Synthesis and reactivity

6 Apr 2020

Schlenk Line Survival guide

Submitted by Adam R. Johnson, Harvey Mudd College
Evaluation Methods: 

This is really more of a resource. I have not used it but I have a link to it in my reserach SOP folder. I think it would be good to show the students a general resource before teaching them the specifics of a local line.

Description: 

I feel like I've shared this resource before but I couldn't find it so maybe it will stick this time :)

This is a good resource created by "Dr. Andryj Borys, a main-group chemist, phosphorus fanatic and Schlenk line enthusiast." He is currently a postdoc in Canada, headed back to Europe in 2020 (supposedly..)

this resource describes the use of a Schlenk line in quite a bit of detail, with a variety of standard applications (cannula transfer, sealing NMR tubes).

Topics Covered: 
Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

A student can use this resource to learn general features of a Schlenk line.

26 Mar 2020
Evaluation Methods: 

Student learning is assessed by answers to simple scenario based questions accompanying this resouce.

Description: 

One of the features of the laboratory associated with my Inorganic chemistry course is learning to do some air sensitive chemistry using Schlenk lines (and sometimes gloveboxes).  Of course, COVID19 is keeping us out of the lab this year!  This is a collection of short web based resources (text and video) detailing begining use of a Schlenk line, something about drying and degassing solvents, and transferring liquids to a reaction flask.  It is accompanied by questions I am having students answer as part of the alternate lab I am creating in place of our usual organometallic lab experiemnt.  If you have a favorite resource that might be better/supplement the ones I found, please add to the comments!

Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

A student will be able to explain the basic operation of a Shlenk line and how to add reagents and solvents to a flask under inert atmosphere.

Time Required: 
2 hours, if all videos are watched and resources read.
21 Mar 2020

Ferrocene acylation - The Covid-19 Version

Submitted by Chip Nataro, Lafayette College
Description: 

This is the classic Chromatography of Ferrocene Derivatives experiment from "Synthesis and Technique in Inorganic Chemistry" 3rd Ed. (1986 pp 157-168) by R. J. Angelici. There are no significant changes from the experiment published in the book so details will not be provided. What is provided are links to some excellent videos showing the experiment and characterization data for students to work with. For the time being this will be a living document. Currently it has 1H, 13C{1H}, COSY, DEPT, HMBC, HSQC IR, UV-Vis, GC-MS and Cyclic Voltammetry raw data files for all compounds for students to work with. It also includes processed 1H, 13C{1H}, COSY, DEPT, HMBC, HSQC, IR, GC-MS and Cyclic Voltammetry data for all compounds. If anyone has any additional means of characterization they would like to include (say Mossbauer) please feel free to contact the author.

Corequisites: 
Learning Goals: 

A student should get an appreciation for what doing this lab would be like by watching videos. In addition, the student will analyze the data provided and learn about the characterization of ferrocene, acetylferrocene and 1,1'-diacetylferrocene.

Equipment needs: 

Nothing.

The NMR data comes from a Bruker instrument and can be opened with TopSpin, MestReNova and perhaps other programs.

Implementation Notes: 

Like most everyone at this time this is going to be a trial by fire.

20 Mar 2020

setting up an air-sensitive reaction (video)

Submitted by Adam R. Johnson, Harvey Mudd College
Evaluation Methods: 

have not done

Evaluation Results: 

n/a

Description: 

This is a video I made to demonstrate the basics of air-sensitive reaction setup under nitrogen flush. It is the simplest, most basic method for setting up a reaction with air/water sensitive reagents.

The link goes to my channel on YouTube.

Corequisites: 
Subdiscipline: 
Learning Goals: 

After watching this video, a student will be able to set up a reaction under nitrogen. Or, if there is a global pandemic and the students are at home, they will at least see how it is done.

Course Level: 
Implementation Notes: 

I made this and am sharing it with my students because they did not get an opportunity to set up an air sensitive reaction this year.

Time Required: 
5 minutes to watch video
19 Mar 2020

Job's Method - The Covid-19 Version

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

Students are generally asked to write a full lab report including an abstract, brief introduction, experimental and results/discussion. I will likely not ask them to do that in this virtual lab. However, they will be asked to determine the value for n for the various [Ni(en)x] solutions as well as questions 1 and 2 from Angelici's book. In addition, I typically ask them to do some literature searching questions, but I am not sure if they will have access to SciFinder so I may have to bypass that or provide them the original papers I have them look at. Links to those papers are included.

Evaluation Results: 

I'll use this in a few weeks and see how it goes.

