This thesis systematically studies the physicochemical properties of non-planar, propeller-shaped, polycyclic aromatic hydrocarbons. The synthesis of several so-called propellerenes is described on a gram scale, using optimized procedures aimed at using less hazardous reagents and reducing the amount…

Understanding how chemical complexity emerges during star formation requires connecting molecular material preserved in interstellar ices with that observed in the gas phase after protostellar heating begins.

Carbohydrates, or sugars, are the most diverse and most abundant biomolecules known. However, the isolation of carbohydrate samples in sufficient amounts and purity is often impractical or even impossible, so the chemical synthesis of glycosides becomes relevant. The glycosylation reaction, in which…

Carbohydrates, alongside proteins and nucleic acids, constitute a crucial and versatile family of biomolecules present in all life forms. They manifest as monosaccharides, oligosaccharides, and polysaccharides, covalently bonded to proteins and fats. Carbohydrates are integral to plant and arthropod…

Hydrogen peroxide (H2O2) is an important bulk chemical that is used in various industrial processes. More than 95% of the H2O2 used in industry is made via the anthraquinone process during which a large amount of energy is going to waste.

Promotor: G.R. de Snoo

This thesis describes the synthesis and biochemical evaluation of a variety of cyclophellitol based activity-based probes and inhibitors targeting various endo- and exo-acting retaining glycosidases. In the last two decades a variety of probes and inhibitors for (hemi)cellulose degrading enzymes have…

In a typical glycosylation reaction, a donor is activated to form a (variety of) electrophilic species which can react with a nucleophilic acceptor, following a reaction mechanism having both SN1 and SN2 character.

The confinement of molecular catalysts in metal-organic frameworks has the potential to lead to significant improvements in selectivity, long term activity and catalyst stability.

This thesis is largely an experimental study on the formation of solid-state simple and complex organic molecules in the H2O-rich and CO-rich ice phases of dense interstellar clouds and dark cores.

Stars like the sun are born in large molecular clouds existing from gas and dust. During the formation process, the chemical composition of the material can be altered drastically by the changing physical conditions.

In deze opleiding, verzorgd door het Leiden Institute of Chemistry, zoek je naar oplossingen voor complexe, maatschappelijke problemen in volksgezondheid en milieuvraagstukken. We bieden op maat gemaakte, individuele studieprogramma’s, en je hebt de mogelijkheid om onderzoek te doen in het buitenland…

Complex Organic Molecules (COMs) have been detected in objects across different stages of stellar evolution.

In this thesis the combinatorial use of bioorthogonal labelling and Electron Microscopy (EM)-based imaging techniques is explored to enable observations of specific molecular targets in their ultrastructural context within the cell.

This thesis describes the synthesis, analysis of various tetrazine bearing compounds and use in bioorthogonal chemistry.

Promotor: Prof.dr.ir. J.G.E.M. Fraaije, Co-promotor: A. Kros

Organic amendments applied to agricultural fields can partially offset our carbon emissions to the atmosphere and improve the resilience of agriculture to the effects of climate change. Driving these benefits, however, are complex and poorly understood interactions between organic amendment properties,…

Large areas of space are filled by molecular clouds that consist of gas and dust grains that are the remnants of dead stars. When these clouds start collapsing, the decreasing temperature and increasing density cause gas particles to start accreting onto dust grain surfaces.

If mankind wants to survive into the 22nd century, we will need to change the way we live drastically. The human impact on our planet is everywhere, we are changing the atmosphere, the oceans and the land, leading to global warming, climate change, loss of biodiversity and pervasive pollution. There…

The research described in this thesis focused on the use of bioorthogonal antigens to investigate immunological processes in antigen presenting cells. Bioorthogonal antigens are antigenic proteins produced through recombinant expression in a methionine auxotrophic E. coli strain.

The work in this thesis has been focused on two subjects. The first is the assembly of alginate oligosaccharides and the generation of building blocks for the enzymatic synthesis of alginate, and the second is the total synthesis of large fragments of the zwitterionic SP1 polysaccharide.

In order to be able to develop effective medicine and treatments to prevent or cure autoimmune diseases or cancer we need to understand the mechanisms how they arise and what drives their course.Unravelling the fundamental molecular mechanisms influencing the onset and course of diseases such as allergies,…

This thesis examines the link between simple molecules and the underlying structure and chemistry within protoplanetary disks - the birthplaces of planets.

Glycosidases are essential in fundamental biological processes and are responsible for the degradation of most (oligo)saccharides, glycolipids and glycoproteins.

This Thesis describes the synthesis of D-alanylated ribitol-based wall teichoic acids from S. aureus to probe their interaction with immune-binding partners.

Afscheidscollege

The glycosylation reaction is a pivotal reaction in creating new and complex oligosaccharides.

Large parts of the research described in this Thesis aims at the development of oligopeptide-masked toxins and their in situ immunoproteasome-mediated activation.

In the current global context, there is a pressing need to address sustainable energy supplies to safeguard our Planet and its ecosystems. The choices made by human society have a significant impact on genetic evolution and climate.

With increasing carbon dioxide levels in the atmosphere and their detrimental effect on the global climate, modern society needs to push for more renewable energy sources. Storing widely accessible and abundant solar energy in chemical bonds in the form of molecular fuel via artificial photosynthesis…

To this day, all cyclophellitol-based inhibitors and ABPs have been close analogues of their natural substrate counterparts. As a result, these probes showed high selectivity towards their target glycosidases.

Sphingolipids are important membrane compounds with a variety of functions. In mammalian cells, different enzymes are involved in the metabolism of sphingolipids, but interruption of this metabolism process leads to different diseases.

Plant-microbe interaction resulted in different physio/chemical responses by host plant and interacting rhizobacteria.

Climate change is a challenge for both current and future generations. New biological resources have to be developed in order to meet the demand for energy as well as the demand for food.

In the search for sustainable energy solutions, the idea of artificial photosynthesis has been proposed as an approach with which to use water and sunlight to produce hydrogen.

Biopolymer sequencing with graphene edge-based tunnel junctions has the potential to overcome current limitations with the third generation of sequencing based on biological nanopores.

In this Ph.D. thesis we study the interaction of low energy electrons with thin materials, namely layered materials (graphene, hexagonal boron nitride, molybdenum disulfide) and organic films. At these low energies the quantum mechanical wavelength of the electron wave function is in the order of a…

The first steps are made in personalised cancer vaccination strategies, which aim to induce a more specific immune response with fewer side effects. The activation of cytotoxic T cells is crucial for an effective immune response.

Laboratory, observation and modeling work on the dissociation of polycyclic aromatic hydrocarbons in interstellar environments and the formation of new molecular species through the fragmentation process.

Light-Harvesting Complex II (LHCII) is responsible for light absorption and excitation energy transfer in plants and photosynthetic algae, while in high light it undergoes conformational changes by which it quenches excitations to prevent photodamage.

Promotor: Prof.dr. H.J.M. de Groot, Co-promotor: Francesco Buda

Voor de omzetting van zonlicht naar brandstof

Met de NMR faciliteit doen we onderzoek naar de synthese van paramagnetische moleculen om kennis te vergaren over de structuur en dynamiek van eiwitten. Deze kennis kan dienen als basis voor een medicijn dat zich hecht aan een eiwit of voor de ontwikkeling van vaccins. Medicijnontwikkeling is één van…

In het schoolvak scheikunde is de concept-context benadering ingevoerd. Hans Vogelzang onderzocht of de Scrum-methodologie kan helpen bij het vormgeven van lessen met deze benadering.

Less than 1 in 10 drug candidates that enter phase 1 clinical trials actually gets approved for human use.

Chapter 2 describes a post-synthetic methodology to introduce a fluorescent label in highly lipophilic, Pam3Cys based conjugates.

Decentralized plug and play systems for energy production are the future picture of our society. Artificial photosynthetic systems are used for this purpose.

Reducing greenhouse gas emissions is one of the most pressing challenges that humanity faces in the coming decades.

Solar energy is used by photosynthetic organisms to drive energy required cellular processes. Is absorbed by two groups of pigments, located in the LHCs.