高等有机化学PPT.ppt

1、nAdvanced Organic Chemistry:Advanced Organic Chemistry:Structure and MechanismsStructure and Mechanisms(Part B),5th Edition，2007，By Francis A.Carey。n高等有机化学基础高等有机化学基础(面向21世纪课程教材)，荣国斌,华东理工大学出版社，化学工业出版社，第3版，出版日期：2009年05月。n高等有机化学反应、机理与结构高等有机化学反应、机理与结构（原著第五版 修订），美史密斯（Smith M.B）马奇（March J），化学工业出版社I.Lewis

2、StructuresII.ResonanceIII.Hybrid orbitalsIV.AromaticityV.Functional GroupsPart 1:THE COVALENT BONDLewis structure:the electron-pair bondThe Lewis structural formula can serve as a convenient starting point to understanding the valence-bond theory of molecular structure.nThe ionic bonding force arise

3、s from the electrostatic attraction between ions of opposite charge.nThe covalent bonding force arises from sharing of electron pairs between atoms.I.Lewis Structures Ionic,covalent,and polar bondsionic bonds:transfer of electronscovalent bonds:sharing of electronselectro negativity,:relative attrac

4、tion for electrons in a bond-increases going up and to the right in the periodic tablenThe valence-shell occupancy must not exceed 2 for hydrogen and must not exceed 8 for atoms of the first row of the periodic table.nFor elements of the second and later rows,the valence-shell occupancy may exceed 8

5、.SF6,H2SO4The heat of hydrogenation of benzene is less exothermic by about 21 kcal mol-1(88kj mol-1)than one would have expected from Lewis structure 1 on the basis of known properties of single and double bonds.Resonance structuresThe superposition of two or more Lewis structures with different ele

6、ctron distributions but identical nuclear positions into a composite picture is called resonance.neither of these accurately describes the formate ionactual species is an average of the two(resonance hybrid)delocalizedelectronsI.Lewis Structures Resonance structuresmore stablemajor contributorless s

7、tableminor contributorDraw resonance structures for the following species.If the structures are not equivalent,indicate which would be the major contributor.CH3NO2CH2CHOResonance and tautomerismResonance and tautomerismResonance and tautomerismTautomerism and H-bondcelluloseProtein and H-bondn氢键是指在氢

8、原子与电负性很大的原子X 以共价键相结合时，同另外一个具有孤对电子对的原子Y 形成的一个弱的键，是一种由氢原子参加成键的特殊的化学键。，如下式中虚线所示：AHBn其中A，B 是氧、氮或氟等电负性大且原子半径比较小的原子。Tautomerism and H-bond原子A 到B 的距离。比范德华半径之和要小，但比共价半径之和大很多。例如甲酸分子之间的氢键，两个氧原子之间的距离为O.267nm，而范德华半径之和约为0.35nm共价半径之和为0162nm。单体甲酸分子中的OH 键长为0.098nm，其二聚体的OH 键长为0.104nm，OHO 键长为0.267nm，因此形成氢键以后OH 键长发生了变

9、化，HO 键的键长为O.163nm，要长于O 一H 键的键长。氢键的键长常见氢键类型：850kJmol-1Resonance and tautomerismResonance and tautomerismtautomerismTetrahedron Letters 41(2000)12971301Tautomerism and reactivityExample:丙环唑、噁醚唑异构体均在缩合反应过程中产生，主要是由于1，2，4三唑在碱性条件下容易转化为1，3，4三唑造成的。question:?n 在 以三唑类杀菌剂为主要生产产品的化工企业，1、2、4-三氮唑的质量关乎几乎所有三唑类杀菌剂的质

10、量，关乎企业生产效益和市场竞争力。1、2、4-三氮唑合成中异构体的分离技术显得尤为重要。n 有限公司预计投资70万用于1、2、4-三氮唑中异构分离技术的改进，提高1、2、4-三氮唑含量，主要是控制其中异构体1、3、4-三氮唑的含量。在保证1、2、4-三氮唑生产成本不影响最终三唑类的杀菌剂成本的前提下，对1、2、4-三氮唑合成技术进行优化，对分离提纯技术进行改进,设计一条可以工业化的合理的小试路线。Tautomer and resonance:more subtle casesCrystalline omeprazole exists as solid solutions of twotauto

11、mers in a continuous composition range,and this raisesquestions pertaining to the definition of the term polymorph.We obtained single crystals of five different forms ofomeprazole,with the 1:2 ratio varying from 0:100 to 15:85Tautomeric polymorphism in omeprazole，Prashant M.Bhatt Gautam R.Desiraju，C

12、hem.Commun.,2007,20572059The crystal structure consists of alternatelayers of molecules,first with the NH moiety anti to the aromaticring(2a)and the next with the NH syn to the ring(2b).(1:1)Diiminoisoindoline:tautomerism,conformations,and polymorphism,C h e m.C o m m u n.,2 0 0 4,8 8 6 8 8 7,Zhi-Qi

13、n Zhang,Jeffrey M.Njus,Daniel J.Sandman,Chengyun Guo,Bruce M.Foxman,PeterErk,Richard van Gelder.only with the NH syn to the ringDiiminoisoindoline:tautomerism,conformations,and polymorphism,C h e m.C o m m u n.,2 0 0 4,8 8 6 8 8 7,Zhi-Qin Zhang,Jeffrey M.Njus,Daniel J.Sandman,Chengyun Guo,Bruce M.Fo

14、xman,Peter Erk,Richard van Gelder.Colors in“ROY”Differences in color can be accounted for from differences in conformation5-Methyl-2-(2-nitro-phenylamino)-thiophene-3-carbonitrile共轭分子n染料光敏剂是纳米晶体太阳能电池的关染料光敏剂是纳米晶体太阳能电池的关键部分。作为光敏剂，不但要求其对太键部分。作为光敏剂，不但要求其对太阳光具有良好的阳光具有良好的nThis compound exhibits an intense

15、 red-shifted absorption spectrum(max)1417 nm;)1.2 105 M-1 cm-1)and a small electrochemical HOMO-LUMO gap(0.61 eV).The crystal structure shows that it forms-stacked dimers with a short Ni Ni distance(3.32).A Porphyrin Fused to Four AnthracenesJ Am Chem Soc.2011;133(1):30-1.Nicola K.S.Davis,Amber L.Th

16、ompson,and Harry L.Anderson III.Valence Bond ModelA.Atomic and molecular orbitalsH+H HHTwo electrons in s1s are lower energy than in the separate atoms covalent bondShape and Orientation n The electron distribution must have thecharacteristics of both s(spherical)and p(node)orbitals.n The four new electron distributions(orbitals)will orient as far away from eachother as possible.Toward the corners of atetrahedron.III.Valence Bond ModelB.Hybrid atomic orbitals1.sp3 hybridizationCH4 facts:tetrahed