Organic Chemistry

Page 1

Allylic carbons have P orbitals and the P orbitals of the alkene (carbons with a double bond) both have a P orbital. They all overlap and bond with each other. Based on molecular bonding theory, when we have overlapping adjacent P orbitals, the atomic P orbitals result in Molecular P orbitals and we have the same amount of molecular P orbitals as their are atomic.

The three molecular orbitals are pi*1, pi*2, and pi*3. Pi*1 is a bonding orbital where all three orbitals are bonding in-phase. It has a region above and below where there is a probability of finding electrons. Pi*2 is a non-bonding orbital and has two orbitals interacting and one orbital not contributing (The center one which is associated with the center carbon). This means if there is an electron it would be found in one carbon or there other but never in the center. Pi*3 is an anti-bonding orbital and it has 2 nodes so all are interacting with each other but they are not in phase. This means if there is an electron then there are six spots where the electron could be. The only thing is that it is higher energy.