Submitted by Emily Sylvester / Duquesne University on Mon, 06/27/2016 - 17:20
My Notes

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
Learning Goals

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.
Implementation Notes

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).

Time Required
I anticipate that this worksheet will require one 50-minute class period.


Evaluation Methods

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.).

Creative Commons License
Attribution, Non-Commercial, Share Alike CC BY-NC-SA
Nicole Crowder / University of Mary Washington

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?

Tue, 04/03/2018 - 08:29 Permalink
Emily Sylvester / Duquesne University

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.

Wed, 04/11/2018 - 15:40 Permalink