Electronic structure

7 Aug 2018
Description: 

Rules for quantum numbers are confusing but not arbitrary.  They are based on wave mathmatics, and once laid out properly are symmetric and beautiful.  Within four animation-clicks of the first slide of this PowerPoint Presentation, this beauty will unfold.  I do not exaggerate to say, faculty members will be agape and students will say, "Why didn't you show us this before."  No other presentation shows in as elegant a way the relationship between 1)  n, l and ml, 2) the ordering of orbitals in hydrogen-like atoms, and 3) the ordering of orbitals in the periodic table (along with the difficulty of assigning orbital filling in transition and f-block elements).  

Beauty is in every atom.  Let it loose.

Topics Covered: 
Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

A student will be able to relate the quantum numbers n, l and ml to each other.

A student will be able to correctly describe the number of subshells and number of orbitals in a shell.

A student will be able to describe the orbital energies in a hydrogen-like atom.

A student will be able to order subshells in a multi-electron system and relate this to the periodic table.

A student will realize the symmetry and beauty of quantum chemistry without ever seeing the shape of one orbtal.  

Implementation Notes: 

In the first two slides, often use the phrase "because it's a square."

This is useful for Inorganic Chemistry students as well because it will cement in their mind long lost rules of quantum numbers.

 

Evaluation
Evaluation Methods: 

1) Short answer quiz questions

2) Multiple choice questions on hour and final exams.

3) Awe.

Evaluation Results: 

1) From a quiz killer to a typical A, B, C student gets it right, the D student is still a bit confused and the F student still misses the idea.

2)  On a question asking, "how many orbitals in the n=3 shell", the results increased from the 40's to 80's %.  

3) As jaws dropped, quarters could be slipped into their mouths.  Faculty pulled out phones to take pictures of a white-board version before I told them I had a PowerPoint version.

23 Jun 2018
Evaluation Methods: 

 A key is provided for the discussion questions. The discussion questions can be collected and graded.

Description: 

The activity is designed to be a literature discussion based on Nicolai Lehnert's Inorganic Chemistry paper, Mechanism of N-N Bond Formation by Transition Metal-Nitrosyl Complexes: Modeling Flavodiiron Nitric Oxide Reductases.  The discussion questions are designed for an advanced level inorganic course. 

 

Corequisites: 
Course Level: 
Learning Goals: 

Upon completion of this activity, students will be able to:

  1. Identify the overall research goal(s) of the paper.

  2. Define and identify non-innocent ligands.

  3. Identify how electron density on the metal center can impact ligand coordination.

  4. Draw molecular orbital diagrams for coordination compounds.

  5. Identify covalency by interpreting molecular orbital diagrams and data.

  6. Define and interpret Enemark-Feltham notation.

  7. Recognize spin multiplicity of the metal and ligand fragments in a complex and how it corresponds to the overall spin multiplicity.

  8. Identify possible electronic structures of {FeNO} complexes.

  9. Describe various characteristics to be considered in the selection of a good reductant.

  10. Explain how occupying bonding versus antibonding orbitals changes the reactivity of a system.

Implementation Notes: 

This is a very involved article with lots of great concepts. It will take a lot of time to read. We suggest giving this as a student group assignment. Give the students a copy of the article and discussion questions. Give them 1-2 weeks to read through the article and complete the discussion questions. Spend one or two 50 min. class periods going over the discussion questions. 

Note: This was developed during the 2018 VIPEr Workshop and has not been implemented, yet. Above instructions are an initial guide, any feedback is welcome and appreciated!

Time Required: 
50-90 min.
22 Jun 2018
Evaluation Methods: 

Discuss students responses with respect to the answer key.

Evaluation Results: 

This activty was developed for the IONiC VIPEr summer 2018 workshop, and has not yet been implemented.

Description: 

Inorganic chemists often use IR spectroscopy to evaluate bond order of ligands, and as a means of determining the electronic properties of metal fragments.  Students can often be confused over what shifts in IR frequencies imply, and how to properly evaluate the information that IR spectroscopy provides in compound characterization.  In this class activity, students are initially introduced to IR stretches using simple spring-mass systems. They are then asked to translate these visible models to molecular systems (NO in particular), and predict and calculate how these stretches change with mass (isotope effects, 14N vs 15N).  Students are then asked to identify the IR stretch of a related molecule, N2O, and predict whether the stretch provided is the new N≡N triple bond or a highly shifted N-O single bond stretch.  Students are lastly asked to generalize how stretching frequencies and bond orders are related based on their results.

 
Learning Goals: 
  1. Evaluate the effect of changes in mass on a harmonic oscillator by assembling and observing a simple spring-mass system (Q1 and 2)

  2. Apply these mass-frequency observations to NO and predict IR isotopic shift (14N vs. 15N) (Q3 and 4)

  3. Predict the identity of the diagnostic IR stretches in small inorganic molecules. (Q5, 6, and 7)

Equipment needs: 

Springs, rings, stands, and masses (100 and 200 gram weights for example).

 

Corequisites: 
Implementation Notes: 

Assemble students into small groups discussions to answer the questions to the activity and collaborate.

 

 

Time Required: 
Approximately 50 minutes
1 Jun 2018
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.

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.

 

Corequisites: 
Course Level: 
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.
3 Jun 2017
Evaluation Methods: 

Students were evaluated by the instructor during the activity. The instructor was available throughout the activity to answer questions and guide inquiry. This activity generated good discussion among students and most were able to work their way through. 

Evaluation Results: 

All students completed the activity during the class period and gained a deeper appreciation for metals in biology, protein structure, and using NMR to determine protein structure. Some students needed more guiding through the rationales of metal toxicities and the multi-dimensional NMR experiments than others. 

Description: 

This activity was designed as an in-class group activity, in which students begin by using basic principles to predict relative toxicities and roles of metals in biological systems. Students then learn about the structures of metallothioneins using information from the protein data bank (PDB) and 113Cd NMR data. By the end of the activity, students will have analyzed data to identify and determine bonding models and coordination sites for multiple cadmium centers in metallothioneins. It is based on recent literature, but does not require students to have read the papers before class.

Learning Goals: 

Students will be able to:

  1. Use fundamental principles to predict toxicities of metals
  2. Apply hard-soft acid-base (HSAB) theory to metals in biological systems
  3. Utilize the protein data bank (PDB) to investigate protein-metal interactions
  4. Explain the roles of metallothioneins in biological systems
  5. Evaluate 1-D and 2-D 113Cd NMR to determine structures of Cd bonding sites in metallothioneins
  6. Explain how NMR can be utilized to determine protein structure
Course Level: 
Corequisites: 
Implementation Notes: 

This activity was developed for a Master's level bioinorganic course, but could be utilized in an advanced undergraduate inorganic course. Students were given the worksheet at the beginning of class and worked together in groups to answer the questions. Students did not have access to the paper and had not read any articles previously. Using the PDB was done as a separate in-class activity, so students had some familiarity with the PDB codes and amino acid sequences. 

A brief refresher of [1H-1H] COSY was presented before beginning the activity. 

Time Required: 
60 min
3 Jun 2017

Introduction to Agostic Interactions

Submitted by Emma Downs, Fitchburg State University
Description: 

A brief introduction to agostic interactions and their importance to common organometallic mechanisms such as beta-hydride elimination. Examples of compounds containing these interactions are discussed and compared to familiar molecules such as diborane. Ways to characterize these interactions are also introduced.

Slides are based on the PNAS review Agostic Interactions in Transition Metal Compounds 

Brookheart, Green, and Parkin Proc. Natl. Acad.Sci. 2007104(7), 6908-6914

 

 
Course Level: 
Corequisites: 
Learning Goals: 

Define an agostic interaction and relate it to other types of bonding.

Provide examples of how the presence of an agostic interaction can be determined experimentally and through computational methods. 

 

Implementation Notes: 

This LO was developed at the VIPEr 2017 workshop at Franklin and Marshall College so it has not yet been implemented. The authors believed that implementation of this LO is best for an inorganic course that is post-organic, post-spectroscopy. It could be helpful after a discussion of 3-center 2-electron bonding and/or Lewis acidity/basicity. A literature discussion on an interesting agostic interaction with silicon was developed in conjunction with this LO and would be appropriate after discussing this five slides about LO.

Time Required: 
20 minutes
3 Jun 2017

Literature Discussion of "A stable compound of helium and sodium at high pressure"

Submitted by Katherine Nicole Crowder, University of Mary Washington
Evaluation Methods: 

Students could be evaluated based on their participation in the in-class discussion or on their submitted written answers to assigned questions.

Evaluation Results: 

This LO has not been used in a class at this point. Evaluation results will be uploaded as it is used (by Spring 2018 at the latest).

Description: 

This paper describes the synthesis of a stable compound of sodium and helium at very high pressures. The paper uses computational methods to predict likely compounds with helium, then describe a synthetic protocol to make the thermodynamically favored Na2He compound. The compound has a fluorite structure and is an electride with the delocalization of 2e- into the structure.

This paper would be appropriate after discussion of solid state structures and band theory.

The questions are divided into categories and have a wide range of levels.

Dong, X.; Oganov, A. R.; Goncharov, A. F.; Stavrou, E.; Lobanov, S.; Saleh, G.; Qian, G.-R.; Zhu, Q.; Gatti, C.; Deringer, V. L.; et al. A stable compound of helium and sodium at high pressure. Nature Chemistry 2017, 9 (5), 440–445 DOI: 10.1038/nchem.2716.

Corequisites: 
Learning Goals: 

After reading and discussing this paper, students will be able to

  • Describe the solid state structure of a novel compound using their knowledge of unit cells and ionic crystals
  • Apply band theory to a specific material
  • Describe how XRD is used to determine solid state structure
  • Describe the bonding in an electride structure
  • Apply periodic trends to compare/explain reactivity
Implementation Notes: 

The questions are divided into categories (comprehensive questions, atomic and molecular properties, solid state structure, electronic structure and other topics) that may or may not be appropriate for your class. To cover all of the questions, you will probably need at least two class periods. Adapt the assignment as you see fit.

CrystalMaker software can be used to visualize the compound. ICE model kits can also be used to build the compound using the template for a Heusler alloy.

Time Required: 
2 class periods

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