Electronic structure

26 Jun 2020

Evans' Method Calculator

Submitted by Bradley Wile, Ohio Northern University
Description: 

A spreadsheet hosted on Pete Wolczanski's webpage for calculating (mu)effective

Topics Covered: 
Prerequisites: 
Course Level: 
Corequisites: 
Implementation Notes: 

Use this mainly for inorganic lab (Mn(acac)3) and my research group.

10 Jun 2020

A copper "Click" catalyst for the synthesis of 1,2,3-triazoles

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

I have not used this in class yet, but anticipate updating this after the fall 2020 semester. This comes as a result of the June 9th LO party.

Description: 

This paper (Gayen, F.R.; Ali, A.A.; Bora, D.; Roy, S.; Saha, S.; Saikia, L.; Goswamee, R.L. and Saha, B. Dalton Trans2020, 49, 6578) describes the synthesis, characterization and catalytic activity of a copper complex with a ferrocene-containing Schiff base ligand. The article is relatively short but packed with information. However, many of the details that are assumed knowledge in the article make for wonderful questions some of which I hope I have captured. The LO includes electron counting using the CBC method, d-orbital splitting, Latimer diagrams and interpretation of catalytic results. There are also opportunities to discuss green chemical practices.

Corequisites: 
Prerequisites: 
Course Level: 
Learning Goals: 

A student should be able

determine the electro count and metal valence in the catalyst

use group theory to determine the number of IR active vibrations in the catalyst

discuss green chemical principles in relation to this article

interpret data from tables and draw conclusions from that data

suggest an additional catalytic experiment that could be performed

Implementation Notes: 

I like the question invoking a Latimer Diagram to get students to rationalize why the copper(I) active catalyst was not isolated. I also enjoyed sneaking in a group theory question. But my favorite quesiton is the last one in which students are asked to go beyond what it presented in the paper and suggest another catalytic reaction to perform. There are some aspects of the paper that were not covered in-depth. In particular the XPS seemed to be a rabbit hole I opted not to go down. The authors do not go into great detail on this topic and perhaps there is a question that could be included, but I opted not to. I also opted not to include anything about the bonding in ferrocene which can be found in many of my other LOs. Also on this list one might include UV-Vis spectroscopy and the computational studies.

Time Required: 
50 minutes
5 Jun 2020

s-p Mixing and the Order of MOs in Diatomic Molecules

Submitted by Michelle Personick, Wesleyan University
Description: 

These slides provide an introduction to s-p mixing in diatomic molecular orbital diagrams appropriate for students in a general chemistry course. 

In particular, my students were looking for a tool to help them remember which ordering of orbital energies to use. I've always thought that the Z ≤ 7 order (with s-p mixing) looks like a tree. In office hours, a student pointed out that the "standard" (Z ≥ 8) ordering of molecular orbitals looks like a light bulb. Thus, because "it's only Christmas sometimes," the MO diagram with s-p mixing--which looks like a Christmas tree--is only used in a few cases. Light bulbs are used most of the time, so the MO diagram that looks like a light bulb is used for most diatomics.

Corequisites: 
Prerequisites: 
Course Level: 
Learning Goals: 

A student should be able to determine which ordering of molecular orbitals to use in generating a MO diagram for homonuclear and heteronuclear diatomic molecules with and without s-p mixing.

A student should be able to qualitatively explain (1) why s-p mixing only occurs for some elements and (2) why s-p mixing increases the energy of the 2σ MO relative to the 1π MOs.

Implementation Notes: 

I teach primarily using chalk, with slides as needed, so I actually go back and draw the shapes (in colored chalk) over MO diagrams I've previously drawn on the board. The students are suprised and excited to see the shapes emerge.

 

Time Required: 
15 minutes
Evaluation
Evaluation Methods: 

Student learning is assessed using homework assignments and exams.

Relevant questions on exams are generally along the lines of "rank the [number of unpaired electrons in/bond strength of/bond length of] the following 3 molecules" or "give an example of a molecule [with unpaired electrons/that is diamagnetic/etc.]" Questions are short answer, so a justification and correct MO diagrams are required.

Evaluation Results: 

Students in my course love MO diagrams, and will almost always choose to draw MO diagrams when they have a choice of questions on an exam. They also have a very high rate of successfully answering these questions. 

