厦门大学化学化工学院：《有机化学》课程教学资源（课件讲稿，双语版）第一章 碳的化合物与化学键 Carbon Compounds and Chemical Bonds（1.12-1.17）

ORGANIC CHEMISTRY Chapter l 1.12 The structure of methane and Ethane: sp3 Hybridization Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 1.12 The Structure of Methane and Ethane: sp3 Hybridization

ORGANIC CHEMISTRY Chapter l 1 12A The structure of methane o sp hybridization The 4 sp orbitals should be oriented at angles of 109.5 with respect to each other o An sp'-Hybridized carbon gives a tetrahedral structure for methane, and with four equivalent ch bonds H H H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 1.12A The Structure of Methane sp3 Hybridization The 4 sp3 orbitals should be oriented at angles of 109.5° with respect to each other. An sp3-Hybridized carbon gives a tetrahedral structure for methane, and with four equivalent C—H bonds. C H H H H

ORGANIC CHEMISTRY Chapter l 1. 12B The Structure of ethane o sp3-Hybridized carbon atoms g I carbon-carbon o-bond and 6 carbon-hydrogen o- ds onas o Because a o-bond has cylindrical symmetry along the bond axis, rotation of groups joined by a single bond does not usually require a large amount of energy(13 26 kJ/mol). Consequently, groups joined by single bonds rotate relatively freely with respect to one another H H He H H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 1.12B The Structure of Ethane sp3-Hybridized carbon atoms 1 carbon-carbon σ-bond and 6 carbon-hydrogen σ- bonds. Because a σ-bond has cylindrical symmetry along the bond axis, rotation of groups joined by a single bond does not usually require a large amount of energy (13- 26 kJ/mol). Consequently, groups joined by single bonds rotate relatively freely with respect to one another. C H H H C H H H

ORGANIC CHEMISTRY Chapter l 1.13 The Structure of ethene (Ethylene): sp2 Hybridization Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 1.13 The Structure of Ethene (Ethylene): sp2 Hybridization

ORGANIC CHEMISTRY Chapter l p Orbital o sp2-Hybridization Orbital o The three sp orbitals that result from hybridization are directed toward the corners of a regular triangle (with angles of 1200 between them). The p orbital that is not hybridized is perpendicular to the triangle formed by the hybrid spd orbitals 5σ- bonds(1CC,4C-H)andlπ-bond 9 Hydrocarbons whose molecules contain a carbon-carbon double bond are called alkenes Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 sp2-Hybridization. The three sp2 orbitals that result from hybridization are directed toward the corners of a regular triangle (with angles of 120° between them). The p orbital that is not hybridized is perpendicular to the triangle formed by the hybrid sp2 orbitals. 5 σ-bonds(1 C—C, 4 C—H) and 1 π-bond. Hydrocarbons whose molecules contain a carbon-carbon double bond are called alkenes. C p Orbital sp2 Orbital

ORGANIC CHEMISTRY Chapter l H C、2118° 121° c88 Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 C C H H H H C C H H H H 121° 118°

ORGANIC CHEMISTRY Chapter l 1. 13A Restricted Rotation and the Double bond o There is a large energy barrier to rotation associated with groups joined by a double bond (264kJ/mo) 90° C otation H H H H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 1.13A Restricted Rotation and the Double Bond There is a large energy barrier to rotation associated with groups joined by a double bond. (264 kJ/mol) C C H H H H C C H H H H 90° rotation

ORGANIC CHEMISTRY Chapter l 1.13b Cis-Trans isomerism CH3 CH CH3 C-C H H CH H cis-2-Butene trans-2-Butene 顺-2-丁烯 反-2-丁烯 o The compound with substituents on the same side of the double bond is referred to as cis-isomer the isomer with substituents on opposite side is trans o The two compounds differ only in the arrangement of their atoms in space. Isomer of this kind are classified formally as stereoisomers(立体异构体) Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 1.13B Cis-Trans Isomerism C C CH3 H H CH3 C C CH3 CH3 H H cis-2-Butene trans-2-Butene 顺-2-丁烯 反-2-丁烯 The compound with substituents on the same side of the double bond is referred to as cis-isomer; the isomer with substituents on opposite side is trans. The two compounds differ only in the arrangement of their atoms in space. Isomer of this kind are classified formally as stereoisomers （立体异构体）

ORGANIC CHEMISTRY Chapter l 1.14 The Structure of Ethyne (Acetylene): sp Hybridization Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 1.14 The Structure of Ethyne (Acetylene): sp Hybridization

ORGANIC CHEMISTRY Chapter l g hydrocarbons that contain a carbon-carbon triple bond are called alkynes o sp hybridization g The carbon-carbon triple bond consists of two n bonds and one o bond H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 1 Hydrocarbons that contain a carbon-carbon triple bond are called alkynes. sp Hybridization The carbon-carbon triple bond consists of two π bonds and one σ bond. H C C H H C C H