Electron transfer

5 Jan 2015

The Color and Electronic Configurations of Prussian Blue

Submitted by Erica Gunn, Simmons College
Evaluation Methods: 

Student answers to the reading comprehension questions were collected at the beginning of class and graded out of 10 points (largely based on participation and completeness of answers). 

Evaluation Results: 

Most students were able to identify the correct answers from the paper, though some were confused by the last section involving orbital calculations (this was expected, as most of these students have not yet had a course in quantum mechanics). 

Some students also had difficulty following the logic presented in the paper to predict differences in absorption band intensity for the different Fe compounds. Most recognized that the absorption band position was important and some realized that intensity also mattered, but most did not fully follow the arguments for assigning absorption spectra to one particular complex geometry. Most of the class discussion involved recreating the logic behind the peak assignment for the absorption spectra.

Description: 

I used this paper to illustrate several course concepts related to materials structure (crystal lattice structure, coordination number, crystal field theory and orbital splitting, symmetry, electronic spectra, allowed and forbidden transitions). This activity was paired with a laboratory experiment (see related VIPEr objects) in which students synthesized Prussian Blue, and gave students a really in-depth look at what was going on when they mixed those solutions together. Combined with another VIPEr activity that uses a more recent literature example (New Blue Solid, in related links), students gained a broad appreciation for how inorganic chemists can use these concepts to rationally design new materials.

 

 

Corequisites: 
Prerequisites: 
Learning Goals: 

Become familiar with reading chemical literature

Use symmetry and electronic configuration to interpret absorption spectra

Integrate understanding of course concepts to understand a "real life" literature example and enhance student interest 

Implementation Notes: 

These activities were used in a 200-level course, which happened to mostly populated by juniors and seniors. The reading questions were designed mainly to check for basic comprehension. Most students had no difficulty answering the "what" questions about the experiments done and facts presented, but many needed significant guidance to understand why the researchers made these particular measurements, and how they interpreted the data to arrive at the conclusions presented. Most of the class discussion focused on building a "big picture" overview of what was going on. This led to interesting questions about design of experiments and use of evidence in science. Several students were surprised at how much of the scientific argument they had missed in their first reading of the paper, even though they felt like they had a good grasp on the data that the authors had reported.

Time Required: 
1 hour
12 Sep 2014

Maggie's LOs

Submitted by Chip Nataro, Lafayette College
Corequisites: 
Prerequisites: 
4 Aug 2014

Suite of LOs on Biomimetic Modeling

Submitted by Sheila Smith, University of Michigan- Dearborn

This suite of activities can be used as a unit exploring the use of small molecule models and biophysical techniques to illuminate complicated biomolecules.  The Parent LO:  Modeling the FeB center in bacterial Nitric Oxide reductase is a short, data-filled and well-written article that is approachable with an undergraduate's level of understanding.

Course Level: 
3 Aug 2014

Isn't It Ionic (with apologies to Alanis Morissette)

Submitted by Craig M. Davis, Xavier University
Description: 

This spoof of the song "Isn't It Ironic" (by Alanis Morissette) summarizes the properties of ionic compounds in verse. Suitable for General Chemistry classes as well as Inorganic Chemistry, although a reference is made to the Born-Meyer equation.

Learning Goals: 

This reviews of properties of ionic compounds via humorous verse.

Prerequisites: 
Corequisites: 
Course Level: 
17 Jul 2014

Introduction to Photoinduced Electron Transfer

Submitted by Robert Holbrook, Northwestern University
Description: 

This 5 slides about will introduce students to the concept of photoinduced electron transfer. These slides go over the energics of photoinduced electron transfer, which implements basic concepts of photochemistry and electrochemistry. The photoinduced electron transer properties of ris-(2,2'-bipyridine)-ruthenium(II) is used as an example. 

Prerequisites: 
Course Level: 
Learning Goals: 

Students will be introduced to photoinduced electron transfer and how to determine the driving force between an electron acceptor/donor pair. Students will be able to incororapte photochemistry and electrochemistry to inorganic complexes. Tris-(2,2'-bipyridine)-ruthenium(II) is used as an example. Students should learn the basic concept of photoinduced electron transfer and how to determine the thermodynmics for determining the driving force for PET. This maybe an interesting way to merge concepts of photochemistry and electrochemistry. The excited state of a molecule effects its reduction potentials dramatically (a 2.12 V shift in reduction potential for Ru(bpy)3). This concept is used in a wide variety of research topics from dye-sensitized solar cells to electron transfer in photosystem II.

