Coordination Chemistry

17 Oct 2016

Ethylene compounds of the coinage metals

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

I found this paper as I was writing an exam for my Inorganic Chemistry 2 class. As I was writing the question I thought this would make a really great literature discussion LO, so here it is. I have not used it in class at this point. I hope to next year at which point I will provide a bit more feedback on it.

Evaluation Results: 

None at this time.

Description: 

This is a literature discussion based on a short paper on ethylene compounds of the coinage metals (Dias, H. V. R.; Wu, J. Organometallics 2012, 31, 1511-1517). In this paper, analogous ethylene compounds are prepared with Cu(I), Ag(I) and Au(I). The other ligand on the coinage metal is a scorpionate tris(pyrazolyl)borate ligand. The strength of the interaction between the metal and the ethylene varies significantly with the coinage metal as seen in X-ray crystallographic and spectroscopic (1H and 13C NMR) data. A particularly interesting feature is the 1H NMR spectra of these compounds under an atmosphere of ethylene in which the coordinated ethylene can exchange rapidly with the free ethylene. 

Corequisites: 
Course Level: 
Learning Goals: 

After completing this literature disussion LO students should be able to

  1. recognize and count electrons for compounds with scorpionate tris(pyrazolyl)borate ligands
  2. explain how metals interact with the orbitals of an alkene
  3. describe the impact of the interaction of a metal with ethylene in terms of structural parameters and NMR data
  4. define coalescence and recognize how the rate of ligand exchange can impact the observed NMR spectrum
Implementation Notes: 

Students should read the paper before coming to class. I think I would see if they seek out the supporting information on their own rather than specifically hinting/suggesting/telling them to pay attention to it. Not having used this in class yet, my opinion on this could change.

Time Required: 
50 minutes
30 Jun 2016

Oxorhenium(V) Methyl, Benzyl, and Phenyl Complexes: New Mechanism for Carbonyl Insertion

Submitted by Matthew Riehl, Minnesota State University, Mankato
Evaluation Methods: 

Students should be assessed based on participation if there is no written portion to hand in.

Evaluation Results: 

This is a new learning object created at the 2016 Summer VIPEr Workshop and has not yet been implemented.  Results will be added by the creators after use in a class.  Please feel free to share your results.

 

Description: 

The article “Synthesis and Reactivity of Oxorhenium(V) Methyl, Benzyl, and Phenyl Complexes with CO; Implications for a Unique Mechanism for Migratory Insertion,” Robbins, LK; Lilly, CP; Smeltz, JL; Boyle, PD; Ison, EA;, Organometallics 2015, 34, 3152-3158 is an interesting read for students studying reaction mechanisms of organometallic complexes.  The reading guide directs students to the sections of the paper that support the question posed in the Discussion Questions document. 

Corequisites: 
Course Level: 
Learning Goals: 

After reading and discussing this paper, students will be able to explain the mechanisms of migratory insertion reactions of CO and explain the evidence supporting a new mechanism of direct insertion.  In addition students will be better prepared to read and appreciate original research articles without a reading guide.

 

A student should be able to

 

1. identify and state the goals and findings of the paper in their own words

2. explain the various methods/techniques used to probe the mechanism, describe what was measured, and explain how the observations support the conclusions presented.

3. apply the CBC method for electron counting of the Re complexes in this paper

4. describe the bonding in metal oxo compounds and explain trans influence

5. understand kinetic parameters such as the reaction rate equation and the reaction order

6. analyze 1H NMR spectra

7. interpret thermodynamic parameters and how they apply to the reaction mechanism

Implementation Notes: 

The reading guide covers the first part of the paper only.  The DFT studies are not included nor are the synthetic details. We suggest giving the reading guide to the students with the original manuscript and allowing two days or longer for the students to read and digest.  Then, in small groups, or as a class discussion, ask students to answer the questions in the Literature Discussion document.

