Lewis Basicity and Affinity Scales: Data and Measurement

478 Pages·2009·9.74 MB·English

by  Christian Laurence

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Lewis Basicity and Affinity Scales
Lewis Basicity and Affinity Scales: Data and Measurement Christian Laurence and Jean-François Gal
© 2010 John Wiley & Sons, Ltd. ISBN: 978-0-470-74957-9
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Lewis Basicity and
Affinity Scales
Data and Measurement
CHRISTIAN LAURENCE
De´partementdeChimie,Universite´ deNantes–CNRS,France
JEAN-FRANC¸OIS GAL
Institut deChimie,Universite´ deNice-Sophia Antipolis–CNRS,France
A John Wiley and Sons, Ltd., Publication
iii
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Thiseditionfirstpublished2010
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LibraryofCongressCataloging-in-PublicationData
Laurence,Christian.
Lewisbasicityandaffinityscales:dataandmeasurement/ChristianLaurence,Jean-Franc¸oisGal.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN978-0-470-74957-9
1.Acids–Basicity. I.Gal,Jean-Franc¸ois. II.Title.
QD477.L382009
546(cid:2).24–dc22 2009030807
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
ISBN9780470749579
Typesetin10/12ptTimesbyAptaraInc.,NewDelhi,India.
PrintedandboundinGreatBritainbyCPIAntonyRowe,Chippenham,Wiltshire
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To
Eliane
Vale´rie,Anne
Hugo,Cle´ment,SimonandLouis
C.Laurence
Inmemory ofmymother
whoenabledmetofulfillmyvocationasaresearcher
J.-F.Gal
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Contents
Preface pageix
1 LewisBasicityandAffinityMeasurement:DefinitionsandContext 1
1.1 TheBro¨nstedDefinitionofAcidsandBases 2
1.2 ScalesofBro¨nstedBasicityandAffinityinSolution 3
1.3 ScalesofBro¨nstedBasicityandAffinityintheGasPhase 6
1.4 TheLewisDefinitionofAcidsandBases 6
1.5 QuantumChemicalDescriptionsofLewisAcid/BaseComplexes 10
1.5.1 Valence-BondModel 10
1.5.2 PerturbationMolecularOrbitalTheory 10
1.5.3 VariationalSupermolecularMethodandEnergy
DecompositionSchemes 12
1.5.4 NaturalBondOrbitalTheory 17
1.5.5 QuantumTheoryofAtomsinMolecules 18
1.6 MeasurementofLewisBasicity 20
1.6.1 Gas-phaseReactions 21
1.6.2 SolutionReactions 22
1.6.3 StandardStateTransformations 23
1.6.4 ChoiceofSolvent 24
1.7 MeasurementofLewisAffinity 24
1.8 TheRoleoftheSolvent 29
1.9 SpectroscopicScalesofBasicity(Affinity) 34
1.10 PolybasicCompounds 38
1.11 AttemptsataQuantitativeFormulationoftheLewisDefinition
ofAcidsandBases 42
1.11.1 HardandSoftAcidsandBases 42
1.11.2 TheECWandECTModels 47
1.11.3 TheBetaandXiEquation 52
1.11.4 AChemometricApproach 53
1.11.5 QuantumChemicalDescriptorsforBasicityScales 56
1.12 ConcludingRemarksandContentofChapters2–7 58
References 60
2 TheDonorNumberorSbCl AffinityScale 71
5
2.1 StructureofSbCl Complexes 71
5
2.2 DefinitionoftheDonorNumberScale 73
2.3 ExperimentalDeterminationoftheDonorNumber 73
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2.4 TheDonorNumberScale:Data 74
2.5 CriticalDiscussion 80
References 81
3 TheBF AffinityScale 85
3
3.1 StructureofBF Complexes 86
3
3.2 DefinitionoftheBF AffinityScale 88
3
3.3 ExperimentalDeterminationoftheBF AffinityScale 89
3
3.4 TheBF AffinityScale:Data 90
3
3.5 Discussion 102
3.5.1 MediumEffects 102
3.5.2 HardnessofBF 102
3
3.5.3 ComparisonoftheBF andSbCl AffinityScales 103
3 5
3.5.4 ComputationoftheBF Affinity 104
3
3.6 Conclusion 105
References 106
4 ThermodynamicandSpectroscopicScalesofHydrogen-Bond
BasicityandAffinity 111
4.1 StructureofHydrogen-BondedComplexes 113
4.2 Hydrogen-BondBasicityScales:EarlyWorks 117
4.3 The4-FluorophenolHydrogen-BondBasicityScale 119
4.3.1 Definition 119
4.3.2 MethodofDetermination 119
4.3.3 PolyfunctionalHydrogen-BondAcceptors 120
4.3.4 Data 121
4.3.5 RangeofValidityoftheScale 167
4.4 Hydrogen-BondAffinityScales:EarlyStudies 168
4.5 The4-FluorophenolAffinityScale 170
4.6 Comparisonof4-FluorophenolAffinityandBasicityScales 185
4.7 SpectroscopicScales 188
4.7.1 InfraredShiftofMethanol 188
