This is the full literature discussion based on a communicaiton (J. Am. Chem. Soc. 2011, 133, 9278). This paper describes a redox-switch yttrium catalyst that is an active catalyst for the polymerization of L-lactide in the reduced form and inactive in the oxidized form. The catalyst contains a ferrocene-based ligand that serves as the redox active site in the catalyst. This full literature discussion is an extension of the one figure literature discussion that is listed below. In addition to presenting all of the same questions as that learning object, this includes interpretation of the XANES spectra presented in the paper. It also asks the students to identify the monomer and polymer in the reaction of interest. A possible extension of this learning object would be to have students examine and take measurements from the crystal structure presented in the paper in order to support the apparently low electron count on the yttrium catalyst. The Covalent Bond Classification system for counting electrons is used in this learning object.
A student should be able to apply their knowledge to
- describe and interpret a plot of conversion vs. time
- count electrons and determine valence states in organometallic compounds
- determine if an organometallic compound is an oxidizing or reducing agent
- decipher a first-order kinetic plot
- interpret XANES spectra to determine the valence of iron in the catalyst