Hydrogen bonds are omnipresent in biological and supramolecular chemistry. Nevertheless, they are still mostly represented in an oversimplified manner (positively charged hydrogen attracts close-by negatively charged heteroatom) which is easy to use but often fails to explain or even qualitatively reproduce experimental findings. In my lecture, I present a state-of-the art physical model, based on quantitative molecular orbital theory, which enables a quantum-mechanically sound, yet intuitive approach to the interesting complexity of the hydrogen bond. The latter can be dissected into understandable contributions such as covalent bonding and Pauli repulsion between occupied orbitals. Complex and seemingly exotic phenomena are unraveled and explained in a unified manner: cooperativity in hydrogen bonds that stabilize quadruplex structures of DNA, variations in bond lengths and energies that are not due to differences atomic charges and the legitimacy of the secondary electrostatic interaction model.
Weak chemical interactions are the driving force for self-assembly in biological and supramolecular systems. The research in my group focusses on understanding these weak chemical interactions with Kohn-Sham MO theory and implement design principles from our computations. Our analyses of cooperativity, π assistance, and substituent effects in Watson-Crick base pairs, DNA mismatches and quadruplexes have provided groundbreaking new insights in the nature of the hydrogen bond and supramolecular aggregation. Furthermore, my group is committed to understanding the role of metal ions in self-assembly processes. The development and the implementation of chemical analysis methods to understand the nature of hydrogen bonding and chemical bonding in general are also part of my research program