I build on this enthusiasm to briefly show MO diagrams for a few polyatomic molecules and a transition metal complex later in the course. Students find these a bit scary to look at, but are excited that they can at least somewhat interpret them, which they couldn't do at the beginning of the semester. (I show a MO diagram for water on the first day of the semester and they panic, but remember it later.)

The students like MO diagrams because there's a process to follow. The conceptual understanding of s-p mixing is a bit more challenging.

 

15 May 2020

Inorganic Active Learning Lesson Plan Design

Submitted by Meghan Porter, Indiana University
Evaluation Methods: 

I use the rubric provided, combined with the peer review feedback (due to COVID, they did not have the chance to revise after the peer review process).  Students must also upload a key with their activity which allows me to catch any misconceptions or inaccuracies in their understanding of the material.

I assigned points as following:

Assignment/Key: See above rubric

Reflection: Worth 5 points total- while mostly graded on completion, I did want to be sure my students were providing more useful feedback than 1 word answers so I gave them the rubric below. (pretty much everyone got a 5)

Completed Reflection

5

3

1

What did you learn from completing this assignment? (i.e. What do you feel that you gained from completing it?)

What did you learn from completing other students' assignments?

What are your thoughts for improving the active learning lesson plan assignment in future iterations?  You may answer this referring to your specific lesson plan or this actual assignment of creating a lesson plan.

 

Meets all criteria at a high level, all questions are thoughtfully addressed

Meets some criteria, some questions are not addressed or non-thoughtful response provided

Meets few criteria, most questions not addressed or responses do not demonstrate thought

Peer Review: Spring 2020 was my first time doing the peer review, and of course covid definitely changed the way I had planned on completing it.  My plan was to have them exchange activities in class or in recitation, work through them in small groups, then be able to provide feedback.  Instead, they had to complete it online and provide feedback- I gave them the basic rubic, but changed the scores to categories of "exceeds expectations", "meets expectations", and "does not meet expectations".

Evaluation Results: 

I am always blown away by the creativity of my students!  While some students submit more group worksheet activities, I have had plenty come up with games, relays, building/using playdough, etc...

Students usually report that they thought they knew a topic- only to begin making an activity and realize they didn't understand it as well as they thought they did.  However, by the time the submitted their activity, they felt like they gained a much more in-depth understanding.  They also loved getting to complete other students' assignments this semester.  Their feedback indicated that they felt it was a great way to review, but also get some insight into how their peers think differently about topics.

Side note: Personally, I love seeing how many students tell me afterward that they have a newfound respect for professors after trying to make their own activity! :-)

Description: 

I created this activity as a way to get the class involved in creating new, fun ways to teach course concepts (selfishly- that part is for me) and for students to review concepts prior to the final exam (for them).  Students use a template to create a 15-20 min activity that can be used in groups during class to teach a concept we have learned during the semester.  We then randomly assign the activities and students work in groups to complete them and provide feedback.

The benefits are twofold:

1. My class is about 100-150 students per semester.  This means that each semester I have a large number of new activities (that I didn't have to make!) to use as a starting point in future semesters as I work to create a more active classroom.

2. The students get a review of the topic they have chosen for their activity, plus, they get to review additional topics from completing and providing feedback on two activities from their peers.

I have run this assignment for three semesters now.  It has been a favorite of my students since the beginning!  I have received a number of activities that I now use in class to teach topics!

Learning Goals: 

A student should be able to

  • Create a lesson plan on an inorganic topic that incorporates active learning
  • Demonstrate understanding of chosen topic via an accurate lesson plan key
  • Review multiple inorganic topics through completion of lesson plans from classmates
  • Provide constructive feedback on classmates’ completed lesson plans

 

Equipment needs: 

None

Corequisites: 
Prerequisites: 
Implementation Notes: 

Since this can be used for any level or any topic, there are plenty of variations you can try!  Some things to consider:

1. You can allow students to select any topic from the entire semester for their activity- this can be helpful prior to a final exam when you want a comprehensive review.  You can also restrict topics if you have areas that you feel your students need to focus on or if you want to assign this before a specific exam.  One of my students also suggested having a sign up sheet for topics on a first-come, first-served basis so that you don't end up with 20 balancing redox reactions and zero crystal field splitting.

