Carl D. Hoff

Catalysis
Thermochemistry
Metal Complexes
Sulfur Chemistry
Kinetic Studies
Spectroscopy

 

The goal of our research is to understand what controls reactions important to catalysis of reactions like nitrogen fixation.  Binding and activation of dinitrogen, nitriles, hydrogen, carbenes, and sulfur to metal complexes are all studied in our laboratory. Our principle focus is on molybdenum chemistry.  Molybdenum is one of the most versatile of all transition metals, and also important in several enzymatic reactions--most notably a Mo/S protein complex is at the center of the active site of the nitrogenase enzyme. It is also the active metal in hydrodesulfurization to remove sulfur containing compounds from gasoline. Both nitrogen fixation, and hydrodesulfurization are of major economic and environmental importance, and there is need for improvement for both. The actual reactions are deceptively simple, but the interactions of the reactants, products, and intermediates with the metal complex catalyst is challenging and not well understood.

Nitrogen Fixation:     
                                  "catalyst"
            2 N2 + 3 H2   ------------->  2 NH3

 

Hydrodesulfurization:           

                                  "catalyst"
            RSR + 2 H2   ------------->  2 RH + H2S

Research in our group focuses on understanding catalytic interactions as well as synthesis of metal complexes of potential use in catalytic processes, both thermal and photochemical. The fundamental steps of individual steps in catalytic processes are investigated to try to understand what controls the reaction process-what barriers are involved, and how these can be lowered. A full range of techniques is used to attack these problems, including synthesis, calorimetry, high pressure infrared studies, ESR,  NMR , kinetic, isotopic labeling, and collaboration with theoretical chemists. Students are trained in skills and techniques of real use in future academic, government, and industrial research.