ERC FUNDED PROJECTS

Homogeneous catalysis is of prime importance for the selective synthesis of high added value chemicals. Many of the currently available catalysts rely on noble metals (Ru, Os, Rh, Ir, Pd, Pt), which suffer from a high toxicity and environmental impact in addition to their high cost, calling for the development of new systems based on first-row transition metals (Mn, Fe, Co, Ni, Cu). The historical paradigm for catalyst design, i.e. one or more donor ligands giving electron density to stabilize a metal center and tune its reactivity, is currently being challenged by the development of acceptor ligands that mostly withdraw electron density from the metal center upon binding. In the last decade, such ligands – mostly based on boron and heavier main-group elements – have evolved from a structural curiosity to a powerful tool in designing new reactive units for homogeneous catalysis. I will develop a novel class of ligands that use C=E (E=O, S, NR) multiple bonds anchored in close proximity to the metal by phosphine tethers. The electrophilic C=E multiple bond is designed to act as an acceptor moiety that adapts its binding mode to the electronic structure of reactive intermediates with the unique additional possibility of involving the lone pairs on heteroelement E in cooperative reactivity. Building on preliminary results showing that a C=O bond can function as a hemilabile ligand in a catalytic cycle, I will undertake a systematic, experimental and theoretical investigation of the structure and reactivity of M–C–E three membered rings formed by side-on coordination of C=E bonds to a first-row metal. Their ability to facilitate multi-electron transformations (oxidative addition, atom/group transfer reactions) will be investigated. In particular, hemilability of the C=E bond is expected to facilitate challenging C–C bond forming reactions mediated by Fe and Ni. This approach will demonstrate a new conceptual tool for the design of efficient base-metal catalysts.

1 500 000 €

Start date: 2017-08-01, End date: 2022-07-31

The amount of information trafficking internet nowadays is enormous and will increase further in the near future. It can be expected that in the next decennia the current technologies to store and process data will no longer suffice and that other strategies to handle information have to be developed. One approach is to explore chemical routes, which nature has also followed during evolution: our brain can store and handle very large amounts of data and process them in a way silicon-based computers cannot do. Although brain-like chemical computers are still far beyond reach, it is of interest to explore how atom and molecule-based systems that can write, read, and store information might be designed and constructed. In this proposal we aim at developing a new technology to write, store, and read information, i.e. on a single polymer chain with the help of a molecular machine that is inspired by the hypothetical device (Turing machine) proposed by the British mathematician Alan Turing in 1936 as the general basis for the operation of a computer. The molecular machine is composed of a chiral catalytic cage compound (tape-head) that moves unidirectionally along a chiral polymer chain (tape) while writing a binary code in the form of (R)- (symbol 0) and (S)- (symbol 1) epoxide functions. This writing process is controlled by light or electrons. The information on the tape will be read by single molecule spectroscopy using a reading device that is also based on a chiral cage compound. It moves along the encoded tape and produces left- or right-handed polarized fluorescence light depending on whether it reads a 0 (R-epoxide) or 1 (S-epoxide). As part of this project we will also make the first steps towards chemical computing by arranging two circular tapes (one left-handed and the other one right-handed), each with an attached writing head, in a teller set-up, which allows them to be addressed separately with light according to a set of instructions (Minsky machine).

2 498 076 €

Start date: 2017-07-01, End date: 2022-06-30

"Nanowires are a powerful and versatile platform for a broad range of applications. Among all semiconductors, the heavy-elements materials exhibit the highest electron mobilities, strongest spin-orbit coupling and best thermoelectric properties. Nonetheless, heavy-element nanowires have been unexplored. With this proposal we unite the unique advantages of design freedom of nanowires with the special properties of heavy-element semiconductors. We specifically reveal the potential of heavy-element nanowires in the areas of thermoelectrics, and topological insulators. Using our strong track record in this area, we will pioneer the synthesis of this new class of materials and study their intrinsic materials properties. Starting point are nanowires of InSb and PbTe grown using the vapor-liquid-solid mechanism. Our aims are 1) to obtain highest-possible electron mobilities for these bottom-up fabricated materials by investigating new materials combinations of different semiconductor classes to effectively passivate the nanowire surface and we will eliminate impurities; 2) to investigate and optimize thermoelectric properties by developing advanced superlattice and core/shell nanowire structures where electronic and phononic transport is decoupled; and 3) to fabricate high-quality planar nanowire networks, which enable four-point electronic transport measurements and allow precisely determining carrier concentration and mobility. Besides the fundamentally interesting materials science, the heavy-element nanowires will have major impact on the fields of renewable energy, new (quasi) particles and quantum information processing. Recently, the first signatures of Majorana fermions have been observed in our InSb nanowires. With the proposed nanowire networks the special properties of this recently discovered particle can be tested for the first time."

2 698 447 €

Start date: 2014-09-01, End date: 2019-08-31

"Communication between immune cells is crucial for regulating the magnitude and quality of immune responses. A newly uncovered means of intercellular communication involves transfer of small cell-derived vesicles. I recently discovered that vesicles released by immune cells are enriched for small noncoding RNAs, which may act as regulatory RNAs that can influence gene expression in vesicle-targeted cells. Furthermore, remarkable parallels emerged between RNAs abundantly present in cell-derived vesicles and a group of host RNAs specifically incorporated into retroviruses. These shared RNAs may underlie the formation or function of both cell-derived vesicles and retroviruses. Until now, mechanisms behind selective incorporation of small RNAs into cell-derived vesicles and their function in vesicle-targeted cells are poorly understood. Aim of INTERCOM: To resolve how the exchange of small RNAs via cell-derived vesicles contributes to intercellular communication between immune cells. Key objectives: 1. To determine the diversity and plasticity of the RNA content of vesicle subpopulations released by immune cells. 2. To explain functional differences between immune cell vesicle populations based on their RNA contents. 3. To determine the function of structural RNAs shared by immune cell-derived vesicles and retroviruses. Tools in virology research will be used in combination with several high-end technologies, which were uniquely adapted in my lab for vesicle-related research. These include a high-resolution flow cytometric method suited to analyze individual nano-sized vesicles, RNA deep sequencing with previously developed data analysis methods, and super-resolution microscopic imaging. The proposed work advances our understanding of communication processes in the immune system. This knowledge can be applied in defining vesicle RNA-based biomarkers for immune-related diseases and in designing genetically engineered cell-derived vesicles for therapeutic application."

1 499 806 €

Start date: 2013-11-01, End date: 2018-10-31