2. I have tried students designing plans individually and also working in partners to create acitivties (both outside of class).  Both methods worked well, but in a class of 150, that many individual submissions to grade was a bit overwhelming!

3. The peer review was new this semester (based on a previous student suggestion).  My original plan was have them use a recitation section to work in groups through randomly assgined activities.  Due to COVID, they completed the activites on their own- they enjoyed it, but the group experience would ave been more fun.

4. Depending on your timing, you could have them go through the peer review process and then give them a chance to revise the activity based on the feedback prior to you grading it.

5. The student reflection questions are given as a survey on Canvas after they have completed both the lesson plan and the peer review process.

25 Jul 2019

1FLO: One Figure Learning Objects

Submitted by Chip Nataro, Lafayette College
Corequisites: 
27 Jun 2019

Porphyrin-Based Metal-Organic Frameworks

Submitted by Amanda Bowman, Colorado College
Evaluation Methods: 

Students completed this activity in small groups, then turned in individual worksheets. Student learning and performance were assessed through 1) in-class group discussion after they had worked on the activity in small groups, and 2) grading the individual worksheets. Participation was most important in the small-group portion.

Evaluation Results: 

In general, students really enjoyed this exercise and felt that it was helpful for visualizing metal-organic frameworks (particularly the extended 3D structure). They also generally felt that it was helpful in visualizing the bonding sites of metal vertices, particularly for thinking about how that influences potential reactivity. We used Mercury as a visualization software for this discussion, and the majority of students felt very comfortable using Mercury and looking at cifs on their own after this activity.

 

The biggest challenge for students seemed to be in relating the 3D structure in the cif to the images and chemicals formulas in the article. They also tended to need some hints about question 5 – to think about what information Mössbauer can provide about oxidation state of the metal, or that you can tell whether or not there are two distinct iron environments. In our class, we do brief units on X-ray crystallography including how to use and interpret cifs, and Mössbauer spectroscopy before this literature discussion. If those topics are not already addressed in a particular class it might be helpful to add them in or directly address those topics for the students as an introduction to the literature discussion.

Description: 

This literature discussion explores the physical structures, electronic structures, and spectroscopic characterization of several porphyrin-based metal-organic frameworks through discussion of “Iron and Porphyrin Metal−Organic Frameworks: Insight into Structural Diversity, Stability, and Porosity,” Fateeva et al. Cryst. Growth Des. 2015, 15, 1819-1826, http://dx.doi.org/doi:10.1021/cg501855k. The activity gives students experience visualizing and interpreting MOF structures, and gives students exposure to some of the methods used to characterize MOFs.

Corequisites: 
Course Level: 
Learning Goals: 

Students will be able to:

  • Interpret and describe the bonding and structural characteristics of MOFs
  • Apply knowledge of ligand field strength to electronic structure of MOFs
  • Analyze X-ray crystallographic data to gain information about structural characteristics of MOFs
  • Interpret Mössbauer spectra to gain information about electronic structure of MOFs
Implementation Notes: 

This literature discussion was designed for use in an advanced (upper-level) inorganic chemistry course, but could be used in a foundational inorganic course if students have already been introduced to d-splitting diagrams and are given some coverage of Mössbauer spectroscopy and X-ray crystallography. When covering MOFs in class, students frequently expressed that visualizing and understanding the bonding sites and extended 3D structures was very challenging. So, this literature discussion was developed specifically to address that. Students completed this activity in small groups. It is very helpful to advise students ahead of time to bring laptops (or instructor should have some available) and to have the cifs from the paper downloaded and ready to go. We used Mercury as a visualization software for this activity. This activity can easily be completed in one class period. It is also helpful if students have been provided with the article ahead of time and encouraged to look it over – otherwise the most time-consuming part of this activity was allowing time for students to examine the MOF structure images in the paper before being able to discuss and answer the questions with their groups.

Note on visualization of MOFs using Mercury: To answer the discussion questions, we used the ‘stick’ or the ‘ball and stick’ style. We also used the default packing scheme (0.4x0.4x0.4) and the 1x1x1 packing scheme. The packing scheme can be changed by selecting Packing/Slicing… in the Calculate menu. I also had students view the 3x3x3 packing scheme – while this is not necessary to answer the discussion questions, it was interesting for students to be able to visualize the extended structure of the MOFs.

 

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