1 Jun 2018

Ytterbium-catalyzed alkene isomerization: A tribute to the f-block chemistry of Richard Andersen

Literature Discussion

Submitted by Joanne Stewart, Hope College
Categories
Description: 

In honor of Professor Richard Andersen’s 75th birthday, a small group of IONiC leaders submitted a paper to a special issue of Dalton Transactions about Andersen’s love of teaching with the chemical literature. To accompany the paper, this literature discussion learning object, based on one of Andersen’s recent publications in Dalton, was created. The paper examines an ytterbium-catalyzed isomerization reaction. It uses experimental and computational evidence to support a proton-transfer to a cyclopentadienyl ring mechanism versus an electron-transfer mechanism, which might have seemed more likely.

 

The paper is quite complex, but this learning object focuses on simpler ideas like electron counting and reaction coordinate diagrams. To aid beginning students, we have found it helpful to highlight the parts of the paper that relate to the reading questions. For copyright reasons, we cannot provide the highlighted paper here, but we have included instructions on which sections to highlight if you wish to do that.

 

AttachmentSize
File Reading questions for students.20 KB
Learning Goals: 

After completing this literature discussion, students should be able to

  • Count the valence electrons in a lanthanide complex

  • Explain the difference between a stoichiometric and catalytic reaction

  • Predict common alkaline earth and lanthanide oxidation states based on ground state electron configurations  

  • Describe how negative evidence can be used to support or contradict a hypothesis   

  • Describe the energy changes involved in making and breaking bonds

  • On a reaction coordinate diagram, explain the difference between an intermediate and a transition state

  • Explain how calculated reaction coordinate energy diagrams can be used to make mechanistic arguments

Implementation Notes: 

This is a paper that is rich in detail and material. As such, an undergraduate might find it intimidating to pick up and read. We have provided a suggested reading guide that presents certain sections of the paper for the students to read. We suggest the instructor highlight the following sections before providing the paper to the students. While students are certainly encouraged to read the entire paper, this LO will focus on the highlighted sections.  

 

Introduction

            Paragraph 1

            Paragraph 2

            Paragraph 3

            Paragraph 4

First 5 lines ending at the word high (you may encourage students to look up exergonic if that is not a term commonly used in your department)

Line 14 starting with “In that sense,” through the end of the paragraph

            Paragraph 6

From the start through the word “endoergic” in line 22

Line 31 from “oxidation of” to the word “described” in line 33

Line 40 from “These” to the word “dimethylacetylene” in line 45

Paragraph 7

            From the start to the word “appears” in line 4

            The words “to involve” in line 4

            Starting in line 4 with “a Cp*” to “transfer” in line 5

Results and Discussion

            Paragraph 1

            Paragraph 2

            Paragraph 3 from the start through “six hours” in line 10

            Paragraph 4

            Paragraph 5

                        From the start to “solution” in line 3

                        From “This exchange” in line 10 to “allene” in line 11

                        From “Hence” in line 19 through the end of the paragraph

            Paragraph 6 from the start through “infrared spectra” in line 19

            Paragraph 7 from “Hence” in line 4 through the end of the paragraph

Mechanistic aspects for the catalytic isomerisation reaction of buta-1,2-diene to but-2-yne using (Me5C5)2Yb p 2579.

            Paragraph 1

            Paragraph 2

            Paragraph 3

            Paragraph 4

Experimental Section

            Synthesis of (Me5C5)2Yb(η2-MeC≡CMe).

            Synthesis of (Me5C5)2Ca(η2-MeC≡CMe).

Reaction of (Me5C5)2Yb with buta-1,2-diene

 

 

 

Time Required: 
One class period.
Evaluation
Evaluation Methods: 

This LO has not been implemented; however, we recommend a few options for evaluating student learning:

  • implement as in-class group work, collect and grade all questions

  • have students complete the literature discussion questions before lecture, then ask them to modify their answers in another pen color as the in-class discussion goes through each questions

  • hold a discussion lecture for the literature questions; then for the following lecture period begin class with a quiz that uses a slightly modified problem.

Evaluation Results: 

This LO has not been implemented yet.

Creative Commons License: 
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