VIPEr

Solid State and Materials Chemistry

Bonding models: Extended systems

Topics Covered:

Acid-base chemistry

Electron transfer

Extended structure

Solids & solid state chemistry

Physical properties

Prerequisites:

Corequisites:

Course Level:

9 Oct 2019

Fourier Transform IR Spectroscopy of Tetrahedral Borate Ions

Submitted by Zachary Tonzetich, University of Texas at San Antonio

Evaluation Methods:

The students perpare laboratory reports displaying their data in proper format with each peak labeled. The report must also contain answers to all of the quetions posed in the manual. Student performance and learning is assessed by the qualtity of their written reports and by a separate quiz covering aspects of vibrational spectroscopy. Teaching assistans also ensure that students' data acquisition is performed in a satisfactory manner during the laboratory period.

Evaluation Results:

Students typically have great difficulty connecting the idea of normal modes, their symmetries, and why we observe IR peaks. They approach IR spectroscopy in much the same way they do NMR spectroscopy (i.e. methane shows four equivalent C-H bonds so I expect one C-H stretching motion) leading to serious misconceptions. This laboratory was designed in part to dispell these misconceptions. Question 1 addresses this issue most directly and many of the class answer incorrectly.

The questions in the laboratory involving harmonic oscialltor analysis are generally more straightforward for students as they just need to use the correct equations. Most of the class answers these correctly.

Likewise, students generally understand that vibrational frequencies are inversely proportional to the mass of the atoms involved in the vibration and are there able to make connections between the observed spectra of BH₄^-, BD₄^- and BF₄^-.

Aspects of functional group analysis are more familiar to students and they generally have little trouble assigning the spectrum of tetraphenylborate.

Description:

This experiment was developed for an upper division Instrumental Analysis course to give students additional experience with infrared (IR) spectroscopy beyond the routine functional group identification encountered in undergraduate Organic Chemistry courses. It shares some aspects with the analysis of gas phase rovibrational spectra typically performed in Physical Chemistry courses, but places a greater emphasis on more practical considerations including data acquisition (using ATR) and interpretation. The molecular ions used in the experiment also demonstrate tetrahedral symmmetry which allows for topics in Group Theory to be exploited.

The experiment has students record the spectra of several tetrahedral borate ions including the isotopomers NaBH₄ and NaBD₄. The students then analyze their data in the context of the symmetry of normal modes, the harmonic osciallator model, comparisons with Raman spectra, and functional group composition. Post lab questions guide students through each of the topics and ask them to make quantative and qualitative predictions based on their data and theoretical models of molecular vibration.

Course Level:

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

Prerequisites:

Corequisites:

Subdiscipline:

Group theory & applications

Learning Goals:

-Students should be able to understand the relationship between molecular structure, normal modes, and peaks in the IR spectrum. This is a major misconception with students as they tend to believe that the presence of four B-H bonds in the borohydride ion will neccessary mean that four peaks (or one since they are equivalent) will be observed by IR. Unlike NMR spectroscopy, there is no 1:1 correspondence between the number of equivalent bonds and the number of peaks observed in the spectrum.

-Students should also be able to apply their knowledge of theoretical models (quantum harmonic oscillator) to quantitaively intrepret IR spectra and predict the energy of transitions that cannot be observed due to instrumental limitations.

-Students should be able to understand at a qualitative level how the masses of atoms affect the energy of molecular vibrations.

Topics Covered:

Isotopic labeling and reduced mass calculations for IR spectroscopy

Equipment needs:

The only required piece of equipment beyond the chemicals is an infrared spectrophotometer. At our institution we use an ATR element to acquire the data, but KBr pellets or nujol mulls should work equally well. All chemicals were purchased from Sigma-Aldrich and are of reasonable price.

Related activities:

CompChem 05: Infrared, Thermochemistry, UV-Vis, and NMR

Vibrational Modes and IR Spectra using Character Tables

Good resource for Teaching IR with Symmetry Elements

Synthesis and Molecular Modeling of Sodium Tetrathionate

Implementation Notes:

See attached file with more details. The data acquisition is very straightforward if ATR sampling is employed. Students need only use the instrument for about 15 - 20 minutes to record all four samples.

Time Required:

30 minutes to 2 hr depending upon the number of students.

25 Jul 2019

1FLO: One Figure Learning Objects

Submitted by Chip Nataro, Lafayette College

Course Level:

First year

Second year

Subdiscipline:

f-block Chemistry

Organometallic Chemistry

Topics Covered:

Acid-base chemistry

Catalysis

Electron transfer

Group theory & applications

f-block chemistry

Kinetics

Organometallic chemistry

Corequisites:

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

Prerequisites:

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

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.

Prerequisites:

Corequisites:

Topics Covered:

Diffraction

Extended structure

Solids & solid state chemistry

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

Subdiscipline:

Solid State and Materials Chemistry

Energy Nuggets: MOF’s for CO2 Sequestration

Related activities:

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.

Web Resources:

Iron and Porphyrin Metal−Organic Frameworks: Insight into Structural Diversity, Stability, and Porosity. Fateeva et al

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.