 

Time Required: 
at least 1 class period
30 Jun 2016

Building Molecular Orbitals for a Square Pyramidal Oxorhenium(V) Complex

Submitted by Murielle Watzky, University of Northern Colorado
Description: 

This activity guides students into building a Molecular Orbital diagram, which focuses on metal-centered orbitals of mostly d character, for a square pyramidal complex that includes different types of ligands. Students are then asked to "fill" the resulting orbitals with metal d electrons, and examine the stability of the complex.

Learning Goals: 

Upon completing this activity, students will be able to....

-build a MO diagram for a square pyramidal complex.

-include the effect of ligands with sigma-donating, pi-donating and/or pi-accepting character.

 

 

Corequisites: 
Course Level: 
Implementation Notes: 

Students should work in small groups of 3-4.

Time Required: 
Up to one lecture period (50 minutes) if working in groups. This will depend on how comfortable students already are with building MO diagrams for an octahedral complex.
30 Jun 2016
Evaluation Methods: 

You could choose other compounds from the Szymczak paper, such as the H2 activated species (5) to test the students’ ability to apply this new knowledge.

Evaluation Results: 

This activity has not yet been implemented or assessed.

Description: 

Electron counting exercise motivated by a recent paper (J. Am. Chem. Soc. 2015, 137, 12808-12814 doi: 10.1021/jacs.5b08406) featuring a proton switchable ligand.

Learning Goals: 

Students will be able to:

- assign charges at ligation points in the ionic formalism (L/X classification in the CBC formalism) to count electrons and assign oxidation states (valence numbers).

- describe how tautomerization in proton-responsive ligands affects bonding and electron count.

Corequisites: 
Equipment needs: 

None.

Implementation Notes: 

This exercise has not been implemented yet. We have provided materials for students and faculty in both the ionic and CBC formalisms. The ChemDraw file used to create all images is also attached in case you want to edit any of the images we provide.

Time Required: 
We estimate that this exercise will take 20-30 minutes for you to explain the ligand tautomerization and have the students work through the exercise.
29 Jun 2016

Ligand Design for Selectivity and Complex Stability

Submitted by daniel kissel, Lewis University
Description: 

This is an overview of some important principles of ligand design. Topics covered include HSAB theory, the chelate effect, the chelate ring size effect, the macrocyclic effect, the cryptate effect, and steric focus in ligand design.

Corequisites: 
Course Level: 
Prerequisites: 
Subdiscipline: 
Learning Goals: 

Students will be able to:

  • identify how to best design a ligand to achieve a specific function
  • evaluate how certain design characteristics can impact metal ion selectivity and complex stability
  • infer what kinds of ligand design characteristic would be important in specific inorganic complexes
  • observe the chelate effect
  • observe the chelate ring effect
  • observe enthalpic contributions in ligand systems
  • observe the macrocyclic effect
  • observe the cryptate effect
  • observe the concept of steric focus in ligand design
Implementation Notes: 

These are some general rules for ligand design that are the result of my own personal research as well as topics I learned from my graduate advisor. This only serves as a general guideline and it should be noted that there are some exceptions to these rules (as is the case in most things we do in inorganic chemistry).

Time Required: 
15-20 minutes
Evaluation
Evaluation Methods: 

I will evaluate how well the students understand the concepts presented here by using class discussion and testing students over the concepts on an exam question about ligand design

Evaluation Results: 

This LO was created at the IONiC VIPEr conference 2016, and has not been implemented or evaluated yet, but will be in the upcoming spring 2017 semester

27 Jun 2016

Online Homework for a Foundations of Inorganic Chemistry Course

Submitted by Sabrina G. Sobel, Hofstra University
Evaluation Methods: 

Students are graded on a sliding scale based on the number of attempts on each question. An overall grade is assigned at the end of the semester, adjusted to the number of points allotted for the homework in the syllabus. 

Evaluation Results: 

Student performance on the overall homework assignments for the semester includes questions assigned on General Chemistry topics that are part of this class syllabus. 

 201420152016
Number404741
Average89%80%83%
S.D.15%19%23%

In addition to gethering data on overall  performance, I and my student assistants, Loren Wolfin and Marissa Strumolo, have completed a statistical study to assess performance on individual questions, and to identify problem questions that need to be edited. We identified two separate issues: incorrect/poorly worded questions, and assignment of level of difficulty. Five problematic questions were identified and edited. The level of difficulty was reassigned for eight questions rated as medium (level 2); six were reassigned as difficult (level 3), and two were reassigned as easy (level 1). I look forward to assessing student performance in Spring 2017 in light of these improvements. Please feel free to implement this Sapling homework in your class, and help in the improvement/evolution of this database.

Description: 

The Committee on Professional Training (CPT) has restructured accreditation of Chemistry-related degrees, removing the old model of one year each of General, Analytical, Organic, and Physical Chemistry plus other relevant advanced classes as designed by the individual department. The new model (2008) requires one semester each in the five Foundation areas: Analytical, Inorganic, Organic, Biochemistry and Physical Chemistry, leaving General Chemistry as an option, with the development of advanced classes up to the individual departments. This has caused an upheaval in the treatment of Inorganic Chemistry, elevating it to be on equal footing with the other, more ‘traditional’ subdisciplines which has meant the decoupling of General Chemistry from introduction to Inorganic Chemistry. No commercial online homework system includes sets for either Foundations or Advanced Inorganic Chemistry topics. Sapling online homework (www.saplinglearning.com) has been open to professor authors of homework problems; they have a limited database of advanced inorganic chemistry problems produced by a generous and industrious faculty person. I have developed a homework set for a semester­-long freshman/sophomore level Inorganic Chemistry course aligned to the textbook Descriptive Inorganic Chemistry by Rayner-Canham and Overton (ISBN 1-4641-2560-0, www.whfreeman.com/descriptive6e ), and have test run it three times. Question development, analysis of student performance and troubleshooting in addition to topic choices, are critical to this process, especially in light of new information about what topics are taught in such a course (Great Expectations: Using an Analysis of Current Practices To Propose a Framework for the Undergraduate Inorganic Curriculum: http://pubs.acs.org/doi/full/10.1021/acs.inorgchem.5b01320 ).This is an ongoing process, and I am working to improve the database all the time.

Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

1.      Increase understanding in these topic areas:

a.      Acid-base chemistry and solvent systems

b.      Bonding models of inorganic molecules and complexes

c.      Bonding models in extended systems (solids)

d.      Descriptive chemistry and Periodic Trends

e.      Electronic structure of inorganic molecules, complexes and solids

f.       Extended structures: unit cells and other solid-state structural features

g.      Molecular structure and shape of inorganic molecules

h.      Inorganic Complexes nomenclature, bonding and shapes

i.       Redox chemistry and application to inorganic systems

j.       Thermodynamics as applied to inorganic solids and inorganic systems

2.      Practice using knowledge in these topic areas:

a.      Acid-base chemistry and solvent systems

b.      Bonding models of inorganic molecules and complexes

c.      Bonding models in extended systems (solids)

d.      Descriptive chemistry and Periodic Trends

e.      Electronic structure of inorganic molecules, complexes and solids

f.       Extended structures: unit cells and other solid-state structural features

g.      Molecular structure and shape of inorganic molecules

h.      Inorganic Complexes nomenclature, bonding and shapes

i.       Redox chemistry and application to inorganic systems

j.       Thermodynamics as applied to inorganic solids and inorganic systems

Implementation Notes: 

The database of homework questions is available through Sapling Learning. They can be implemented as an online homework set for a class. Students need to buy access to the Sapling online homework for the duration of the class, typically $45.

Time Required: 
variable
27 Jun 2016

Determining transition metal oxidation states: Recognizing bond metal-ligand types

Submitted by Brandon Quillian, Georgia Southern University
Evaluation Methods: 

Students are given a follow-up problem set.

Evaluation Results: 

Preliminary results reveal that students have difficulty understanding the bonding interactions between the metal and the cyclopentadienyl ligand (principally recognizing its negative charge). Additional instruction on this concept may be required.