4.7.2 SolvatochromicShiftsof4-Nitrophenoland4-Nitroaniline 210
4.8 Conclusion 221
References 221
5 ThermodynamicandSpectroscopicScalesofHalogen-Bond
BasicityandAffinity 229
5.1 StructureofHalogen-BondedComplexes 231
5.2 TheDiiodineBasicityScale 237
5.2.1 DefinitionoftheScale 237
5.2.2 MethodsfortheDeterminationofDiiodine
ComplexationConstants 238
5.2.3 TemperatureCorrection 239
5.2.4 SolventEffects 239
5.2.5 Data 243
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5.3 IstheDiiodineBasicityScaleaGeneralHalogen-BondBasicityScale? 283
5.4 TheDiiodineAffinityScale 285
5.5 SpectroscopicScales 286
5.5.1 InfraredShiftsofICN,I andICl 286
2
5.5.2 TheBlueShiftoftheDiiodineVisibleBand 306
5.6 Conclusion 309
References 309
6 Gas-PhaseCationAffinityandBasicityScales 323
6.1 CationsasLewisAcidsintheGasPhase 323
6.2 StructureofCation/MoleculeAdducts 326
6.3 ExperimentalTechniquesforMeasuringGas-PhaseCationAffinities
andBasicities 334
6.3.1 High-PressureMassSpectrometry(HPMS) 334
6.3.2 Collision-InducedDissociationThreshold(CIDT) 335
6.3.3 Ligand-ExchangeEquilibriumMeasurementsinTrappingDevices 336
6.3.4 SelectedIonFlowTube(SIFT) 337
6.3.5 KineticMethod 337
6.3.6 RadiativeAssociationKinetics(RAK) 338
6.3.7 BlackbodyInfraredRadiativeDissociation(BIRD) 338
6.3.8 VaporizationandLatticeEnergies 339
6.4 IonThermochemistryConventions 339
6.5 Lithium,Sodium,Potassium,Aluminium,Manganese,
Cyclopentadienylnickel,CopperandMethylammoniumCations
AffinityandBasicityScales 340
6.5.1 Lithium 340
6.5.2 Sodium 346
6.5.3 Potassium 353
6.5.4 Aluminium 354
6.5.5 Manganese 354
6.5.6 Cyclopentadienylnickel 360
6.5.7 Copper 366
6.5.8 Methylammonium 371
6.6 SignificanceandComparisonofGas-PhaseCationScales 370
6.6.1 PropertiesofCationsandSignificanceofMCBandMCAScales 370
6.6.2 RelationshipofMCAwithMCB 381
6.6.3 TheComputationofMCBandMCAScales 382
6.6.4 MCAandMCBScalesandtheConceptofaCation/π Interaction 383
6.6.5 ConventionalVersusIonicHydrogen-BondBasicityand
AffinityScales 386
6.6.6 ComparisonofCationBasicityScales 387
References 389
7 TheMeasurementofLewisBasicityandAffinityintheLaboratory 401
7.1 CalorimetricDeterminationoftheBF AffinityofPyridine
3
byGas/LiquidReaction 401
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7.1.1 Introduction:PrinciplesandDifficultiesintheCalorimetric
MeasurementoftheEnthalpyofaGas/LiquidReaction 401
7.1.2 ReagentsandEquipment 403
7.1.3 Experiment 404
7.1.4 Results 405
7.2 CalorimetricDeterminationoftheBF AffinityofPyridine
3
byLiquid/LiquidReaction 406
7.2.1 Introduction:MeasuringRelativeBF AffinitybyLigand
3
ExchangeinSolution 406
7.2.2 ReagentsandEquipment 407
7.2.3 Experiment 407
7.2.4 Results 407
7.3 DeterminationbyFTIRSpectrometryoftheComplexationConstants
of4-FluorophenolwithIsopropylMethylKetoneandProgesterone 408
7.3.1 Introduction:RecognitionofProgesteronebyitsReceptor 408
7.3.2 ReagentsandEquipment 409
7.3.3 Experiment 409
7.3.4 ResultsandDiscussion 410
7.4 DeterminationbyFTIRSpectrometryoftheComplexationEnthalpy
andEntropyof4-FluorophenolwithCyclopropylamine 413
7.4.1 Introduction 413
7.4.2 ReagentsandEquipment 414
7.4.3 Experiment 414
7.4.4 Results 414
7.4.5 ComparisonwithTheoreticalCalculations 417
7.5 FTIRDeterminationoftheOHShiftofMethanolHydrogen
BondedtoPyridine,Mesityleneand N-Methylmorpholine 418
7.5.1 Introduction 418
7.5.2 ReagentsandEquipment 418
7.5.3 Experiment 419
7.5.4 ResultsandDiscussion 419
7.6 SolvatochromicShiftsof4-NitrophenoluponHydrogen
BondingtoNitriles 420
7.6.1 Introduction 420
7.6.2 ReagentsandEquipment 421
7.6.3 Experiment 421
7.6.4 ResultsandDiscussion 422
7.7 DeterminationoftheComplexationConstantofDiiodine
withIodocyclohexanebyVisibleSpectrometry 424
7.7.1 Introduction:MeasuringtheWeakDiiodineBasicity
ofHaloalkanes 424
7.7.2 TheRose–DragoMethod 424
7.7.3 ReagentsandEquipment 426
7.7.4 Experiment 426
7.7.5 ResultsandDiscussion:IllustrationoftheHSABPrinciple 427
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7.8 DeterminationoftheComplexationEnthalpyandEntropyofDiiodine
