Five-coordinate iron(II) NXHY complexes supported by tris(phosphino)silyl ligands: Oxidation and reduction of iron bound hydrazine

Mapping the pathway of N_2 redn. by nitrogenase enzymes remains a coveted goal for synthetic chemists. To aid in elucidating the pathways of biol. nitrogen fixation, studies of the coordination behavior of various reduced N_2 ligands bound to a single iron site are of interest. Recently we began to work with anionic SiP^R_3 ligands (R = Ph and iPr) in order to accommodate mononuclear 5-coordinate iron species that exhibit paramagnetic ground states in both the iron(I) and iron(II) oxidn. states. Details of various iron complexes with nitrogenous ligands, such as 5-coordinate iron(II) dinitrogen, hydrazine, ammonia, hydrazido and diazenido species, will be presented in addn. to reactivity studies including base catalyzed N-N bond cleavage, oxidn. and hydrogenation chem