Annulenes hydrocarbons with alternating single and double bonds cyclobutadiene benzene cyclooctatetraene cyclodecapentaene [4]annulene [6]annulene [8]annulene [10]annulene 013 Pearson Education.Ine. Not all cyclic conjugated hydrocarbons are ● cyclobutadiene is and ● Cyclooctatetraene can Br2 to the double bond. 2013 Pearson Education,Inc. Chapter 16
© 2013 Pearson Education, Inc. Chapter 16 6 Annulenes • hydrocarbons with alternating single and double bonds. • Not all cyclic conjugated hydrocarbons are ________. • cyclobutadiene is ________ and __________ • Cyclooctatetraene can ____ Br2 to the double bond
Molecular Orbitals of Benzene all antiboeding all antibonding node node node antibonding node node bonding node all bonding
© 2013 Pearson Education, Inc. Chapter 16 7 Molecular Orbitals of Benzene
Energy Diagram for Benzene energy π哈 π4 nonbonding line π1 02013代arson Educaton nc All bonding orbitals are ·filled(“closed shell"with the6☐ very 2013 Pearson Education,Inc. Chapter 16 8
© 2013 Pearson Education, Inc. Chapter 16 8 Energy Diagram for Benzene • All bonding orbitals are : ▪ filled (“closed shell”)with the 6 ▪ very ______
MOs for Cyclobutadiene all antibonding node node antibonding bonding bonding antibonding antibonding nonbonding line node ·two lone electrons in all bonding separate nonbonding MOs. ·Avey_ diradical e2接Prinon Eacaon Inc 2013 Pearson Education,Inc. Chapter 16 9
© 2013 Pearson Education, Inc. Chapter 16 9 MOs for Cyclobutadiene • two lone electrons in separate nonbonding MOs. • A very ________ diradical
Polygon Rule nonbonding line benzene cyclobutadiene cyclooctatetraene 2013 Pearson Educaton.inc The energy diagram for an annulene has the same shape as the cyclic compound with one vertex at the bottom. 2013 Pearson Education,Inc. Chapter 16 0
© 2013 Pearson Education, Inc. Chapter 16 10 Polygon Rule • The energy diagram for an annulene has the same shape as the cyclic compound with one vertex at the bottom