Co-Fe-Mn/γ-Al O Fischer-Tropsch synthesis (FTS) catalysts were synthesized, characterized and tested for CO hydrogenation, mimicking end-of-life-tire (ELT)-derived syngas. It was found that an increase of C -C olefin selectivities to 49 % could be reached for 5 wt % Co, 5 wt % Fe, 2.5 wt % Mn/γ-Al O with Na at ambient pressure. Furthermore, by using a 5 wt % Co, 5 wt % Fe, 2.5 wt % Mn, 1.2 wt % Na, 0.03 wt % S/γ-Al O catalyst the selectivity towards the fractions of C and CH could be reduced, whereas the selectivity towards the fraction of C olefins could be improved to 12.6 % at 10 bar. Moreover, the Na/S ratio influences the ratio of terminal to internal olefins observed as products, that is, a high Na loading prevents the isomerization of primary olefins, which is unwanted if 1,3-butadiene is the target product. Thus, by fine-tuning the addition of promoter elements the volume of waste streams that need to be recycled, treated or upgraded during ELT syngas processing could be reduced. The most promising catalyst (5 wt % Co, 5 wt % Fe, 2.5 wt % Mn, 1.2 wt % Na, 0.03 wt % S/γ-Al O ) has been investigated using operando transmission X-ray microscopy (TXM) and X-ray diffraction (XRD). It was found that a cobalt-iron alloy was formed, whereas manganese remained in its oxidic phase.

Main group chemistry of dinucleating ligands based on a xanthene backbone and two parallel diiminato binding sites (Xanthdim) has been investigated. To complement studies concerning the coordination modes adopted by Xanthdim in combination with alkali metal ions a di-rubidium complex with toluene co-ligands has been prepared. Its structural parameters lie in between those previously observed AlMe 2 ) 2 (5) were isolated and fully characterised.They were found to be dynamic in solution and Al-CH 3 ···F-aryl interactions were detected in case of 5. The solid-state structures and NMR spectroscopic properties of all compounds were determined and analysed. ARTICLEScheme 3. Synthesis of 1(tol) 2 (R = 2,3-dimethylphenyl).of lithium, potassium, caesium, magnesium and calcium complexes (whereas the second valences of magnesium and calcium were saturated by amido and diiminato ligands, respectively). [31] The research described here expands these investigations to organometallic chemistry of the elements rubidium and magnesium. Moreover, for the first time a group 13 element, namely aluminium, has been included, as the Xanthdim ligand matrix may also be expected to support the cooperation of two aluminium atoms in polymerisation catalysis. Results and Discussion Group 1 Organometallics: Coordination of Rubidium Ions with Toluene Co-LigandsAddition of RbOtBu·0.81tBuOH to a solution of [ Me 2 C 6 H 3 Xanthdim]H 2 in thf caused a rapid colour change from yellow to orange indicating a spontaneous deprotonation of the ligand precursor. Subsequent addition of excessive hexane to a concentrated solution of the product in toluene led to the precipitation of [ Me 2 C 6 H 3 Xanthdim](Rb(tol)) 2 (1(tol) 2, Scheme 3). It is noteworthy that the toluene molecules coordinated to the rubidium ions can be removed completely in vacuo, resulting in [ Me 2 C 6 H 3 Xanthdim](Rb) 2 (1), which could be isolated in 81 % yield. Complex 1 is readily soluble in benzene, toluene, thf and dichloromethane; stability in dichloromethane is clearly limited, though, due to the not unexpected reactivity of 1 against halogenated solvents. However, NMR spectroscopic characterisation of a [D 2 ]dichloromethane solution was offhandedly possible, and the 1 H NMR spectrum showed characteristics that confirmed the quantitative formation of [ Me 2 C 6 H 3 Xanthdim] 2and thus a complete conversion of [ Me 2 C 6 H 3 Xanthdim]H 2 to 1: a singlet resonance at δ = 7.84 ppm for the diiminato protons instead of a doublet (as observed in case of [ Me 2 C 6 H 3 Xanthdim]H 2 ), and the absence of the signal at around 12 ppm corresponding to the acidic NH protons of the ligand precursor.Crystals of 1(tol) 2 ·2(tol) suitable for single-crystal X-ray diffraction analysis could be obtained by slow evaporation of the solvent from a concentrated solution of 1 in toluene at room temp. The molecular structure is shown in Figure 1. As recently reported for dinuclear potassium as well as caesium complexes of the [ Me 2 C 6 H 3 Xanthdim] 2ligand, [31] also in 1(tol) 2 · 2(tol) the β-di...

