Reactivity studies on [Cp′Fe(μ-I)]2: nitrido-, sulfido- and diselenide iron complexes derived from pseudohalide activation. Issue 5 (11th April 2017)

• Record Type: Journal Article
• Authors: Reiners, Matthias; Maekawa, Miyuki; Daniliuc, Constantin G.; Freytag, Matthias; Jones, Peter G.; White, Peter S.; Hohenberger, Johannes; Sutter, Jörg; Meyer, Karsten; Maron, Laurent; Walter, Marc D.
• Is Part Of: Chemical science. Volume 8:Issue 5(2017)
• Page Start: 4108
• Page End: 4122
• Publication Date: 2017-04-11
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7sc00570a
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Facile pseudohalide activation occurs in the reaction of SCN −, SeCN − and N3 − with the iron half-sandwich [Cp′Fe(μ-I)]2 . Abstract : The iron half-sandwich [Cp′Fe(μ-I)]2 (Cp′ = 1, 2, 4-(Me3 C)3 C5 H2, 1 ) reacts with the pseudohalides NCO −, SCN −, SeCN − and N3 − to give [Cp′Fe(μ-NCO)]2 (2 ), [Cp′Fe(μ-S)]2 (3 ), [Cp′Fe(μ-Se2 )]2 (4 ) and [Cp′Fe(μ-N)]2 (5 ), respectively. Various spectroscopic techniques including X-ray diffraction, solid-state magnetic susceptibility studies and 57 Fe Mössbauer spectroscopy were employed in the characterization of these species. Mössbauer spectroscopy shows a decreasing isomer shift with increasing formal oxidation state, ranging from Fe(ii ) to Fe(iv ), in complexes1 to5 . The sulfido-bridged dimer3 exhibits strong antiferromagnetic coupling between the Fe(iii ) centers. This leads to temperature-independent paramagnetism (TIP) at low temperature, from which the energy gap between the ground and the excited state can be estimated to be 2 J = ca. 700 cm −1 . The iron(iv ) nitrido complex [Cp′Fe(μ-N)]2 (5 ) shows no reactivity towards H2 (10 atm), but undergoes clean reactions with CO (5 bar) and XylNC (Xyl = 2, 6-Me2 C6 H3 ) to form the diamagnetic isocyanate and carbodiimide complexes [Cp′Fe(CO)2 (NCO)] (7 ) and [Cp′Fe(CNXyl)2 (NCNXyl)] (8 ), respectively. All compounds were fully characterized, and density functional theory (DFT) computations provide useful insights into their formation and the electronic structures of complexes3 and5 .