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氧化加成反应（OA）和还原消除反应（RE）胡爱国背景知识金属有机化合物的定义及金属有机化学发展历史金属有机化合物中的结构和化学键化合价、氧化态、d电子数、饱和度、有机配体、配位数和18电子规则空间点群（PointGroup）、立体构型价键理论（ValencebondTheory）、晶体场理论（CrystalFieldTheory）分子轨道理论（MolecularOrbitalTheory）金属有机化合物的反应配合反应氧化加成反应和还原消除反应（OxidativeAddition&ReductiveElimination）迁移插入和消除反应（MigrationInsertion&Elimination）、配体上的反应金属有机化学在高分子合成中的应用阴离子聚合反应(AnionicPolymerization)配位聚合反应(CoordinationPolymerization)卡宾配合物和烯烃复分解聚合反应（OlefinMetathesisPolymerization）交叉偶联反应及相关聚合反应(CrossCouplingPolymerization)原子转移自由基聚合反应(AtomTransferRadicalPolymerization)金属有机高分子化合物（新型功能高分子）教学大纲配体交换反应（LigandExchange）DissociativeligandsubstitutionAssociativeligandsubstitutionHomeworkofLastWeekQuestion:以下哪个反应会生成顺铂（cis-Platin）？为什么？FYI：Transeffect/influenceseries:H-,CH3-,olefins,COPR3,I-Br-Cl-NH3OH-H2Ocis-PlatinHomeworkofLastWeekCl-NH3cis-Platin氧化加成反应和还原消除反应AdditionofR-Xtoametalcenterresultinginanincreaseofoxidationstateby2units,anincreaseincoordinationnumberby2or1,andanincreaseintheelectroncountby2or0OA反应后，金属的氧化态增加2，配位数增加2（外界配位时为1），总电子数增加2（外界配位时，内界电子数不变）OA&REOxidativeAddition(OA):metalmediatedbreakingofasubstrates-bondandformationof1or2newM-Lsbonds金属（配合物）破坏R-X的s键，并形成1到2个新的M-Ls键的反应氧化加成反应（OA）的特点：OAoflowvalent,electronrichmetalstopolarsubstratesisthebestwaytoformM-Csbondswithinthecontextofacatalyticcycle.(金属-碳键形成)氧化加成反应和还原消除反应EliminationoftwoligandsfromametalcentertogiveanewA-Bbond.Themetalcenterisreducedby2unitsandhas2fewercoordinatedligands.Thecomplexhas2lesselectronsRE反应后，金属的氧化态减少2，配位数减少2，总电子数减少2OA&REReductiveelimination(RE):microscopicreverseofoxidativeadditionwheretwoM-Lsbondsarebrokentoformonesubstratesbond2个M-Ls键破坏，并形成1R-X的s键的反应，是OA反应的逆反应还原消除反应（RE）的特点：ThetwoM-Lsbondsundergoingreductiveeliminationmustbeorientedcistoeachother.REisthemostcommonwaytoformC-Cbondsviatransitionmetalcomplexes.(顺式消除，碳碳键形成的反应)氧化加成反应和还原消除反应OA&REOxidativeadditionandreductiveeliminationarethemicroscopicreverseofeachother.Theyrepresenttheforwardandreversereactionofanequilibrium.Thepositionoftheequilibriumdependsonthethermodynamicsoftheoxidativeaddition(orreductiveeliminationprocess).ForexamplemanymetalcomplexeswilloxidativelyaddCH3I,butfewwillreductivelyeliminatethiscompound.IncontrastM(H)Rusuallyundergorapidreductiveelimination,butoxidativeadditionofalkanesismuchlesscommon.氧化加成反应和还原消除反应是微观可逆反应，该反应的平衡点取决于平衡两端化合物的热力学稳定性，例如，很多金属配合物可以与CH3I发生OA反应，而有些金属配合物则会排斥CH3I的加成氧化加成反应和还原消除反应OA&REThermochemistryofOxidativeAdditionDG=DH-TDS氧化加成反应ThreePossibleMechanisms1Concerted（协同反应）(generallyfornon-polarsubstrates)Requirescoordinativeunsaturation中心金属配位不饱和Retentionofconfigurationatcarbon碳原子上的构型保持不变cisstereochemistryatthemetal中心金属上的顺位加成MostlyobservedforOAofarylhalides在芳基卤化物的氧化加成反应中比较常见MncabXMncabXMn+2cabX2Nucleophilicdisplacement（亲核取代）(generallyforpolarsubstrates)氧化加成反应ThreePossibleMechanismsCationicintermediate碳正离子型中间体Inversionatcarbon碳原子上的构型发生翻转Secondorderkinetics遵循二级反应动力学TypicalSN2reactivitypatterns表现为典型的SN2反应序列，伯仲叔M:ncabXMn+2cabX-Mn+2cbaX-3Radical（自由基）(bothnon-polarandpolar)氧化加成反应ThreePossibleMechanismsEvidenceforR•(EPR,trapping)有可检测到的自由基Racemizationatcarbon碳原子上的构型消旋Secondorderkinetics遵循二级反应动力学tertiarysecondaryprimarymethyltypicaloffreeradical表现为典型的自由基反应序列，叔仲伯MncabXMn+1cabXMn+2cbaX.cab.Mn+2cabX氧化加成反应Inner-SphereElectronTransfer/CagedRadical-PairMechanismOuter-SphereElectronTransferMechanismRadicalMechanismOnlyoccurswhenRXcoordination(inner-sphere)isinhibited氧化加成反应MetalComplex:electronrichmetalsinlowoxidationstates,withstrongdonorligandsandasiteofcoordinativeunsaturationd10,tetrahedral,18e--d10,ML2,14e--d8,ML4,SP,16e(e.g.Ni0,Pd0,Pt0)d8,ML4,squareplanar,16e--d6,ML6,octahedral,18e(e.g.RhI,IrI)Substrates:twogroupssegregatedintonon-polarandpolar.Currently,themostfacilewaytoformC-Msbondsiswithpolarsubstrates(e.g.alkyl,aryl,andvinylhalides).氧化加成反应Non-polarsubstrates:R-H(inrarecase,R-C)Polarsubstrates:R-XwhereX=I,Br,Cl,OTf非极性底物的OA1.HydrogenOxidativeadditionofH2isakeystepinthehydrogenationofalkenesandotherrelatedreactions.Itisthebestunderstoodoxidativeadditionofnon-polarreagents.Therearethreemajormechanismsbywhichdihydrogencanundergooxidativeaddition.Wewillseethatthesealsoapplytoothernonpolarcompounds.ConcertedHomolyticHeterolyticOAofHydrogena.Concerteds-complex:intermolecularbindingofasubstrateviait'ss-bondtoametalcomplexConcertedmechanism:s-complexformationprecedesanearly(littles-bondbreaking),3-centeredtransitionstatewherestrongp-backbondingresultsinoxidativeadditionoftheboundsubstratetothemetal.OAofHydrogenDihydrogens-complexesThefirststabledihydrogenmetalcomplexwasisolatedbyKubas.ThelengthenedH-Hbond(0.84Å)is20%greaterthantheH-HbondlengthinfreeH2(0.74Å).ThisisthoughttoarisefrommetalbackbondingintotheH-Hs*orbital.KubasAcc.Chem.Res.1988(21)120.OAofHydrogenDihydrogens-complexesTheKubasdihydrogencomplexundergoesreversibleoxidativeadditiontogivethedihydride.AvariabletemperatureNMRstudyshowedthatat50°C,the1JH-Ddisappearsreversibly.(JACS,1986,133,9).Sincepopulationofthes*orbitalisrequiredforoxidativeaddition,predictionscanbemadeaboutwhetherametalcomplexwilloxidativelyaddH2,formanH2complex,orfailto