Zeolite Synthesis
This lab was part of the materials science portion of my second-year inorganic chemistry course. Students synthesize a zeolite structure and grow a chemical garden as examples of silicate chemistry.
This lab was part of the materials science portion of my second-year inorganic chemistry course. Students synthesize a zeolite structure and grow a chemical garden as examples of silicate chemistry.
Students use a Java-based website to explore the faujasite zeolite structure. The activity questions guide them through identifying different atomic positions within the structure, and orienting the zeolite pores and "cages" relative to the crystal axes.
This lab handout and supplementary materials were developed based on a publication in the Journal of Chemical Education:
Berger, P.; Adelman, N.; Beckman, K.; Campbell, D.; Ellis, A.; Lisensky, G. Preparation and Properties of an Aqueous Ferrofluid. J. Chem. Educ. 1999, 76 (7), 943-48
In this activity, students apply knowledge of the trans effect to the synthesis of planar Pt(II) complexes that contain cis-amine/ammine motifs. These complexes are of interest as both potential novel chemotherapeutic Pt(II) complexes and as intermediates for promising chemotherapeutic drugs such as satraplatin. The questions in this LO are based on recent research described in the paper “Improvements in the synthesis and understanding of the iodo-bridged intermediate en route to the Pt(IV) prodrug satraplatin,” by Timothy C. Johnstone and Stephen C.
I used this paper to illustrate several course concepts related to materials structure (crystal lattice structure, coordination number, crystal field theory and orbital splitting, symmetry, electronic spectra, allowed and forbidden transitions). This activity was paired with a laboratory experiment (see related VIPEr objects) in which students synthesized Prussian Blue, and gave students a really in-depth look at what was going on when they mixed those solutions together.
In this activity, the provided d orbital splitting patterns need to be matched with ligand geometries. Students are provided with the d orbital splitting diagrams for 6 ligand geometries (octahedral, trigonal bipyramidal, square pyramidal, tetrahedral, square planar, and linear). A web browser is used to view an animation (developed by Flick Coleman) which allows for the visualization of the relationship between the positions of the metal d orbitals and the ligands. Given this information, students should then be able to qualitatively rank the orbitals from highest to lowest energy.
I use this literature discussion in my second year inorganic class as a follow-up to a lab experiment where students synthesize Werner complexes and then (with much guidance) analyze their IR spectra using symmetry and group theory arguments. This paper provides an excellent example of how cobalt complexes are used in modern applications, and serves as a bridge to bioinorganic chemistry, which is a central feature later in the course.
Over the past several years, I've been doing this in-class exercise shortly after discussing mechanisms of ligand exchange. The exercise expands on the lecture material by having the students think about metal ions, rather than ligands, exchanging from a coordination complex. The students are encouraged to work in groups of 3-5 and actively discuss the material amongst themselves before we go over it as a class. I do not provide the students with the article ahead of time, so that they may come up with their own conclusions, as opposed to simply repeating those of the authors.
Late in their junior year and into the first two months of their senior year, chemistry majors at Willamette write and submit a research proposal. Shortly before entering the lab for their thesis work, I lead this activity that takes place in our Senior Projects seminar class. The class meets one hour per week and we cover topics such as how to write an effective grant proposal, ethics in science, presenting data, etc., as well as this safety activity.