Daniel Leitner

Sulfur hexafluoride (SF ₆ ) is a persistent, highly potent greenhouse gas that is accumulating in the atmosphere at an increasing rate, exacerbating climate change. Whereas current degradation methods rely on forcing conditions to dissociate the inert molecule and additionally require post-treatment with basic solution to obtain harmless products, we show that SF ₆ is mineralized in a single step at ambient temperature using potassium hydroxide in water/isopropyl alcohol mixtures under UV irradiation. The reaction proceeds via an autocatalytic mechanism, where in situ-generated acetone acts as a photosensitizer, leading to the selective formation of potassium sulfite and fluoride salts. Compared to existing methods, this approach eliminates the need for extreme temperatures, hazardous catalysts, or post-treatment, providing a scalable and easy-to-apply strategy for SF ₆ degradation.

We report the synthesis of a series of molybdenum nitrido complexes supported by bis-phenolate N-heterocyclic and mesoionic carbenes, to investigate their (electro-)chemical properties in the absence and presence of protons for ammonia production.

We report the facile and high‐yielding multi‐gram synthesis of pentavalent heavy group VI mono‐imido complexes with the general formula M(NR)Cl₃L_n (M=Mo, W, R=Aryl or Alkyl, L=DME n=1 or Py n=2) following a comproportionative imido group transfer procedure starting from the corresponding bis‐imido complexes and MCl₄. The procedure works well for both aryl and alkyl imido ligands, in the case of molybdenum but only for alkyl imidos in the case of tungsten. Overall, five mono‐imido complexes have been structurally characterized and purity is established by elemental analysis and EPR spectroscopy.

Twenty‐one vanadium bis‐phenolate benzimidazolylidene complexes, spanning three oxidation states, have been investigated. Special emphasis is placed on their salt metathesis reactivity and the accessibility of the +IV oxidation state by reductive or oxidative routes, starting from vanadium(V) or vanadium(III) respectively. While the reductive route is highly dependent on the reducing agent and starting material used, the oxidative route gives clean access to vanadium(IV) dihalide complexes. The low‐valent vanadium(III) complexes are excellent precursors for salt metathesis reactions which lead to the isolation of a rare vanadium(III) NHC alkyl complex. All new complexes have been characterized by (paramagnetic) ¹H NMR and ⁵¹V NMR, UV–VIS, IR and EPR spectroscopy as well as elemental analysis. Cyclic voltammetry has been performed in selected cases to study the influence of imido or phenolate supporting ligands towards the redox‐potential of the vanadium(V/IV) redox couple compared to the parent oxo‐chlorido complex A.