepublishernorauthorshallbeliableforanylossofprofitoranyother
commercialdamages,includingbutnotlimitedtospecial,incidental,consequential,orotherdamages.
Forgeneralinformationonourotherproductsandservicesorfortechnicalsupport,pleasecontactourCustomer
CareDepartmentwithintheUnitedStatesat(800)762-2974,outsidetheUnitedStatesat(317)572-3993orfax
[phone].
Wileyalsopublishesitsbooksinavarietyofelectronicformats.Somecontentthatappearsinprintmay
notbeavailableinelectronicformats.FormoreinformationaboutWileyproducts,visitourwebsiteat
http://www.wiley.com.
WileyBicentennialLogo:RichardJ.Pacifico
LibraryofCongressCataloging-in-PublicationData:
Jacobsen,NeilE.
NMRSpectroscopyExplained:SimplifiedTheory,ApplicationsandExamplesforOrganicChemistryand
StructuralBiology/NeilEJacobsen,Ph.D.
p.cm.
ISBN978-0-471-73096-5(cloth)
1. Nuclearmagneticresonancespectroscopy.2. Chemistry,Organic.3. Molecularbiology. I.Title.
QD96.N8J332007
543(cid:2).66--dc22
2007006911
PrintedintheUnitedStatesofAmerica
10987654321
CONTENTS
Preface xi
Acknowledgments xv
1 FundamentalsofNMRSpectroscopyinLiquids 1
1.1 IntroductiontoNMRSpectroscopy, 1
1.2 Examples:NMRSpectroscopyofOligosaccharidesandTerpenoids, 12
1.3 TypicalValuesofChemicalShiftsandCouplingConstants, 27
1.4 FundamentalConceptsofNMRSpectroscopy, 30
1
2 InterpretationofProton( H)NMRSpectra 39
2.1 Assignment, 39
2.2 EffectofB FieldStrengthontheSpectrum, 40
o
2.3 First-OrderSplittingPatterns, 45
2.4 TheUseof1H–1HCouplingConstantstoDetermineStereochemistry
andConformation, 52
2.5 SymmetryandChiralityinNMR, 54
2.6 TheOriginoftheChemicalShift, 56
2.7 JCouplingtoOtherNMR-ActiveNuclei, 61
2.8 Non-First-OrderSplittingPatterns:StrongCoupling, 63
2.9 MagneticEquivalence, 71
3 NMRHardwareandSoftware 74
3.1 SamplePreparation, 75
3.2 SampleInsertion, 77
3.3 TheDeuteriumLockFeedbackLoop, 78
vi CONTENTS
3.4 TheShimSystem, 81
3.5 TuningandMatchingtheProbe, 88
3.6 NMRDataAcquisitionandAcquisitionParameters, 90
3.7 NoiseandDynamicRange, 108
3.8 SpecialTopic:OversamplingandDigitalFiltering, 110
3.9 NMRDataProcessing—Overview, 118
3.10 TheFourierTransform, 119
3.11 DataManipulationBeforetheFourierTransform, 122
3.12 DataManipulationAftertheFourierTransform, 126
4 Carbon-13(13C)NMRSpectroscopy 135
4.1 Sensitivityof13C, 135
4.2 Splittingof13CSignals, 135
4.3 Decoupling, 138
4.4 HeteronuclearDecoupling:1HDecoupled13CSpectra, 139
4.5 DecouplingHardware, 145
4.6 DecouplingSoftware:Parameters, 149
4.7 TheNuclearOverhauserEffect(NOE), 150
4.8 HeteronuclearDecouplerModes, 152
5 NMRRelaxation—Inversion-RecoveryandtheNuclear
OverhauserEffect(NOE) 155
5.1 TheVectorModel, 155
5.2 OneSpininaMagneticField, 155
5.3 ALargePopulationofIdenticalSpins:NetMagnetization, 157
5.4 Coherence:NetMagnetizationinthex–yPlane, 161
5.5 Relaxation, 162
5.6 SummaryoftheVectorModel, 168
5.7 MolecularTumblingandNMRRelaxation, 170
5.8 Inversion-Recovery:MeasurementofT Values, 176
1
5.9 Continuous-WaveLow-PowerIrradiationofOneResonance, 181
5.10 HomonuclearDecoupling, 182
5.11 PresaturationofSolventResonance, 185
5.12 TheHomonuclearNuclearOverhauserEffect(NOE), 187
5.13 SummaryoftheNuclearOverhauserEffect, 198
6 TheSpinEchoandtheAttachedProtonTest(APT) 200
6.1 TheRotatingFrameofReference, 201
6.2 TheRadioFrequency(RF)Pulse, 203
6.3 TheEffectofRFPulses, 206
6.4 QuadratureDetection,PhaseCycling,andtheReceiverPhase, 209
CONTENTS vii
6.5 ChemicalShiftEvolution, 212
6.6 Scalar(J)CouplingEvolution, 213
6.7 ExamplesofJ-couplingandChemicalShiftEvolution, 216
6.8 TheAttachedProtonTest(APT), 220
6.9 TheSpinEcho, 226
6.10 TheHeteronuclearSpinEcho:ControllingJ-CouplingEvolution
andChemicalShiftEvolution, 232
7 CoherenceTransfer:INEPTandDEPT 238
7.1 NetMagnetization, 238
7.2 MagnetizationTransfer, 241
