Bio-organometallic Approaches to Nitrogen Fixation Chemistry

Biological and industrial nitrogen fixation are the processes by which one of the most inert molecules, N_2, is transformed into a bioavailable nitrogen source (e.g. NH_3) that can be incorporated into all nitrogen-containing biomolecules [1]. As such, nitrogen fixation is essential to sustaining life on this planet, and has attracted intense scrutiny among biological and chemical communities for decades [2-4]. The mechanism by which nitrogenase enzymes promote the biological reduction of nitrogen under ambient conditions remains an unsolved and fascinating problem [4-6]. Nature's solution to fixing nitrogen stands in sharp contrast to that which humanity has adopted, i.e. the Haber-Bosch process for ammonia synthesis that is carried out at approximately 200 atm and 500°C. This Herculean feat of chemical engineering provides, in net, about 50% of the nitrogen atoms that wind up in all human beings on this planet [7]. From a chemists perspective, however, this remains a brute force and high-energy solution to the nitrogen fixation problem, especially given the knowledge that nature can fix N_2 under ambient conditions.