Bonding models: Discrete molecules

3 Feb 2017

Six-coordinate Carbon In-class Activity

Submitted by Kyle Grice, DePaul University
Evaluation Methods: 

Dr. Grice will evaluate this LO later this year. 

Description: 

This is an in-class exercise developed based on a recent paper in Angewandte Chemie International Edition that reported a crystal structure of "six-coordinate" carbon. We normally think of carbon being four-coordinate at most, but this case has definitive evidence otherwise. However, we can use our inorganic chemistry knowledge to understand the structure and bonding of this molecule and rationalize its stability. Students do a pre-class exercise and then construct the MO of fhe molecule in class together. 

Learning Goals: 

After completion of this Learning Object, students will be able to:

-Assign point groups to organic molecules

-Analyze and discuss chemistry primary literature

-Identify the properties and charges of ligands

-Use Wade's rules to describe clusters

-Construct qualitative MO diagrams using symmetry as a guide

Corequisites: 
Course Level: 
Equipment needs: 

None

Prerequisites: 
Implementation Notes: 

Dr. Grice will be implementing this later this year. 

We have included an instructor guide file under Faculty files. 

Time Required: 
50 min
25 Jan 2017

Synthesis and reactivity of palladium and platinum carbenes

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

This paper was presented late in the fall semester and as such I was unable to use it in class. I look forward to using it in the fall.

Description: 

The literature discussion is based on a paper (Organometallics ASAP) in which the synthesis and reactivity of a palladium and platinum carbene compound. The palladium and platinum compounds exhibit some interesting differences that show up throughout the paper. There is a lot of detail in the experimental section so this paper seems longer than it actually is for the purposes of having students read it. The authors do a good job of going through the rationale of the work that was done and students should be able to follow along. There is a large amount of spectroscopic data in the paper and a nice presentation of coupling to spin 1/2 nuclei that is less than 100% naturally abundant.

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

Upon completing this LO students should be able to 

  1. Use the CBC method to count electrons in the compounds in this paper
  2. Describe the bonding in carbene compounds presented in this paper
  3. Present a rationale for the differences in the reactivity of related palladium and platinum compounds
  4. Formulate reaction mechanisms for the compounds in this paper
  5. Explain 195Pt satellites
Implementation Notes: 

Students should read the paper before coming to class. Although there are a lot of questions in the LO, if the students have done a good job reading the paper I would anticipate that they can get through them all. Certainly some of the questions can be left out, or perhaps only provide the students with a few of them before class, in particular the students should be able to do electron counts before class.

Time Required: 
50 minutes or so
23 Jan 2017

Reactivity of a platinum benzyne compound

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: 

The literature discussion is based on a paper by Gagné (Organometallics 2015, 34, 2707).  In this work, the in situ generation of benzyne is examined. The benzyne coordinates to a platinum center with a tridentate (pincer) phosphine ligand and a methyl group. This provides an opportunity to discuss the characterization of compounds that have NMR active nuclei that are not 100% naturally abundant. Protonation of the benzyne compound results in the formation of toluene. Different mechanisms are considered.

Prerequisites: 
Course Level: 
Corequisites: 
Learning Goals: 

Upon completing this LO students should be able to 

  1. Describe what benzyne is and how it is formed
  2. Explain the coordination of benzyne (and therefore all alkynes) as L type donors to a metal center
  3. Use the CBC method to count electrons in all of the compounds and intermediates in this study
  4. Rationalize reaction pathways using electron counting techniques
  5. Explain 195Pt satellites
Subdiscipline: 
Time Required: 
50 minutes or so
19 Jan 2017

Nucleophilic attack at an iridium arene

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 paper describing the nucelophilic attack on a coordinated arene (Organometallics, 2015, 34, 4626). The basic goal is to devise a catalytic method for converting an alkene into a phenol. While the authors do not accomplish that goal, they do manage to present a series of steps that would be the basis for a catalytic cycle. The compounds are relatively straightforward, and while there are some additional reactions that might be a little complicated for students, they should be able to get through the main parts of the short paper.

Prerequisites: 
Course Level: 
Corequisites: 
Learning Goals: 

Upon completing this LO students should be able to

  1. Use the CBC method to count electrons in the iridium compounds in this paper
  2. Describe the bonding interaction between a metal and an arene
  3. Discuss nucleophilic attack on a coordinated arene
  4. Rationalize the point of attack on a substituted arene
Time Required: 
50 minutes or so
18 Jan 2017

calistry calculators

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

I just stumbled on this site while refreshing myself on the use of Slater's rules for calculating Zeff for electrons. There are a variety of calculators on there including some for visualizing lattice planes and diffraction, equilibrium, pH and pKa, equation balancing, Born-Landé, radioactive decay, wavelengths, electronegativities, Curie Law, solution preparation crystal field stabilization energy, and more.

I checked and it calculated Zeff correctly but I can't vouch for the accuracy of any of the other calculators. 

Prerequisites: 
Corequisites: 
Learning Goals: 

This is not a good teaching website but would be good for double checking math

 

Implementation Notes: 

I used this to double check my Slater's rules calculations (and found a mistake in my answer key!)

17 Jan 2017

Reactions of Cp*2Zr(2,3-dimethylbutadiene)

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. I anticipate having students read the paper prior to coming to class to answer these questions in a group.

Description: 

This literature discussion is based on a paper detailing the structure and reactivity of the title compound (Organometallics, 201635, 3163). The 2,3-dimethylbutadiene ligand is a bit misleading as these typically bond as X type ligands to early transition metals. Students will get a lot of pracitce counting electrons, in particular considering the different ways the 2,3-dimethylbutadiene ligand might be thought of in terms of bonding. These will then be compared to X-ray data to help the students arrive at the proper binding mode. The reactivity of these compounds with carbon monoxide and isonitriles (isocyanides) is examined. Students should be given the paper to read before coming to class for discussion. I use the CBC method of electron counting and that is reflected in the questions on electron counting. Students are taught this at the beginning of a senior level course that is primarily focused on organometallic chemistry.

Prerequisites: 
Course Level: 
Corequisites: 
Learning Goals: 

Upon completing this LO students should be able to

  1. Use the CBC method to count electrons in the zirconium compounds in this paper
  2. Describe the bonding interaction between a metal and a Cp* ligand
  3. Describe the bonding of a 2,3-dimethylbutadiene ligand to zirconium based on the available X-ray data
  4. Classify the reactions of CO and isonitriles with the complexes by reaction type
Time Required: 
50 minutes or so
13 Jan 2017

Ruthenium catalyzed transfer hydrogenation

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 paper detailing catalytic transfer hydrogenation of various unsaturated organic molecules (Organometallics, 2016, 35, 943). In this paper, two ruthenium compounds with N-heterocyclic carbene (NHC) ligands are examined as catalytic precursors for transfer hydrogenation. This LO walks students through the paper, but it does so in a slightly different order than the paper presents the material. In parcticular, the proposed catalytic mechanism appears very late in the paper, but very early in the LO.

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 ruthenium compounds in this paper
  2. Describe the bonding interactions in a N-heterocyclic carbene (NHC) ligand
  3. Describe catalytic transfer hydrogenation and identify the reactions taking place in the proposed mechanism
  4. Examine a series of catalytic results and rationalize observed trends
Time Required: 
50 minutes or so
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: 
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

Pages

Subscribe to RSS - Bonding models:  Discrete molecules