9 Jun 2020

Gold carbonyl complexes

In-Class Activity

Submitted by Adam R. Johnson, Harvey Mudd College

I've been meaning to write an LO on non-classical metal carbonyl complexes for a long time. This paper describes the synthesis and characterization of a gold carbonyl prepared in superacidic media. The LO asks the students to do some relatively straightforward reduced mass calculations to predict the 13C labeled CO stretch from the unlabeled one, but then asks the students to think about /why/ the Au-CO stretch is /higher/ than that of free CO.

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Learning Goals: 

Students will practice using reduced mass calculations to calculate labeled stretching frequencies

Students will practice the Dewar-Chatt-Duncanson model of bonding

Students will use an MO diagram and their understanding of MOs to answer the question as to why the CO stretch in a non-classical carbonyl is higher than that of free CO


Equipment needs: 


Implementation Notes: 

This is billed as an in-class activity because the fourth question is quite difficult. I assigned it as a challenge homework problem during the COVID semester (Spring 2020) but no one did it as far as I can tell. 

Time Required: 
30 minutes with time for discussion at the end
Evaluation Methods: 

the first 3 problems are skill practice. The fourth problem is tough and would lead natrually to an in class discussion of bonding models, and how theories change over time.

Evaluation Results: 

I don't have any, unfortunately. 

Creative Commons License: 
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