Using the technique of X-ray crystallography, we explore the detailed structures of organic compounds and transition metal complexes of biological interest. Our work has focused on two areas: substituted benzimidazoles and zinc compounds. Benzimidazole derivatives have numerous pharmacological uses. Zinc plays an important role in structural biochemistry (e.g., zinc fingers) and in enzymes (e.g., carbonic anhydrase). Examples of each obtained in our laboratory are shown below.
Calculation of weak intermolecular interaction energies
C-H…p and p…p, as well as nontraditional hydrogen bonding interactions (e.g., C-H…N) play an important role in protein-drug binding and in crystal engineering. Our efforts have focused on using density functional theory (DFT) calculations to estimate the interactions energies of such interactions that we have observed in the extended structures of compounds we have explored using X-ray crystallographic techniques. The figure below shows an example of the types of interactions we explore.
Coordination complexes employing ligands capable of bridging two or more metal atoms can be used to form polymeric compounds and/or extended structures based on the metal and framework ligands, metal organic frameworks (MOFs). These compounds are of inherent interest as catalysts (they can hold substrate molecules in close proximity) and as small molecule storage systems (e.g., hydrogen storage, carbon dioxide sequestration, etc.). Below is an example of a zinc MOF that contains ethanol in the voids. This compounds was synthesized and characterized in our laboratory.