5.01 | The MO-Diagram of Ethylene and Butadiene

Monday June 6th 2022 | In this lecture we are transition to a new type of molecule. Before we have mainly discussed molecules in which the center of symmetry is also the central atom of the molecule. Now we are going to discuss a new type of molecule, where there is no central atom. As a result, symmetry adapted linear combinations need to be constructed for all the atoms involved. We will illustrate this principle by using ethylene (an olefin) as example. We will construct the complete MO diagram, that allows us the identify the framework of C-H, C-C, and C=C bond that are present in the molecule. As we will discover we will find that the Pz orbitals of the pi-framework have unique symmetry and will form the HOMO and the LUMO from which new reactivity can be found.

The link to the video can be found below: