Single iron sites

Single iron site proposal illustrating essential features of the lowest energy path forwarded by Blochl and coworkers. 

Model Studies that May be Relevant to N2 Fixation Involving a Single Iron Site... 

As noted previously, it is possible that a single iron site initiates the N2 reduction process, but that hi- or polymetallic N Hj, intermediates are formed at later stages. While SeUmanris work provides examples of some such complexes for octahedral iron, scant precedent exists for such species with respect to low-coordinate iron, and this is especially true for bridged N, NH and NH2 Hgands. Our laboratory has therefore pursued the systematic preparation of such species using the [BP3]Fe platforms and has found that several unique species can indeed be prepared [89, 101]. 

Active Site Structure of Rubredoxin There are several non-heme iron-sulphur proteins that are involved in electron transfer. They contain distinct iron-sulphur clusters composed of iron atoms, sulphydryl groups from cysteine residues and inorganic or labile sulphur atoms or sulphide ions. The labile sulphur is readily removed by washing with acid. The cysteine moieties are incorporated within the protein chain and are thus not labile. The simplest type of cluster is bacteria rubredoxin, (Cys-S)4 Fe (often abbreviated FelSO where S stands for inorganic sulphur), and contains only non labile sulphur. It is a bacterial protein of uncertain function with a molecular weight of 6000. The single iron atom is at the centre of a tetrahedron of four cysteine ligands (Fig.). 

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