Synthesis and reactivity

11 Jan 2017

Group VI metal carbonyl compounds with pincer ligands

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

This was developed after the semester in which I teach this material. I look forward to using it next fall and I hope to post some evaluation data at that point.

Description: 

This literature discussion is based on a short paper describing a series of Group VI metal carbonyl compounds that have pincer ligands (Organometallics, 201635, 229). While the paper is relatively straightforward, there are many subtle points that can be brought out by asking the right questions which hopefully this LO does. Some of the questions the students should be able to answer directly from the paper. I feel it is important that they do this. However, these questions nicely set up further questions that require the students to go beyond what is covered in the paper. In addition to the synthesis, there are many questions related to the spectroscopic characterization of these compounds. And of course, it wouldn't be one of my LOs if students weren't being asked to count electrons and do group theory.

Corequisites: 
Prerequisites: 
Learning Goals: 

Upon completing this LO students should be able to

  1. Use the CBC method to count electrons in the tungsten compounds in this paper
  2. Describe the bonding interaction between a metal and a terminal carbonyl ligand
  3. Explain how NMR can be used to characterize these compounds including a discussion of 183W satellites
  4. Relate data from IR spectroscopy to the bonding interaction between a metal and a ligand and describe how the IR data can provide information about the electron donor ability of related ligands
  5. Recognize that some observed trends just do not have good explanations
 
Course Level: 
Implementation Notes: 

This might be a bit on the long side, you could certainly omit some of the questions or have the students work on it outside of class.

Time Required: 
50 minutes or so
4 Jan 2017
Description: 

This is a great new textbook by George Luther III from the University of Delaware.  The textbook represents the results of a course he has taught for graduate students in chemical oceanography, geochemistry and related disciplines.  It is clear that the point of the book is to provide students with the core material from inorganic chemistry that they will  need to explain inorganic processes in the environment.  However the material is presented in such a clear, logical fashion and builds so directly on fundamental principles of physical inorganic chemistry that the book is actually applicable to a much broader audience.  It provides a very welcome presentation of frontier orbital theory as a guide to predicting and explaining much inorganic chemical reactivity.  There are numerous very  helpful charts and tables and diagrams.  I found myself using the book for a table of effective nuclear charges when I was teaching general chemistry last semester.  The examples are much more interesting that the typical textbook examples and would be easy to embellish and structure a course around.  There is also a helpful companion website that provides powerpoint slides, student exercises and answers.  The book covers some topics not typically seen in inorganic textbooks like the acidity of solids but the presentation of this information makes sense in light of the coherent framework of the text.  We so often tell our students "structure dictates function".  This text really make good on that promise.  My only complaint is that I wish the title were something more generic so that I could use it for a second semester of introductory-esque material that we teach after students have taken a single semester of intro chem and two semesters of organic chemistry.  So much of what is covered in this textbook is precisely what a second semester sophomore chemistry major should know before proceeding on in the major.  But the title makes the book hard to sell to chemistry majors and that is regrettable. 

Prerequisites: 
Course Level: 
3 Jan 2017
Description: 

This Guided Literature Discussion was assigned as a course project, and is the result of work originated by students Stefanie Barnett and Katelyn Yowell.  It is based on the article “Synthesis, Electrochemistry, and Reactivity of Half-Sandwich Ruthenium Complexes Bearing Metallocene-Based Bisphosphines”, Shaw, A.P.; Norton, J.R.; Bucella, D.; Sites, L.A.; Kleinbach, S.S.; Jarem, D.A.; Bocage, K.M.; Nataro, C. Organometallics 2009, 28, 3804-3814. It includes a Reading Guide that will direct students to specific sections of the paper emphasized in the discussion.  This article presents the study of an array of metallocene-based bisphosphine ligands.

Course Level: 
Corequisites: 
Learning Goals: 

After reading and discussing this article, a student should be able to…

-       Understand the nomenclature of metallocene-based bisphosphine ligands.

-       Apply the CBC electron-counting method in the presence of metallocene-based bisphosphine ligands, which may be in an oxidized form.

-       Appreciate the role of phosphine cone angles in organometallic synthesis.

-       Understand the effect of a ligand’s electron donor ability on a metal’s redox potential.

-       Appreciate how synthetic methods may emphasize either the kinetic or thermodynamic product.

-       Understand how 1H NMR can help differentiate dihydride/dihydrogen isomers.

29 Dec 2016

The Monsanto acetic acid process

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

This was developed after the semester in which I teach this material. I look forward to using it next fall and I hope to post some evaluation data at that point.

