In this house we obey the laws of thermodynamics!
Homer J. Simpson, The Simpsons 1995, S06E21.
Research in the mulksgrp
We are a young independent research group at the Institute for Organic Chemistry (iOC) of the RWTH Aachen University in Germany. We embarked on our exciting journey in March 2022. Aachen is an atmospheric old German city in immediate vicinity of the borders to the Netherlands and to Belgium. The RWTH Aachen University is Germany's largest university of technology and ranks 108 worldwide across all subjects in the 2021 QS ranking. It scored place 54 worldwide and 3 in Germany for Chemistry. We are always open for discussion, students, and collaborations. Get in touch!
Doubly charged molecules with the charges placed as close as possible to each other and with as little mesomeric stabilisation as possible are highly reactive supernucleophiles or superelectrophiles. They can collectively be called superphiles. Double ylides of the type R₃N⁺–C²⁻–N⁺R₃ are the main focus for supernucleophiles, featuring almost purely Coulomb stabilisation with a double anionic central atom. Diiminium compounds such as [R₂N–C²⁺–NR₂ ↔ R₂N⁺=C=N⁺R₂] have strongly polarised double bonds which localise a major fraction of the two cationic charges at the central atom which creates a superelectrophile. Superphiles deliver strongly exergonic and very fast reactions. We are interested in the potential of carbon and silicon superphiles as fascinating reactive intermediates and, also, in their potential applications as strong Lewis acidic/basic reagents or catalysts, main group redox reagents, and as ligands for stabilising high/low oxidation state transition metal complexes. They have the potential of unleashing unseen reactivity and of replacing expensive and toxic transition metal complexes in many applications.
Steric repulsion, a direct consequence of the Pauli exclusion principle, is well-understood and is inherently included in typical quantum mechanical models of defined molecular compounds. The impact of steric pressure on reaction kinetics, however, is difficult to describe particularly in solution and in second or third order reactions due to the significant involvement of anharmonic vibrations, due to microscopic non-equilibrium states, and due to the complexity of the involved transition entropy. We develop empiric models for semi-quantitative reaction rate predictions based on directed congested volumes. Using our knowledge of reaction mechanisms allows us to introduce weighted congested volumes which consider more heavily steric bulk in the optimal reaction trajectory. These simple and intuitive cone volume models can be fitted to known reaction data to allow meaningful extrapolation and prediction of the rates of unknown reactions. This helps us design syntheses with several subsequent similar reactions, avoiding altogether the use of protecting groups due to our ability to identify the reaction rates at different reactive sites.
Featured recent contribution
The review article "Gold Carbene Complexes and Beyond: New Avenues in Gold(I)-Carbon Coordination Chemistry" is out in Gold Bulletin. It contains an overview of the title compounds (see also the image) and gives a good beginner-friendly introduction into the field.
Stable Connections/ Stabile Verbindungen
The story of how my plans were rapidly adjusted in response to travel restrictions in 2020. In a great collaboration with the Alexander von Humboldt-Foundation, Guy Bertrand's group, and Mookie Baik's group we figured out how to make the most of it for all parties in a collaboration between the UCSD (San Diego, USA), and the IBS/KAIST (Dajeon, South Korea).
The article is featured as opener of a three-part series on the homepage of the Alexander von Humboldt-Foundation that is showcasing how the new difficulties were tackled and how some people unexpectedly ended up, e.g., doing great in South Korea instead of California.