Abstract: “Metal ions usually exist in the form of coordination complexes. The properties of such complexes include different colors, photo-physical characteristics, magnetics, reactivity, biological activity, and catalytic properties.(1) The biological activity of metal-ligand interactions has found many pharmaceutical, clinical and other practical applications. The experiments being presented here are part of a series of inorganic chemistry lab experiments designed to examine the solubility of metal ions and their ability to form coordination complexes. This particular lab focuses on the complex formations of copper by performing a series of color changing reactions. Four primary objectives include: i) Improve hands-on skills in how to prepare chemical solutions of specific molarities. ii) Understand how to prepare a series of Cu metal complexes in solution. iii) Observe color changes and precipitation reactions associated with complex formations, and iiii) analyze results in regards to metal-ligand formation. This lab experiment provides students with a multi-faceted look at different chemical principles including formation of coordination complexes, solubility, redox chemistry and the chemistry of transition metals.
New Laboratory Module, Why Metals and Ligands Like Each Other, Purdue, Inorganic Chemistry Laboratory, CHM342, Experiment developed in 2020.
Great presentation, Allyson. I would like to know if you will discuss with the students your reasoning when selecting the various ligands? Can you envision allowing the students to have more ownership in the experimental process by letting them choose ligands?
Hi Allyson,
Great job! I was curious about what level of undergraduate lab you are targeting? Would you just be keeping it to a more basic ligand exchange discussion for general chemistry students, or might you discuss strong-field/weak-field ligands, splitting and spin in a more advanced inorganic chemistry course? Could you make it modular so that both of these are options?
Thanks!
Joe
Hi Joe,
This lab is for a second level inorganic chemistry course. Most students taking this class will be in either their third or forth year of their undergraduate degree. It is currently designed to just cover the basics of ligand exchange but could definitely be extended to involve more advanced topics. However, to keep the lab short and manageable for students only the basics are currently covered.
Thank you!
Allyson Imfeld
Interesting presentation and nice delivery. So did the students have any difficulty in seeing any of the changes? Also did you think about having them try the procedure in different order, to show that it does depend on ligand strength?
As this lab was just recently developed, students have not yet been able to perform this lab in person. The lab is currently set up to be online due to the global pandemic, but the hope is to have students perform it in person when safe to do so. Currently it is set up so that students will watch a video of the reaction series being performed and then analyze what they saw. Performing the procedures in a different order would definitely provide another interesting look at the processes–perhaps we can explore this possibility once the lab can be tested by students in person!
Thank you!