1. Switchable Catalysis based on Molecular Photoswitches

Supervisors: Prof.dr. Bas de Bruin (Homogeneous Catalysis), Prof.dr. Wybren Jan Buma (Molecular Photonics)

Project description
This project builds on recently developed series of novel T-type molecular photoswitches. These molecules switch to a meta-stable state with visible light and can be reverted back to the stable state by heating. The two states of these molecules have a large difference in shape and color. This makes them ideal for the development of new switchable materials and switchable catalysts. You will have the opportunity to use these new molecular photo-switches for the development of new photoswitchable polymeric materials for molecular imprinting, development of new photoswitchable catalytic cages and MOFs,  and development of new photoswitchable catalyst using the switch as a ligand. Cages in polymeric material obtained by molecular imprinting techniques are expected to change shape and size upon photochemical excitation and thermal relaxation, creating strain and stress to molecules captured in the cavities of these materials. As such, the catalytic activity of these molecular imprinting materials should change under light or heat. Photoswitchable cages or MOFs would also have several interesting applications in switchable catalysis. Furthermore new switchable bidentate ligands can be developed on the basis of these new photoswitches, imposing different reactivity of the catalyst in the two switching states. Additional experiments focused on the switch itself will focus on increasing the quantum yields, reducing fatigue, increasing the molar extinction coefficients, and red-shifting the absorption wavelengths for switching.

2. Rational synthesis of zeolites by combining experiments and simulation

Supervisors: Prof.dr. Gadi Rothenberg (Heterogeneous Catalysis and Sustainable Chemistry), Prof.dr. Evert Jan Meijer (Computational Chemistry)

Summary
Zeolites are known for over 150 years. In theory, there are over two million structures. In practice, only 292 have been made. We know how their formation starts, and we know how it ends, but the rest is a complex colloidal mess. Now, using advanced computational and experimental methods, we will connect the entire process. Moreover, we will use the models and experiments to understand and optimise the conditions for formation of metal-carbide sites in the zeolites. Ultimately, we look to make new zeolite catalysts for applications such as selective biomass conversion, methane oxidation and plastics recycling.

Project description
In the first part of the project we will run advanced computational models in two stages. First, we will work with a few hundred atoms, unraveling the assembly of small oligomers into nanoscale precursors. The atomistic scale models will be validated with experimental spectroscopic data. Second, we will develop coarse-grained models to study the growth of sub-micron colloidal crystallites. The models will be designed using the experimental parameters from hydrothermal zeolite synthesis, and based on the insights from the atomistic scale simulations. The results would give sufficient information for designing zeolites which we will then synthesise and validate in the lab. We seek candidates with a PhD in chemistry, materials science or chemical engineering. You must have proven experience in atomistic and coarse-grained modelling, but you’re also enthusiastic about labwork and catalyst synthesis. You have excellent communication skills in English and strong people skills.  We offer a supporting work environment in a multicultural setting, intelligent and sympathetic colleagues who care about each other as well as about getting results.

For more information see:
http://hims.uva.nl/hcsc
https://hims.uva.nl/content/research-groups/computational-chemistry/computational-chemistry.html

3. Homogeneous Catalysis for CO2 hydrogenation and methanol dehydrogenation  

Supervisors: Prof.dr. Joost Reek (Homogeneous Catalysis), Prof.dr. Bas de Bruin (Homogeneous Catalysis)

Project description
Hydrogenation of captured CO2 to methanol, and the subsequent on-demand dehydrogenation to produce electricity is a viable strategy to mitigate climate change. In this project we aim to contribute to achieving a “methanol economy” by designing, synthesizing and studying new homogeneous base-metal catalysts for CO2 hydrogenation. Although several homogenous catalysts have been reported for CO2 hydrogenation, ones that selectively form methanol are very scarce as typically metal complexes are optimized for one of the steps of the cascade from CO2 to methanol, i.e. the CO2 reduction to formic acid, or the CO reduction to methanol.  In this research program we will explore various approaches to develop suitable homogeneous catalysts for these conversions.

4. Exploring emerging properties from a complex catalyst mixture

Supervisors: Prof. dr. Joost Reek (Homogeneous Catalysis), dr. Bob Pirok (Analytical Chemistry)

Project description
Chemical catalysis currently is often focused on single steps under well controlled conditions. In nature, on the other hand, chemical synthesis occurs in a complex medium of compounds and is based on a complex network of reactions. Control over the outcome typically is based on feedback loops, the presence of effector molecules and responsive systems. Generating synthetic systems that operate via similar principles is scientifically challenging yet hold promise for the future development of sustainable chemical processes in new ways. In this proposal we will explore three different strategies to generate complex catalyst systems in which emergent properties such as responsive behavior and new catalytic networks. We will use supramolecular cages as catalysts to design reaction networks with feedback loops, and develop analytical tools for the analysis of multiple reactions under various reaction conditions.

5.  Sustainable production of chemicals and fuels using liquid-phase plasma reactors

Supervisors: dr. Shiju Raveendran Shiju (Catalysis Engineering), Prof.dr. Jan van Maarseveen (Synthetic Organic Chemistry)

Summary
Traditionally, chemical reactions are done in thermally heated reactors. The objective of this project is to develop plasma-in-liquid reactor to conduct chemical reactions at low temperature and pressure. The reactor will produce energetic species which will react with the liquid reactants and convert them into value-added products, without the using external reactor heating. The addition of catalysts to the reactor may benefit from the plasma-catalysis synergistic interaction, which could enhance the selectivity to desired products in complex catalytic reactions.

