This activity uses Gaussian with the WebMO interface to investigate the role of the metal in backbonding to CO as well as effects of the trans ligands. It can also be used as a way of introducing computational chemistry in an inorganic course.
Learning Goals: After this exercise you will be able to…
• Explain the effect of changing the metal on the CO stretching frequencies of a metal carbonyl complex
• Understand the role of σ and π donors/acceptors in modifying the amount of π backdonation into a trans CO ligand
• Predict the degree of backdonation into a trans carbonyl that will be observed with an unfamiliar ligand
• Perform DFT calculations to find the minima and vibrational frequencies of a molecule using WebMO/Gaussian.
You will need some kind of computational program, preferably one that does DFT calculations. Gaussian with the WebMO interface is suggested.
I have attached some of the Gaussian output files of the complexes. They can be imported into WebMO and used as starting geometries. If you do not have your own computational program, they can also be imported into the WebMO Demo site (http://www.webmo.net/demo/index.html) and students can look at the outputs and animate the vibrations, etc.