Advanced-Organic-Chemistry1-高等有机化学课件

1、Advanced Organic Chemistry(1)高等有机化学（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 有机活性中间体Free radicals (自由基) Ion radicals ( Cation radical, anion Radicals) 离子自由基Carbene(卡宾), Nitrenes(乃春)Benzyne (arynes)( 苯炔 )Carbocations ( Carbon Cation )(碳正离子)Carbanions ( Carbon Anion )(碳负离子)Antiaromatic compounds(反芳香化合物) Strained rings(张力环) Introduction, Properties,

4、Preparations, Reactions, Determination3Chapt4: Organic reactive inteAdvanced-Organic-Chemistry1-高等有机化学课件Advanced-Organic-Chemistry1-高等有机化学课件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(生命力多短的片段决定反应的结果). The reactions in question can in themselves come from totally different fields. Studies of the visual process in the eyes retina(视网膜), 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(化学气相沉积法）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 (六电子体系) (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等及其他两性元素有相似可能性12carbenes, nitrenes, silylenes,中间体稳定性不一样 some very stable can be isolated , but others (highly reactivity) do not Two types of Organic Reactions:1), Step wise Reactions(分步反应): 可以分出中间体2), Concerte

13、d Reaction(协同反应) 理想状态: 没有中间体(?)My Hypothesis: too fast and very high reactivityand can not be checked by current instrument? 13中间体稳定性不一样Two types of Organic (活性中间体)14(活性中间体)141515电荷转移复合物(Charge Transfer Complex, CTC) Electron Transfer, ET16电荷转移复合物(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(叶立德)Ketyl Radical 羰游离基16 VE19keteneisocyanateYlide(叶立德)KetyCation /Anion Radical(阳/阴离子自由基)20Cation /Anion Radical(阳/阴离子自由基只作参考21只作参考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) 只做参考!“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.只做参考!27KeywordsComputer chemistry; DChapt 4.2 Free Radicals(自由基)有未成对（unpaired)电子的中性原子、基团或分子。Neutral Chemical species that have a single unpaired elect

19、ron反应特点： 与溶剂极性无关 易在气相生成 不被酸或碱催化 取代基效应与离子型反应不同 (既可被吸电子，也可被供电子基团稳定？） 一般没有很好的线性自由能关系（或特别小0） 对杂质非常敏感：O2，NHR1R2，SH，PhOH(可形成不 活泼的自由基，可用于反应机理判断） 有特定的电子自旋（ESR/EPR）或核磁（CIDNP）共振谱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(外消旋体)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(热解)Photolysis(光解)Oxidation_Reduction (氧化还原)34The Production of Free Radi

24、calESR: Electron Spin Resonance 电子自旋共振谱EPR: Electron Paramagnetic Resonance 电子顺磁共振谱CIDNP: Chemically Induced Dynamic nuclear Polarization 化学诱导动态核极化（核磁）ENDOR: Electron_Nuclear Double Resonance Spectroscopy 电子和核双重共振谱自由基的检测手段和仪器35ESR: Electron Spin Resonance自由基波谱特征有未成对电子的顺磁性未成对电子在磁场中有两种可能的能态：其能量差E随外磁场的

25、增加而增加E=h =gH光谱分裂因子玻尔磁子外磁场强度 当外场符合上述关系时即发生能量吸收产生磁能级间跃迁(Lande g factor)36自由基波谱特征有未成对电子的顺磁性未成对电子在磁场中有两种可（负电荷电子）电子自旋量子数 + 1/2 或 - 1/2未成对电子无外场时自旋是随机无顺序，宏观无磁性未成对电子有外场时自旋要分裂， 态（低能量）： -1/2对应磁矩与外场（H0）方向相同 态（高能量）： + 1/2对应磁矩与外场（H0）方向相反37（负电荷电子）电子自旋量子数未成对电子无外场时自旋是随机无顺eH0eh/2mcms=-1/2ms=+1/20H0: 外场强度g: 磁旋比 =磁矩/电

26、子角动量 自由电子：2.002319e: 波尔磁子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，强度，超精细分裂常数得到自由基结构信息）39Similar to Chemical Shift, CouFor most organic compounds: g=2.0022.006 (in HNMR as Chemical shifts, 对等于核磁中的化学位移)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(精细结构）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)偶合常数46CH3CH2. Proton spit the signa()()()Th