Exploring the effects of ligand substituents on the electron density of transition metal centers: Tuning a system in inorganic chemistry

CHED 114

John T. York, jyork@stetson.edu, Department of Chemistry, Stetson University, Unit 8271, DeLand, FL 32720
One of the most important concepts encountered in the study of inorganic chemistry is how the electron donor-acceptor properties of a ligand impact the electron density of a metal center. Indeed, in compounds ranging from industrial catalysts to metalloproteins, the careful “tuning” of a metal's properties by subtle ligand variation is often at the heart of achieving a desired reactivity. Herein is presented a laboratory experiment designed to allow inorganic chemistry students to observe such effects by synthesizing a series of metal-CO complexes having a variety of auxiliary ligands with differing electronic properties. Utilizing FT-IR spectroscopy to characterize these analogous compounds, students can correlate the electron-donating or -accepting nature of each ligand with its impact on the electron density of the metal center as measured by observed changes in the carbonyl C-O stretching frequencies. This simple, yet effective, analysis provides important insight into metal-ligand electronic interactions.
 

General Posters
7:30 PM-9:30 PM, Sunday, April 6, 2008 Morial Convention Center -- Hall A, Poster

Division of Chemical Education

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008