ORGANIC CHEMISTRY Chapter 13 13.6 Alkadienes and polyunsaturated hydrocarbons Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 13 13.6 Alkadienes and Polyunsaturated Hydrocarbons
ORGANIC CHEMISTRY Chapter 13 o a hydrocarbon whose molecules contain two double bonds is called an alkadiene( alkatriene for three double bonds) g a hydrocarbon with two triple bonds is called an alkadiyne o a hydrocarbon with a double and triple bond is called an alkenyne An alkadiene An alkatriene HC≡C-CH2-C≡CH HC≡C-CH2-CH=CH An alkadiyne An alkenyne Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 13 A hydrocarbon whose molecules contain two double bonds is called an alkadiene(alkatriene for three double bonds); A hydrocarbon with two triple bonds is called an alkadiyne; A hydrocarbon with a double and triple bond is called an alkenyne. HC C CH2 C CH HC C CH2 CH CH2 An alkadiene An alkatriene An alkadiyne An alkenyne
ORGANIC CHEMISTRY Chapter 13 ● Cumulated dienes(累积二烯)— The molecules have cumulated double bonds g Isolated dienes(孤立二烯)— one or more saturated carbon atoms intervene between the double bonds of an alkadiene o Conjugated dienes(共轭二烯)— the double and single bonas alternate along the chain C=C C=C=C (CH a cumulated diene A conjugated diene An isolated diene(n+0) Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 13 Cumulated dienes（累积二烯）— The molecules have cumulated double bonds Isolated dienes（孤立二烯）— one or more saturated carbon atoms intervene between the double bonds of an alkadiene. Conjugated dienes（共轭二烯）— the double and single bonds alternate along the chain C C C C C (CH2)nC C C C C C A cumulated diene A conjugated diene An isolated diene (n = 0)
ORGANIC CHEMISTRY Chapter 13 13.71.3-Butadiene. electron Delocalization Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 13 13.7 1,3-Butadiene: Electron Delocalization
ORGANIC CHEMISTRY Chapter 13 13.7A Bond Lengths of 1, 3-Butadiene o All of the 1, 3-butadiene are sp hybridized and as a result the central bond of butadiene results from overlapping sp? orbitals Bond lengths 1337pm C-C C=C CH=CH一CH=CH 154pm 134pm 146pm 足 Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 13 13.7A Bond Lengths of 1,3-Butadiene All of the 1,3-butadiene are sp2 hybridized and as a result, the central bond of butadiene results from overlapping sp2 orbitals. C C C C 154 pm 134 pm Bond lengths CH2 CH CH CH2 133.7 pm 146 pm C C C C