The potential of iron molybdates as catalysts in the Formox process stimulates research on aggregated but molecular iron-molybdenum oxo compounds. In this context, [(Me3TACN)Fe](OTf)2 was reacted with (nBu4N)2[MoO4], which led to an oxo cluster, [[(Me3TACN)Fe][μ-(MoO4-κ(3)O,O',O″)]]4 (1, Fe4Mo4) with a distorted cubic structure, where the corners are occupied by (Me3TACN)Fe(2+) and [Mo═O](4+) units in an alternating fashion, being bridged by oxido ligands. The cyclic voltammogram revealed four reversible oxidation waves that are assigned to four consecutive Fe(II) → Fe(III) transfers and motivated attempts to isolate compounds containing the respective cations. Indeed, a salt with a Fe(II)2Fe(III)2Mo(VI)4 constellation, [Fe4Mo4](TCNQ)2 (2), could be isolated after treatment with TCNQ. The Fe(II)Fe(III)3Mo(VI)4 stage could be reached via oxidation with DDQ or 3 equiv of thianthrenium hexafluorophosphate (ThPF6), giving [Fe4Mo4](DDQ)3 (4) or [Fe4Mo4](PF6)3 (5), respectively. The fully oxidized Fe(III)4Mo(VI)4 state was generated through oxidation with 4 equiv of ThPF6, leading to [Fe4Mo4](PF6)4, which showed a unique behavior: upon storage, one of the [Mo═O](4+) corners inverts, so that the terminal oxido ligand is located in the interior of the cage, leading to the formation of [[(Me3TACN)Fe]4[μ-([MoO4]3[MoO4(MeCN-κN)])-κ(3)O,O',O″)](PF6)4 (7). In this form, the compound could no longer be employed to enter the cyclic voltammogram recorded for 1, 3, and 5 from the oxidized side; no discrete redox events were observed. Compounds 1-3 and 7 were characterized structurally and 1, 3, and 7 additionally by SQUID measurements and Mössbauer spectroscopy. The data reveal a high degree of charge delocalization. (16)O/(18)O exchange experiments with labeled water performed with 1 revealed an interesting parallel with the Formox catalyst: water-(18)O exchanges its label with all of the oxido ligands (bridging and terminal). This property relates to the ion mobility being held responsible for the activity of iron molybdate catalysts compared to neat MoO3 or Fe2O3.

The fluorinated complex [(Cp(f))Ir(CO)2] (2) [Cp(f) = C5H4(CH2)2(CF2)5CF3] serves as a precursor for the photolytic activation of C-H bonds in alkanes to give [(Cp(f))Ir(CH3)(H)(CO)] (3), [(Cp(f))Ir(C5H9)(H)(CO)] (4), [(Cp(f))Ir(C6H11)(H)(CO)] (5) or [(Cp(f))Ir(C8H15)(H)(CO)] (6). In C7F14 as a solvent the latter react to yield the corresponding olefins as well as [(Cp(f))Ir(H)2(CO)] (7). Photocatalytic experiments revealed that [(Cp(f))Ir(CO)2] (2) and the non-fluorinated compound [(Cp)Ir(CO)2] (1) dehydrogenate cyclohexane in C7F14. In C6H12 as a solvent a decomposition of the catalysts was observed.

The reaction between [(TPA)Fe(MeCN)2](OTf)2 and [nBu4N](Cp*MoO3) yields the novel tetranuclear complex [(TPA)Fe(μ-Cp*MoO3)]2(OTf)2, 1, with a rectangular [Mo-O-Fe-O-]2 core containing high-spin iron(ii) centres. 1 proved to be an efficient initiator/(pre)catalyst for the autoxidation of cis-cyclooctene with O2 to give cyclooctene epoxide. To test, which features of 1 are essential in this regard, analogues with zinc(ii) and cobalt(ii) central atoms, namely [(TPA)Zn(Cp*MoO3)](OTf), 3, and [(TPA)Co(Cp*MoO3)](OTf), 4, were prepared, which proved to be inactive. The precursor compounds of 1, [(TPA)Fe(MeCN)2](OTf)2 and [nBu4N](Cp*MoO3) as well as Cp2*Mo2O5, were found to be inactive, too. Reactivity studies in the absence of cyclooctene revealed that 1 reacts both with O2 and PhIO via loss of the Cp* ligands to give the triflate salt 2 of the known cation [((TPA)Fe)2(μ-O)(μ-MoO4)](2+). The cobalt analogue 4 reacts with O2 in a different way yielding [((TPA)Co)2(μ-Mo2O8)](OTf)2, 5, featuring a Mo2O8(4-) structural unit which is novel in coordination chemistry. The compound [(TPA)Fe(μ-MoO4)]2, 6, being related to 1, but lacking Cp* ligands failed to trigger autoxidation of cyclooctene. However, initiation of autoxidation by Cp* radicals was excluded via experiments including thermal dissociation of Cp2*.

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