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. Lippard (Inorganica Chimica Acta, Volume 424, 1 January 2015, Pages 254–259). Students can be given this paper either prior to class or during class. Student then work in groups of 3-4 to determine whether the sterochemistry of the Pt(II) complexes synthesized in the paper and in previous work is predicted by the trans effect, as well as whether the bond lengths in a crystal structure of one of these Pt(II) complexes is predicted by the trans influence.
|The Importance of the Trans Effect in the Synthesis of Novel Anti-Cancer Complexes LO.docx||82.99 KB|
After completing this activity, students should be able to:
- define the trans effect and trans influence
- explain what properties of a ligand cause it to have a strong trans effect, and be able to predict the relative trans-directing ability of ligands
- explain how the trans effect can be utilized to develop synthetic methodologies that produce the desired isomer of a square planar complex
- apply their knowledge of the trans effect to predict the stereochemistry of a product formed from substitution of a square planar complex
- explain why the stereochemistry of a product formed substitution of a square-planar complex may differ from that predicted by the trans effect
- explain the effect of the trans influence on metal-ligand bond lengths
This was done as an in-class activity in which students worked in groups of 3-4 to complete the assignment. This LO could also be incorporated into a homework assignment instead.
A student volunteer from each group was asked to share their answer with the class. Written answers could also be collected and graded.
Most students did very well in all parts of this activity, although some students initially had trouble explaining the relative trans-directing ability of the ligands.