1、Advanced Organic Chemistry(1)高等有機化學（I）Instructor: JingKui YANGCollege of Chemistry and Chemical EngineeringGraduate University of CAS(GUCAS)1Advanced Organic Chemistry(1)Advanced Organic Chemistry(1)Chapt1: Organic Reaction Mechanism (3-4)Chapt2: Solvents Effects (5) National Holiday Day (6) Solvent

2、s Effects (7)Chapt3: Stereochemistry (9,10,11)Chapt4: Organic reaction active intermediates and determination. (12,13)Chapt5: Concerted Reaction (14)Chapt6: Organic Photochemistry and Electrochemistry (15,16A)Chapt7: Catalytic Reaction and Mechanism (16A,17)2Advanced Organic Chemistry(1)CChapt4: Org

3、anic reactive intermediates 有機活性中間體Free radicals (自由基) Ion radicals ( Cation radical, anion Radicals) 離子自由基Carbene(卡賓), Nitrenes(乃春)Benzyne (arynes)( 苯炔 )Carbocations ( Carbon Cation )(碳正離子)Carbanions ( Carbon Anion )(碳負離子)Antiaromatic compounds(反芳香化合物) Strained rings(張力環(huán)) Introduction, Properties,

4、Preparations, Reactions, Determination3Chapt4: Organic reactive inteAdvanced-Organic-Chemistry1-高等有機化學課件Advanced-Organic-Chemistry1-高等有機化學課件Nobel Prize for Chemistry in 1994 George Olah, 1927 -,Hungary(匈牙利） USAUniversity of Southern CaliforniaLos Angeles, CA, USA Biographyfor his contribution to car

5、bocation chemistry6Nobel Prize for Chemistry in 1Others Nobel Prize for Chemistry in 1999 in femtosecond spectroscopyAhmed H. Zewail, 1946-, Egypt and USACalifornia Institute of TechnologyPasadena, CA, USA Nobel Prize for Chemistry in 1992 in The Theory of electron transfer reactions Marcus, 1923 -

6、Montreal, Canada and USA California Institute of Technology Pasadena, CA, USAAlso in 1967, 19837Others Nobel Prize for ChemisReactive Intermediates: The Methods The Field of Reactive Intermediates is a highly interdisciplinary field that requires the combination of a multitude of methodstraditional

7、spectroscopic methods ultrafast spectroscopic methods electrochemistry computational chemistry synthetic chemistry photochemistry kinetics biochemistry Intelligence/ Imagination8Reactive Intermediates: The MeReactive Intermediates: The Compounds What unifies these disciplines and defines the field i

8、s the simple question of :How short lives species determine the outcome of chemical reactions(生命力多短的片段決定反應的結果). The reactions in question can in themselves come from totally different fields. Studies of the visual process in the eyes retina(視網(wǎng)膜), explosions or growth of material through CVD processe

9、s. Mechanistic research nearly synonymous(同意,等同于) with research into reactive intermediates because the majority of chemical reactions involve short lived intermediates. CVD: Chemical Vapor Deposition(化學氣相沉積法）9Reactive Intermediates: The Co.tw/htchiu/cvd/home.html / CVDChemical Vapor Deposition is c

10、hemical reactions which transform gaseous molecules( precursor), into a solid material in the form of thin film or powder, on the surface of a substrate GasSolid materialssubstrate10.twRadicals Carbenium cation Carbenium anions Sextet species (六電子體系) (carbenes, nitrenes etc) 16 VE transition metal c

11、omplexes Antiaromatic compounds Strained rings Biochemical reactions frequently involve species from the list above and, in addition, unusually reactive intermediates that owe their high reactivity to the violation of more subtle stability criteria.Examples: 11Radicals Examples: 11carbenes, nitrenes

12、, silylenes, free radicals, radical ions, diradicals, carbocations, carbanions, N,S,O,P,Si等及其他兩性元素有相似可能性12carbenes, nitrenes, silylenes,中間體穩(wěn)定性不一樣 some very stable can be isolated , but others (highly reactivity) do not Two types of Organic Reactions:1), Step wise Reactions(分步反應): 可以分出中間體2), Concerte

13、d Reaction(協(xié)同反應) 理想狀態(tài): 沒有中間體(?)My Hypothesis: too fast and very high reactivityand can not be checked by current instrument? 13中間體穩(wěn)定性不一樣Two types of Organic (活性中間體)14(活性中間體)141515電荷轉移復合物(Charge Transfer Complex, CTC) Electron Transfer, ET16電荷轉移復合物(Charge Transfer Comple多重性2I+1I000117多重性2I+1I17Haloni

14、um ionEnolate/enol/Ynol(烯醇或炔醇)diradicalsOxireneBenzyne(苯炔)18Halonium ionEnolate/enol/Ynol(keteneisocyanateYlide(葉立德)Ketyl Radical 羰游離基16 VE19keteneisocyanateYlide(葉立德)KetyCation /Anion Radical(陽/陰離子自由基)20Cation /Anion Radical(陽/陰離子自由基只作參考21只作參考21222223232424/c_symposia/c_symp_9.htm25/c_syAngewandte

15、Chemie International Edition Volume 37, Issue 24,1999, 3340-3350 Dynamic Behavior of Organic Reactive Intermediates (p3340-3350) Barry K. Carpenter Abstract | Full Text: PDF (Size: 301K) 只做參考!“Organic Reactive Intermediates, Chem. Rev. 1992, 92, 1611-1647.26Angewandte Chemie InternationaKeywordsComp

16、uter chemistry; Diradicals; Kinetics; Molecular dynamics; Supercritical fluids; Computer chemistry; Diradicals; Kinetics; Molecular dynamics; Supercritical fluids AbstractAn unexpected yes is the answer the author gives to the following questions: If a reactive intermediate was faced with two equall