Description: 

This literature discussion is based on one of early papers detailing the mechanism for the Monsanto acetic acid process (J. Am. Chem. Soc., 1976, 98, 846). In this communicaiton the identification of key intermediates in this process is carried out using infrared spectroscopy. While the paper is an easy read, there are lots of subtle points that can be brought out by asking the right questions which hopefully this LO does. Although we have plenty of excellent LOs asking students to identify the individual steps in the catalytic mechanism, this LO takes a slightly different approach and marches students through the mechanism.

Course Level: 
Prerequisites: 
Corequisites: 
Subdiscipline: 
Learning Goals: 

Upon completing this LO students should be able to

  1. Use the CBC method to count electrons in the rhodium compounds in this paper
  2. Describe the bonding interaction between a metal and a terminal carbonyl ligand
  3. Identify the various reactions taking place in the Monsanto acetic acid process
  4. Relate data from IR spectroscopy to the bonding interaction between a metal and a ligand and to the identification of intermediates in this process
Time Required: 
50 minutes or so
28 Dec 2016

Virtual Issue of Organometallics

Submitted by Chip Nataro, Lafayette College

You can find the virtual issue with our editorial and all of the papers here.

Subdiscipline: 
Prerequisites: 
Corequisites: 
Course Level: 
27 Dec 2016

Binding dinitrogen to titanium sandwich compounds

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

This LO was developed after the course I would use it in had ended. I am looking forward to using it next year and I hope to post some evaluation results at that point.

Description: 

The literature discussion is based on one of the early papers from the Chirik group (J. Am. Chem. Soc., 2004, 126, 14688). In this communication, the coordination of N2 to a series of (C5H4R)2Ti fragments is examined. Being a communication, it is very short and that helps make it less intimidating for undergraduates. But don't be fooled, it is very rich in the fundamental concepts of orgnaometallic chemistry. The nitrogen fixation reaction has real world significance and is therefore an interesting big picture idea to talk about in relation to this paper. The bonding of Cp ligands is discussed in the context of this paper. In addition, this paper also presents paramagnetic and dimagnetic Ti(II) compounds and thus provides an opportunity to discuss the characterization of paramagnetic compounds. The use of X-ray crystallography and IR spectroscopy in relation to the strength of a bonding interaction between ligands and a metal center is also discussed. Finally, there is an opportunity to apply group theory to determine the number of IR active bands in the IR spectrum of a carbonyl compound. The supporting info for this paper is such a key part of this LO that links to both the paper and the supporting info are included below. In addition, there is a link to a Hoffman paper detailing the MO diagram for Cp2M compounds which might prove useful in discussing the paramagentic and diamagnetic Ti(II) compounds.

Prerequisites: 
Course Level: 
Corequisites: 
Learning Goals: 

Upon completing this LO students should be able to

  1. Describe why nitrogen fixation is a significant chemical reaction worthy of study
  2. Use the CBC method to count electrons in the titanium compounds in this paper
  3. Describe the bonding in compounds with Cp ligands
  4. Describe how a paramagnetic substance can be recognized when using standard characterization techniques and suggest other means of characterizing paramagnetic compounds
  5. Relate data from IR spectroscopy and X-ray crystallography to the bonding interaction between a metal and a ligand
Time Required: 
50 minutes
15 Dec 2016
Evaluation Methods: 

I had the students prepare for the discussion before class by reading the entire article. Students then answered the guiding questions in small groups during a class period.

I graded this assignment based upon class participation. All 33 students participated in the discussion. 

Evaluation Results: 

The average grade on this assignment was an A. Students very much enjoyed reading an article from the literature and connecting it to topics we discussed in class. This article opened up our discussion on catalysis and mechanisms. The article nicely describes the rational design of experiments to probe and catalytic reaction. 

Good paper to introduce kinetics and mechanistic studies.

Description: 

Reading and understanding a journal article is a critical skill to obtain as a student. After college, many students will pursue careers in which learning occurs exclusively from the literature. Students  will read a full paper from the journal Inorganic Chemistry and answer guiding questions pertaining to the article. There will be an in class discussion about the article to introduce which is used to introduce the topic of catalysis. This assignment breaks down the article through a series of questions that helps students to navigate a journal article.

Students will look copper complexes which catalyze atom transfer radical addition (ATRA) under sustainable means. 

The citation is Inorganic Chemistry 2012, 51, 11917-11929. 

