Main Group Chemistry

9 Jun 2019

Triphenylphosphine: Transformations of a Common Ligand

Submitted by Bradley Wile, Ohio Northern University
Evaluation Methods: 

This lab report is graded using the attached rubric (see faculty files). 

Evaluation Results: 

Over the last four iterations of this lab, the average total score was ~42/50 (n = 21). Students are generally good at recognizing that a redox process is occurring, though some struggle with this realization. Most students generate a Lewis structure with a dative bond, though some do not use the MO diagram to infer a reasonable direction for the dative interaction. I typically work through this with the students, asking them questions like "which orbitals have electrons?" and "what orbitals are interacting in your Lewis depiction?" This has been a good introduction to these synthetic and instrumental methods, and gives the lab partners an opportunity to divide up their responsibilities.

Description: 

This experiment tasks students with preparing triphenylphosphine sulfide, and the corresponding I2 adduct, then characterizing these products using common instrumental methods. Students are asked to consider MOs and tie this to their Lewis bonding depiction for the final product. This discussion is supported by WebMO calculations and tied to the experimental data obtained by the student.

If you would like to use this lab, please complete the feedback form (faculty files) and let me know how you adapt it. I would like to publish this procedure (eventually), and I am open to collaborative projects to get this to the best final form.

Course Level: 
Prerequisites: 
Topics Covered: 
Learning Goals: 
After completing this lab report, students should be able to:
  • Construct an MO diagram for I2, and relate this to the bonding in the Ph3PS-I2 complex
  • Using MO theory as a basis, decide on the best Lewis representation for Ph3PS-I2
  • Discover the wealth of bonding modes within main group species
  • Identify changes in the observable spectra for P(III) and P(V) compounds
  • Search and reference the primary chemical literature using correct ACS reference formatting
 
Subdiscipline: 
Corequisites: 
Equipment needs: 

This experiment is run using our in house instumentation including:

  • NMR spectrometer capable of acquiring 1H and 31P spectra
  • IR spectrometer
  • UV-vis spectrometer (we acquire data on a Spec200 that works just fine for this)
  • GC-MS (optional)

These spectra are provided as faculty files. If you do not have any of these capabilities, the spectra may be given to students as a handout.

Additionally, the experiment will require use of round-bottomed flasks, condensers, beakers, scintillation vials, hot plates, and gravity filtration apparatus (stemless if hot filtration required). Solvents and reagents are typically already present in the department, or may be purchased at reasonable cost.

Implementation Notes: 

I use this lab as the first experiment of the semester, and begin the first week's activity after the introduction and lab safety discussion. 

Prior to running the experiment, I prepare approximately one batch of each product (Ph3PS and Ph3PS-I2) in case of a laboratory mishap. The products are indefinitely stable under ambient conditions.

I do not describe the reaction as a redox process, or suggest a bond order (i.e. I try to write the formula for Ph3PS with an ambiguous bond order, as shown here). 

Depending on the age of your bottle of Ph3P, you may spot a small quantity of Ph3P=O in the 31P spectrum (small peak around 30 ppm in the included spectrum). This may be an opportunity to discuss connections to biochemistry or atmospheric oxidation, or ask students to draw Lewis depictions of these species. 

I teach my students how to manually run their own NMR spectra using TopSpin at this point (they have previously learned 1H and 13C using the autosampler). I typically discuss the differences between 31P{1H} and 31P (non decoupled) spectra at this time. Note that the lab handout has some instructions specific to the Bruker software that may be updated if you use a different spectrometer.

Literature articles describing the crystal structure of the final adduct (and related I2 species) are linked here. I have not typically gone into great detail about this, as the assembled I2 ribbons can confuse the students that are just putting the basic concepts together.

Time Required: 
Two full 3 hour labs, and approximately 1 additional hour (first week). If characterization is done outside of normal lab hours, this could be accomplished in one full 3 hour lab and one additional hour.
8 Jun 2019

VIPEr Fellows 2019 Workshop Favorites

Submitted by Barbara Reisner, James Madison University

During our first fellows workshop, the first cohort of VIPEr fellows pulled together learning objects that they've used and liked or want to try the next time they teach their inorganic courses.

3 Jan 2019

Venn Diagram activity- What is inorganic Chemistry?

Submitted by Sheila Smith, University of Michigan- Dearborn
Evaluation Methods: 

I did not assess this piece, except by participation in the discussion

Evaluation Results: 

I asked my students to write an open ended essay to answer the question (asked in that first day exercise): What is Inorganic Chemistry.

Interestingly, 2 of my 15 students drew a version of this Venn Diagram to accompany their essays.

Description: 

This Learning Object came to being sort of (In-)organically on the first day of my sophomore level intro to inorganic course. As I always do, I started the course with the IC Top 10 First Day Activity. (https://www.ionicviper.org/classactivity/ic-top-10-first-day-activity).  One of the pieces of that In class activity asks students- novices at Inorganic Chemistry- to sort the articles from the Most Read Articles from Inorganic Chemistry into bins of the various subdisciplines of Inorganic Chemistry.  As the discussion unfolded, I just sort of started spontaneously drawing a Venn Diagram on the board.  

I think Venn diagrams are an excellent logic tool, one that is too little applied these days for anything other than internet memes.  This is a nice little add-on activity to the first day.
 

Your Venn diagram will likely look different from mine.  You're right.

 

Learning Goals: 

The successful student should be able to:

  • identify the various sub-disciplines of inorganic chemistry.  
  • apply the rules of logic diagrams to construct overlapping fields of an Venn diagram.

 

Prerequisites: 
Corequisites: 
Equipment needs: 

colored chalk may be handy but not required.

Implementation Notes: 

I used this activity in conjuction with a first day activity LO (also published on VIPEr).

I shared a clean copy (this one) with the students after the class where we discussed this.

 

Time Required: 
10-15 minutes
12 Dec 2018

Foundations Inorganic Chemistry for New Faculty

Submitted by Chip Nataro, Lafayette College

What is a foundations inorganic course? Here is a great description

https://pubs.acs.org/doi/abs/10.1021/ed500624t

 

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

This LO was craeted at the pre-MARM 2017 ViPER workshop and has not been used in the classroom.  The authors will update the evaluation methods after it is used.

Description: 

This module offers students in an introductory chemistry or foundational inorganic course exposure to recent literature work. Students will apply their knowledge of VSEPR, acid-base theory, and thermodynamics to understand the effects of addition of ligands on the stabilities of resulting SiO2-containing complexes. Students will reference results of DFT calculations and gain a basic understanding of how DFT can be used to calculate stabilities of molecules.

 
Prerequisites: 
Corequisites: 
Learning Goals: 

Students should be able to:

  1. Apply VSEPR to determine donor and acceptor orbitals of the ligands

  2. Identify lewis acids and lewis bases

  3. Elucidate energy relationships

  4. Explain how computational chemistry is beneficial to experimentalists

  5. Characterize bond strengths based on ligand donors

Course Level: 
Implementation Notes: 

Students should have access to the paper and have read the first and second paragraphs of the paper. Students should also refer to scheme 2 and table 2.

 

This module could be either used as a homework assignment or in-class activity. This was created during the IONiC VIPEr workshop 2017 and has not yet been implemented.

 
Time Required: 
50 min
3 Jun 2017
Evaluation Methods: 

This was created during the IONiC VIPEr workshop 2017 and has not yet been implemented.

 
Description: 

This module offers students an introductory chemistry or foundational inorganic course exposure to recent literature work. Students will apply their knowledge of VSEPR and basic bonding to predict geometries of complex SiO2-containing structures. Students will gain a basic understanding of how crystallography is used to determine molecular structures and compare experimental crystallographic data to their predictions.

Prerequisites: 
Course Level: 
Corequisites: 
Learning Goals: 

Students will be able to:

  1. Describe the bonding in SiO2 and related compounds
  2. Apply bonding models to compare and contrast bond types
  3. Apply VSEPR to predict bond angles
  4. Utilize crystallographic data to evaluate structures
Implementation Notes: 

Students should have access to the paper and read the first and fourth paragraphs on the first page and the third paragraph on the second page. Students should also reference scheme 1 and figure 1.

 

This module could be either used as a homework assignment or in-class activity.

 
3 Jun 2017
Evaluation Methods: 

This learning object was created at the pre-MARM workshop in 2017 and as such has not been used in a classroom setting. The authors will update the learning object once they have used it in their classes.

Description: 

This module offers students in an introductory chemistry or foundational inorganic course exposure to recent literature. Students will apply their knowledge of Lewis dot structure theory and basic thermodynamics to compare and contrast bonding in SiO2 and CO2.

Corequisites: 
Course Level: 
Prerequisites: 
Learning Goals: 

Students should be able to:

  1. Describe the bonding in SiO2 and related compounds (CO2)

  2. Use Lewis dot structure theory to predict bond orders

  3. Apply bonding models to compare and contrast bond types and bond energies (sigma, pi)

  4. Characterize bond strengths based on ligand donors

Implementation Notes: 

Students should read the first paragraph of the paper prior to completing this learning object. They can be encouraged to read more of the paper, but the opening paragraph is the focus of this learning object.

