My Notes
Categories
This in-class worksheet introduces students to the different ways we describe organometallic ligands – bonding, properties, spectroscopy, etc. – using carbon monoxide as an example. It is structured as an inquiry-based activity, where students work together in small groups but check in with the entire class at appropriate intervals. I plan to use this activity with my advanced inorganic students next year.
| Attachment | Size |
|---|---|
| Carbonyl Ligand Activity | 389.47 KB |
Students will be able to:
- Use the MO diagram, specifically frontier orbitals, of a ligand to predict the bonding (sigma, pi, donation, acceptance) interactions in an organometallic complex.
- Describe and draw the molecular orbital interactions of a terminal CO ligand and a symmetric μ2-CO ligand with a metal.
- Describe and explain the σ-donating and π-accepting nature of the CO ligand.
- Understand and apply the terms backbonding and backdonation.
- Articulate the relationship between the M-C and C-O bond strengths in a carbonyl complex.
- Relate the CO stretching frequencies of two or more carbonyl complexes to the strength of the metal-ligand interaction and to the electron density on the metal fragment.
- Describe various possible binding modes of a CO ligand.
I haven’t used this in class yet, but I plan to implement it in my advanced inorganic course. My class size ranges from 4-12 students. Students must have learned MO theory, and we will have already discussed electron counting. I anticipate that this worksheet will require one 50-minute class period. Though students will work on the activity on their own, we will convene as a class after each section to make sure all of the groups are on the right track. I anticipate that this activity will provide a solid framework for subsequent discussions of OM ligands (hydrides, dihydrogen, pi systems).
Evaluation
I will assess this activity with a problem set question and/or exam question. I generally ask students to explain/predict bonding or properties of a similar or isoelectronic ligand (CN-, N2, etc.).
This looks really great. I wish I had seen it before I started discussing CO as a ligand in class yesterday! I think I'm going to pull out some of the IR questions to use on an exam.
Have you run it with your class yet? How did it go?
Thanks! Unfortunately, I have not been able to use it in class yet. I planned to use it in my Advanced Inorganic course, but we haven't offered the course in two years. I'm thinking of reorganizing our required Inorganic course to include organometallics, because I miss it. Or, I might incorporate it into a laboratory experiment, maybe as a pre-lab exercise.
I used this in Fall 2022 and it was effective in walking them through backbonding concepts methodically. Thanks Emily!