17、y high energy barriers to product formation, could the kinetic product ratio ever be anything other than 1:1? If the two barriers were of unequal height, could there ever be a preference to form the product that corresponds to the higher barrier pathway? The basis for this yes are the results from m

18、olecular dynamics simulations and experiments that suggest that the interpretation of reaction mechanisms by statistical models is not always correct.只做參考!27KeywordsComputer chemistry; DChapt 4.2 Free Radicals(自由基)有未成對（unpaired)電子的中性原子、基團或分子。Neutral Chemical species that have a single unpaired elect

19、ron反應特點： 與溶劑極性無關 易在氣相生成 不被酸或堿催化 取代基效應與離子型反應不同 (既可被吸電子，也可被供電子基團穩(wěn)定？） 一般沒有很好的線性自由能關系（或特別小0） 對雜質非常敏感：O2，NHR1R2，SH，PhOH(可形成不 活潑的自由基，可用于反應機理判斷） 有特定的電子自旋（ESR/EPR）或核磁（CIDNP）共振譜28Chapt 4.2 Free Radicals(自由基)有First used by : Lavoisier in 18 th century to designate some polyatomic fragment of a molecule which

20、remains unchanged during 1 or more chemical transformations.1849, Frankland, believed but really produce mixture gases.1900 Moses Gomberg Ph3CCl + Hg/PhH = Ph3C. - Dimer yellow colour1927:Paneth/Hofeditz; 1937, Kharasch(Radical Chain mechanism), Hey/Waters: Proposing a radical mechanism 30 years lat

21、er, theory suggested, and more and more free radicals reactions found as the important intermediates in many reactionsHistory of Radical29First used by : Lavoisier in 1Deep violet(紫) crystalsBlue CrystalsRed-Brown liquid30Deep violet(紫) crystalsBlue CrStructure of Organic Free RadicalsMost of the Or

22、ganic Free Radicals have the following stereo structure:SP3 SP2 (planar conformation)(unpaired electron in P orbit)G=2.5KJ/mol31Structure of Organic Free RadiG=2.5KJ/mol is too small, turn over of it is very easy, so many free radical reaction of achiral compounds will give the raceme(外消旋體)Stability

23、 of radicals: More substitutes, more stable R3C. R2CH.RCH2.Reason: Hyper conjugation32G=2.5KJ/mol is too small, turIn solution: several days As solid:Stable up to 300oC 33In solution:33The Production of Free RadicalsThermolysis(熱解)Photolysis(光解)Oxidation_Reduction (氧化還原)34The Production of Free Radi

24、calESR: Electron Spin Resonance 電子自旋共振譜EPR: Electron Paramagnetic Resonance 電子順磁共振譜CIDNP: Chemically Induced Dynamic nuclear Polarization 化學誘導動態(tài)核極化（核磁）ENDOR: Electron_Nuclear Double Resonance Spectroscopy 電子和核雙重共振譜自由基的檢測手段和儀器35ESR: Electron Spin Resonance自由基波譜特征有未成對電子的順磁性未成對電子在磁場中有兩種可能的能態(tài)：其能量差E隨外磁場的

25、增加而增加E=h =gH光譜分裂因子玻爾磁子外磁場強度 當外場符合上述關系時即發(fā)生能量吸收產(chǎn)生磁能級間躍遷(Lande g factor)36自由基波譜特征有未成對電子的順磁性未成對電子在磁場中有兩種可（負電荷電子）電子自旋量子數(shù) + 1/2 或 - 1/2未成對電子無外場時自旋是隨機無順序，宏觀無磁性未成對電子有外場時自旋要分裂， 態(tài)（低能量）： -1/2對應磁矩與外場（H0）方向相同 態(tài)（高能量）： + 1/2對應磁矩與外場（H0）方向相反37（負電荷電子）電子自旋量子數(shù)未成對電子無外場時自旋是隨機無順eH0eh/2mcms=-1/2ms=+1/20H0: 外場強度g: 磁旋比 =磁矩/電

26、子角動量 自由電子：2.002319e: 波爾磁子9.2732x10-24J/T38eH0eh/2mcms=-1/2ms=+1/20H0Similar to Chemical Shift, Coupling Constant, area amount, and spilt info. of HNMR,used to predict/ determine the structure of compounds, ESR info. can be used to check the structure info. Of free radicals too.Position, strength, hy

27、perfine split constant ( 位置，強度，超精細分裂常數(shù)得到自由基結構信息）39Similar to Chemical Shift, CouFor most organic compounds: g=2.0022.006 (in HNMR as Chemical shifts, 對等于核磁中的化學位移)depending on the electronic environment of the unpaired electron(less useful than HNMR because of little difference)40For most organic com

28、pounds: Two important hyperfine spiltting H at -Carbon and Unpaired Electron H at -Carbon and Unpaired Electron long distance effect is very smaller ( S Orbit of H on -C may have hyperconjugation with Unpaired electron43Coupling Constant of hyperfineThe Interaction between the Unpaired electron coup

29、ling with the neighbored nuclear spin (核自旋） 1H, 13C, 14N,19F,31P,35Cl will give the hyperfine structure(精細結構）spiltting, fit to the（n+1) (2nI+1) rule used in HNMR.44The Interaction between the UnCH3. : 1:3:3:123.0G spinSlight excess of spinHSlight excess of spin45CH3. : 1:3:3:123.0G spinSlighCH3CH2. Proton spit the signal to 4, then Proton spilt to it to 3, total 3x4=1226.9G22.4Ga= -2.24mT(2H)a=+2.69mT(3H)偶合常數(shù)46CH3CH2. Proton spit the signa()()()Th