A Series of Iron Nitrosyl Complexes {Fe-NO} and a Fleeting {Fe-NO} Intermediate en Route to a Metalacyclic Iron Nitrosoalkane.

Iron-nitrosyls have fascinated chemists for a long time due to the noninnocent nature of the NO ligand that can exist in up to five different oxidation and spin states. Coordination to an open-shell iron center leads to complex electronic structures, which is the reason Enemark-Feltham introduced the {Fe-NO} notation. In this work, we succeeded in characterizing a series of {Fe-NO} complexes, including a reactive {Fe-NO} intermediate.

Monomeric Fe(iii) half-sandwich complexes [Cp'FeX] - synthesis, properties and electronic structure.

The half-sandwich complex [Cp'Fe(μ-I)] (1; Cp' = η-1,2,4-(MeC)CH) is cleaved when heated in toluene to form a cation-anion pair [{Cp'Fe(η-toluene)}{Cp'FeI}] (2), in which the two Fe(ii) atoms adopt different spin states, i.e., a low-spin (S = 0) and a high-spin (S = 2) configuration.

Reactivity studies on [Cp'Fe(μ-I)]: nitrido-, sulfido- and diselenide iron complexes derived from pseudohalide activation.

The iron half-sandwich [Cp'Fe(μ-I)] (Cp' = 1,2,4-(MeC)CH, ) reacts with the pseudohalides NCO, SCN, SeCN and N to give [Cp'Fe(μ-NCO)] (), [Cp'Fe(μ-S)] (), [Cp'Fe(μ-Se)] () and [Cp'Fe(μ-N)] (), respectively. Various spectroscopic techniques including X-ray diffraction, solid-state magnetic susceptibility studies and 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 complexes to .

Synthesis and characterization of divalent manganese, iron, and cobalt complexes in tripodal phenolate/N-heterocyclic carbene ligand environments.

Two novel tripodal ligands, (BIMPN(Mes,Ad,Me))(-) and (MIMPN(Mes,Ad,Me))(2-), combining two types of donor atoms, namely, NHC and phenolate donors, were synthesized to complete the series of N-anchored ligands, ranging from chelating species with tris(carbene) to tris(phenolate) chelating arms. The complete ligand series offers a convenient way of tuning the electronic and steric environment around the metal center, thus, allowing for control of the complex's reactivity. This series of divalent complexes of Mn, Fe, and Co was synthesized and characterized by (1)H NMR, IR, and UV/vis spectroscopy as well as by single-crystal X-ray diffraction studies.

Characterization of an iron-ruthenium interaction in a ferrocene diamide complex.

Reaction of [fc(NH2)2]RuCl2(PPh3)2 (fc = 1,1'-ferrocenylene) with 2 equiv of KO(t)Bu led to the formation of a diamido ruthenium complex, [fc(NH)2]Ru(PPh3)2, whose solid-state molecular structure revealed a short Fe-Ru distance. A metal-to-metal charge transfer band was observed in the electronic absorption spectrum of [fc(NH)2]Ru(PPh3)2. The Fe-Ru interaction was characterized by resonance Raman spectroscopy for the first time and also by (1)H NMR, UV-vis, NIR, Mössbauer spectroscopy, and X-ray crystallography.

The biology and chemistry of high-valent iron-oxo and iron-nitrido complexes.

Selective functionalization of unactivated C-H bonds and ammonia production are extremely important industrial processes. A range of metalloenyzmes achieve these challenging tasks in biology by activating dioxygen and dinitrogen using cheap and abundant transition metals, such as iron, copper and manganese. High-valent iron-oxo and -nitrido complexes act as active intermediates in many of these processes.