Submitted by Brad Wile / Ohio Northern University on Mon, 09/07/2020 - 20:51
My Notes

This literature discussion was based on a short, readable piece from the trade magazine Chemical and Engineering News. Since this was written in a more general tone, it served as a reasonable introduction to carbenes for students in my advanced inorganic class. I have been looking to expand the examples of carbenes presented to students beyond those in the text. Simple examples of Fischer, Schrock, and N-heterocyclic carbenes are plentiful, but modern applications haven't been featured in the text that I use. Rather than having the students work through some pretty heavy pieces of primary literature, this gave them as sense of the types of carbenes being made and used in the 2010s.

Attachment Size
In class activity directions 36.32 KB
Learning Goals

The main objective was to build on our relatively straightforward classroom discussion of singlet and triplet carbenes, and focus on the role of an adjacent N atom in stabilizing a singlet carbene. I had covered the basics of N-heterocyclic carbenes, but this provided an opportunity to see more current applications than those in the class textbook. I expected the students to consider the role of sterics (specifically nitrogen substituents) as well as electronics (sigma and pi character). 

Implementation Notes

This activity has been offered in both a remote (Spring 2020) and in-person (Spring 2022) format. When conducted remotely, discussion was conducted via a video meeting platform, while the instructor shared a collaborative document with the class. All members of the class participated in editing and contributing to the document. With larger groups, offline discussion or several groups presenting their answers to these prompts would work in a similar fashion. When conducted in person, discussion was more facile, but less documentation was noted. Collaboratively editing a document is suggested in both modes, in order to encourage a more substantial response and to provide group answers to be graded after the class meeting.

Time Required
I devote one class period (~50 minutes) to this
Evaluation Methods

Students were evaluated on the basis of their participation, general quality of responses, and the extent to which they modify their responses based on the discussion and instructor feedback. An example rubric for evaluation of student performance is included in the KEY. Points were assigned based on a 5 point scale. 

Evaluation Results

Good performance in general. I found that this activity worked well as a group activity, and despite several incorrect assumptions about bonding, student were able to arrive as a group at the answers indicated in the KEY. 

Creative Commons License
Attribution, Non-Commercial, Share Alike CC BY-NC-SA