Time Required: 
50 min
11 Apr 2017

Johnson Matthew Catalytic Reaction Guide

Submitted by Sheila Smith, University of Michigan- Dearborn
Evaluation Methods: 

No evaluation yet

Evaluation Results: 

No results yet

Description: 

This guide, available in print, online and in an app, allows users to look up appropriate catalysts and conditions to accomplish a wide variety of reactions.

 

Prerequisites: 
Course Level: 
Learning Goals: 

A student should be able to use the Catalytic Reaction Guide (CRG) to identify appopriate reaction conditions and catalysts to accomplish a wide variety of reactions.

Implementation Notes: 

I have not yet used this... I just picked up a copy at ACS, but will add to this as I implement it in my classroom.

 

Time Required: 
variable
27 Mar 2017

Nanomaterials for Carbon Dioxide Reduction

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Methods: 

The problems presented here represented half the points on the final exam – I have included point totals to give an idea of the weight assigned to each problem.

Evaluation Results: 

Twelve students were enrolled in my course in the fall 2016. The average overall score for these problems was 78%.

For problem 1b, I calculated the oxidation numbers using the familiar general chemistry method of assigning oxygen as –2 and hydrogen as +1. Students recently coming through organic may have some other way to do it, and you may need to provide directions for your students about your preferred method.  I think I could have worded part (c) better to try to emphasize the redox processes involved. I wanted them to think of combustion, but I think they needed to be specifically prompted, such as "Give an example of the combustion processes that generate CO2 and trace the oxidation state of carbon through the reaction." Overall my students scored 86% on problem 1.

The second problem (about another method that could be used to measure d-spacing) was fairly hit or miss.  Five students got full credit, six students got 3 points, and one got zero. Eleven out of twelve did answer part (a) correctly.  I realized as I made this LO that the article says the carbon-based material doesn’t diffract X-rays, but doesn’t actually directly explain whether or not the Cu nanoparticles diffracted X-rays, so you may need to adjust the question to be technically accurate.

Question three (re: surfactants in nanoparticle synthesis) referred back to knowledge from earlier in the course. The overall score was 61%.

Question 4 (define and describe electrodes) was fairly straightforward, and students scored 85%.

Question 5 caused some confusion, as some students missed that I was looking for “carbon-containing” products only. I didn’t count off for that mistake, but it made the problem harder for students who included hydrogen in each box.  Overall, students did very well on this problem (89% correct).

Question 6 – again, not too much trouble here (84% correct).

Question 7 – I was surprised that students didn’t do better on this question, as I thought that water reduction was mentioned often in the article.  Only three (of 12) students scored 5 points on this problem, and the average score was 53%.  This was probably my favorite question, as it foreshadows electrochemistry topics I cover in my inorganic course.

Description: 

This literature discussion is based on an article describing the use of copper nanoparticles on an N-doped textured graphene material to carry out the highly selective reduction of CO2 to ethanol (Yang Song et al., “High-Selectivity Electrochemical Conversion of CO2 to Ethanol using a Copper Nanoparticle / N-Doped Graphene Electrode” ChemistrySelect 2016, 1, 6055-6061.  DOI: 10.1002/slct.201601169). The article provides a good introduction to the concepts of electrochemical reduction, selectivity and recycling of fossil fuels. The literature discussion assignment shared here was used as half of the final exam in a half-credit nanomaterials chemistry course, but could be adapted for use as a take-home or in-class assignment.

Corequisites: 
Course Level: 
Learning Goals: 

After reading this paper and working through the problems, a student will be able to:

  • assign oxidation states to carbon and trace the oxidation and reduction of carbon through fossil fuel combustion and CO2 conversion
  • describe the role of control experiments in studying the CO2 conversion presented in the article
  • define the word “selective” in the context of this research
  • use the proposed mechanism to explain why the electrode studied produces ethanol in such a high proportion
  • identify the primary reaction competing with CO2 reduction for available electrons
Implementation Notes: 

These questions comprised half of the final exam for my half-credit nanomaterials chemistry course in the fall of 2016.  I gave the article to the students one week ahead of time. They were encouraged to read the article, make any small notes they liked, and meet with me in office hours with questions. At the final exam they were allowed to use their copy of the article, but they were also required to hand in their copy with their exam so that I could make sure they hadn't written lots of extraneous information on the exam copy.

The nanomaterials course features near-weekly homework assignments centered around articles from the literature. Because I used this article at the end of the course, students were already familiar with nanomaterials synthesis and characterization techniques. Thus, some of the questions I asked relied on previous knowledge. 

Please feel free to adapt these questions and add some of your own. Leave comments describing any new questions you’ve added.

Time Required: 
one hour

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