Project description
This project aims to develop a plasma-in-liquid reactor will produce energetic species which will react with the liquid reactants, converting them into value-added products. This is expected to avoid external reactor heating which is an advantage for temperature sensitive chemical conversions.

This reactor system will be used to do oxidation reactions and reactions with temperature sensitive substrates. The experiments will also involve the use of catalysts within the reactor which is expected to produce a plasma-catalysis synergistic interaction, which could enhance the selectivity to desired products in complex catalytic reactions.

For this project, we are looking for a motivated, independent post-doctoral candidate who has already experience in working with plasma reactor systems. Knowledge/experience in catalysis, organic chemistry, common laboratory analytical techniques are desirable.

6. Electrifying Organic Synthesis

Supervisors: dr. Tati Fernández-Ibáñez (Synthetic Organic Chemistry), dr. Amanda Garcia (Heterogeneous Catalysis and Sustainable Chemistry)

Summary
The use of renewable electricity instead of stoichiometric amounts of oxidizers or reducing agents in synthesis is very appealing for economic and ecological reasons. However, in certain reaction the functional-group compatibility with electrochemical methods is limited by the high overpotentials required for the electron transfer from the electrode to the substrate, which can cause decomposition of functional groups and side reactions. In this project, we aim to unlock the full potential of electrochemicals methods by investigating the electron transfer processes in direct (DE) and indirect (IE) mediated electrolysis.

Project description
The implementation of electrochemical methods to the synthesis of organic molecules has undergone a revival during the last few decades. The use of renewable electricity (i.e. solar, and wind) instead of stoichiometric amounts of oxidizers or reducing agents in synthesis is very appealing for economic and ecological reasons, and it represents a major driving force for research efforts in this area.

Oxidation reaction are among the most relevant transformation in organic synthesis because of their ability to increase chemical complexity, incorporate new heteroatoms and other functional groups into organic molecules, and streamline synthetic routes to target molecules. However, the use of chemical oxidants is still a commun practice in organic laboratories as electrooxidation reactions lack generality. In this context, one of the most relevant electrochemical oxidations is the Shono oxidation reaction that allows the α-functionalization of amines and carbamates to an iminium ion intermediates that can be trapped with an alcoholic solvent molecule. However, the functional-group compatibility of this method for both the nitrogen-containing compound and the nucleophile is limited by the high overpotentials required for the electron transfer (ET) from the electrode to the substrate, which can cause decomposition of functional groups and side reactions.

In this project we aim to unlock the full potential of the Shono oxidation reaction by using two different strategies. In the first one, we will design and synthesize new redox organic-mediators that will permit to perform oxidation reactions at lower overpotentials to increase the functional-group compatibility (indirect electrolysis). In the second approach, we will develop inexpensive heterogeneous Ni-based electrode materials on glassy carbon support to perform selective oxidtion reactions (direct electrolysis). The lastest goal of the project will be to develop enantioselective electrochemical processes.

7. Molecular Analytics for Closed-loop (photo)Catalysis Optimization

Applicants: dr. Andrea Gargano (Analytical Chemistry), dr. Timothy Noël (Flow Chemistry)

Summary
Photocatalytic reactions enables a highly selective approach to unlock unique reaction pathways, provide mild reaction conditions and allow for efficient green energy use. However, choice of reaction conditions in requires extensive optimizations and, detecting and monitoring the molecular species generated often the bottleneck.

In the Molecular Analytics for Closed-loop (photo)Catalysis Optimization project the team of dr. T.Noel and A.Gargano will combine automated reaction optimization platform to liquid chromatography and mass spectrometry methods to monitor the chemical species produced during photocatalysis experiments. Algorithm based optimization will allow to optimize for conditions such as  high yield and productivity, and for green metrics.

Project description
Photocatalytic reactions enables a highly selective approach to unlock unique reaction pathways, provide mild reaction conditions and allow for efficient green energy use. However, choice of reaction conditions in requires extensive optimizations and, detecting and monitoring the molecular species generated often the bottleneck.

In the Molecular Analytics for Closed-loop (photo)Catalysis Optimization we propose to research novel approaches to couple online flow chemistry experiments with ultrahigh-pressure liquid chromatography-mass spectrometry to obtain online quantitative measurements of the molecular structures generated in flow experiments and couple them with AI-driven synthetic optimization processes. The combination of these will allow for performing quantitative molecular analysis. Data integration and extraction will be performed via python scripts, allowing us to monitor the yield and impurity profile of each condition, allowing us to develop models for synthetic optimization.

This post doc position is embedded in the labs of both the Flow Chemistry group and the Analytical Chemistry Group at University of Amsterdam, where you will be supervised by prof. dr. T. Noel and dr. Andrea Gargano.

Requirements

• Ph.D. degree in chemistry or chemical engineering with a good publication record
• Ability to work independently, design, and execute experimental strategies to advance projects.
• If specific skills or experiences described in this project are not part of your background, you are willing to learn and develop them in your career

Desired Experience, Skills, and Interests

• Familiarity with statistical methods for data analysis
• Experience with liquid chromatography and mass spectrometry
• Familiarity with flow chemistry, catalysis
• Experience with programming (e.g. python/ Matlab)