withDimethylSulfoxidebyVisibleSpectrometry 429
7.8.1 Introduction 429
7.8.2 ReagentsandEquipment 429
7.8.3 Experiment 429
7.8.4 Results 430
7.8.5 Discussion 432
7.9 FTIRDeterminationoftheShiftoftheI CStretchingofIodine
CyanideuponHalogenBondingtoPhosphineChalcogenides 434
7.9.1 Introduction 434
7.9.2 ReagentsandEquipment 435
7.9.3 Experiment 435
7.9.4 ResultsandDiscussion:∆ν(ICN)asaSpectroscopicScale
ofHalogen-BondAffinity 435
7.10 BlueShiftoftheVisibleDiiodineTransitionUponHalogen
BondingtoPyridines 436
7.10.1 Introduction 436
7.10.2 ReagentsandEquipment 437
7.10.3 Experiment 437
7.10.4 ResultsandDiscussion:SubstituentEffects 438
7.11 MassSpectrometricDeterminationoftheGas-PhaseLithiumCation
BasicityofDimethylSulfoxideandMethylPhenylSulfoxidebythe
KineticMethod 439
7.11.1 TheKineticMethod 439
7.11.2 ReagentsandEquipment 440
7.11.3 Experiment 441
7.11.4 DataTreatment 442
7.11.5 Discussion:SubstituentEffects 444
References 445
Index 447
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Preface
In 1923, G.N. Lewis proposed an electronic definition of acids and bases founded on
electronpairsharing.ComparedwiththeprotonicdefinitionofBro¨nstedbasedonproton
exchange,thenewLewisdefinitionbroadenedconsiderablythefieldofacid/basereactions.
It incorporates heterolysis, coordination, solvation, complexation, hydrogen-bond forma-
tion, halogen-bond formation and electrophilic and nucleophilic reactions into acid/base
chemistry.ItisthereforenotsurprisingthatdiscussionsofLewisacidityandLewisbasicity
appearinalmosteverytextbookongeneral,organicandinorganicchemistry.
A major criticism, however, is often made of the Lewis definition. Contrary to the
Bro¨nsteddefinition,itisnotpossibletoestablishanyuniversalorderofacidorbasestrength.
IntheBro¨nsteddefinition,theprotonisusedasthereferenceandthequantitativestudyof
proton exchange reactions between bases, by means of electrochemical or spectrometric
methods,enabledthestrengthofseveralthousandBro¨nstedacidsandbasestobemeasured
unambiguously. Thermodynamic databases for proton exchange in the gas phase (NIST
webbook, http://webbook.nist.gov.) or in water (e.g. D.D. Perrin, Dissociation Constants
of Organic Bases in Aqueous Solution, Butterworths, London, 1965, and supplement,
1972)arethereforeextremelyusefulinanalytical,organicandinorganicchemistryandin
biochemistry.
Incontrast,intheLewisdefinitionthereisnosinglereferencethatisnaturallyoperational.
Since there is no obvious reason to choose one reference rather than another, there are
potentiallyasmanyacidityorbasicityscalesaspossiblereferences.
Concerningbasicity,however,whichisthesubjectofthisbook,thestatisticaltreatment
ofvariousscalesofLewisbasicity,aswellastheoreticalstudies,showthatalimitednumber
of factors influence the strength of Lewis bases. Consequently, the judicious choice of a
fewreferenceLewisacidsshouldallowLewisbasicityscalestobeconstructedandusedas
ageneralguidetobasicity.Althoughnoneofthesescalescanbeconsideredasuniversal,
eachwillhaveadomainofvaliditythatissufficientlywidetobeusefulinmanybranches
ofchemistryandbiochemistry.
Itiswiththisobjectivethatthisbookpresentsthermodynamicandspectroscopicdataon
thestrengthofLewisbasescomingfromboththeliteratureandourlaboratories.Wedonot
aimtoprovideexhaustivescalesbutratheraselectiveguide.Fromamassofdata,sometimes
contradictoryandoftenlackingconsistency,wehavechosentypicalreferenceLewisacids.
These are SbCl , BF , 4-FC H OH, CH OH, 4-NO C H OH, 4-NO C H NH , I , ICl,
5 3 6 4 3 2 6 4 2 6 4 2 2
ICN, Li+, Na+, K+, Al+, Mn+, CpNi+, Cu+ and CH NH+. This choice is justified in
3 3
the first chapter. For each of these acids, we have selected only the data determined
by the most accurate techniques and/or the most reliable methods. In cases of doubt,
somemeasurementsfromtheliteraturehavebeenrepeatedinourlaboratories.Additional
measurementshavealsobeencarriedoutinordertofillsignificantgaps.Finally,datahave
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