Chapter 14, Problem 14.7P

Interpretation Introduction

Interpretation:

The complete MO energy diagram for butadienyl dication ${\left[\text{CH2-CH=CH-CH2}\right]}^{\text{2+}}$ similar to the one shown in Figure 14-12 is to be drawn.

Concept introduction:

MOs arise from interacting AOs on different atoms. The number of MOs formed must equal the number of contributing AOs. MO energies differ as a result of constructive and destructive interference among contributing AOs. For a linear system of conjugated p orbitals, all nodal planes in a resulting $\text{π}$ MO must be positioned symmetrically about the centre of that set of p orbitals. The energy of the MO with only bonding interactions is the lowest. As the number of antibonding interactions increases, so does the energy of the resulting MO. The MO with only antibonding interactions has the highest energy.