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1: The influence of confinement on on-surface reactions, revealed in real space

The aim of the project is to determine the effect of the dimensionality of confinement onto elementary surface reactions and disentangle geometrical confinement effects from changes due to electronic alterations of the molecules on a fundamental level. Laser-induced photochemical reactions are studied on patterned surfaces on metal surface. The molecules comprise nitrenes, phosphines, and phthalocyanines. Several scanning tunneling microscope techniques are applied, e.g. at low temperature in ultrahigh vacuum or with meV resolution, complemented by in-situ molecule deposition and laser activation as well as Low-temperature infrared spectroscopy under UHV conditions with sub-meV resolution.

Principal Investigator: Karina Morgenstern (Ruhr-Universität Bochum)

2: Towards QM-based machine learning potentials for supramolecular metallacages and enzymes

The use of machine learning for developing quantum mechanics-based potential energy functions that can describe chemical reactions and are at the same time computationally efficient is revolutionizing chemistry.
In this computational chemistry PhD project, efficient and accurate potentials will be developed and applied to study confinement effects in metal-containing systems, such as supramolecular metallacages and metalloenzymes. The project is carried out in collaboration with the group of Fernanda Duarte (Oxford University), and a 3-month research stay (fully funded) of the PhD candidate in Oxford is an integral part of the project.

Principal Investigator: Lars Schäfer (Ruhr-Universität Bochum)

3: Catalysis in the confined space of metallocontainers

The aim of the project is to utilize charge-neutral self-assembled metallocontainers as catalysts for enantioselective C-C bond formations. The design is guided by computational models and the ligand synthesis for the formation of metallocontainers is based on a wide range of organic reactions, e.g., ester or ether formations, bromination or substitution reactions, Sonogashira or Suzuki coupling reactions and click chemistry. The container self-assembly is driven by coordination of ligands to suitable metal centers and the properties towards guest uptake and the catalytic activity of the systems is investigated by a broad range of analytical methods. Resulting from this, the project offers a conclusive training in a variety of fields for PhD candidates while having a strong focus on organic chemistry which arises from the synthetic part and the goal of using the systems as catalysts.

Principal Investigator: David Van Craen (TU Dortmund)

4: Properties of metallocontainers in membrane-like structures at interfaces

The aim of the project is to study the performance of charge-neutral metallocontainers at the water / organic interface towards host-guest binding, guest transport and catalysis. Aqueous solutions are of utmost importance since biological processes take place in such solutions and water is essential for green chemistry. However, receptor systems are often not water soluble which hinders investigations in this important medium. The container development follows the same strategy as before and the receptors will be embedded into membrane-like structures and studied by analytical methods such as NMR, UV/Vis, fluorescence or CPL spectroscopy, ITC and different imaging techniques. Because of that, the PhD candidate will obtain a broad training with a strong focus on physical organic chemistry.

Principal Investigator: David Van Craen (TU Dortmund)

5: Understanding the role of micelle nanoconfinement on the electrochemical synthesis of metallic nanoparticles from multiscale molecular dynamics simulations

Synthesis of nanomaterials with desired shape and size is very important for their potential applications in catalysis, sensing, plasmonics. The reverse micellar method allows to control size and morphology through the micelle cavity diameter. In this method reverse micelles are formed by two non-miscible components and a surfactant which is characterized by amphiphilic properties. The electrochemical synthesis of metallic gold nanoparticles using micelle confinement has been experimentally achieved [1] and is currently under investigation e.g. in sodium dodecyl sulphate in toluene and HAuCl₄ solutions with and without HBF₄. The confined nanoreactor in the micelle cavity provide a unique environment whose properties can be exploited to obtain control not only on morphology, but also in mass distribution to obtain alloy or core-shell nanoparticles. To advance the tailored synthesis a microscopic understanding of the confined nanoreactor environment is a key step. In this project we aim to use multiscale molecular dynamics simulations to address the following questions: (i) what is the micelle structure and different molecular species distribution? (ii) what is the role of the cations and anions in the solutions and how charges species can be used to tune shape and morphology? (iii) what happens when the micelle is adsorbed on the electrode during reduction?
The project will be in close collaboration with the groups of K. Tschulik and A. Rosenhahn who will permit to access structural data (SAXS, FTIR) as well as electrochemical data (voltammetry, chronoamperometry)

[1] M. V. Evers, M. Bernal, B. Roldan Cuenya, K. Tschulik, Angew. Chem. Int. Ed. 2019, 58, 8221.

Principal Investigator: Marialore Sulpizi (Ruhr-Universität Bochum)