Corequisites: 
Course Level: 
Prerequisites: 
Learning Goals: 
Students should be able to:
  1. Read a full journal article pertaining to organometallic chemistry
  2. Critically think about the chemical literature
  3. Read about and understand organometallic mechanistic and kinetic studies
  4. Determine that structural and electronic ligand modification influences the reactivity of catalysts
  5. Describe spectroscopic methods used to obtain rate constants
  6. Distinugish between coordinating and non-coordinating anions and effects on catalysis
  7. Define inner and outer spehere electron transfer and relate this to the proposed reaction mechanism
  8. Explain the mechanistic studies done to probe the lability of the TPMA ligand
Implementation Notes: 

I conducted this with a class of senior and junior chemistry majors and it went very well! This is a very long article so you could break this up into more basic topic and then more challenging ones.

Some of these questions could also be used on an exam. 

The questions are doable as students in the course actually helped develop these questions. I broke the article up into sections and assigned each section to a group of 4 students who were required to develop at least two questions per section. I then helped form the questions with the students. This model worked well and may be of interest to other people in the community.

But this assignment can be delivered as is - as a literature assignment with the focus on electron transfer, catalysis, mechanistic studies, and kinetics.

Time Required: 
50 minutes to 1 hour
1 Jul 2016

Introduction to Atom Economy and the Hydroamination Reaction

Submitted by Eugene Chong, University of Michigan
Description: 

This 5 slides about introduces the term "atom economy" as a means for undergraduates to start thinking about the efficiency of synthetic reactions. While this term may not be the best measure of the overall process of a reaction (as it ignores other factors such as solvents and materials used in purification), it provides a nice introduction to a concept on green chemistry. An example of an atom economic reaction, hydroamination, is briefly highlighted as it is an important ongoing research area. Notes for the instructor are included in the slides.

Corequisites: 
Subdiscipline: 
Learning Goals: 

Students should be able to:

- define atom economy and use it to assess the efficiency of a reaction

- explain the hydroamination reaction and the strategies involved to facilitate the reaction with a metal catalyst

- describe the bonding of metal-imido bonds and metal-pi-C=C bonds

 

Implementation Notes: 

Calculation of atom economy or drawing of molecular orbitals of the bonds involved could be a useful classroom activity. The mechanisms presented are selected examples that have been simplified, and one should keep in mind that other mechanisms exist, as well as other metals.

30 Jun 2016

Oxorhenium(V) Methyl, Benzyl, and Phenyl Complexes: New Mechanism for Carbonyl Insertion

Submitted by Matthew Riehl, Minnesota State University, Mankato
Evaluation Methods: 

Students should be assessed based on participation if there is no written portion to hand in.

Evaluation Results: 

This is a new learning object created at the 2016 Summer VIPEr Workshop and has not yet been implemented.  Results will be added by the creators after use in a class.  Please feel free to share your results.

 

Description: 

The article “Synthesis and Reactivity of Oxorhenium(V) Methyl, Benzyl, and Phenyl Complexes with CO; Implications for a Unique Mechanism for Migratory Insertion,” Robbins, LK; Lilly, CP; Smeltz, JL; Boyle, PD; Ison, EA;, Organometallics 2015, 34, 3152-3158 is an interesting read for students studying reaction mechanisms of organometallic complexes.  The reading guide directs students to the sections of the paper that support the question posed in the Discussion Questions document. 

Corequisites: 
Course Level: 
Learning Goals: 

After reading and discussing this paper, students will be able to explain the mechanisms of migratory insertion reactions of CO and explain the evidence supporting a new mechanism of direct insertion.  In addition students will be better prepared to read and appreciate original research articles without a reading guide.

 

A student should be able to

 

1. identify and state the goals and findings of the paper in their own words

2. explain the various methods/techniques used to probe the mechanism, describe what was measured, and explain how the observations support the conclusions presented.

3. apply the CBC method for electron counting of the Re complexes in this paper

4. describe the bonding in metal oxo compounds and explain trans influence

5. understand kinetic parameters such as the reaction rate equation and the reaction order

6. analyze 1H NMR spectra

7. interpret thermodynamic parameters and how they apply to the reaction mechanism

Implementation Notes: 

The reading guide covers the first part of the paper only.  The DFT studies are not included nor are the synthetic details. We suggest giving the reading guide to the students with the original manuscript and allowing two days or longer for the students to read and digest.  Then, in small groups, or as a class discussion, ask students to answer the questions in the Literature Discussion document.

 

Time Required: 
at least 1 class period
30 Jun 2016
Evaluation Methods: 

This LO was created at the VIPEr Workshop in June 2016 and has not yet been evaluated.

