My Notes
Categories
This is a really interesting paper in J. Am. Chem. Soc. (2025, 147, 34641-34646) involving a complex salt in which both the cation and anion are metallocenes. While a majority of the paper is focused on the characterization of two new compounds, it presents some excellent opportunities to practice counting electrons, one of which was a challenge to this author. It also provides the opportunity to consider redox reactions and how reduction potentials impact the outcomes of reactions. Students might not even actually need to read the paper, but rather just look at several of the figures it contains.
| Attachment | Size |
|---|---|
| Questions for students | 22.68 KB |
| Questions for students | 400.03 KB |
Students will
- Use the Covalent Bond Classification method to classify and count electrons in several metallocene and metallocene adjacent species
- Examine the relationship between the electron donor ability of ligands and the reduction potentials of compounds
As suggested in the documentation, students should attempt to answer the first two questions prior to reading the paper. The will require some knowledge of counting electrons and should provide an interesting challenge as they think about ways to lower the electron count of the anion. These first two questions could certainly serve as stand alone homework or test questions.
Evaluation
I have not yet used this discussion in class. I used a combination of the first two questions as part of an exam.
Here is the combined question:
A very recent paper (J. Am. Chem. Soc. 2025, 147, 34641-34646) reports a unique ionic complex in which both the monocation and the monoanion are organometallic compounds. One of the ions is [Co(C5Me5)2] and the other is [Rh(C5Me5)(C5(CF3)5]. Both of these ions are 18-electron species. Which ion is likely to be the cation and which is the anion? Why? How can you possibly make them both 18-electron species? It would behoove you to determine their VN, LBN, EN and dn count.
The results from my students that had the first two questions on an exam are presented in a faculty only file.