17 Jan 2020

Formal oxidation states in Ru-catalyzed water oxidation

In-Class Activity

Submitted by Margaret Scheuermann, Western Washington University

This LO is an in-class assignment to prepare students for literature readings involving catalytic cycles in which multiple protons and electrons are transferred. Students practice assigning oxidation states to complexes with aquo, oxo, superoxo, and hydroperoxo ligands then use this information to analyze a proposed water oxidation mechanism from the literature.

Students are asked to add in the substrates and products entering and leaving the catalytic cycle. While this is, at its heart, a stoichiometry excercise, it helps calibrate students for the level of attention to detail needed to effectively engage with reading about multi-electron catalytic mechanisms.

File Ru electron tracking.docx186.18 KB
Learning Goals: 

After completing this activity:

A student should be able to assign formal oxidation states to monometallic complexes with aquo, oxo, hyrdoperoxo, and superoxo ligands

A student should be able to apply their knowledge of formal oxidation states to the analysis of a proposed mechanism of a catalytic water oxidation reaction

Implementation Notes: 

I used this activity during a lab lecture before an inorganic laboratory experiment in which students would be preparing and testing the Ru-based OEC mimic. 

I began the class period with a brief review of L/X type ligands and formal oxidation states. 

Students then worked in groups to complete this activity. 


Other implementation options:

While I used this activity as part of a lab lecture it could also be used in a lecture setting or as part of a problem set.

It could also be modified for use as an equation balancing excercise in a majors or honors general chemistry course.

Time Required: 
10-20 minutes
Evaluation Methods: 

I did not grade this activity.

Evaluation Results: 

Three students out of 14 explicitly mentioned that this activity was helpful on the free response section of the course evaluations.

Creative Commons License: 
Creative Commons Licence

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