Chapter 3, Problem 3.42P

Interpretation Introduction

Interpretation:

The MO picture for $\text{buta-1, 2, 3-triene}$ is to be drawn.

Concept introduction:

MOs are constructed from the AOs of different atoms. The AOs of one atom overlap the AOs of the other atom, enabling them to undergo constructive and destructive interference to produce a new orbital. Atoms that are bonded to two or more other atoms are considered to be hybridized. Such atoms contribute their valence orbitals for mixing. The new orbitals are formed by mixing just two AOs. Each $\text{σ}$ interaction of AO gives both a $\text{σ}$ and a ${\text{σ}}^{\text{*}}$ MO to the molecule. Each single bond corresponds to a filled $\text{σ}$ MO. Mixing of two p AOs with the same phase results to form a bonding MO of $\text{π}$ symmetry which has a lobe on the either side of the bonding axis. Mixing two p AOs with opposite phase results to form antibonding MO of $\text{π}$ symmetry which has a total of four lobes.