Universität Regensburg - "Between Frustration and Cooperation: Ring Formation and Dihydrogen Release in Silicon-Based Systems" The interplay of frustration and cooperation opens up new perspectives for applications in bond activation and catalysis, such as the development of reversible systems for the splitting and release of dihydrogen. Small inorganic ring systems have always been highly attractive targets for exploring new bonding concepts, and they impressively demonstrate the diversity of the structural chemistry of main-group element compounds. For example, we recently reported the stereochemical influence on dihydrogen release from a protonated and isolable hydridosilane intermediate and examined the phosphine sulfide-assisted ring formation and opening. This presentation will provide an overview of the role of frustration and cooperation in ring formation and dihydrogen release processes in silicon-based systems.
Lu-Events-Kollektion
Making, Seeing, and Using Subvalent Nitrogen Species Direct C H amination chemistry via electrophilic subvalent nitrogen intermediates could radically simplify access to nitrogen containing small molecules by providing the chemical tools to selectively convert ubiquitous C H bonds to valuable C N bonds At present, challenges in chemoselectivity sustainability, and synthetic versatility prevent realization of the synthetic potential of C H amination.This talk will describe recent efforts from the Powers Laboratory that advance 1 new strategies to structurally characterize transient intermediates in C H functionalization reactions, 2 novel metal free approaches to the sustainable generation of strong oxidants needed in C H functionalization reactions, and 3 bifunctional reagent platforms that enable rapid elaboration of the primary products of C H amination Future directions and challenges will be discussed.
Ligand Based C-H Bond Weakening for Synthesis and Electrocatalysis with Earth-Abundant Metals The selective, efficient, and sustainable activation of carbon-hydrogen bonds continues to be a critical area of research. Current synthetic methodologies heavily rely on transition metal catalysts to mediate the reactivity of C-H bonds for making medicines, fuels, agrochemicals, and materials. Broadly speaking, we are interested in leveraging C-H bonds housed within chelating ligand frameworks to understand the fundamentals of C-H activation and discover new (electro)catalytic transformations.
Supramolecular Gels & Polymers: From Superhydrophobic and Slippery Surfaces to Directional Transport along Gradients In the first part, a very simple production procedure for superhydrophobic and slippery surfaces is reported. The deposition of a gel leads to the surface roughness needed for superhydrophobicity and in a way mimics the Lotus leaf effect. The second part of the talk discusses approaches to chemically and light-switchable mono- and multilayers of rotaxanes on gold surfaces. With alternating layer-by-layer deposition of the tetralactam macrocycles or the corresponding rotaxanes and various connecting metal ions, coordination oligomers with well-defined sequences can be built that are anchored on one end on the surface. The third part discusses how to use a supramolecular polymer self-assembling from easy-to-synthesize monomers as a supramolecular machine for the directional transport of particles as their cargo over millimeter distances.