This may be because the second silylation resulted in the formation of an iron(iv) complex with Fe=N double bond. This migration is reminiscent of the migration of alkyl groups to the N atom in imidoiron(iv) complex. .
This may be due to the formation of an iron (IV) complex with Fe = n double bond due to the second silylation, which is associated with the migration of alkyl groups to the N atoms in the imidoiron (IV) complex.<br>