14th Hermann Staudinger Lecture with Nobel Laureate Richard R. Schrock: "How to reduce dinitrogen catalytically to ammonia with protons and electrons"

How to reduce dinitrogen catalytically to ammonia with protons and electrons

Since the middle of the 19th century it has been known that leguminous plants (alfalfa, clover, peas, beans, etc.) have the ability to "fix" atmospheric nitrogen (N₂, 78% of our atmosphere) to give ammonia (NH₃), which can then be assimilated by plants. This process is necessary for all life and is estimated to be carried out on a scale of >10⁸ tons per year on earth. Reduction of N₂ is carried out by an enzyme in bacteria in the soil, the most efficient of which contains iron and molybdenum. The process is arguably the most complex catalytic reaction in biology. Hundreds of man years over a period of forty years were expended in efforts to reduce nitrogen to ammonia outside the enzyme before it finally was achieved with a molybdenum catalyst in 2003. The mechanism of this remarkable reaction will be discussed in some detail.