7.3 TheProductOperatorFormalism:Introduction, 242
7.4 SingleSpinProductOperators:ChemicalShiftEvolution, 244
7.5 Two-SpinOperators:J-couplingEvolutionandAntiphaseCoherence, 247
7.6 TheEffectofRFPulsesonProductOperators, 251
7.7 INEPTandtheTransferofMagnetizationfrom1Hto13C, 253
7.8 SelectivePopulationTransfer(SPT)asaWayofUnderstanding
INEPTCoherenceTransfer, 257
7.9 PhaseCyclinginINEPT, 263
7.10 IntermediateStatesinCoherenceTransfer, 265
7.11 Zero-andDouble-QuantumOperators, 267
7.12 SummaryofTwo-SpinOperators, 269
7.13 RefocusedINEPT:AddingSpectralEditing, 270
7.14 DEPT:DistortionlessEnhancementbyPolarizationTransfer, 276
7.15 ProductOperatorAnalysisoftheDEPTExperiment, 283
8 ShapedPulses,PulsedFieldGradients,andSpinLocks:
Selective1DNOEand1DTOCSY 289
8.1 IntroducingThreeNewPulseSequenceTools, 289
8.2 TheEffectofOff-ResonancePulsesonNetMagnetization, 291
8.3 TheExcitationProfileforRectangularPulses, 297
8.4 SelectivePulsesandShapedPulses, 299
8.5 PulsedFieldGradients, 301
8.6 CombiningShapedPulsesandPulsedFieldGradients:
“ExcitationSculpting”, 308
8.7 CoherenceOrder:UsingGradientstoSelectaCoherencePathway, 316
8.8 PracticalAspectsofPulsedFieldGradientsandShapedPulses, 319
8.9 1DTransientNOEusingDPFGSE, 321
8.10 TheSpinLock, 333
8.11 Selective1DROESYand1DTOCSY, 338
8.12 Selective1DTOCSYusingDPFGSE, 343
8.13 RFPowerLevelsforShapedPulsesandSpinLocks, 348
viii CONTENTS
9 Two-DimensionalNMRSpectroscopy:
HETCOR,COSY,andTOCSY 353
9.1 IntroductiontoTwo-DimensionalNMR, 353
9.2 HETCOR:A2DExperimentCreatedfromthe1DINEPTExperiment, 354
9.3 AGeneralOverviewof2DNMRExperiments, 364
9.4 2DCorrelationSpectroscopy(COSY), 370
9.5 UnderstandingCOSYwithProductOperators, 386
9.6 2DTOCSY(TotalCorrelationSpectroscopy), 393
9.7 DataSamplingint andthe2DSpectralWindow, 398
1
10 AdvancedNMRTheory:NOESYandDQF-COSY 408
10.1 SpinKinetics:DerivationoftheRateEquationforCross-Relaxation, 409
10.2 DynamicProcessesandChemicalExchangeinNMR, 414
10.3 2DNOESYand2DROESY, 425
10.4 ExpandingOurViewofCoherence:QuantumMechanics
andSphericalOperators, 439
10.5 Double-QuantumFilteredCOSY(DQF-COSY), 447
10.6 CoherencePathwaySelectioninNMRExperiments, 450
10.7 TheDensityMatrixRepresentationofSpinStates, 469
10.8 TheHamiltonianMatrix:StrongCouplingandIdealIsotropic
(TOCSY)Mixing, 478
11 InverseHeteronuclear2DExperiments:HSQC,HMQC,andHMBC 489
11.1 InverseExperiments:1HObservewith13CDecoupling, 490
11.2 GeneralAppearanceofInverse2DSpectra, 498
11.3 ExamplesofOne-BondInverseCorrelation(HMQCandHSQC)
Without13CDecoupling, 501
11.4 ExamplesofEdited,13C-DecoupledHSQCSpectra, 504
11.5 ExamplesofHMBCSpectra, 509
11.6 StructureDeterminationUsingHSQCandHMBC, 517
11.7 UnderstandingtheHSQCPulseSequence, 522
11.8 UnderstandingtheHMQCPulseSequence, 533
11.9 UnderstandingtheHeteronuclearMultiple-BondCorrelation
(HMBC)PulseSequence, 535
11.10 StructureDeterminationbyNMR—AnExample, 538
12 BiologicalNMRSpectroscopy 551
12.1 ApplicationsofNMRinBiology, 551
12.2 SizeLimitationsinSolution-StateNMR, 553
12.3 HardwareRequirementsforBiologicalNMR, 558
12.4 SamplePreparationandWaterSuppression, 564
12.5 1HChemicalShiftsofPeptidesandProteins, 570
CONTENTS ix
12.6 NOEInteractionsBetweenOneResidueandtheNextResiduein
theSequence, 577
12.7 Sequence-SpecificAssignmentUsingHomonuclear2DSpectra, 580
12.8 MediumandLong-RangeNOECorrelations, 586
12.9 Calculationof3DStructureUsingNMRRestraints, 590
12.10 15N-Labelingand3DNMR, 596
12.11 Three-DimensionalNMRPulseSequences:3DHSQC–TOCSY
and3DTOCSY–HSQC, 601
12.12 Triple-ResonanceNMRonDoubly-Labeled(15N,13C)Proteins, 610
12.13 NewTechniquesforProteinNMR:ResidualDipolarCouplings
andTransverseRelaxationOptimizedSpectroscopy(TROSY), 621
AppendixA:APictorialKeytoNMRSpinStates 627
AppendixB:ASurveyofTwo-DimensionalNMRExperiments 634
Index 643