Some possible evaluation methods:

  • The LO could be evaluated from written student work individually or from small groups, from the in-class discussion, or both. One method may be to allow students to write their answers to the discussion questions as homework in one color pen and then have them make changes during the in-class discussion in a different color pen. The resulting worksheets could be collected and some questions graded based on individual student answers and some questions graded based on group answers.

  • Faculty could ask students to read the article and then divide them into groups to prepare short presentations on different concepts (NMR, CV, electron-counting, etc.). These presentations could be rated by faculty and students.

  • Faculty could ask problem set, quiz and/or exam questions related to questions and concepts. A problem set related to this LO is posted on VIPEr.

Evaluation Results: 

This LO was created at the VIPEr Workshop in June 2016. No evaluation results have yet been obtained but two of the team members who created this LO will be using it in their classes during AY2016-2017. We will report back on the evaluation results.

Description: 

This literature discussion is designed for upper-level inorganic chemistry students. The article explores the motivations, design, and characterization of novel nickel(II) and nickel(IV) complexes for carbon-heteroatom bond forming reactions. Students can apply and integrate their knowledge of organic chemistry mechanisms, organometallic chemistry, and techniques for characterizing metal-ligand compounds that include NMR and CV.

This literature discussion was created as part of the NSF TUES VIPEr Workshop 2016 at the University of Michigan Ann Arbor based on the article “Design, synthesis, and carbon-heteroatom coupling reactions of organometallic nickel (IV) complexes.”

Reference: Nicole M. Camasso and Melanie S. Sanford Science 2015, 347, 1218-1220.  DOI: 10.1126/science.aaa4526. Supplementary materials at www.sciencemag.org/ content/347/6227/1218/suppl/DC1.

The article was read by a team of seven workshop participants and the corresponding author, Prof. Sanford, presented the work to this audience. Following discussions with Prof. Sanford and between workshop participants, the LO was created.

Corequisites: 
Course Level: 
Subdiscipline: 
Learning Goals: 

 

General learning goals for literature discussions

 

Through reading this article, students will be able to…

  • integrate information from different subdisciplines of chemistry as they apply to answering research questions

  • extract information from figures, schemes, and tables in a scientific paper.

  • relate content in the current literature to concepts covered in class.

  • discuss scientific material with peers in an academic manner.

  • develop opinions and arguments related to a scientific paper and support them using external sources.

  • articulate the motivation and implications of scientific research presented in a scientific paper.

  • use references in the article to find and read literature precedents for concepts described in the primary article.

 

Learning goals specific to this literature discussion.

 

Students will be able to…

  • utilize general chemical knowledge to interpret research motivation and suggest potential issues (Question 1)

  • determine molecular geometries and count electrons for inorganic complexes (Question 3)

  • interpret and characterize intermediate products by NMR (Question 4)

  • demonstrate ability to interpret a voltammogram at a basic level. (Question 5a)

  • determine d-orbital splitting for multiple oxidation states and use this to determine potential characterization methods (Question 5b-d)

  • analyze NMR spectral data to compare characteristics (electron density, Lewis acidity, geometry, etc.) of metals discussed in the article. (Questions 6-8)

  • analyze the ligand environment around a metal center and make detailed comparisons between a series of related complexes. (Question 9)

  • draw transition states for and cite evidence to support a proposed reaction mechanism. (Question 10)

  • discuss the details of the nucleophilicity parameter and how it relates to reacton rate. (Question 11)

  • analyze the features of a cyclic voltammogram and compare with chemical reactivity (Question 12)

Implementation Notes: 

We have included a wide range of discussion questions, but expect that those who adopt this LO will pick and choose questions as they see fit.

There are a couple ways we plan to implement this literature discussion:

1. Students will read the article and answer a few of the simpler questions before coming to class. In class, students will discuss several questions at a time in small groups, followed by whole class discussion. Small groups may revise their answers accordingly, and will submit their group answers in addition to their individual responses at the end of the period.

2. Students will be divided into small groups and assigned a question from the lit exercise, then given 1 week to read over the article outside of class. During this time, students will be expected to answer questions 1-3 individually, and work with their groups to answer their assigned question. Each group will share their thoughts and opinions regarding the answers to their assigned question by presenting to the entire class in a “chalk talk” type discussion at the white board. Groups will be provided with images of any figure listed in the paper and lit discussion exercise in powerpoint so they can project images relevant to their discussion to the entire class.

Time Required: 
1-2 class periods for entire LO. Can be modified to be shorter

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