Mononuclear five- and six-coordinate iron hydrazido and hydrazine species

Caroline T. Saouma, Connie C. Lu, Jonas C. Peters

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


This article describes the synthesis and characterization of several low-spin iron(II) complexes that coordinate hydrazine (N2H 4), hydrazido (N2H3-), and ammonia. The sterically encumbered tris(di-meta-terphenylphosphino)borate ligand, [PhBPmter3]-, is introduced to provide access to species that cannot be stabilized with the [PhBPPh 3]- ligand ([PhBPR3]- = PhB(CH2PR2)3-). Treatment of [PhBPmter3]FeMe with hydrazine generates the unusual 5-coordinate hydrazido complex [PhBPmter3] Fe(η2-N2H3) (1), in which the hydrazido serves as an L2X-type ligand. Upon coordination of an L-type ligand, the hydrazido shifts to an LX-type ligand, generating [PhBPmter 3]Fe(L)(η2-N2H3) (L = N 2H4 (2) or NH3 (3)). In contrast, treatment of [PhBPPh3]FeMe with hydrazine forms the adduct [PhBP Ph3]Fe(Me)(η2-N2H4) (5). Complex 5 is thermally unstable to methane loss, generating intermediate [PhBPPh3]Fe(η2-N2H3), which undergoes bimolecular coupling to produce {[PhBPPh 3]Fe}2(μ-η11-N 2H4)(μ-η22-N 2H2). The oxidation of these and related hydrazine and hydrazido species is also presented. For example, oxidation of 1 or 5 with Pb(OAc)4 results in disproportionation of the N2H x ligand (x = 3, 4), and formation of [PhBPR 3]Fe(NH3)(OAc) (R = Ph (9) and mter (11)).

Original languageEnglish (US)
Pages (from-to)10043-10054
Number of pages12
JournalInorganic chemistry
Issue number18
StatePublished - Sep 17 2012


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