Description: 

In this in-class activity, students will determine the formal oxidation state of transition metal complexes by performing bonding type analysis of ligand−metal bonds. This in-class project is intended for those with little background in inorganic chemistry and aims to provide simple methods to calculate the formal charge of transition metals through bond-type analysis. While there are more sophisticated models already available to assign transition metal oxidation states, such as the LXZ (CBC) model, this exercise is intended for students who are coordination chemistry novices.

Learning Goals: 

On completion of this activity, a student will be able to:

  • calculate formal charges of ligands;
  • determine if the ligand metal interaction is Lewis derived or covalent;
  • assign formal oxidation states to metals with somewhat complicated ligand interactions
Corequisites: 
Course Level: 
Implementation Notes: 

Students are paired in groups of two and given time to work on the problems. After completion, the instructor provides the solution to two of the problems then the students are given additional time to reflect on and correct their answers.

Time Required: 
30-45 min
27 Jun 2016
Evaluation Methods: 

The practical exam (uploaded) is used as a metric to determine how well students are capable of answering a science question they haven't seen before on their own.  In other words, the practical exam tests them on their understanding of the material, and the scientific method itself.  If you'd like to measure this against students who have performed the experiment, but did not participate in a discussion session following the experiment, the practical exam scores should give you a measure for how students compare.  The questions asked on the practical exam are designed to be as objective as possible to eliminate variation in grading between sections.

Evaluation Results: 

TBA.

Description: 

This learning object is aimed at getting students to think critically about the data they collect in lab as they collect the data similar to how chemists typically conduct research.  They will be given a pre-lab video and a procedure prior to lab, conduct the experiment, and then upload their data to an Excel spreadsheet.  Students will then stay in their group to discuss the questions given to them on the worksheet in class with the instructor, and are allowed to continue working on them as a group up until the due date.

Class data from the original experiment will be uploaded to a public Excel spreadsheet that students will have access to in lab and at home, where the averages and standard deviation will be automatically calculated for them.  Students will be responsible for all other statistical analysis.  TVs, computers, or projectors are required in the lab in order to project data to the students.  Directly after the experiment, students will enter a discussion section with a worksheet to work on as a group that relates the collected data back to the original lecture on the topic covered in the experiment.

Course Level: 
Prerequisites: 
Learning Goals: 

The purpose of this Learning Object is to teach students not only a difficult concept such as "what is electrochemical potential", but also to teach students how to think about a science question, write a hypothesis, write a procedure to answer said hypothesis, analyze the data, discuss the results as a group, and make a conclusion about their original hypothesis.  Although this learning object is written for a general chemistry electrochemistry experiment, it can be easily modified to fit any laboratory experiment in any level of college chemistry (including organic chemistry, biochemistry, etc.  The end of the semester for a course that incorporates this template involves a practical exam.  In this exam, students are given a science question related to one of the experiments they conducted during the semester such that they use the same techniques used in the original experiment, but answers a far different question.  With their laboratory notebooks and previous procedure available to them during the exam, the instructor will be required to not assist the students (outside of safety and waste disposal concerns) in any way regarding the exam.

Corequisites: 
Equipment needs: 
  • TV, computer or projector to project data for students to look at class data.
  • Proper aqueous solutions and electrodes needed for the experiment outlined in the experimental procedure.
  • If desired, a potentiostat.  However, students should be able to design simple galvanic cells to answer the questions.
  • Solutions should be prepared before the laboratory experiment and practical exams are administered.  However, it is up to your discretion whether you want your students to also make the solutions themselves.
Implementation Notes: 
  • Lab should take ~2-2.5 hours
  • Discussion should be ~1 hr
  • DIfferent practical exams for different days in which the lab is being taught, in order to prevent students from sharing what the lab is about
  • Students should know what experiment the practical exam will be based on, but should not know the exact question being asked until the day of the exam.
  • Worksheets should be due 1 week after the lab, even though students discuss the questions that day.  This gives them time to complete the assignment.
  • Questions on discussion worksheet should be difficult, given that they have the instructor and students within their group to talk to for help.
  • For the practical exam, the solutions should be prepared beforehand to focus their efforts on answering the questions rather than making solutions and preparing to answer the questions. However, it is up your discretion.
Time Required: 
~3-4 hrs
27 Jun 2016