Implementation Notes: 

These slides can be used in a lecture or a reference to introduce the concept of photoinduced electron transfer. Students must have had an introduction to basics of photochemistry and electrochemistry prior to these notes. 

Evaluation
Evaluation Methods: 

This LO has been developed for the 2014 VIPER workshop and has yet to be tested in the classroom.

17 Jul 2014

Principles and imaging applications of CEST

Submitted by Justin Massing, Northwestern University
Description: 

This five slides about chemical exchange transfer (CEST) discusses the magnetic properties of paramagnetic metal ions and their use as MR imaging agents. This includes tranditional contrast agents that affect the relaxation rate of nearby water protons and paramagnetic shift reagents suitable for CEST imaging applications. A recent redox-active cobalt complex is presented as an innovative agent for mapping redox imbalances in vivo.

Note: slides 2 and 3 are hidden. These slides present the basis of MR signal (slide 2) and relaxation mechanisms pertinent to T1 and T2 contrast agents (slide 3). This information is relevant to CEST agents since kex must be equal to or less than the frequency difference between the exhangeable protons and bulk water. Increasing the frequency difference between these two signals permits faster exchange, which may then outcompete T1 and Trelaxation mechanisms.

Corequisites: 
Course Level: 
Learning Goals: 

Following presentation of these five slides, students will be able to:

  • Discuss MR signal origin and why Gd(III)-based agents improve image contrast.
  • Identify magnetic properties relevant to relaxation and shift agents.
  • Rationalize the CEST phenomenon and why paramagnetic transition metals are suitable for developing CEST agents.
Implementation Notes: 

This LO was developed at the 2014 VIPEr Workshop: Bioinorganic Applications of Coordination Chemistry, and therefore has yet to be implemented in a classroom setting.

Evaluation
Evaluation Methods: 

This LO was developed at the 2014 VIPEr Workshop: Bioinorganic Applications of Coordination Chemistry, and therefore has yet to be graded or assessed.

7 Jul 2014

Dissecting Catalysts for Artificial Photosynthesis

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

Anne’s student led a 20-minute class discussion of this article in the spring of 2014.  The other students in the class were asked to post two questions about the article to moodle before the class meeting, but they were not asked to complete the literature discussion questions due to assignment overload at the end of the semester.

Evaluation Results: 

Students’ questions varied from the very specific to the very general.  One wanted to know what the parameter “tau” referred to, and another was confused about the concept of overpotential.  Many students weren’t sure why making carbon monoxide would be a good idea, as they see it as poisonous.  One student wanted to know if these catalysts could ever be used in ambient conditions.  Students were curious to know more about the catalytic mechanism.

Description: 

Anne asked the students in her junior/senior inorganic course to develop their own literature discussion learning objects and lead the rest of the class in a discussion of their article.  Each student chose one article from a list of suggestions provided.  Student Hayley Johnston chose this article describing a Mn-containing catalyst for carbon dioxide reduction (Jonathan M. Smieja, Matthew D. Sampson, Kyle A. Grice, Eric E. Benson, Jesse D. Froehlich, and Clifford P. Kubiak, “Manganese as a Substitute for Rhenium in CO2 Reduction Catalysts: The Importance of Acids” Inorganic Chemistry 2013, 52, 2484-2491. DOI: 10.1021/ic302391u).  The article describes the development of a Mn-based homogeneous catalyst for electrocatalytic CO2 reduction.  Hayley met with Anne for an hour to discuss the article, then generated a list of questions drawn from the article's content.  Using Hayley’s original set of questions as a starting point, Anne and Kyle developed this literature discussion, which is suitable for use in inorganic chemistry courses.

Corequisites: 
Course Level: 
Learning Goals: 

After reading and discussing this paper, a student will be able to:

  • Describe the value of CO2 reduction catalysts
  • Outline the structure of the catalyst and identify the path electrons take throughout the catalytic cycle
  • Compare and contrast the Mn-based and Re-based catalysts in terms of their CO2 reduction efficiency
Implementation Notes: 

The learning object we've developed contains fifteen questions that cover most of the article's content in great depth.  It's likely too long for an individual assignment, depending on the students' backgrounds.  We encourage instructors to pick and choose from among the questions. 

Before discussing this article, students should be familiar with the concepts of renewable fuels/artificial photosynthesis and maybe also the Keeling curve demonstrating the sharp increase in atmospheric carbon dioxide over the past two hundred years.

