有机化合物分子的结构基础ppt课件

1、第一章第一章 有机化合物分子的有机化合物分子的结构基础结构基础第一章重点讲解问题n1. 简要回顾有机化学的形成，并回答有机简要回顾有机化学的形成，并回答有机化学是怎样的一门学科化学是怎样的一门学科n2. 价键理论基础回顾和分子轨道理论简介价键理论基础回顾和分子轨道理论简介n3. 杂化轨道理论与有机化合物结构特点杂化轨道理论与有机化合物结构特点n4. 有机化合物的基本骨架和官能团有机化合物的基本骨架和官能团n5. 有机化合物的结构与性质的关系有机化合物的结构与性质的关系n 1、价键、价键 2、非共价力、非共价力 3、立体结构、立体结构 n6. 质子酸碱和路易斯酸碱理论质子酸碱和路易斯酸碱理论1.

2、1 有机化学及其发展历史和趋势n1. HistorynIn 1770, Swedish chemist Torberm Bergman was the first to express the difference between “organic” and “inorganicsubstances1.1 有机化学及其发展历史和趋势nOrganic -n derived from living organismnOriginally, nStudy of compounds extracted from living organisms and their natural products 1

3、.1 有机化学及其发展历史和趋势nVital force theory: nOrganic compounds needs a “vital force” to create them1.1 有机化学及其发展历史和趋势nIn 1828, Fridrich Wohler convert the “inorganic” salt ammonium cyanate into the “organic” substance ureaNH4+ -OCNNH2ONH2 Heat1.1 有机化学及其发展历史和趋势nWohlers synthesis led to the realization that m

4、olecules found in nature can be described, handled, and synthesized in the same way as minerals and metals. What an astounding insight-that atoms and molecules move freely between the living and nonliving worlds, that the living and nonliving share fundamental attributes that can be studied. With th

5、is discovery, organic chemistry was born.1.1 有机化学及其发展历史和趋势n作业作业 1：n查阅有关书籍和文献，了解有机化学的发查阅有关书籍和文献，了解有机化学的发展历史和趋势。并就发展历史中可以称之展历史和趋势。并就发展历史中可以称之为里程碑的一个发现作介绍和评述。为里程碑的一个发现作介绍和评述。n字数要求在字数要求在1500字以内字以内,第六周周三交第六周周三交1.1 有机化学及其发展历史和趋势n2. Definition of Organic ChemistrynOrganic Chemistry is the Chemistry of Carb

6、on Compounds Organic Chemistry is the Chemistry of Carbon CompoundsnQuestion: nWhy is an entire branch of chemistry devoted to the study of carbon-containing compounds?Organic Chemistry is the Chemistry of Carbon CompoundsnThe answer is :nCarbon-containing compounds makes life possiblenWe need carbo

7、n-containing compounds in nature for our food, medicines, clothing, and energynWe depend on millions of synthetic carbon -contaning compounds in our daily lifeOrganic Chemistry is the Chemistry of Carbon CompoundsnQuestion: nWhat makes carbon so special?nWhy are there so many carbon-containing compo

8、unds?Organic Chemistry is the Chemistry of Carbon CompoundsnPlease try to draw out all the structures corresponding to the formula: na. C2H6Onb. C3H6OnIt shares electrons with other carbon atoms nIt shares electrons with several kinds of atomsnC-C single, double and triple bondnchain, or cyclo-links

9、 nIsomerism phenomenonC2H6O: CH3OCH3 CH3CH2OH C3H6O: CH2=CHOCH3 CH2=CHCH2OH CH3C(OH)=CH2 CH3CH=CHOH CH3COCH3 CH3CH2CHO CH3HHHOHHCH3HOOHOCCHOHHCH3CCOHHHCH31.2 价键理论基础回顾和分子轨道理论简介n1.2.1 The Structure of an Atomn1.2.2 Distribution of Electrons in an Atom nAtomic orbitals: sp (px,py,pz)d (dx,dy,dz,d , d )

10、x2-y2z21.2 价键理论基础回顾和分子轨道理论简介n(1) The aufbau priciplenThe closer the orbital is to the nucleus, the lower its energyn1s2s2p3s3p4s3d4p5s4d5p6sn(2) The Pauli exclusion priciplenDegenerate orbitals - have the same energyn(3) Hunds rulenC: 1s2 2s2 2px12py12pz01.2 价键理论基础回顾和分子轨道理论简介n1.2.3 Ionic, Covalent,

11、and Polar BondsnAn atom is most stable if it has a filled shell or an outer shell of eight electrons and no electrons of higher energynIonic bond: LiClnCovalent bond: H2, O2, CO2 n C: 1s2 2s2 2px12py12pz0n Neither readily gives up electrons n Nor readily accepts electronsnNonpolar bond (H-H)and Pola

12、r bond ( C-H, C-O )1.2 价键理论基础回顾和分子轨道理论简介n常见价键的表示方法：常见价键的表示方法：nLewis StructuresnKekule StructuresnCondensed StructuresCOHOHH C OOHH C OOHHCO2H1.2 价键理论基础回顾和分子轨道理论简介n思考题思考题n共价键化合物与离子键化合物性质有哪些差异？共价键化合物与离子键化合物性质有哪些差异？n请记住有机化合物中常见元素的电负性请记住有机化合物中常见元素的电负性nElectronegativity:nH: 2.1 B: 2.0 C: 2.5 N: 3.0 O: 3.

13、5nF: 4.0 Cl: 3.0 Br: 2.8 I: 2.5nLi: 1.0 Mg: 1.21.2 价键理论基础回顾和分子轨道理论简介n1.2.4 Introduction of Molecular TheorynOrbitals are conserved - the number of atomic orbitals combined must equal the number of molecular orbitals formed=H HH : H1s atomic orbital1s atomic orbitalbonding molecular orbital.1.2.4 Int

14、roduction of Molecular TheorynThe above only shows the bonding molecular orbital, the other one is antibonding molecular orbital, but it contains no electrons.H HH : H1s atomic orbital1s atomic orbitalbonding molecular orbital.antibonding molecular orbital1.2.4 Introduction of Molecular TheorynThe 1

15、s atomic orbitals can combine in one of two ways+wave reinforce each other, resulting in bonding+nodewave cancel each otherand no bond forms1.2.4 Introduction of Molecular Theoryn- The 1s atomic orbitals combine in a way that enhance each other, similar to two light waves or two sound waves that rei

16、nforce each other. It is a sigma bonding molecular orbital 键键 n- The 1s atomic orbitals can also combine in a way that cancel each other, producing a node between the nuclei. It is a sigma antibonding molecular orbital * 键键 1.2.4 Introduction of Molecular TheorynSide-to-side overlapping of in-phase

17、p orbitals produces a bonding pi- molecular orbital 键键 nSide-to-side overlapping of out-of-phase p orbitals producing an antibonding pi- molecular orbital * 键键 2p atomic orbital2p atomic orbitalbonding pi-molecular orbitalantibonding pi- molecular orbital1.3 碳的杂化轨道理论 Hybridizationn1.3.1 sp3 Hybridiz

18、ationnC 1s22s22p2 - 2s22px12py12pz0 2s12px12py12pz1 n2s + 2px2py2pz 4 sp3 hybridization orbitals neach orbital has one electron 1.3.1 sp3 Hybridizationn to form a tetrahedron carbon (see the structure of methane)HHHHHHHHMirrorHHOCH3CH2ClHOHClH2CH3CMirror1.3.1 sp3 HybridizationnConfiguration isomers

19、- enantiomersn a chiral carbon - a carbon linked with four different kinds of atomsnConformation isomer - ethane1.3.2 sp2 HybridizationnC 1s22s22p2 - 2s22px12py12pz0 2s12px12py12pz1 n2s + 2px2py + 2pz 3 sp2 hybridization orbitals + 1 2pzneach orbital has one electron1.3.2 sp2 Hybridizationnto form a

20、 planer carbon (see the structure of Ethene)nanother kind of stereo-isomer - Geometric Isomerization - cis, transCCHOHHH3CCCOHHHH3C1.3.3 sp Hybridizationnto form a liner carbon (see the structure of Ethyne)nOptical Activity in AllenesCCHHCCCCCC1.3.4 有机化合物异构现象 IsomerismC2H6O: CH3OCH3 CH3CH2OH C3H6O:

21、CH2=CHOCH3 CH2=CHCH2OH CH3C(OH)=CH2 CH3CH=CHOH CH3COCH3 CH3CH2CHO H3CHHHOHHCH3HOOHOCCHOHHH3CCCOHHHH3C1.3.4 有机化合物异构现象 Isomerismn关于碳化合物的异构问题请参阅 -邢其毅“基础有机化学P166n Isomers n Constitutional isomers Stereoisomersn Configurational isomers Conformational isomersn Optical isomers Geometric isomers nEnantiomer

22、s Diastereomers1.4 有机分子的基本骨架和官能团n1.4.1 基本骨架 - 由碳碳键和碳氢键构成n1.4.2 官能团Functional Groups)：n1.4.2.1 Containing Nitrogen: n Amines: RNH2, R2NH, R3N, （R4N+X-）n Imines: -C=NH, -C=NR; n Nitrile: RCN (-CN, cyano group )1.4.2.1 Containing NitrogennThe structure Features:nN: ( 1s2 )2s22p3 n sp3, sp2, sp hybridiz

23、ation n C-N single, double, triple bondn 4 orbitals, but 5 electrons in an atoms there is a lone pair of electronsn Hydrogen-Bond - electronegativitynPolar Covalent Bond - electronegativity1.4.2.2 Containing Oxygenn Ethers R-O-Rn Alcohols R-OHn Aldehydes, Ketones R(H)C=O, R2 C=On Carboxylic Acids an

24、d their Derivatives RCOOH, RCOOR, RCONR2, RCOX1.4.2.2 Containing OxygennThe structure Features:nO: ( 1s2 )2s22p4 n sp3, sp2 hybridization n C-O single, double bondn 4 orbitals, but 6 electrons in an atoms there is two lone pairs of electronsn Hydrogen-Bond - electronegativityn Polar Covalent Bond -

25、electronegativity1.4.2.3 Containing halogennAlkyl Halides +R-X - R+ + X-nStructural Features:nX: ns2np5nhalogen - electronegativity is bigger than carbonnPolar Covalent Bond1.4 有机分子的基本骨架和官能团n以下内容请参阅教材第二十五章结构部分n1.4.2.4 Containing Sulfurn1.4.2.5 Containing Phosphorusn1.4.2.6 Containing Boronn1.4.2.7 C

26、ontaining Silison 1.5 有机化合物的结构与性质的关系n1.5.1 共价键的结构与性质关系 - nKey Part of Organic Chemistryne.g. 1. Hydrocarbons nAlkanes, Alkenes, Alkynes and AromaticnCH3CH3, CH2=CH2, CH CH, nSubstitute Reaction, Addition Reaction,nC6H6 - Addition, difficult; n Substitution, easy 1.5 有机化合物的结构与性质的关系neg 2 C=O, C=C addi

27、tion reaction n but mechanism are differentneg 3 RH, ROH, RCOOH n acidity increase from left to rightneg 4 Compounds containing O or N, comparing with C, have lone pair of electron, so they often work as Lewis base. n作业作业2：n阅读教材相关部分，从有机化合物的结构阅读教材相关部分，从有机化合物的结构出发，简要概括各主要官能团化合物的化出发，简要概括各主要官能团化合物的化学性质建

28、议列表格对应性质与结构特征）学性质建议列表格对应性质与结构特征）n （第六周交）（第六周交）1.5.2 非共价力与性质的关系n非共价力包括：非共价力包括：n 氢键氢键 Hydrogen Bondn 范德华作用力范德华作用力 （吸引力和斥力）（吸引力和斥力）n 偶极偶极-偶极作用力等见下表）偶极作用力等见下表）n作用于分子间和分子内作用于分子间和分子内n影响化合物的物理性质和化学性质影响化合物的物理性质和化学性质n 熔点、沸点、溶解性能熔点、沸点、溶解性能n 酸碱性、反应速度和反应方向酸碱性、反应速度和反应方向非共价力及其强度InteractionsStrength Ion-Ion intera

