Electrochemistry

23 Sep 2014

Five Slides about Spectroelectrochemistry (SEC)

Submitted by Kyle Grice, DePaul University
Description: 

This "Five slides about" is meant to introduce faculty and/or students to Spectroelectrochemistry (SEC), a technique that is used in inorganic chemistry research and other areas. SEC is a powerful tool to examine species that are normally hard to synthesize and isolate due to instability and high reactivity. Papers with examples of SEC techniques are provided on the last slide. 

 

Corequisites: 
Course Level: 
Learning Goals: 

Students should be able to describe spectroelectrochemistry

Students should be able to conceptually explain how a spectroelectrochemical cell works 

Students should be able to explain the benefits of spectroelectrochemistry as compared to standard synthesis and spectroscopy approches

Implementation Notes: 

Ideally, the students would take this introduction and then go and examine specific instances of SEC in the literature. Alternatively, this can be used to help explain research papers that are being discussed that use SEC techniques. 

Students should already have an understanding of the basics of electrochemistry and spectroscopy prior to learning SEC, so this would be best suited for an upper division, special topics course in Inorganic Chemistry or Spectroscopy. There are some nice LO's on these techniques already on Ionic Viper (see related activities). 

There are some good images of the specifics of SEC cell designs on company websites or journal articles (the Organometallics article shown in the web resources is one such article). 

IR-SEC is included in the paper that is the focus of the "Dissection Catalysts for Artificial Photosynthesis" LO. 

Time Required: 
15 min
Evaluation
Evaluation Methods: 

This LO was made as a followup to the 2014 Ionic Viper workshop and has not been implemented yet. However, I plan on implementing it in a "Special Topics in Inorganic Chemisry" course in the future. 

Evaluation Results: 

None yet, will be provided upon implementation. 

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: 
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.

16 Jul 2014

A Redox-Activated MRI Contrast Agent that Switches Between Paramagnetic and Diamagnetic States

Submitted by Vivian Ezeh, Clemson University, Department of Chemistry
Evaluation Methods: 

The success of the discussion will be evaluated by completing the take home study and the quality of the in-class discussion

Description: 

Students are asked to read an article detailing the development of a cobalt-based MRI contrast agent ("A Redox-Activated MRI Contrast Agent that Switches Between Paramagnetic and Diamagnetic States", Tsitovich, P. B.; Spernyak, J. A.;  Morrow, J. R. Angew. Chem. Int. Ed. 201352, 14247-14250,  DOI: 10.1002/anie.201306394). Before coming to class the students are asked to answer a series of questions designed to guide them through the first half of the article, and to be prepared to discuss their answers in class. During class, the answers of the questions are briefly reviewed before addressing a second set of questions in class.

Course Level: 
Corequisites: 
Learning Goals: 

1) Students explore the coordination geometry of a hexadentate N-donor ligand
2) Students pratice deriving a crystal field orbital diagram from the  magnetic properies of Co(II)/Co(III) complexes
3) Student recognize and understand the origin of the differences of 1H-NMR spectra for paramagnetic and diamagnetic complexes
4) Students understand the basic principles of how a paraCEST contrast agent works, and develop a sense of how to decide on the suitability of a metal complex as a paraCEST contrast agent based on experimental data.
5) Students become more adept at interpreting representations of data

Implementation Notes: 

This reading guide accompanies A Redox-Activated MRI Contrast Agent that Switches Between Paramagnetic and Diamagnetic States, Tsitovich, P. B.; Spernyak, J. A.;  Morrow, J. R. Angew. Chem. Int. Ed. 201352, 14247-14250,  DOI: 10.1002/anie.201306394

The LO is designed to help guide students through the reading of a scholarly article and prepare them for in-class discussion after completing the reading. 

Time Required: 
50 mins
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
25 Jun 2013
Evaluation Methods: 

Students write a formal report which is evaluated with respect to whether each learning goal is achieved.

Evaluation Results: 

Earlier versions of this project have been assigned to approximately 30 students in three senior-level inorganic chemistry courses over a six year period, with substantial revisions made each time. Students were generally able to reproduce the literature results successfully and to gauge which method is expected to be most reliable for first-principles calculations of redox potentials. There was some variability in students’ choice of fullerenes which appropriately span the range of interest. Some students were able to make fairly sophisticated suggestions for future work. 

Description: 

In this project students are asked to reproduce published calculations of molecular orbital energies of a series of derivatized fullerenes and correlate them with published reduction and oxidation potentials obtained from cyclic voltammetry. The particular subset of the derivatives to be studied are chosen by the student and this choice is part of the learning activity. The students then carry out additional calculations using other theoretical models to see whether they improve the correlation between computed and experimental properties. Interpretation of the trends and suggestions for additional work are discussed in a formal report. 

Corequisites: 
Learning Goals: 

After completing this project, students will be able to

  • Summarize the use of cyclic voltammetry to measure redox potentials;
  • Use computer software to build and visualize molecular models of derivatives of buckminsterfullerene;
  • Carry out density functional theory and semiempirical calculations of buckminsterfullerenes;
  • Discuss how derivatization affects the energies of the frontier orbitals;
  • Implement different theoretical models and correctly choose the one which best correlates with the experimental data;
  • Discuss which computational method is likely to be most useful in the prediction of redox potentials from first principles; and
  • Write a formal report describing their findings.
Course Level: 
Equipment needs: 

Modern computer workstation with 6+ GB RAM; molecular structure building and visualization software; quantum mechanics software. Spartan 8 has all of the capabilities required for this project.

 

Implementation Notes: 

The models are built and the calculations are carried out at our institution using Spartan 10, but Gaussian, GAMESS, Q-Chem, NW-Chem or other programs with similar capabilities could be used instead. 

Time Required: 
Students are asked to complete this as an independent project, although the work could be done as a group in one or two laboratory periods if a computer classroom is available.
19 Jul 2012

Electrocatalysis and Proton Reduction

Submitted by Matt Whited, Carleton College
Description: 

These slides provide a brief introduction to the concept of electrocatalysis using the glyoximato cobalt catalysts for hydrogen production recently examined by Peters, Gray, and others.  They provide a suitable introduction to the topic for students interested in reading the primary literature on these topics.

Prerequisites: 
Corequisites: 
Subdiscipline: 
Learning Goals: 
  • A student should be able to define what an electrocatalyst is and the general mechanism by which an electrocatalyst operates.
  • A student should be able to identify a cyclic voltammetric trace corresponding to an operating electrocatalyst and explain why it is different from the electrochemistry of the same complex in the absence of substrate.
  • A student should be able to identify the important features in evaluating the efficiency of an electrocatalyst and define the term "overpotential".
Implementation Notes: 

This set of slides is recommended as background reading (or in-class presentation) for students working on the LO developed from the Valdez et al. PNAS paper "Catalytic hydrogen evolution from a covalently linked dicobaloxime" (the LO is referenced above).

Time Required: 
10-15 minutes
19 Jul 2012
Evaluation Methods: 

Collect responses to questions not covered in class.

Grade class participation.

Assign a more in depth question on an exam. 

Description: 

This learning object was developed at the 2012 NSF sponsored cCWCS VIPEr workshop at UNC-CH where we were fortunate to hear Jillian Dempsey present this research that has appeal to students. This work focuses on an exciting and promising strategy to develop new technology to support a solar energy economy. This literature discussion leads students through a current application in the field of electrocatalysis. The primary literature article for the discussion is found in Proc. Natl. Acad. Sci. USA 2012 109 (39) 15560-15564.

Corequisites: 
Prerequisites: 
Learning Goals: 

Students should be able to:

- identify the chemical reaction presented and balance the half reactions for water splitting

- explain the role of a catalyst in an electrochemical reaction

- propose and evaluate the validity of possible mechanisms based on the experimental data

- find and rationalize trends in the series of catalysts presented in the article

- identify the features associated with electrocatalysis

Subdiscipline: 
Implementation Notes: 

The intent of this literature discussion is geared to provide a broad introduction to the field of electrocatalysis.

Two implementation strategies we thought of are:

  1. Have the students read the article, answer questions 1-4, and watch Chip Nataro’s 5-slides about cyclic voltammetry. In class, discuss questions 5 and 6. For a more in depth discussion, assign questions 7-11.
  2. Have the students read the article and watch Chip Nataro’s 5-slides about cyclic voltammetry the night before. Discuss questions 1-4 in class and assign the questions 5 and 6 for homework.


For a more in depth discussion on electrocatalysis we included a more challenging questions in our document (7-11). These questions could also be used on exams.

Time Required: 
1 class period
9 May 2012

VIPEr Screencast

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

If we can attract one person to VIPEr through this screencast it has been successful.

Evaluation Results: 

When I first created this screencast, the VIPEr administrators seemed to enjoy it.

Description: 

This screencast is a brief introduction to some of the features of VIPEr.

Topics Covered: 
Prerequisites: 
Corequisites: 
Learning Goals: 

Publicity, pure and simple.

Course Level: 
Implementation Notes: 

I would not use it in my teaching, but I hope it teaches others to visit VIPEr.

Time Required: 
5 minutes and 30 seconds

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