Students may not know that CO, carbon monoxide, is very useful. They will likely be most familiar with its dangers, not its importance in industrial chemistry. Instructors could discuss the uses of CO: synthesis of methanol (nearly all industrial methanol comes from CO), synthesis of acetic acid (nearly all of the acetic acid comes from CO and methanol), hydroformylation, and Fischer-Tropsch chemistry (which could be used to make gasoline/diesel – South Africa has used this technology for some time).

A discussion of cyclic voltammetry would also be useful, including discussing the role of ferrocene as an internal reference. We have referenced the “five slides about” LO Cyclic Voltammetry created by Prof. Chip Nataro as a related activity.

In terms of placing this manuscript in context, previous studies included rhenium complexes, which work without added proton sources but are much improved in the presence of proton sources. The seminal work on rhenium complexes was performed by Jean-Marie Lehn (of supramolecular Nobel Prize fame) in the 1980s.

A comprehensive review of the history of these Re and Mn complexes from their discovery up to early 2013 can be found in “Chapter Five  – Recent Studies of Rhenium and Manganese Bipyridine Carbonyl Catalysts for the Electrochemical Reduction of CO2” Kyle A. Grice and Clifford P. Kubiak Advances in Inorganic Chemistry201466, 163-188  (see web resources below).

Several more recent papers have also been published on the Re and Mn systems from the Kubiak group and other groups since early 2013, including mechanistic studies of the Re and Mn systems using a variety of methods. A forward search of the Mn manuscript by Smieja et al. can be used to find these articles.

For more detailed information about IR-SEC, see this reference and references therein: Charles W. Machan, Matthew D. Sampson, Steven A. Chabolla, Tram Dang, and Clifford P. Kubiak Organometallics, 2014, ASAP  (see web resources below).

 

 

Time Required: 
45 minutes
10 Jun 2014

Protein Electrochemistry 3rd Bioinorganic Workshop

Submitted by Sheila Smith, University of Michigan- Dearborn
Description: 

This is a 90 minute talk by Fraser Armstrong of Oxford University (http://armstrong.chem.ox.ac.uk) explaining the electrochemistry of proteins immobilized on surfaces.  The talk was presented at the 3rd Bioinorganic Workshop in 2014 at Pennsylvania State University.  The talk contains an excellent basic tutorial on simple electron transfer on immobilized substrates using simple iron sulfur proteins as the primary example.  Talk continues on to more complicated subject matter including trumpet plots, electrocatalysis by enzymes focusing on the hydrogenases as an example.  The talk concludes with case studies presented on NiFe Hydrogenases, FeFe hydrogenases, and CO dehydrogenase.

Course Level: 
Corequisites: 
Learning Goals: 

The student should be able to explain the information available from electrochemistry on immobilized proteins.

Implementation Notes: 

This is an excellent presentation by the developer of many of the modern techniques for electrochemistry on immobilized proteins.  

Time Required: 
90 minute
24 Jan 2014

Student choice literature-based take home exam question

Submitted by Hilary Eppley, DePauw University
Evaluation Methods: 

This question was 30 points on a 100 pt take home exam (the year I did this, there was also a 100 point in class exam as well).   I've included the title page of the take home exam as well as this question.   

The grading scale allowed most of the points for the student chosen course content to highlight.   Of the 30 points, 10 focus on chemical information skills, 20 on summarizing the article and analyzing it using concepts from the class.   

Evaluation Results: 

I gave back a number of the exams before I was able to tally, but of the ones I had remaining: 

60% got full credit on the part a (those who missed neglected to include a summary) 

100% got full credit on part b

60% got full credit on part c (those who missed searched by formula rather than connectivity or provided an insufficient explanation of what they searched on 

100% got full credit on part d

On part e, answers varied widely from 7/17 to 15/17, with an average of 12/17 or a 70%.  

In some cases they lost points for just repeating things verbatim from the paper without explaining them to show they understood the concepts.   The main reason for loss of points however was just a lack of effort at picking apart the paper for parts that were relevant to the course content.   

They were able to successfully apply things such as electron counting and mechanism identification in a catalytic cycle, point groups, descriptions of sigma and pi bonding in ligands.   

