Biological nitrogenase

Complex hydride reductions of Nj, N O, [CN] and nitriles in reactions containing complex mixtures of metal-ion species produce N—H bonded products " by reactions that may relate to those of the biological nitrogenases". Complete reaction stoichiometries are not well established. These reactions are not competitive with other methods for NH or amine synthesis. Nitrogen reacts in H O with a mixture of NaBH, S-donor ligands (e.g., NH CjM SH) and Mo and Fe salts to form NHj and NjH in low yield . In similar systems, nitriles and isonitriles are reduced to NHj and amines in low yield . 

The activation of dinitrogen molecule is a process to break or weaken the N=N bond. There are three methods to be used to activate nitrogen molecule (1) Adsorbed activation of catalyst (2) Electron donation activation by using dinitrogen complex (3) Coordinated activation by biologic nitrogenase. 

The Chinese scientists researched biological nitrogenase as well as its chemical simulation since that later parts of 1970s and have reported some achievements. However, the industrial catalyst activities are several magnitudes... 

Metal clusters in biology quest for a synthetic representation of the catalytic site of nitrogenase. R. H. Holm, Chem. Soc. Rev., 1981,10, 455-490 (137). 

Non-enzvmatic simulation of nitrogenase reactions and the mechanism of biological nitrogen fixation. G. N. Schrauzer, Angew. Chem., Int. Ed. Engl., 1975, 14, 514-522 (36). 

To overcome these problems many molecular-biological, biochemical, physiological, and technological studies were done. This mini-review will discuss possible impact of technological methods to the solution of problems shown above in the case of nitrogenase-driven hydrogen production. 

Figure 6.16 Proposed nitrogenase catalytic cycle. (Adapted with permission from Scheme 1 of Pickett, C. J. j. Biol. Inorg. Chem., 1996, 1, 601-606. Copyright 1996, Society of Biological Inorganic Chemistry.)...

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