ic1021627_si_002.cif (260.34 kB)

Iron-Mediated Hydrazine Reduction and the Formation of Iron-Arylimide Heterocubanes

Download (260.34 kB)
posted on 21.02.2011, 00:00 by Michael J. Zdilla, Atul K. Verma, Sonny C. Lee
The reaction of Fe(N{SiMe3}2)2 (1) with 1 equiv of arylthiol (ArSH) results in material of notional composition Fe(SAr)(N{SiMe3}2) (2), from which crystalline Fe2(μ-SAr)2(N{SiMe3}2)2(THF)2 (Ar = Mes) can be isolated from tetrahydrofuran (THF) solvent. Treatment of 2 with 0.5 equiv of 1,2-diarylhydrazine (Ar′NH−NHAr′, Ar′ = Ph, p-Tol) yields ferric-imide-thiolate cubanes Fe43-NAr′)4(SAr)4 (3). The site-differentiated, 1-electron reduced iron-imide cubane derivative [Fe(THF)6][Fe43-N-p-Tol)4(SDMP)3(N{SiMe3}2)]2 ([Fe(THF)6][4]2; DMP = 2,6-dimethylphenyl) can be isolated by adjusting the reaction stoichiometry of 1/ArSH/Ar′NHNHAr′ to 9:6:5. The isolated compounds were characterized by a combination of structural (X-ray diffraction), spectroscopic (NMR, UV−vis, Mössbauer, EPR), and magnetochemical methods. Reactions with a range of hydrazines reveal complex chemical behavior that includes not only N−N bond reduction for 1,2-di- and trisubstituted arylhydrazines, but also catalytic disproportionation for 1,2-diarylhydrazines, N−C bond cleavage for 1,2-diisopropylhydrazine, and no reaction for hindered and tetrasubstituted hydrazines.