19 Feb 2014

Water Oxidation Catalyzed by NHC Complexes of Iridium

Literature Discussion

Submitted by Peter M Graham, Saint Joseph's University
Categories
Description: 

A literature discussion based on an interesting paper from Bernhard and Albrecht about a catalytic water oxidation promoted by irdium complexes featuring abnormal/mesoionic NHC ligands.

I used this in an upper-level Organometallics course after discussing NHC ligands in class.

 

Learning Goals: 

The students should read and understand a communication from the chemical literature.

The students should be able to search the literature to find the accepted mechanism for Ir water oxidation.

The students should research and  learn about water spitting/water oxidation.

The students should be able to explain the bonding, oxidation state, and electron counting for the NHC complexes described in the paper.

The students should understand how the slight differences in the complexes described lead to slightly different catatlytic activity

The students should learn the features of click chemistry.

The students should learn and understand TON and TOF.

Related activities: 
Implementation Notes: 

I provided the questions one week before and I facilitated the discussion of the paper during one whole class period.

Time Required: 
50 minutes
Evaluation
Evaluation Methods: 

I evaluated students informally, mostly by participation. For the relevant questions I had volunteers go the board to write our stuctures.

 

Evaluation Results: 

My students seemed to have a good understanding of the paper before the discussion, especailly for the questions that required doing a little research to find  a "textbook" answer. All were well prepared to answer mutiple questions.

The discussion uncovered a few areas that required some longer discussions, especially the role of silver in the synthesis of the complexes and understanding the 1H NMR data (restricted rotation of benzyl).

Students seemed to like the paper's application to the interesting and important topic of water oxidation.

Creative Commons License: 
Creative Commons Licence

Comments

Peter, thank you for your contribution of this interesting article for literature discussion. I apologize for the long period of time this LO spent under review. All the questions pertinent to the ACIE article were nicely directed and within the scope of an undergraduate organometallic course.

There were primarily 3 questions that involved extra information outside the scope of the article. 

1) Find the accepted mechanism for homogeneous water oxidation...

2) What is "click chemistry"?

3) What is the role of Ag2O...

The answers to these questions, as indicated on your key, are rather lengthy and complicated. You had indicated that literature searching was a learning outcome fo this exercise. However, I found it difficult to locate the specific Chem Commun. article that you referred to in the question about the mechanism. And did your students have other sources for looking up click chemistry? It would be more straightforward to give your students these references directly and have a literature searching exercise in a different context.

This is only a suggestion and if you let me know that you'd rather keep the assignment the way it is, I will go ahead and approve it. If you decide to change it, please upload the new version and send me a reply letting me know it is there.

Once again, thank you for this excellent LO.

 

 

Thank you for the message and for your edits. The LO has been approved on VIPEr. The only addition change that was made was that I linked this activity to another LO regarding solar oxidation of water.

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