21 Mar 2020

chromium and molybdenum arene complexes (COVID-19 version)

Lab Experiment

Submitted by Adam R. Johnson, Harvey Mudd College
Categories
Description: 

The synthesis of (arene)Cr(CO)3 and (arene)Mo(CO)3 complexes are fairly standard experiments in the organometallic curriculum. I present here some student data and experimental descriptions of real procedures carried out at Harvey Mudd College over the previous two to three years. The word document has the answers in it so it is posted under "faculty resources" but the raw data (pdf or png form) is presented for those who need data to support their distance learning classrooms in the Spring of 2020. I also include an input file for Mo(benzene)(CO)3 should you desire to use WebMO or Gaussian to carry out some calculations. 

 

there was a minor mistake in the reported integrations for one of the complexes in the original faculty only file; it has been fixed in the v2 version.

Learning Goals: 

Students will interpret provided data to write their own experimental sections for molecules they were unable to prepare in the lab. The guided inquiry part allows students to use data to predict the outcome of a chemical reaction.

Equipment needs: 

be able to view PDF/PNG files

Implementation Notes: 

I have not used this yet but will be using it spring 2020.

Time Required: 
unknown
Evaluation
Evaluation Methods: 

i have no idea.... yet! (growth mindset!)

Evaluation Results: 

I will report this later this spring.

Creative Commons License: 
Creative Commons Licence

Comments

Mistake found! The IR spectra for Mo(N,N-dimethylaniline)(CO)3 and for the phosphine reaction product are identical (the same spectrum was submitted by two different students for two different products). Based on who the students were, I think I know which is which, but I can't verify it without remaking the compounds. Anyway, I had hoped to do this experiment with my students live this year to get some good data sets and that didn't happen. Maybe I will be able to hunt this down and figure it out in the fall. I haven't been able to find a literature IR spectrum of either product, so if someone has this info, please contact me directly! thanks.

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