Iron complexes oxygen ligands

In summary, the fragmentary evidence at hand suggests that sulfur was the primordial iron complexing material and that this ligand system was selectively modified by stepwise transition to a mixed sulfur-nitrogen and sulfur-oxygen and, finally, to an all-oxygen type of coordination. 

As already briefly mentioned, the oxygen-atom insertion into Si—H bonds of silanes constitutes a selective method for the chemoselective preparation of silanols, which has been much less studied compared to the CH oxidation. This unique oxyfunctionalization of silanes is also highly stereoselective (equation 35) since, like the CH insertions, it proceeds with complete retention of configuration. A novel application of the SiH insertion process is the synthesis of the unusual iron complex with a silanediol functionality, in which selectively both Si—H bonds of the silicon atom proximate to the iron ligand are oxidized in the silane substrate (equation 36). ... 

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