Subdiscipline:

Atomic Structure and Periodicity

Bioinorganic Chemistry

Introductory Chemistry

Main Group Chemistry

Science Skills, Practices, and Resources

Nanochemistry

Organometallic Chemistry

Solid State and Materials Chemistry

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

Prerequisites:

No Prerequisites

Physical Chemistry: Thermodynamics

Corequisites:

Physical Chemistry: Thermodynamics

Course Level:

First year

Second year

Christopher Durr, Amherst College

6 Jun 2019

Guided reading and in-class discussion questions for "High-Spin Square-Planar Co(II) and Fe(II) Complexes and Reasons for Their Electronic Structure"

Submitted by John Miecznikowski, Fairfield University

Additional Authors:

Colleen Partigianoni, Ferris State University

Maria Carroll, Providence College

Evaluation Methods:

The guided reading questions may be graded using the answer key.

Evaluation Results:

These questions have not yet been assigned to students.

Description:

Guided reading and in-class discussion questions for "High-Spin Square-Planar Co(II) and Fe(II) Complexes and Reasons for Their Electronic Structure."

Prerequisites:

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

Corequisites:

Course Level:

Subdiscipline:

Science Skills, Practices, and Resources

Learning Goals:

1. Bring together ligand field theory and symmetry.

Students should be able to identify symmetry of novel molecules in the literature.
Students should be able to explain d-orbital ordering in a coordination complex using ligand field theory.
Students should be able to identify donor/acceptor properties of previously unseen ligands.
Students should be able to apply your knowledge of electronic transitions to the primary literature.
Students should be able to become more familiar with 4-coordinate geometries.
Students should be able to predict magnetic moments of high-spin and low-spin square-planar complexes.
Students should be able to identify properties of ligands that favor formation of the highly unusual high-spin square planar complexes.

2. Students should comfortable with reading and understanding primary literature.

Topics Covered:

Diffraction

Group theory & applications

Physical properties

High-Spin Square-Planar Co(II) and Fe(II) Complexes and Reasons for Their Electronic Structure

Related activities:

Geometry Indices

Implementation Notes:

You do not have to assign all of the guided reading questions at once. You may consider assigning questions as they pertain to where you are in your inorganic chemistry class.

Time Required:

this has not been used yet for in-class discussion.

Web Resources:

6 Jun 2019

The Synthesis and Electronic Structure of [NiX₄]^2- Complexes and the Role of Crown Ethers in Inorganic Synthesis

Submitted by Wesley S. Farrell, United States Naval Academy

Additional Authors:

Denyce Wicht, Suffolk University

Jeremy Andreatta, Worcester State University

Nathaniel J Hartmann, Boston University

Evaluation Methods:

The classroom discussion (participation, answers, etc) may be assessed by the instructor, or alternatively, these questions could be given to students to turn in.

Evaluation Results:

None yet available. Please leave yours in the comments!

Description:

This literature discussion aims to have students in an advanced inorganic chemistry course interpret reaction schemes and electronic spectra, relate chemical formulae to molecular structure, and gain an understanding of how inorganic synthesis is planned and executed. Students should gain an understanding of how counterions and crown ethers affect structure. Question 7 may be expanded to ask students to why pi-donor ability affects ligand field splitting, or as an introfuction to this topic.

An associated 1FLO based on this paper is linked in the related content.

Corequisites:

Course Level:

Topics Covered:

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

Prerequisites:

Learning Goals:

Students will be able to:

Interpret reaction schemes and write balanced equations.
Rationalize the position of a ligand in the spectrochemical series based upon its π-donor/acceptor properties
Relate the electronic structure of tetrahedral d⁸ complexes to their magnetic properties
Analyze the impact of countercations on the geometry and electronic properties of the complexes.

Subdiscipline:

1FLO: Relating Electronic Spectra and Ligand Field Strength of [NiX4]2- Anions

Related activities:

Implementation Notes:

This LO is intended for an advanced inorganic chemistry course. Students should read the communication before class with questions above as guidance. A classroom discussion should insue, in which students gain an insight into inorganic synthesis, and recognize how minor differences between compounds, such as counterions, have significant effects on electronic structure.

Time Required:

50 minutes

Web Resources:

The Synthesis and Electronic Spectra of fluorinated aryloxide and alkoxide [NiX₄]^2- anions

6 Jun 2019

1FLO: Relating Electronic Spectra and Ligand Field Strength of [NiX₄]^2- Anions

Submitted by Wesley S. Farrell, United States Naval Academy

Additional Authors:

Denyce Wicht, Suffolk University

Jeremy Andreatta, Worcester State University

Nathaniel J Hartmann, Boston University

Evaluation Methods:

Evaluate students' comprehension based on verbal in-class answers and ensuing discussion.

Evaluation Results:

None yet available.

Description:

This 1FLO asks students to interpret an electronic spectrum of 5 NiX42- anions. Students will determine the relative ligand field strength, (re)familiarize themselves with terms such as "redshift" and "blueshift", and consider possible metal complex geometries.