29、ctioncomparable to covalent bondingIon-dipole50200 kJ/molDipole-dipole550 kJ/molHydrogen bonding4120 kJ/molCation- interactions580 kJ/mol- stacking050 kJ/molvan der Waals forces 5 kJ/mol, variableHydrophobic effects1.5.2 非共价力与性质的关系n氢键的饱和性和方向性氢键的饱和性和方向性n饱和性饱和性由于氢原子特别小，而原子由于氢原子特别小，而原子A和和B比较大，所以比较大，所以A

30、-H中的氢原子只能和一个中的氢原子只能和一个B原子结合形成氢键；同时，由于负离子之原子结合形成氢键；同时，由于负离子之间的相互排斥，另一个电负性大的原子间的相互排斥，另一个电负性大的原子B 就难于再接近氢原子就难于再接近氢原子.ABBH+1.5.2 非共价力与性质的关系n方向性方向性由于电偶极矩由于电偶极矩A-H与原子与原子B的相的相互作用，只有当互作用，只有当A-HB在同一直线上时最在同一直线上时最强；同时，由于原子强；同时，由于原子B一般含有未共用电子一般含有未共用电子对，在可能的范围内氢键的方向和未共用对，在可能的范围内氢键的方向和未共用电子对的对称轴一致，这样可使原子电子对的对称轴一致

31、，这样可使原子B中负中负电荷分布最多的部分最接近氢原子，这样电荷分布最多的部分最接近氢原子，这样形成的氢键最稳定。形成的氢键最稳定。1.5.2 非共价力与性质的关系n氢键的强弱氢键的强弱A、B的电负性越大，氢键的电负性越大，氢键越强；越强；B的原子半径越小，氢键越强。（的原子半径越小，氢键越强。（F-HF最强）最强）1.5.2 非共价力与性质的关系n氢键对分子构象的影响氢键对分子构象的影响HHClOHHHClHHOHHHCH3HHOHHHIIIIII1.5.2 非共价力与性质的关系n氢键对互变异构平衡的影响氢键对互变异构平衡的影响H3CCHOH2CCOHHOCCH3H3CH2CCOHCH3OO

32、OOHOOHOOOOH0.000025%1.2%0%92% in hexane16% in water100%1.5.2 非共价力与性质的关系n氢键对酸性的影响OOOHHOHHOOO -HOHHHOOHHOOHHOO -HOOHpKa1=1.83; pKa2=6.07pKa1=3.03; pKa2=4.441.5.2 非共价力与性质的关系n天然化合物中的氢键举例核酸结构中的氢键；蛋白质结构中的氢键1.5.3 立体结构与性质的关系OOOHHOHHOOO -HOHHHOOHHOOHHOO -HOOHpKa1=1.83; pKa2=6.07pKa1=3.03; pKa2=4.441.6 质子酸碱和路

33、易斯酸碱理论n1.6.1 酸碱概念的发展n1663年 （英Boyle, R. n 酸具有酸味，能使蓝色石蕊变红n 碱具有苦涩味，能使红色石蕊变蓝n18世纪后期，从物质内在性质认识酸碱n1781年 （法Lavoisier, A. L.n 酸是一类含氧化合物，氧酸素n19世纪初，HCl，HI等被发现n 1811年 Davy, D. P. n 提出“氢是酸的基本元素的论点1.6 质子酸碱和路易斯酸碱理论n1.6.1 酸碱概念的发展n19世纪后期，近代酸碱理论开始形成nA、1889年 Arrhenius, S. A. 水-离子论n20世纪 nB、 Franklin, F.C. 溶剂论nC、Bronsted, J. N.-Lowry, T. M. 质子论nD、Lewis, G. N. 电子论nE、Pearson, R. G. 软硬酸碱理论1.6 质子酸碱和路易斯酸碱理论n1.6.2 Arrihenius 离子论n 在水溶液中能电离出氢离子的物质称为酸；能电离出氢氧根离子的物质称为碱n局限性：n不能解释非水体系和非溶剂体系的问题（1） C2H5O- Na+ 溶于乙醇（2） 2 Na + 2 NH32 Na + + 2NH2- + H2（3） NH3(g) + HCl(g)NH4+Cl-1.6 质子酸碱和路易斯酸