Building a Single Conceptual Framework for Metal-Ligand Compounds
Dr. Ronald See
Metal-containing compounds typically consist of a metal atom surrounded by 4 or more groups of non-metal atoms, called ligands. Each ligand has a binding atom, such as nitrogen, oxygen or carbon. For ligands that bind through nitrogen or oxygen, previous work in this lab has established a detailed understanding of the strength and characteristics of the metal-ligand bonds. The research done for U-SOAR seeks to extend this understanding to ligands that bind through carbon, starting with the prototypical carbon-binding ligand, CO (carbon monoxide). The data consists of searches of the Cambridge Structural Database (CSD), which contains the known structures of over one million molecules. This data records the metal-carbon and carbon-oxygen distances, these distances are inversely proportional to the strength of the chemical bonds. This data is analyzed to show changes in bonding for different metals, molecular charge and composition of the ligands surrounding the metal. Once the data collection for CO is complete, we plan to go on to CN (cyanide) and alkane-based ligands, such as CH3.
The objective of this research is to bring all ligand types into a single conceptual model that will be useful to experimental chemists. Metal-ligand bonding is a phenomenon of growing importance in chemistry, and one that lacks a consistent, useable model across all ligand types. Several currently important areas of chemical inquiry, such as metalloproteins, homogeneous catalysts and metal-organic frameworks, depend on an accurate understanding of metal-ligand bonding.
The first step in this process is to develop solid working knowledge of the strength of metal-ligand bonds, and how these bonds change with different metals, charges or chemical environment. Once the metal-ligand bonding is well understood for a wide variety of metals and ligands, we can use this knowledge to build a practical model to help guide experimental chemists.