Catalysis

We are interested in finding fundamentally new ways to transform molecules. In this spirit, we have introduced catalysis with anion-π interactions in 2013, followed by catalysis with chalcogen bonds in 2017 and catalysis with pnictogen bonds in 2018. All three discoveries relate to our general objective to integrate unorthodox or "exotic" interactions into functional systems, and more generally, to apply lessons from supramolecular chemistry to create function.

The idea of anion-π catalysis is to stabilize anionic transitions states on π-acidic aromatic surfaces. Currently, basic research focuses on anion-π catalysts, particularly naphthalenediimides (NDIs), perylenediimides (PDIs), fullerenes and higher carbon allotropes. We are passionate about their integration into more complex systems: Anion-π enzymes, synergistic anion-(π)n-π-catalysis on π-stacked foldamers, electric-field-assisted anion-π catalysis, fullerene-centered catalytic triads. We are equally excited about applications to different reactions: Asymmetric anion-π catalysis for enolate, enamine, iminium and transamination chemistry, non-adjacent stereogenic centers, long-distance charge displacements in cascade cyclizations, concerted cycloadditions (exo Diels-Alder), the holy grail in the group is something like the anionic version of the cyclization of triterpenes into steroids. Ultimately, it seems reasonable to expect that the introduction of new ways to transform molecules should provide access to new reactivities and new molecules with new properties.

Catalysis with other "exotic" interactions is also very appealing to us. Early 2017, we reported the first example for non-covalent catalysis with chalcogen bonds. The extension to catalysis with pnictogen bonds emerged in 2018 from a screen over the periodic table, with antimony as the winner. Dithienothiophenes (DTT) and benzodiselenazoles (BDS) have been introduced as privileged scaffolds for transition-state stabilization in the focal point of precisely oriented sigma holes, comparable of classics such as bipyridines for cation binding or bipyrroles for anion binding with hydrogen bonds. For catalysis, chalcogen and pnictogen bonds can be considered as complementary to the highly delocalized anion-π interactions, with focused sigma holes to operate at high precision in hydrophobic media.

Methods: These projects generate expertise in synthetic methodology, in combination with total synthesis, supramolecular analysis and (optional) extension to molecular modeling, optoelectronic materials characterization, surface chemistry (heterogeneous catalysis on electrodes), biocatalysis.

Collaborations: These projects offer optional in-house collaboration possibilities with regard to computational chemistry and ultrafast photophysics. They are loosely connected to the NCCR Molecular System Engineering, with possible collaboration with other members (artificial enzymes, device engineering), NCCR group meetings and retreats.

Some recent graphical abstracts: