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Two-Dimensional(2D)NMRMethods

Two-Dimensional(2D)NMRMethods

InternationalTomographyCenter,Novosibirsk,Russia

P.K.Madhu

TataInstituteofFundamentalResearch,Hyderabad,India

G.Rajalakshmi

TataInstituteofFundamentalResearch,Hyderabad,India

Thiseditionfirstpublished2023. © 2023JohnWiley&SonsLtd

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Dedication

DedicationandtributetoKostya

K.IvanovatthemeetingoftheAlexandervonHumboldtfoundationscholarshipholdersinNovosibirsk,2012.

OuresteemedcolleagueandgoodfriendKonstantinL’vovich(“Kostya”)Ivanovbecameoneofthefirstvictimsofthe Covid-19pandemicintheNMRcommunity.HepassedawayatahospitalinNovosibirskonMarch5,2021.Hewas notonlyagreatscientist,butalsoagoodhumanbeing,alwayssincere,honest,joyous,andconsiderate.Inaddition, hewasagreatcitizenofthescientificcommunity.AsidefromhisdemandingjobastheDirectoroftheInternational TomographyCenter(ITC),Novosibirsk,hekepthisresearchataveryhighlevelandorganizedamultitudeof meetings,seminars,andwebinars.

AlexandraYurkovskayametKostyaforthefirsttimein1998attheITCwhenhewasamasterstudentinthe theoreticalchemistrygroupheadedbyNikitaLukzen.HavingdefendedhisPh.D.thesisin2002attheITC,Kostya teamedupwiththeexperimentalgroupofAlexandraYurkovskayainsolvingtheoreticalproblemsrelatedto chemicallyinduceddynamicnuclearpolarization.Since2005bothofthemworkedinHans-MartinViethgroupat theFreeUniversityofBerlinaspartofthelargeEUproject"Bio-DNP"undertheleadershipofThomasPrisner.In 2007,KostyabecameafellowoftheAlexandervonHumboldtFoundationattheFreeUniversityofBerlinand

AlexandrahadaMarieCurieInternationalfellowshipwithHans-MartinViethasthehostprofessor.Thescientific collaborationhadsincecontinuedforalmost20yearsandledtoover100jointpublicationsonnuclear hyperpolarizationandpolarizationtransferprocesses,combiningmoderntheoreticalandsophisticated experimentaltechniques.Inparticular,overthelastdecade,AlexeyKiryutinfromtheYurkovskyayagroupattheITC pushedthelimitsbydevelopinguniquehigh-resolutionfastfield-cyclingNMRapparatusovernineordersof magnitudeofmagneticfield.Kostyaproposedmultiplesmartapplicationsofthetechniquetohyperpolarizationand relaxation,establishingKostyaasoneoftheleadersofanewscientificdirection.In2007,Kostyadefendedhissecond doctoralthesis,whichisthesecondscientificdegreeinRussia,awardedforasignificantandsustainable contributiontoscientificknowledge,whichisanalogoustothehabilitationdegreeinGermany.Thethesistitlewas: “Kineticsofmulti-stageliquid-phaseprocessesinvolvingparticleswithspindegreesoffreedom”.Hecompletedhis degreeattheInstituteofChemicalPhysicsinMoscow,whichistheleadinginstituteoftheRussianAcademyinthe fieldofchemicalphysics.Hisscientificworkwashonoredwithseveralimportantprizesandawards,includingthe MedaloftheEuropeanAcademyofSciencein2010,Voevodskyprizein2012,aFellowshipoftheJapaneseSociety forPromotionofSciencein2016,andtheLaukienPrizein2020forhiscontributiontotheSABREresearchfield.

ThecooperationbetweenFrench(ENS)andRussian(ITC)groupsdoingfastfield-cyclingNMRstartedin2017 withavisitofKostyatoÉcoleNormaleSupérieure(ENS,Paris)organizedbyGeoffreyBodenhausen.Thisledto severalcollaborationswithBodenhausen,DanielAbergel,andFabienFerrageontopicsasdiverseaslong-lived states,mechanismsofdynamicnuclearpolarization,andcoherenceeffectsinfield-cyclingexperiments.A comparativestudyofZULFspectroscopywithNMRdetectionusinganatomicmagnetometerandinductive detectionathighmagneticfieldwasinspiredbyKostya’stutorialtalkattheZULFseminarorganizedbytheMarie CurieZULF-NMRInnovativeTrainingNetworkinMainzinthefallof2019.Duringthoseseveralunforgettable days,followedbyfantasticmusicaleveningsincludingKostyaandDimaBudkersingingtogetherwithaband formedbyDima’sresearchgroupmembers,theatmosphereofwarmmutualcooperationwascreatedandthe fruitfulalthoughdramaticallyshortjointworkstarted.

DimaBudker’sacquaintanceandcollaborationwithKostyawerebothrelativelyshort,sometwo-threeyears, dependingonwhereonemarksthebeginning.Nevertheless,thiscollaboration,consistingofseveraljointprojectsthat haveresultedinatleastfivejointpapersandbookchapters,hashadaprofoundeffectonDima’sresearchinterests. Inmostcases,thecollaborationwasinitiatedbyKostyaandwascenteredaroundanideaformulatedbyhimwith suchclarityandenthusiasmthatitwasimpossiblenottoembracetheprojectwholeheartedly.

Thiswasalsothecasewiththechapterforthis2D-NMRbook.OntheFebruary3,2021,Dimareceivedane-mail fromKostyathatsaid:“MadhuandmyselfhavegotanofferfromWileytoeditabookon2D-NMR.Asapartofthis initiative,Iwanttocoversomeaspectsoffield-cyclingNMRandzero-fieldNMR.Although2Dmethodsarenotthat widespreadinthesebranchesofNMR,theyareusedaswellandcanbeofinteresttoNMRpeople.Wouldyouliketo writesuchachaptertogetherwithmeandFabienFerrage,withwhomIcooperateonfield-cyclingNMR?”Thiswas followedbyadetailedoutlineofthechapterproposedbyKostya.KostyaandDimathenmetonSkypetodiscussthis suggestion,includingthescopeandwhomtoinviteasco-authors.TheirlastcommunicationwasontheFebruary11, 2021,andtheyagreedtotalkagainverysoon...Thatconversationwasnotdestinedtooccur.

FabienFerrage’sfirstacquaintancewithKostyawasbyreadinghiswork,particularlytheseriesofarticleshe publishedwithHans-MartinVieth,RobKaptein,andAlexandraYurkovskayaonlevelanti-crossingsandcoherent effectsinfield-cyclingexperiments.AsFabienwasmakinghisfirststepsinrelaxometry,thesewereenlightening contributionsthatdefinedveryclearlywhatheshouldnotdoifhewantedtomeasurepurerelaxationratesatlow fields.GeoffreyBodenhausenandFabiendiscussedseveralofKostya’sarticlesbeforemeetinghim,oftenwithpraise, inparticulartheintroductionofSABREathighfield.FabienmetKostyainpersoninMay2015,whenKostyacame toParisforaCOSTmeetingonhyperpolarization.Neverwastinganytime,KostyacametoENStovisitthelaband giveaseminarduringthelunchbreakofthemeeting.Overtheyears,severalmeetingsandaninvitedprofessorship atENS(anhonourrarelygiventoscientistsofsuchayoungage),KostyaandFabiendiscussedmanytopicsonfield

cycling,relaxometry,andhyperpolarization.IfKostyawasalwaysaskingforchemicalinsightfromFabienside, FabienwasalwaysimpressedbyKostya’scommandoftheory,inquantummechanicsingeneralaswellas,ofcourse, inbothnuclearandelectronmagneticresonance,thelattersubjectbeinginvariablychallengingformanyNMR specialists.ThecollaborationbetweenFabienandKostyareallytookoffwhenIvanZhukov,atalentedgraduate studentsupervisedbyAlexandraYurkovskaya,oneofKostya’smentors,cametoworkonfieldcyclingwiththe Ferragegroupin2018.Asoftenhappens,Ivan’sworkwithatENSendedupbeingguidedbyserendipityandledusto aninvestigationofinterestingeffectsofscalarcouplingsatlowfieldsdiscussedinthisbook.Thisworkinspired KostyatoproposetheZULF-TOCSYexperiment,suchabeautifulidea,thattheyhavejuststartedexploring.

FabienFerragerecalls:Kostyawasatrueforce,initiatingandleadingmanyprojectswithintelligence,ambition andintensitywhile,atthesametime,beingthenicest,kindestandmostgenerouscolleague.Sucharare combination.KostyaandIwerebornthesameyear.Hisdaughterandmysonareaboutthesameage.Iconsidered himasacompass,settingapathtoinspireothers.InFebruary2021,weexchangedaboutthescopeofthisbook chapter.OneofthelastemailsIreceivedfromKostya,onFebruary15,2021,wasaboutaconversationhehadhad withDmitryBudkertowritethisbookchaptertogether,whichIamgladweaccomplished.OnMarch5,mycolleague DanielAbergelcalledmetoinformmethatKostyahaddied.Thecompasswasbroken,buttheinspirationliveson.

MadhurecollectshisassociationwithKostyawhichstartedin2016attheWindischleubaSchoolonNMR,aseries beingorganisedbyJoergMatysik:Wehadbeenregularteachersinthisworkshopseriesin2017,2018,and2020. Somewherein2018,westarteddiscussingtheprospectsofwritingabookonsolid-stateNMR.WemetupinLeipzig inJune2019foradiscussionregardingthis,havingdonesomeamountofwritingalready.Duringthismeeting KostyahadthiswonderfulsparkandtoldmethatwhydonotwewriteareviewonFloquettheorywithnewideas embeddedandwithmoreexamplesthanexistingreviews.Thisreviewkeptusbusytillhepassedawaywhenwewere refiningitaftercommentsfromtheeditors.Infact,weinbetweentookuptheassignmentwithWileytobringoutthis bookandKostyawas,asusual,veryenthusiasticandfullofideasaboutwhattobeincludedandhowtheyshouldbe. Writingthereviewwithhim,inparticular,wasveryrewarding.Irememberthelargenumberofextensivediscussions wehadfromwhichIlearnedquiteabit.WeactuallyhadtheSkypewindowalwaysactiveinourcomputers,and eitherofuswouldcalltheotherinformallyincaseofanyquestions.Wewerealsodiscussingsomeofthesolid-state NMRexperimentsthatmygroupwascarryingoutwhichwerethetopicsofdiscussionjustbeforehegothospitalized. Needlesstosay,theothermajorthingKostyadidforthemagneticresonancecommunitywasstartingtheFriday IntercontinentalSeminarSeriesonApril8,2020(whichwasaWednesday).Aweekbeforethatasweweretalking aboutthereview,heasusualwantedtodosomethingforthecommunity.WegotintouchwithDanielAbergeland GerdBuntkowskyandtheseminarserieshasbeenrunningsincethensmoothlywithgreattalks.AsKostyawanted,it combinestalksbyseniorandyoungerresearchers.HealsostartedtheICONSconferencein2020andjustbeforehe passedaway,wehadthesecondofthatmeeting.ICONSconferenceshavebeencontinuingsincethenonaregular basiswiththethirdheldinSeptember2021,thefourthinFebruary2022,thefifthinAugust-September2022,andthe sixthinJanuary2023.AlltheseclearlyrevealthevitalityinKostyawithasharpeyefordetails.Besidesscience,we hadfundiscussingpolitics,literature,music,andmanyotherthings.

MuslimDvoyashkinrecallsthefirstmeetingwithKostyaonthewaytoWindischleubaNMRschoolin2020, pickingupKostyaatthetrainstationinLeipzig.Kostyamadethefirstimpressionofaveryintelligentandvery modestperson,whichlaterturnedouttobequitetrue.Ashiscountryman,itwasveryinterestingforMuslimtofind outhowheandhiscolleaguesmanagetoremainattheforefrontoffundamentalsciencegivenitsverylimited financialsupportinRussia.Therefore,KostyawillremaininMuslim’smemoryasarealhero,andthankstowhom, manystudentswereabletofindtheirwaytotheacademialateron.

MalcolmLevittrecallsthathiscloseassociationwithKostyastartedaround2017whenMalcolmexpressedhis appreciationofKostya’sconferencetalkandhisinsightfultheoreticalapproach.Thisledtoextensivediscussionsand theidentificationofvariouspossiblethemesforcollaboration.Vigorousdiscussionsledtoseveralcollaborative papersonthethemeofsingletNMR.In2019MalcolmvisitedNovosibirskandhadthepleasureofgettingtoknow

Kostyaandhiscolleagues,intheir“naturalhabitat”.Itwasaverypleasantandinstructivevisit.Malcolm’smost strikingimpressionofKostyawashowhemanagedthislargeandprestigiousinstitute,fullofcompetingegos,with theminimumofperceptiblefriction,andalwayswithremarkablegoodhumour.Hewasbasicallyanextremelyrare personwhocombinedrefinedpoliticalskillswithasharpandcreativescientificmindaswellaspossessing remarkablepatienceandenergy,agreatsenseofhumour,andlegendarypowersofconcentration.Hislossis extraordinarilytragic.

WeshalldeeplymissKostyaasanexceptionalhumanbeing.Hewasacreativeandrigorousscientist,agenerous andattentivefriend,andaconsiderateandeminentlycivilizedcolleague.Wededicateourcontributionstohimand thewholebookitself,whichwasinitiatedbyKostya,thatwillbeabrilliantscientifictestamenttohismemory.

Contents

Dedication v ListofContributors xvii

Preface xix

1BasicsofTwo-dimensionalNMR 1 MalcolmH.Levitt

1.1Introduction 1

1.1.1Time-domainNMR 1

1.1.2HansPrimasandthe“CorrelationFunctionoftheSpectrum” 2

1.2SpinDynamics 2

1.2.1DensityOperator 2

1.2.2SpinHamiltonian 3

1.2.3LiouvilleSpace 3

1.2.4Liouvillian 4

1.2.5PropagationSuperoperator 6

1.3One-dimensionalFourierNMR 6

1.3.1TheOne-dimensionalNMRExperiment 6

1.3.2One-dimensionalNMRSpectrum 10

1.4Two-dimensionalNMR 11

1.4.1TheTwo-dimensionalNMRExperiment 11

1.4.2Two-dimensionalNMRSignal 12

1.4.3Two-dimensionalNMRSpectrum 13

1.4.4Two-dimensionalExperiments 13

1.5Summary 14

Acknowledgments 15 References 15

2DataProcessingMethods:FourierandBeyond 19 VladislavOrekhov,PawełKasprzak,andKrzysztofKazimierczuk

2.1Introduction 19

2.2Time-domainNMRSignal 19

2.3NMRSpectrum 20

2.4TheMostImportantFeaturesofFT 20

2.5Distortion:Phase 23

2.6Kramers-KronigRelationsandHilbertTransform 23

2.7Distortion:Truncation 25

2.8Distortion:NoiseandMultipleScans 27

2.9Distortion:SamplingandDFT 27

2.10QuadratureDetection 30

2.11Processing:Weighting 31

2.12Processing:ZeroFilling 33

2.13FourierTransforminMultipleDimensions 33

2.14QuadratureDetectioninMultipleDimensions 36

2.15ProjectionTheorem 37

2.16NDSamplingAspectsandSparseSampling 40

2.17ReconstructingSparselySampledDataSets 41

2.18Deconvolution 42

References 44

3ProductOperatorFormalism 47 RolfBoelensandRobertKaptein

3.1Introduction 47

3.2ProductOperatorsandTimeEvolution 48

3.2.1AdvantagesofProductOperators 51

3.3TimeEvolutionoftheProductOperators 55

3.3.1EffectofPulses 56

3.3.2EffectofEvolutionUndertheHamiltonian 58

3.4Applications 59

3.4.1Spin-echoExperiments 59

3.4.2Multiple-quantumCoherence 62

3.4.3CompositePulses 65

3.5Two-dimensionalExperiments 66

3.5.1Two-dimensionalJ-Resolved 67

3.5.2COSY 68

3.5.3Two-dimensionalNOE 70

3.5.4Double-quantumFilteredCOSY 72

3.5.5Two-dimensionalDouble-quantumSpectroscopy 74

3.5.6Relayed-COSY 75

3.5.7TOCSYorHomonuclearHartmann-HahnTransfer 76

3.5.8INEPTandHSQC 77

3.5.9HMQCandHMBC 79

References 81

4RelaxationinNMRSpectroscopy 93 MatthiasErnst

4.1Introduction 93

4.2Theory 95

4.2.1BlochEquations 95

4.2.2Transition-rateTheory 96

4.2.3Semi-classicalRelaxationTheory 99

4.2.4Quantum-mechanicalRelaxationTheory–LindbladFormulation 103

4.3RelaxationinSpin-1/2Systems:DipolarandCSARelaxation 104

4.3.1LongitudinalRelaxationinaTwo-spinSystem 107

4.3.2TransverseRelaxationinaTwo-spinSystem 119

4.3.3Double-quantumRelaxation 124

4.3.4RelaxationinLargerSpinSystems 125

4.4OtherRelaxationMechanisms 125

4.4.1QuadrupolarRelaxation 125

4.4.2ScalarRelaxation 128

4.5ConcludingRemarks 130

References 131

5CoherenceTransferPathways 135 DavidE.KorenchanandAlexejJerschow

5.1CoherenceTransferPathways:WhatandWhy? 135

5.2PrinciplesofCoherenceSelection 137

5.2.1Precessionofacoherenceaboutthez-componentofamagneticfield 139

5.2.2Effectofchangingthephaseofaradiofrequencypulsethatconvertsonecoherenceorderterm intoanother 139

5.3CoherenceTransferPathwaySelectionbyPhaseCycling 140

5.3.1CYCLOPS 144

5.3.2EXORCYCLE 145

5.4CogwheelPhaseCycling 146

5.5CoherenceTransferPathwaySelectionbyPulsed-fieldGradients 147

5.6ComparisonBetweenPhaseCyclingandPulsed-fieldGradients 150

5.7CTPSelectioninHeteronuclearSpinSystems 150

5.8AdditionalApproachestoCoherenceSelection 151 References 151

6NuclearOverhauserEffectSpectroscopy 153 P.K.Madhu

6.1Introduction 153

6.2NuclearOverhauserEffect 153

6.2.1QualitativePicture 153

6.2.2NOE:QuantitativePicture 155

6.2.3NOEandDistanceDependence:Many-spinSystem 159

6.2.4NOEComparisonandDistanceElucidation 160

6.2.5IndirectNOEEffects 160

6.3MeasurementofNOE 161

6.4HeteronuclearNOE 161

6.5NOEKinetics 162

6.5.1Initial-RateApproximation 163

6.6NuclearOverhauserEffectSpectroscopy,NOESY 164

6.6.1NOESYPulseScheme 164

6.6.2NOESYTheory 165

6.7Rotating-frameNOE,ROE 166

6.8RelativeSignsofCrossPeaks 168

6.9GeneralisedSolomon’sEquation 169

6.10NOESYandROESY:PracticalConsiderationsandExperimentalSpectra 170

6.11Conclusions 170

Acknowledgements 172 References 172

7DOSYMethodsforStudyingNon-equilibriumMolecularandIonicSystems 175 MuslimDvoyashkin,MonikaSchönhoff,andVille-VeikkoTelkki

7.1Introduction 175

7.2SpatialSpin“Encoding”UsingMagneticFieldGradient 175

7.3FormationofNMRSignalandSpinEchointhePresenceofFieldGradient 176

7.4NMRofLiquidsinAnElectricField:ElectrophoreticNMR 178

7.4.1MeasurementofDriftVelocities 178

7.4.2TechnicalDevelopment 181

7.4.3ApplicationAreas:FromDilutetoConcentratedElectrolytes 181

7.4.4MethodsofTransformationandProcessing:MOSY 182

7.4.5IseNMRanon-equilibriumexperimentorasteady-stateexperiment? 183

7.5UltrafastDiffusionMeasurements 186

7.6UltrafastDiffusionExchangeSpectroscopy 189 References 191

8MultipleAcquisitionStrategies 195 NathanielJ.Traaseth

8.1Introduction 195

8.2TypesofMultipleAcquisitionExperiments 195

8.3Utilizationof Forgotten SpinOperators 196

8.4ApplicationofMultipleAcquisitionTechniques 198

8.4.1SolutionNMRSpectroscopy 198

8.4.2Solid-StateNMRSpectroscopy 199

8.5ModularityofMultipleDetectionSchemesandOtherNovelApproaches 201

8.6FutureofMultipleAcquisitionDetection 202 Acknowledgments 203 References 203

9AnisotropicOne-dimensional/Two-dimensionalNMRinMolecularAnalysis 209 PhilippeLesotandRobertoR.Gil

9.1Introduction 209

9.2AdvantagesofOrientedSolvents 210

9.2.1DescriptionofOrientationalOrderParameters 211

9.2.2TheGDOConcept 212

9.3DescriptionofUsefulAnisotropicNMRParameters 213

9.3.1ResidualDipolarCoupling(RDC) 213

9.3.2ResidualChemical-shiftAnisotropy(RCSA) 215

9.3.3ResidualQuadrupolarCoupling(RQC) 218

9.3.4SpectralConsequencesofEnantiodiscrimination 219

9.4Adapted2DNMRTools 221

10.6.5UF2DNMRinSpatialInhomogeneousFields 323

10.7Conclusion 326 References 326

11Multi-dimensionalMethodsinBiologicalNMR 333

TobiasSchneiderandMichaelKovermann

11.1Introduction 333

11.2ExperimentalApproaches 334

11.2.1NMRSpectroscopicInformationonStructuralFeatures 334

11.2.2SpectroscopicInformationonDynamicalFeatures 335

11.2.3NMRSpectroscopicInformationObtainedfromInteractionStudies 336

11.2.4QuenchFlowMethodologyinCombinationwithNMR–Hydrogen-to-deuteriumExchange 336

11.2.5ExpandingMulti-dimensionalNMRSpectroscopyfrominvitrotoinvivoApplications 337

11.2.6Multi-DimensionalNMRSpectroscopyasanIntegratedApproachinStructuralBiology 337

11.3CaseStudies 338

11.3.1DeterminingThermodynamicStabilityofBiomoleculesatAtomicResolution 338

11.3.2ExoticHeteronuclearNMRSpectroscopyCorrelating 31Pwith 13C 341

11.3.3FollowingBiomolecularDynamicsbyHomonuclearandHeteronuclearZZExchange 341

11.3.4ProbingStructuralFeaturesbySolventPREs 344

11.3.5DiscerningProteinDynamicsbyProbingFastAmideProtonExchange 346

11.3.6IntegratedApproachesUtilizingStructuralInformationfromNMRSpectroscopy 348

11.3.7Multi-dimensionalNMRSpectroscopyonexvivoSamples 351 References 357

12TROSY:PrinciplesandApplications 365 HarindranathKadavathandRolandRiek

12.1Introduction 365

12.2ThePrinciplesofTROSY 366

12.2.1ThePhysicalPictureofTROSY 367

12.2.2TheoryofTROSY 369

12.3PracticalAspectsofTROSY 371

12.3.1FieldStrengthDependenceofTROSYfor 1H–15NGroups 372

12.3.2PeakPatternof 1H-15NTROSYSpectrum 373

12.4ApplicationsofTROSY 374

12.4.1Two-Dimensional[1H,15N]-TROSY 374

12.4.2[1H,15N]-TROSYforBackboneResonanceAssignmentsinLargeProteins 374

12.4.3[1H,15N]-TROSYforAssignmentofProteinSide-chainResonances 376

12.4.4Applicationof[1H,15N]-TROSYforRDCMeasurements 378

12.4.5[1H,15N]-TROSY-basedNOESYExperiments 378

12.4.6StudiesofDynamicProcessesUsingthe[1H,15N]-TROSYConcept 379

12.5TransverseRelaxation-optimizationinthePolarizationTransfers 379

12.6 15NDirectDetectedTROSY 380

12.7[1H,13C]-TROSYCorrelationExperiments 380

12.7.1Methyl-TROSYNMR 381

12.8ApplicationstoNucleicAcids 382

12.9IntermolecularInteractionsandDrugDesign 383

12.10Conclusion 383

12.AAppendix 384 Acknowledgement 385 References 385

13Two-DimensionalMethodsandZero-toUltralow-Field(ZULF)NMR 395 K.Ivanov,JohnBlanchard,DmitryBudker,FabienFerrage,AlexeyKiryutin,TobiasSjolander, AlexandraYurkovskaya,andIvanZhukov

13.1IntroductionandMotivation 395

13.2EarlyWork 396

13.3Two-dimensionalNMRMeasuredatZeroMagneticField 397

13.4NuclearMagneticResonanceatMilliteslaFieldsUsingaZero-FieldSpectrometer 403

13.5FieldCyclingNMRandCorrelationSpectroscopy 404

13.6ZERO-Field-High-FieldComparison 409

13.7ConclusionandOutlook 412 Acknowledgments 412 References 412

14MultidimensionalMethodsandParamagneticNMR 415 ThomasRobinson,KevinJ.Sanders,AndrewJ.Pell,andGuidoPintacuda

14.1Introduction 415

14.2NMRMethodsforParamagneticSystemsinSolution 416

14.2.1HomonuclearCorrelations 416

14.2.2HeteronuclearCorrelations 419

14.2.3Long-RangeParamagneticEffects 420

14.2.4HeteronuclearDetectionStrategies 421

14.3NMRMethodsforParamagneticSystemsinSolids 423

14.3.1AdiabaticPulses 423

14.3.2HomonuclearCorrelations 423

14.3.3HeteronuclearCorrelations 425

14.3.4Long-RangeParamagneticEffects 426

14.3.5SeparationofShiftandShift-anisotropyInteractions 426

14.3.6SeparationofShift-anisotropyandQuadrupolarInteractions 427 Acknowledgments 432 References 432

15ChemicalExchange 435

AshokSekharandPramodhVallurupalli

15.1Introduction 435

15.2Bloch-McConnellEquations 436

15.2.1SlowExchange 440

15.2.2FastExchange 441

15.2.3DependenceoftheLinewidthOnMagneticFieldStrength 441

15.2.4ExchangeintheAbsenceofChemical-ShiftDifferences 442

15.2.5Multi-StateExchange 442

15.3StudyingExchangeBetweenVisibleStates 443

15.3.1LineshapeAnalysis 444

15.3.2ZZ-ExchangeExperiment 444

ListofContributors

JohnW.Blanchard

QuantumTechnologyCenter,Universityof Maryland,Maryland,USA

RolfBoelens DepartmentofChemistry,UtrechtUniversity, TheNetherlands

DmitryBudker

HelmholtzInstitutMainz,Johannes Gutenberg-UniversitätMainz,Germany DepartmentofPhysics,UniversityofCalifornia, Berkeley,California,USA

MuslimDvoyashkin InstituteofChemicalTechnology,LeipzigUniversity, Leipzig,Germany

MatthiasErnst PhysicalChemistry,ETHZürich,Switzerland

FabienFerrage

LaboratoiredesBiomolécules,LBM, Départementdechimie,Écolenormalesupérieure, PSLUniversity,SorbonneUniversité,Paris,France

RobertoR.Gil DepartmentofChemistry,CarnegieMellon University,Pittsburgh,USA

BorisGouilleux UniversitéParis-Saclay,laboratoireICMMO,Orsay, France

K.Ivanov InternationalTomographyCenterSBRAS, Novosibirsk,Russia

AlexejJerschow DepartmentofChemistry,NewYorkUniversity, NewYork,USA

HarindranathKadavath LaboratoryofPhysicalChemistry,ETHZurich, Switzerland

RobertKaptein DepartmentofChemistry,UtrechtUniversity, TheNetherlands

PawelKasprzak FacultyofPhysics,UniversityofWarsaw,Warsaw, Pasteura,Poland CentreofNewTechnologies,UniversityofWarsaw, Warsaw,Poland

KrzysztofKazimierczuk FacultyofPhysics,UniversityofWarsaw,Warsaw, Poland

AlexeyKiryutin InternationalTomographyCenterSBRAS, Novosibirsk,Russia

DavidKorenchan

AthinoulaA.MartinosCenterforBiomedical Imaging,MassachusettsGeneralHospitalBoston, Massachusetts,USA

MichaelKovermann

DepartmentofChemistry,UniversitätKonstanz, Konstanz,Germany

GraduateSchoolChemicalBiologyKoRS-CB, UniversitätKonstanz,Konstanz,Germany

PhilippeLesot UniversitéParis-Saclay,RMNenMilieuOrienté, France

MalcolmH.Levitt DepartmentofChemistry,Universityof Southampton,Southampton,UK

P.K.Madhu DepartmentofChemicalSciences, TataInstituteofFundamentalResearchHyderabad, India

VladislavOrekhov DepartmentofChemistryandMolecularBiology, UniversityofGothenburg,Gothenburg,Sweden

AndrewJ.Pell

CRMN,CentredeRMNàTrèsHautsChampsde LyonUniversitédeLyon,Villeurbanne,France

GuidoPintacuda

CRMN,CentredeRMNàTrèsHautsChampsde LyonUniversitédeLyon,Villeurbanne,France

RolandRiek LaboratoryofPhysicalChemistry,ETHZürich, Switzerland

ThomasRobinson CRMN,CentredeRMNàTrèsHautsChampsde LyonUniversitédeLyon,Villeurbanne,France

KevinJ.Sanders

CRMN,CentredeRMNàTrèsHautsChampsde LyonUniversitédeLyon,Villeurbanne,France

TobiasSchneider

DepartmentofChemistry,UniversitätKonstanz, Konstanz,Germany

GraduateSchoolChemicalBiologyKoRS-CB, UniversitätKonstanz,Konstanz,Germany

MonikaSchönhoff InstituteofPhysicalChemistry,Universityof Münster,Münster,Germany

AshokSekhar MolecularBiophysicsUnit,IndianInstituteof Science,Bengaluru,Karnataka,India

TobiasSjolander DepartmentofPhysics,UniversityofBasel, Klingelbergstrasse82,Basel,Switzerland

Ville-VeikkoTelkki NMRResearchUnit,UniversityofOulu,Oulu, Finland

NathanielJ.Traaseth DepartmentofChemistry,NewYorkUniversity, NewYork,USA

PramodhVallurupalli

TataInstituteofFundamentalResearchHyderabad, Hyderabad,India

AlexandraYurkovskaya

InternationalTomographyCenterSBRAS, Novosibirsk,Russia

YvanZhukov

InternationalTomographyCenterSBRAS, Novosibirsk,Russia

Preface

NMRspectroscopyhasgrowntremendouslysinceitsinceptioninthe1940’swhenNMRsignalswerefirstrecorded byFelixBlochandEdwardPurcell.Thedevelopmentsinthefieldhavebeenfuelledbyadvancementsinvarious fields,suchas,superconductingmagnets,spectrometerhardwareandsoftware,isotopelabelling,andthetheorybehindunderstandingthevariousNMRexperiments.Theapplicationshavebeenvastfromsmallmolecules, materials,structureanddynamicsofbiomolecularcomplexestomedicalapplicationsofNMRandMRI.NMR hasbecomeastandardcharacterisationtoolinmanyChemistrylaboratoriesandwidelyusedinvariousindustrial applications,forexample,inthepharmaceuticalindustry.

OneofthemostimportantmilestonesinthetimelineofNMRisthedevelopmentof2DNMRmethods,which provideanelegantwaytogetaroundtheproblemof“spectralcrowding”andprovideversatileandhighlydetailed informationaboutmolecularstructureanddynamicsthroughcorrelationspectroscopy.Thisbookattemptstogive arigorousaccountofthebasicconceptsin2DNMRmethods,bothintermsoftheoryandapplications.Whilstthe listofcontentcoveredhereisnotexhaustive,webelieveitcertainlygivesthereaderagoodflairandcomprehensionofthefieldandnecessarybackgroundtograspmoreadvancedtopics,includinghigher-dimensionalNMR methods.

ThebookhasChaptersonthebasicsofNMR,analysisofpulsesequences,zero-toultralow-fieldNMR,NMR methodsinbiomoleculesinsolutionstate,methodsondataprocessing,pushingthefrontiersofresolution,and speedingupof2Ddataacquisition,diffusionspectroscopy,NMRofanisotropicandparamagneticsystems,and chemicalexchange.WehavealsoincludedaChapterasAppendixthatwehopewillcomplementmanyofthe otherChapters,andinparticularChapters11and12.TheChaptersareallwrittenbyleadingresearchersinthe fieldwhohavealsocontributedsignificantlytothetopicoftheirrespectiveChapter.Wehopethatthisbookwill beusefultoestablishedaswellasbeginningresearcherswhowanttoexplorethebenefitsofNMRspectroscopy andnewareasofitsmultidimensionalfacets.

Wethankalltheauthorswhohavecontributedtothisbookandalsoinatimelyfashion.Thesignificantamount ofcarethathasgoneintoeachChaptermeritsattentionanddeepacknowledgement.Wealsothankthepeople atWileyforputtingupthisbookverynicely,someofthembeing,JennyCossham,SarahHigginbotham,Elke Morice-Atkinson,andRichaJohn.

Finally,thisbookalsohasatributesectionwrittenforKostya(K.Ivanov)bysomeoftheauthors.Theconcept ofthisbookwasKostya’sidea,however,unfortunatelyhepassedawayonMarch5,2021,attheyoungageof44. Agreatscientist,afantastichumanbeing,wededicatethisbooktohismemories.

BasicsofTwo-dimensionalNMR

MalcolmH.Levitt

DepartmentofChemistry,UniversityofSouthampton,SO171BJ,Southampton,UK

1.1 Introduction

1.1.1 Time-domainNMR

Theintroductionofpulse-Fouriertransform(pulse-FT)NMRin1966byErnstandAnderson[1]representeda paradigmshift,notonlyinnuclearmagneticresonancebutalsoinmanyotherformsofspectroscopy.Priorto thisseminalexperiment,thereweretwoformsofNMR,whichweregenerallyviewedasbeingquitedistinctand practicedmainlybychemistsontheonehand,andphysicistsontheother.

ChemicalapplicationsofNMRspectroscopyuseda“continuous-wave”(cw)method,inwhichchemicalshifts andspin-spincouplingswereprobed,eitherby(i)varyingthefrequencyofappliedradiofrequencyirradiationand detectingachangeinthenuclearmagneticresponsewhentheappliedfrequencymatchesanuclearenergylevel spacing,or(ii)byapplyingradiofrequencyirradiationoffixedfrequencyandvaryingtheappliedmagneticfield whilemonitoringtheresponse.Fortechnicalreasons,thelattermethod(fixedfrequency,variablefield)waseasier toperformandmorecommon.Aresidueofthishistoricalmethodstillpersistsinthecommonnomenclatureof modernNMR,wheretheterms“highfield”and“lowfield”arestilloftenused(despiteajarringlogicalinconsistency)tocharacterizenucleiinelectronenvironments,whicharerelativelyweaklyshieldedfromtheexternal magneticfield(lowfield!),andforthosethatarerelativelystronglyshieldedfromtheexternalmagneticfield(high field!).

In1966,manyimportanttime-domainNMRexperimentsandphenonemaalsoexisted,buttheywerelargely developedandusedbyphysicists.Theseincludethespinecho[2],themodulationofspinechoesbyspin-spincouplings[3],theuseofspinechoestoprobemoleculardiffusioninafieldgradient[3],thedevelopmentofmultiple spinechoes[3,4],andHartmann-Hahncross-polarizationbetweendifferentnuclearspeciesinsolids[5].

Theintroductionofpulse-FTNMRestablishedapermanentlinkbetweenthetime-domain“physics”phenomenaandthecontinuous-wave“chemistry”procedures.

Theperturbationofnuclearspinsbyastrong,short,resonantradiofrequencypulseelicitsanextended time-domainelectricalresponsetermeda free-inductiondecay,followingBloch[6].ErnstrealizedthatFourier transformationofthetime-domainNMRsignal��(��)yieldsafrequency-domainfunction��(��),whichundercertain assumptions,isidenticaltotheNMRspectrumgeneratedfarmoreslowlybyacontinuous-wavefrequency-domain NMRexperiment:

Two-Dimensional(2D)NMRMethods,FirstEdition.EditedbyK.Ivanov,P.K.MadhuandG.Rajalakshmi. © 2023JohnWiley&SonsLtd.Published2023byJohnWiley&SonsLtd.

Inonestroke,Ernstunifiedtime-domainNMR,withitscentralobjectthefree-inductiondecay ��(��),and frequency-domainNMR,withitscentralobjecttheNMRspectrumatfixedfield ��(��).Furthermore,thisgroundbreakingtheoreticalunificationwasaccompaniedbyalargeincreaseinsignal-to-noiseratio,ofgreatpractical importance.Thetimingofthisadvancewasexceptionallyfavorable.PracticalapplicationoftheFouriertransform requiresnumericalcomputation.Sufficientlypowerfulcomputationalhardwarewasbecomingwidelyavailable, andfurthermore,afastalgorithmfornumericalFouriertransformationhadjustbeendeveloped[7].Astheysay, therestishistory.NMRwasrevolutionized,withahugeimpactonmanyothersciences,asrecognizedbyErnst’s Nobelprizein1991.ItwasprobablyoneoftheleastcontentiousNobelprizesinhistory.

1.1.2

HansPrimasandthe“CorrelationFunctionoftheSpectrum”

TheseminalcontributionofErnstandAndersoniswellknowntomostNMRspectroscopists.Lesswellknown isthatanEquationverysimilartoEquation 1.1 hadbeenpublishedbyaclosecolleagueofErnstatETH-Zürich afewyearsearlier.ThiscolleaguewasHansPrimas,whoenjoyedaparticularlyremarkablecareer.Primaswasa self-taughtgeniuswhorosetobecomeaProfessorofPhysicalandTheoreticalChemistryattheETH-Zürichand anauthorityinquantumtheoryandthephilosophyofscience,despitetheabsenceofsecondaryschooleducation orauniversitydegreeofanykind[8].The1963paperbyBanwellandPrimas[9]introducesaquantitycalledthe “correlationfunctionofthespectrum”andgivenby

(omittinganunimportantnormalizationfactor).SincetheFouriertransformisreversible,Equations 1.1 and 1.2 areentirelyequivalent(overlookingatechnicaldifferenceinintegrationlimits).BanwellandPrimasintroduced theterm ��(��) asanobjectoftheoreticalinterestandpresumablymisseditssignificanceasbeingidenticaltothe free-inductiondecay ��(��) generatedbyanuclearspinsystemsubjectedtopulseexcitation–andwascertainlynot awareofitspracticalsignificance.

ImentionPrimas’worknottodisparageErnst’sachievement–onthecontrary,IfeelthattheworkbyPrimasand colleagueshelpsusunderstandbetterthehistoricalprovenanceofErnst’sinsight.Ernst’sskillwasinmarrying thecontemporarythinkingattheETH-ZürichwiththehighlypracticalmotivationofAndersonattheVarian Corporation,withwhomErnstdevelopedtheconceptandapplicationofFT-NMR[1].

Remarkably,Equation1.2isfarfrombeingtheonlyimportantinsightinreference[9].Thispaperalsointroduces theconceptsofsuperoperatorsandLiouvillespaceandalsoanticipatesCartesianproductoperatortechniques, broughttofruitionbySørensenetal.[10]andothergroupsnearly20yearslater(seeChapter3).

1.2 SpinDynamics

1.2.1

DensityOperator

Time-domainFourierNMRismostconvenientlyanalyzedbythemodernoperatordescriptionofNMR,as expoundedinthetextbookbyErnst,Bodenhausen,andWokaun[11].

Thequantumstateofthenuclearspinsinthesampleisdescribedbyaspindensityoperator ��,defined:

where |��⟩ isthespinstateofanindividualspinsystemandtheoverbarindicatesanensembleaverage.

1.2.2 SpinHamiltonian

Inmanycases,thespinHamiltonian ℋ maybewrittenasthesumofa coherent term,whichisidenticalforall membersofthespinensemble,anda fluctuatingterm,whichisstronglytime-independent,hasadifferentvalue fordifferentensemblemembers,andazeroaverageovertheensemble:

ThecoherentpartofthespinHamiltonian ℋcoh containsterms,whichareresponsibleformajorfeaturesof theNMRspectrumsuchaschemicalshifts,spin-spincouplings,andresidualdipolarcouplingsinanisotropic phase[12].

Ingeneral,thecoherentspinHamiltonian ℋcoh possessesasetof ���� eigenstates |��⟩ andeigenvalues ����, satisfyingthefollowingeigenequation:

Whenmultipliedby ℏ,theeigenvalues ���� correspondtothequantumenergylevelsofthespinsystem.

ThefluctuatingpartofthespinHamiltonian ℋfluc(��) isresponsiblefor dissipative phenomena,includingrelaxationprocesses,whichbringthespinsystembacktoequilibriumwiththemolecularenvironmentaswellas importantdissipativeeffectssuchasthenuclearOverhausereffect,whichunderpinsmanyapplicationsofNMR tostructuralbiology[13].

1.2.3 LiouvilleSpace

Theprinciplesoftime-domainNMRareexpressedmostcompactlyin Liouvillespace,meaningthespaceofall orthogonaloperatorsforthespinsystem[11,14,15].Thedimensionofthisspaceis ����

AconvenientbasisforLiouvillespaceisgivenbyallpossibleproductsoftheketsandbrasofthecoherent Hamiltonianeigenstates,eachoperatorhavingtheform

The ���� operatorswith ��=�� areknownas populationoperators:

The ����(���� −1) operators ������ with ��≠�� areknownas coherenceoperators. Inthisrepresentation,thedensityoperatormaybewrittenasa ����-dimensionalvector,termeda Liouvilleket | | |��⟩,asfollows:

Ingeneral,theLiouvillianhas ���� righteigenkets or righteigenoperators denoted | | | | ������⟩,and ���� lefteigenbras or lefteigenoperators denoted ⟨������ | | | |,withthefollowingproperties:

wheretheindex��takesvalues{1,2…����}andΛ�� aretheLiouvillianeigenvalues.Byconvention,theleftandright eigenoperatorsarenormalized:

Theleftandrighteigenketsareorthogonaltoeachother:

wheretheKroneckerdelta ������ isequalto 1 for ��=��,and 0 otherwise.However,theleftandrighteigenoperators arenot,ingeneral,mutuallyadjoint:

TheinequalityinEquation 1.21 mayonlybereplacedbyanequalityinthecasethatrelaxationisignored, ortheenvironmentaltemperatureisassumedtobeinfinite.Inordertomaintaingenerality,theleftandright eigenoperatorsarekeptdistinctinthischapter.

TheLiouvillianeigenvaluesarecomplexingeneral,andmaybewritten

where ���� and ���� arereal,and ���� ≥ 0.Foreacheigenoperator | | | | ������⟩,thequantity ���� representsitsoscillation frequency,and ���� itsdecayrateconstant.

Eigenoperators| | | | ������⟩withrealeigenvaluesrepresentparticularconfigurationsofthespinstatepopulationsthat decaymonotonicallyandexponentially,withoutoscillating,astheevolutionproceeds.Eigenoperators| | | | ������⟩with complexeigenvalues,ontheotherhand,oscillatewhiledecaying.Theoscillationfrequencyofaneigenoperator | | | | ������⟩isgivenbytheimaginarypart���� oftheeigenvalueΛ��.Theirdecayrateconstantisgivenbythequantity����, whichisminustherealpartoftheeigenvalue Λ��

Inmostcases,aneigenoperator|

| ������⟩withacomplexeigenvalueisveryclosetoacoherenceoperator| | |������⟩,with �� ≠��.Theeigenfrequency ���� ofsuchanoperatoris(minus)thedifferenceineigenvaluesbetweentherelevant Hamiltonianeigenstates[9]:

ThecorrespondenceinEquation 1.23 isnotexactingeneral.Thisisbecausethesuperoperators ̂ ℋcoh and ̂ Γ donotalwayscommute.Thisimpliesthatnewpropertiesmayemergewhenthetwotermsarecombined.For example,therelaxationpropertiesofthespinensemblemaybeprofoundlymodifiedbychangingthecoherent Hamiltonian,evenwhentherelaxationsuperoperator ̂ Γisleftuntouched.Oneexampleistheemergenceofslowly

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