Constructing Molecular Orbitals Pi molecular orbitals are the sideways overlap of p orbitals. p orbitals have 2 lobes.Plus (+)and minus (-)indicate the opposite phases of the wave function,not electrical charge. When lobes overlap constructively,(and +or-and-)a bonding MO is formed. When and-lobes overlap,waves cancel out and a node forms;antibonding MO.= Chaper 15 6
Chaper 15 6 Constructing Molecular Orbitals • Pi molecular orbitals are the sideways overlap of p orbitals. • p orbitals have 2 lobes. Plus (+) and minus (-) indicate the opposite phases of the wave function, not electrical charge. • When lobes overlap constructively, (+ and +, or - and -) a bonding MO is formed. • When + and - lobes overlap, waves cancel out and a node forms; antibonding MO. =>
MO for 1,3-Butadiene ·Lowest energy. ·All bonding interactions. ·Electrons are delocalized over four nuclei. > Chaper 15
Chaper 15 7 1 MO for 1,3-Butadiene • Lowest energy. • All bonding interactions. • Electrons are delocalized over four nuclei. =>
2 MO for 1,3-Butadiene 。2 bonding interactions 。1 antibonding interaction ·A bonding MO => Chaper 15 8
Chaper 15 8 2 MO for 1,3-Butadiene • 2 bonding interactions • 1 antibonding interaction • A bonding MO =>
3*MO for 1,3-Butadiene ·Antibonding MO ·Empty at ground π state ·Two nodes => Chaper 15 9
Chaper 15 9 3 * MO for 1,3-Butadiene • Antibonding MO • Empty at ground state • Two nodes =>
4*MO for 1,3-Butadiene ·All antibonding interactions. 刘 ·Highest energy. ·Vacant at ground state. 二> Chaper 15 10
Chaper 15 10 4 * MO for 1,3-Butadiene • All antibonding interactions. • Highest energy. • Vacant at ground state. =>