有机化学课件Chapter 1 Structure of Organic Compounds

1、有机化学课件有机化学课件Chapter 1 Structure of Organic CompoundsChapter 1 Structure of Organic CompoundsReferences :/ /reusch/VirtualText/intro1.htm#contnt Organic Chemistry, Francis A.Carey, edition: 4th, Pub. Date: 2000, Publisher(s): McGraw-HillReferences ?有机化学?郭书好主编，广州：广东科技出版社, 2004 ?有机化学?第二版 胡宏纹

2、主编 高等教育出版社 1990Chapter 1Structure of Organic Compounds1.1 Inorganic and organic Compounds In early time Inorganic compound: from mineral sources Organic compounds: from plants or animals The differences:“ vital force Could not be synthesized in the lab1.1 Inorganic and organic Compounds Organic comp

3、ounds Main atoms:carbon and hydrogen Limited number of other elements: H,O,N- hydrogen,oxygen,and nitrogen.1.2 Atomic Structure Atomic orbitals Designated by the letters s,p,d,f Differ in energy, shape, and orientation Consider the only s, p orbitals Nucleus is the center of s, p orbitals1.2 Atomic

4、Structure s Orbital:spherical region of space-global p Orbital:like dumb bells 2p orbital contain: three orbitals px ,py. pz x,y,z emphasize that they are mutally perpendicular to one another.1.2 Atomic Structure Valence shell electrons The valence shell:outermost shell,higher electrons location. Pa

5、rticipate in chemical reaction Valence electrons:H-1e,C-4e,N-5e,O-6e Form bonds: H-1,C-4,N-3,O-21.3 Types of Bonds Lewis octet rule Seond period atoms:such as C,O,N Form bonds by transferring or sharing electrons Each atom surrounded by eight electrons(ns2 + npx2 + npy2 + npz2). Highest energy shell

6、:such as C,2s and 2p1.3 Types of Bonds Ionic bonds One or more electrons transfer among atoms Negative ions are called anions: obtain electron Positive ions are called cations: lost electron1.3 Types of Bonds Lewis structure:valence electrons,dot represent a electron Chloride is much more electroneg

7、ativity Covalent bonds Two atoms Mutal shareing pairs of electrons Forming conditionNa + ClNa+Cl1.3 Types of Bonds Too small different electronegativity between two atoms Cannt tranfer elctrons to form ion Bonding electrons Shared electrons Located in the space between the two nuclei Nonbonding elec

8、trons, lone pair electrons, or unshared electron pairs Valence electrons1.3 Types of Bonds Electrons pair Not share with other atom Lewis structure Covalent bond: a dash line Nonbonding electrons:pairs of dots located about the atomic symbolsCClHHHchloromethanenonbonding pairs of electrons bonding e

9、lectrons1.3 Types of Bonds 4.Multiple covalent bonds Double bonds:two shared pairs of electrons Triple bonds:three shared pairs of electrons A carbon atom can form single,double,triple bonds with other atoms.CCHHHHHHsingle bondshareing 2 e-CCHHHHdouble bondshareing 4 e-CCHHtriple bondshareing 6 eeth

10、ane ethylene acetylene1.3 Types of Bonds Polar covalent bonds Difference electronegativities For HCl, atom Cl: Higher electronegativity,partial negative charge (show with -) For HCl, atom H: Lower electronegativity,partial positive charge (show with+) Electronegativity :the power of electrons attrac

11、tion1.4 Orbitals and Molecular Shapes Mixing of two or more orbitals in the bonded atoms For carbon:2s mix with 2p Hybridized orbital:same energy,same shape,contain one electron Differ only in the position in space Maximum separation of electron in the space Formbond with H or C and other atoms sp3

12、Hybridization of carbon1.4 Orbitals and Molecular Shapes One s + three p orbitals= four sp3 orbitals Extend to the corners of a tetrahydron Form four bonds1.4 Orbitals and Molecular Shapes1.4 Orbitals and Molecular Shapes sp2 Hybridization of carbon A 2s + two 2p orbitals=three sp2 orbitals Extend t

13、o the corner of triangle Three hybridized orbitals form 3 bonds In ethylene,two with H,one with C Left p orbital form bond with C Each p orbital is perpendicular to the plane containing the sp2 orbitals The double bond contain one and bonds1.4 Orbitals and Molecular Shapes1.4 Orbitals and Molecular

14、Shapes1.4 Orbitals and Molecular Shapes sp hybridization of carbon A 2s + one 2p orbitals=two sp orbitals Extend to two end of a line Two hybridized orbitals form 2 bonds In acetylene,one with H,one with C Left 2 p orbitals form two bonds with C1.4 Orbitals and Molecular Shapes1.5 Structural Formula

15、s Molecular formula-atomic composition butane C4H10 Structural formula-arrangement of atoms and bonds butane CH3CH2CH2CH3 Condensed structural formula-specific bonds Butane CH3CH2CH2CH3 or CH3(CH2)2CH3 CH2 unit:methlene group 1.5 Structural Formulas Bond-line structureCH3CH2CHBrCH3is CH3CH2CHBrCH3is

16、BrCH2CH2CH2CH2isCH2CHCH2CH2COCH3isO1.5 Structural Formulas Three-dimensional structures and models Perspective structure Ball-and-stick model Space-filling modelCHHHHdashed line:behind the paperwedge line:infront the paper1.6 Isomers Same molecular formula,different structures Skeletal isomers:different carbon skeleton Functional isomers:different functinal groupCH3CH2CH2CH3CH3CHCH3CH3bu