Electrochemical analysis of redox-active ligands and their transition metal complexes: applications towards CO2 reduction

My research explored the development and design of ligands (chemicals that bind to metals) and metal complexes that can transfer and release energy in the form of electrons. In addition, my work aimed investigate how small molecules, like carbon dioxide, can bridge over the complex and bind to both the metal and the ligand (called metal-ligand cooperative binding). The goal is to investigate how this type of binding affects the transfer of electrons of metal complexes. To investigate this event new metal complexes with redox-active ligands (ligands that can transfer electrons) were made.

I use a variety of spectroscopic, crystallographic, and electrochemical techniques to study their structures and properties and confirm their identity. Electrochemical studies showed that small molecules binding across the metal and ligand limit electron transfer from the redox-active ligands. However, electron transfer can still occur as long as one of the ligand’s binding sites is left free, and not attached to another chemical. We tested the metal complexes to see if they could bind carbon dioxide and convert it into carbon monoxide, a useful starting material for synthesis of fuels and useful raw goods. Our tests showed that our metal complexes were able to transform carbon dioxide to carbon monoxide as intended, but the amount of carbon monoxide formed varied depending on the chemical variations of the ligands. This is a very exciting first step, and these results will have significant influence on the development new metal complexes that can be even better at transforming carbon dioxide.