 

Description: 

During my junior/senior level inorganic course, we did several guided literature discussions over the course of the semester where the students read papers and answered a series of questions based on them (some from this site!).  As part of my take home final exam, I gave the students an open choice literature analysis question where they had the chance to integrate topics from the semester into their interpretation of a recent paper of their own choice from Inorganic Chemistry, this time with limited guidance.  I also included a number of questions that required them to make use of various literature search tools to show that they had mastered those skills.   I gave them a list of topics that they could incorporate, but based on the poor quality of the responses I received, I encourage you to be more specific in your instructions.  I'd love to see some new versions!      

Corequisites: 
Course Level: 
Prerequisites: 
Learning Goals: 
Students will
  • choose a recent paper that interests them from Inorganic Chemistry
  • summarize why a particular paper is important to the field of inorganic chemistry
  • use literature search tools including Web of Science, Cambridge Structural Database, and SciFinder Scholar to find information aobut cited references, structurally similar compounds, and the authors of the paper
  • integrate ideas such as bonding models, symmetry, spectroscopy structural data, and chemical reactivity from class into a detailed analysis of aspects of the paper

The instructor will

  • get up to date on new literature for possible new literature discussions
  • get a chance to stretch his/her own intellectual muscles on some papers perhaps outside of his/her area of expertise
Implementation Notes: 

The students were given the take home exam about 1 week before it was due (but that was during the final exam period).   The format of the chemical information questions were similar to things they did earlier in the class, however the analysis of the paper was much more open ended, giving them the freedom to choose a paper that interested them and to presumably focus on concepts from the class that they felt comfortable with.   I gave them a date range from April 1 - April 30, 2012 for their paper because those were the most recent issues at the time.  If you use this LO, you will probably want to change those dates to more recent ones.   

Time Required: 
at least an hour, possibly more depending on the student
26 Jun 2013

Literature summary through student presentation - free choice of topic.

Submitted by Cameron Gren, University of North Alabama
Evaluation Methods: 

I typically weight this assignment as one-half of an exam, i.e. 50 points when exams are worth 100 points each. The question should be worth a portion, perhaps 10 points with the remaining points coming from the presentation. Another option could be, if it would be appropriate for your class, to dedicate a few points to students preparing questions of other presenters. For large classes, they need not all be asked, but simply handed in to you prior to each presentation. then YOU could ask a few of them. As far as a rubric for the presentations, this could vary greatly. I typically count off for things like incorrect information, extremely vague descriptions, or very weak question answering. Specific deductions may vary. Other evaluation options could include student evaluations on each other's presentations, giving a post-presentation quiz (covering all presentations), or possibly including questions on the final exam over the presentations.

Evaluation Results: 

I generally give good grades for this assignment if I can tell the students put in an appropriate amount of work. Students tend to enjoy this assignment (more so after completing it, of course), as they can truly take ownership of their work. They seem to have a good sense of accomplishment after tackling a difficult journal article and breaking it down so they can understand it.

Description: 

(1) Student choses and reads a journal article of his/her choice that is related to a topic we have discussed during the semester. (i.e. atomic structure, MO theory, group theory, solid state structure, band theory, coordination chemistry, organometallics, catalysis). Suggested journals include, but are not limited to JACS, Inorg. Chem., Organometallics, Angew. Chem., JOMC, Chem. Comm.)

(2) Student answers the following questions regarding their chosen article:

    (a) Describe, in 1 or 2 sentences the goal of this work. 

    (b) Define the primary topic(s) from our course that relate to this work. 

    (c) Do you feel the authors achieved their goal? Why or why not?

    (d) What questions remained about the work?

(3) Student prepares a brief (~15 min) PowerPoint (or equivalent program) presentation describing the article. The question set should aid the student in developing the presentation.

(4) Students are encouraged to ask questions following each other student’s presentation.

Course Level: 
Learning Goals: 

• Students will improve their overall reading comprehension with regards to chemical literature.

• Students will be able to identify the relationship between current chemical literature and key concepts in inorganic chemistry.

• Students will improve their ability to present chemical research in a concise but detailed manner.

• Students will become critical observers of other’s presentations, being able to formulate and ask insightful questions.

Implementation Notes: 

I have this assignment due the last few days of the semester. It may be valuable for the students to see the professor summarize an article in this manner first, although I do not do this. It may be valuable to make the journal articles available to the other students prior to the presentations. This might help them formulate insightful questions for the presenters.

Time Required: 
I usually assign this at the beginning of the semester, although ~ 2 weeks might be sufficient prep time. In-class time is about 20 mins per student.

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