Exploring the fundamentals of chemical bonding and reactivity at the atomic scale

• Applicant: Dr. Alexander Riss
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Analytical Chemistry ; Experimental Condensed Matter Physics ; Solid State and Surface Chemistry, Material Synthesis
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 453903355

This project will investigate chemical reactivity and bonding at the atomic scale. We will measure the interaction potential between individual reactants with a precision in the picometer/piconewton range. These experiments will help to establish a coherent and fundamental understanding of basic concepts of reactivity and bonding, which lie at the core of chemistry, biosciences and other related fields.In particular, we will explore metal-organic bonding, pi interaction, as well as Lewis acid-Lewis base interaction. Comparative measurements and systematic use of reactants will provide insights into longstanding questions, such as the influence of heteroatom substitution and aromaticity on pi stacking, as well as the effect of fractional atomic charge states on metal-organic coordination. Furthermore, we will quantify and map reactivity, such as Lewis acidity and basicity, at the sub-nanometer scale.These studies will be performed by direct measurements of the forces between two atomically defined reactants via atomic force microscopy (AFM) experiments in ultrahigh vacuum. Both reactants – one of them attached to the AFM tip and the other one adsorbed at the surface – will be thoroughly characterized to determine their exact structures and adsorption geometries. Analysis of the multidimensional force field of the interaction between the two reactants, measured in unprecedented detail as a function of their relative distance, spatial alignment and orientation, will provide insights into chemical behavior at the atomic scale. This project will have significant implications for the understanding and prediction of chemical reactivity, as well as for modeling of chemical bonding. Our results will contribute to technological applications, such as the fabrication of catalysts, drug discovery and rational reaction design in synthetic chemistry.

• DFG Programme: Research Grants