Student Oral Presentations of a Communication from the Primary Literature

Submitted by Carmen Works, Sonoma State University
Evaluation Methods: 

see rubric that is attached 

Description: 

In the humanities it is common practice to read a piece of literature and discuss it.  This is also practiced in science and is the purpose of this exercise.  Each student is assigned a communication from the current  literature (inorganic, JACS, organometallics, J. Phys. Chem) and the student presents this paper to the class.  The class will also have the opportunity to read the article prior to the presentation, and I post each paper on my LMS page.  The presenter will be responsible for explaining the paper, and leading a critical discussion.  This is not an easy assignment since these papers are filled with chemical jargon, but an important part of their chemical education is to be able to tackle the literature.  In addition a lot of this jargon is covered during the semester.

  

 

Course Level: 
Learning Goals: 

·      Students will learn to read a paper from the primary literature

·      Students will learn to present the a paper from the primary literature

·      Students will learn to create a group discussion

·      Students will learn how to relate chemical jargon learned throughout the four years of chemistry to the literature

·      Students will learn how to answer exam questions from the primary literature

 

Implementation Notes: 

I hand out selected communications during the second week of class.  Students are allowed to swap papers. They have the entire semester to read the paper and prepare a talk but the talks are during the last 3 weeks of class.  Each student is give 25 min to present their paper to the class.  The assignment is graded using the attached rubric and is worth 15% of their final grade.  I selected about 7 exam questions for the final exam and ask students to answer 5 of these questions.  I try to structure the questions so that they don't have to "know" every paper.  I have attached an example of such a question.  

27 Jun 2016

Coordination Compound Nomenclature Worksheet

Submitted by Elizabeth Jensen, Aquinas College
Evaluation Methods: 

I do not grade the students’ answers because we discuss them in class. While the students are working through the items, I walk around the room and observe to make sure that students are applying the nomenclature rules correctly.  I offer hints or reminders as needed.

Typically, if I ask students to take the worksheet home and complete it before the next class, they are able to do this successfully. I will start the following class by calling on individual students to share their answers and then discuss as needed.

 

 

Evaluation Results: 

After completing this worksheet, most of the students were able to correctly answer similar questions from the textbook as homework.

One difficult part for my students has been the correct names of ligands. They rely on the lists of ligands in the textbook until those names become familiar.

Description: 

This is a worksheet for students to complete in class to practice nomenclature of coordination compounds. It may alternatively be assigned as homework after a lesson on nomenclature. Includes examples of Ewing-Bassett system as well as Stock system.

Learning Goals: 

Given a formula, students should be able to correctly apply the nomenclature rules in order to write names  for coordination complexes.

Given a name, students should be able to correctly apply the nomenclature rules in order to write the formula for the coordination complex.

Given a correct name (or formula),  students should be able to draw a representation of a coordination complex.

Subdiscipline: 
Equipment needs: 

None

Corequisites: 
Implementation Notes: 

I hand out this worksheet after an introductory lecture on nomenclature, in which I list the rules and give a few illustrative examples. I ask students to work in groups of three or four on the worksheet items, stopping them frequently to compare answers between groups and answer questions. If we do not complete all of the items during the class period, I will ask students to complete the rest on their own and then discuss their results at the beginning of the next class period.

Except for cis/trans, which most students have used previously in organic chemistry, I don't include isomers at this point. However, several of the items on the second page are left unspecific so that when students attempt to draw the structures, they often come up with different answers and this allows me to introduce the idea of isomers and let the students think about that a little.

Time Required: 
The first page takes about 30 minutes to complete in class as described. The second page typically goes a little faster.

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