Description: 

This is the classic Job's Method experiment from "Synthesis and Technique in Inorganic Chemistry" 2nd Ed. (1977 or 1986 pp 108-114) by R. J. Angelici. There are slight changes from the experiment published in the book but they just include running solutions with ethylenediamine mole fractions of 0.67 and 0.75, so details will not be provided. What is provided are a series of pictures and videos showing the experiment being performed. Also included are the raw files of the absorbance spectra in EXCEL. It is not perfect but given the situation many of us are facing at the time this is published, it is better than nothing.Note that this lab was updated on 4/4/2020. The previous data was terrible. New solutions using a fresh bottle of ethylenediamine were prepared. The two solutions mentioned previously were also included. The data is much better. The worked up data has also been included in the instructor only files.

My apologies to my coauthors who spent way too much time looking over the original data set and trying to make sense of it. Their thoughts and insight led to this update. My sincere apologies to anyone else that scuffled over the original data.

Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

A student should get an appreciation for what doing this lab would be like by watching videos. In addition, the student will analyze the data provided and determine the species present in solutions containing various mole fractions of ethylenediamine and Ni(II).

Equipment needs: 

Nothing

Implementation Notes: 

Like most everyone at this time this is going to be a trial by fire.

2 Mar 2020

ChemCrafter

Submitted by Michelle Personick, Wesleyan University
Evaluation Methods: 

Student learning is not assessed directly after the activity, but rather is assessed indirectly through student performance on related homework and exam questions. More specifically, the second section of the exams in my general chemistry course always asks students to "provide a concise (but complete) explanation or rationalization for [some number] of the following statements." This section is particularly suited to assessing the learning goals above.

Evaluation Results: 

This activity was recently introduced, and student performance has not been evaluated yet.

Description: 

ChemCrafter, from the Science History Institute (formerly the Chemical Heritage Foundation), is a free iPad app that mimics a classic chemistry set. It is set up as a game, with three sections: reactions with water, reactions with acid, and salts. The app shows the progress of the reaction (smoke, color change, etc.) when two elements are mixed in a reaction vessel, and also gives the change in enthalpy of the reaction.

Pros: It's a safe and fun way to demonstrate some visually exciting chemical reactions. It's free and the graphics are high quality. The app projects well on a large screen using a standard classroom projector.

Cons: Accessing later sections of reactions requires completion of the previous sections, and there is some artificial gating of chemical and glassware replenishment behind wait times. As a result, it's best used as a demo rather than as a dry lab. It's also only available for the iPad.

 

Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

Students should be able to explain the difference between thermodynamics and kinetics.

Students should be able to explain why even thermodynamically favorable reactions sometimes do not proceed on an observable timescale.

Students should be able to explain why heat is sometimes necessary to make a highly exothermic reaction proceed.

Implementation Notes: 

Once everything is unlocked, it's possible to set up any reaction using the chemicals in the given "set" for each category of reaction. I use ChemCrafter in my second semester general chemistry course to transition from a unit on reactions of ions in aqueous solution (hydration/hydrolysis, Bronsted acid/base and hard-soft acid base principles of solubility/reactivity, etc.) to a unit on kinetics. I show a series of reactions from the salt section that the students would expect to have roughly increasing enthalpies of lattice formation based on the Born-Lande equation:

[Note: All reactants are in their elemental form in the app, so the enthalpies of formation aren't truly lattice energies.]

2 Na + Cl2 --> 2 NaCl   (1+ cation with a 1- anion) 

2 K + F2 --> 2 KF (1+ cation with a 1- anion)

Zn + Cl2 --> 2 ZnCl(2+ cation wtih a 1- anion)

These combinations were selected because their reactions in the app become increasingly dramatic (and colorful) in this order. I then show the students a set of reactions that they would expect to be even more exciting, but which don't actually proceed without heat. They hold their breath for the first one to react.

Zn + S --> ZnS (2+ cation with a 2- anion)

2 Al + 3 I2 --> 2 AlI3 (3+ cation with a 1- anion)

The app provides an option for heating these mixtures of elements with a bunsen burner, and then they react dramatically. At this point, we're ready to discuss the difference between thermodynamics--which is all they've seen up to this point--and kinetics.

Time Required: 
5-10 minutes of class time
9 Oct 2019

2019 Nobel Prize - Li-ion battery LOs

Submitted by Barbara Reisner, James Madison University

Congratulations to the 2019 recipients of the Nobel Prize - John B. Goodenough, M. Stan Whittingham and Akira Yoshino. It's a well deserved honor!

There are several LOs on VIPEr that talk about lithium ion batteries and related systems. The 2019 Nobel is a great opportunity to include something about these batteries in your class.

I hope to see more LOs in the coming weeks so we can bring this chemistry into our classrooms!

Prerequisites: 
Corequisites: 
25 Jul 2019

1FLO: One Figure Learning Objects

Submitted by Chip Nataro, Lafayette College
Corequisites: 

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