Chalcogen-nitrogen compounds and their coordination complexes

The main challenge in the extensive research carried out for heterocyclic sulfur-nitrogen compounds was originally to understand the unexpected structural and bonding properties of these species. The superconducting properties of (SN)_x have aroused tremendous interest in this area of chemistry and is boosting the activity in the synthetic and structural work of sulfur-nitrogen compounds and directing it towards the preparation of heavier chalcogen nitride polymers (SeN)_x, (TeN)_x, and the mixed chalcogen-nitrogen polymers, which are expected to have enhanched electrical properties. Our objective is the preparation and characterization of mixed chalcogen-nitrogen molecules and their transition metal complexes with the goal of finding usable precursors for the polymeric chalcogen nitrides and to establish the plausibility of the polymer formation.

Organotellurium and –selenium compounds and their ligand chemistry

Binary transition metal selenides and tellurides such as PdTe and NiTe continuously find potential applications in materials science. A low-temperature route to these important compounds may be provided by transition metal complexes containing organoselenide and -telluride ligands, an area of organometalic chemistry that has been rapidly expanding during the past decades. The preparation of complexes containing organochalcogen ligands can be carried out by the oxidative addition of the organochalcogen compounds to low-valent transition metal centers or by direct ligand substitution.

Homo- and Heteronuclear Chalcogen Molecules and Ions

The present work on polyatomic chalcogen molecules and chalcogen-halogen cations aims at the understanding of their novel bonding features and complicated solution behaviour. While many chalcogen-halogen cations have been identified in the solid state and characterized by single crystal X-ray crystallography, the speciation is not necessarily the same in solution, especially in the case of dications which are generally thermodynamically unstable in the gas phase. For example, solid S₃N₂(AsF₆)₂ completely dissociates in liquid SO₂ to give SN⁺, SNS⁺, and AsF₆^- ions.

Precursors for Exhaust Gas Catalysts

The requirement of high thermal stability and activity, which the current three-way catalysts have to fulfill, is one of the most crucial demands for a successful commercial application. Therefore, the understanding of deactivation phenomena and deactivation correlations is an important issue in the design and preparation of a catalytic system. Temperature has become an increasingly important factor for the deactivation of a three-way catalyst due to the fact that pre-converter is installed near to the engine to confirm the efficient purification of hydrocarbons, and therefore, catalytic materials are exposed to high operation temperatures. Catalyst testing and ageing in an engine bench or on-road is slow and expensive, and thus, there is a need for a rapid laboratory scale ageing procedures.