27 Dec 2016

Energetics and mechanisms of reductive elimination from Pt(IV)

Literature Discussion

Submitted by Adam R. Johnson, Harvey Mudd College
Categories
Description: 

This literature discussion is based on a paper by Karen Goldberg (J. Am. Chem. Soc., 1995, 117, 6889-6896). In this early paper by Goldberg, she studied the reductive elimination of ethane and methyl iodide from dppePtMe3I. The paper is well written, and approachable for undergraduates. It shows a real, interesting application of thermodynamic and kinetic methods to the study of a problem in mechanistic chemistry. The experimental details are complete, and this paper would serve as a good review of kinetics, thermodynamics, and organometallic reaction mechanisms. 


This LO presents a series of guided reading questions that help a student approach some of the material presented in the paper in a more thorough way. It asks students to derive equations and understand how experimental data can be combined into a reaction coordinate free energy diagram. The LO is suitable for junior or senior undergraduates in an organometallics course or unit within an inorganic course.

An update and correction was made to the LO in April 2018. Questions 7 and 8 in the learning object have students address the point of the differing M-C and M-I bonds. For the purposes of understanding what was written at the time, the questions are still valid, but the conclusions drawn in the paper about M-X bond strengths are not. For more information, see the "faculty only" file entitled "Goldberg Update 201804."

AttachmentSize
File Goldberg questions22.96 KB
PDF icon Discussion guide for students21.37 KB
Learning Goals: 

upon completing this LO students should be able to

1. demonstrate where thermodynamic parameters come from in a reaction coordinate free energy diagram

2. derive complex rate equations using the steady state approximation

3. describe the principle of microscopic reversibility

4. gain a deeper appreciation for the experimental methods (thermodynamic and kinetic) used in mechanistic chemistry

Implementation Notes: 

I used this LO as a guided reading handout for a senior-level organometallics class. The questions and the paper were provided to the students a week in advance and the in-class activity was a student-led discussion of the paper.

Time Required: 
one 50-75 minute class period
Evaluation
Evaluation Methods: 

This LO was used in class to help a student guide a discussion of the paper. We did not cover all of the LO in a 75 minute class period, as we let the discussion take us where it wanted to.

A better way to ensure student preparation would be to collect the questions at the beginning (or end, if they wanted to use their notes in class) of class to ensure that they had really studied the paper.

Evaluation Results: 

I used this LO as a guided reading handout and did not collect the answers so I do not have any assessment data at this time.

My students found this paper to be highly readable and very clear. It is dense, with a lot of information presented, but once the students dove in, we were able to discuss it at a high level.

Creative Commons License: 
Creative Commons Licence

Comments

I used this LO in the past semester in my organometallics unit for a junior/senior level inorganic course. I was unable to be in class for the class discussion so I prepared a discussion handout which I'm attaching here. It allowed the class to track the discussion both in summary form and using a Harkness diagram. In general, students did very well on this assignment. I did change my methods and collect the answers to the questions after class (I let them write on and update their answers during class). The scribes both received full credit for participation, and other students' participation scores were determined based on quantitative (Harkness diagram) and qualitative (scribed comments) metrics.

 

In addition, one of the students attempted the last question, and I am including his work here as it is actually quite a difficult problem (at least for a synthetic chemist).

An update and correction was made to the LO in April 2018. Questions 7 and 8 in the learning object have students address the point of the differing M-C and M-I bonds. For the purposes of understanding what was written at the time, the questions are still valid, but the conclusions drawn in the paper about M-X bond strengths are not. For more information, see the "faculty only" file entitled "Goldberg Update 201804."

The VIPEr community supports respectful and voluntary sharing. Click here for a description of our default Creative Commons license.