Learning Goals:

Students (re)familiarize themselves with relationship between wavelength (λ) and wavenumber (cm-1).
Students recall 4-coordinate geometries.
Students define the terms “redshift” and “blueshift.”
Students analyze data to construct a partial spectrochemical series.

Corequisites:

Subdiscipline:

Course Level:

Equipment needs:

None

Topics Covered:

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

Prerequisites:

Ligands that Favor/Force Tetrahedral Geometry

Related activities:

Ligand Lineup

Inorganic Chemistry Spectroscopy Tutorial: Theoretical Principles and Applications

Implementation Notes:

This activity could be used as either a guided introduction to the spectrochemical series, or as an in-class activity to review after introduction. If used as an introduction, question 4 may need modification.

Time Required:

15 - 20 Minutes

Web Resources:

Synthesis and Electronic Spectra of Fluorinated Aryloxide and Alkoxide [NiX4]2- Anions

5 Jun 2019

Zinc-Zinc Bonds (Expanded and Updated)

Submitted by Wesley S. Farrell, United States Naval Academy

Additional Authors:

Alexandra Strom, Smith College

Anthony L. Fernandez, Merrimack College

Betsy Jamieson, Smith College

Brian Anderson, Keene State College

Chip Nataro, Lafayette College

Christopher Durr, Amherst College

Colleen Partigianoni, Ferris State University

Denyce Wicht, Suffolk University

Jeremy Andreatta, Worcester State University

Joanne Smieja, Gonzaga University

John Miecznikowski, Fairfield University

Leon Tilley, Stonehill College

Maria Carroll, Providence College

Nathaniel J Hartmann, Boston University

Evaluation Methods:

Performance and participation in the discussion will be assessed

Evaluation Results:

None collected yet. Evaluation data will be added in the future.

Description:

This paper in Science reports the synthesis of decamethyldizincocene, a stable compound of Zn(I) with a zinc-zinc bond. In the original LO, the title compound and the starting material, bis(pentamethylcyclopentadienyl)zinc, offer a nice link to metallocene chemistry, electron counting, and different modes of binding of cyclopentadienyl rings as well as more advanced discussions of MO diagrams. More fundamental discussion could focus on the question of what constitutes the evidence for a chemical bond, in this case, the existence of a zinc-zinc bond. In this updated LO, these topics are still covered, however additional topics, such as point group idenitifaction, details regarding the reaction mechanism, electronic structure, and searching the literature using SciFinder are covered. Additionally, electron counting is divided into both the covalent and ionic models.

Corequisites:

Course Level:

Topics Covered:

Organometallic chemistry

Periodic trends

Reaction mechanisms

First Semester Inorganic Chemistry / Foundation Course in Inorganic Chemistry

Prerequisites:

Learning Goals:

Students should become more confident reading the primary literature
Students should be able to apply existing knowledge to interpret research results.
Students should be able to apply electron counting formalisms to organometallic compounds.
Students should be able to use 1H NMR spectroscopy data to rationalize structure.
Students can rationalize bond distances based on periodic trends in atomic radii
Students use SciFinder to put this work into a larger context.
Students identify redox reactions based on oxidation changes.
Students identify molecular point groups based upon structures.
Students should be able to connect d electron count to observed colors of compounds.

Subdiscipline:

Organometallic Chemistry

Article: Decamethyldizincocene, A Stable Compound of Zn(I) with a Zn-Zn Bond

Related activities:

Zinc-Zinc Bonds

Implementation Notes:

Students are asked to read the paper and the accompanying Perspectives article before class as well as answer the discussion questions. The questions serve as a useful starting point for class discussion.

Time Required:

50 minutes

Web Resources:

Perspective: Zinc-Zinc Bonds: A New Frontier

31 May 2019

Helping Students with Visual Impairments See Colors

Submitted by Douglas Balmer, Warwick High School

Evaluation Methods:

Do these students identify the same colors as the students without visual impairments?

Are their lab results correct?

Evaluation Results:

Students were able to accurately describe colors.

Description:

I have had some students in class have a hard time identifying colors (flame tests, solution color, acid-base indicators, etc.) because of a visual impairment. There are many cell-phone apps that are helpful in aiding these students. "Pixel Picker" allows the students to load a picture from a device (cell phone, ipad). This is helpful because students are now dealing with a "frozen" image. Moving the cross-hair to different parts of the picture changes the R-G-B values. The "Color Blind Pal" app uses a more qualitative approach. It names the color in the cross-hair using various color scales. There are also different options for different types of color blindness.

Both of these apps are free and availble in the App Store.

Prerequisites:

No Prerequisites

Corequisites:

Topics Covered:

Acid-base chemistry

Descriptive chemistry

Science Skills, Practices, and Resources

Physical properties

Visualization

Course Level:

First year

Learning Goals:

A student should be able to correctly identify an unknown metal by the color of its flame.

A student should be able to correctly identify the endpoint in a titration by the indicator's color change.

A student should be able to correctly describe the physical properties (color) of a sample.

A student should be able to correctly predict the visible absorbance spectrum of a solution based on correctly identifying the color of the solution.

Subdiscipline:

Introductory Chemistry