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

Amines are crucially important classes of chemicals, widely present in pharmaceuticals, agrochemicals and surfactants. Yet, surprisingly, a systematic approach to obtaining this essential class of compounds from renewables has not been realized to date. The aim of this proposal is to enable chemical pathways for the production of amines through alcohols from renewable resources, preferably lignocellulose waste. Two key scientific challenges will be addressed: The development of efficient cleavage reactions of complex renewable resources by novel heterogeneous catalysts; and finding new homogeneous catalyst based on earth-abundant metals for the atom-economic coupling of the derived alcohol building blocks directly with ammonia as well as possible further functionalization reactions. The program is divided into 3 interrelated but not mutually dependent work packages, each research addressing a key challenge in their respective fields, these are: WP1: Lignin conversion to aromatics; WP2: Cellulose-derived platform chemicals to aromatic and aliphatic diols and solvents. WP3: New iron-based homogeneous catalysts for the direct, atom-economic C-O to C-N transformations. The approach taken will embrace the inherent complexity present in the renewable feedstock. A unique balance between cleavage and coupling pathways will allow to access chemical diversity in products that is necessary to achieve economic competitiveness with current fossil fuel-based pathways and will permit rapid conversion to higher value products such as functionalized amines that can enter the chemical supply chain at a much later stage than bulk chemicals derived from petroleum. The proposed high risk-high gain research will push the frontiers of sustainable and green chemistry and reach well beyond state of the art in this area. This universal, flexible and iterative approach is anticipated to give rise to a variety of similar systems targeting diverse product outcomes starting from renewables.

1 500 000 €

Start date: 2016-05-01, End date: 2021-04-30

Do even the smallest clouds simply drift with the wind? Vast areas of our oceans and land are covered with shallow cumulus clouds. These low-level clouds are receiving increased attention as uncertainties in their representation in global climate models lead to a spread in predictions of future climate. This attention emphasizes radiative and thermodynamic impacts of clouds, which are thought to energize the large-scale Hadley circulation. But broadly overlooked is the impact of shallow cumuli on the trade-winds that drive this circulation. Reasons for this negligence are a lack of observations of vertical wind structure and the wide range of scales involved. My project will test the hypothesis that shallow cumuli can also slow down the Hadley circulation by vertical transport of momentum. First, observations of clouds and winds will be explicitly connected and the causality of their relationship will be exposed using ground-based and airborne measurements and high-resolution modeling. Second, new lidar techniques aboard aircraft are exploited to validate low-level winds measured by the space-borne Aeolus wind lidar and collect high-resolution wind and turbulence data. Third, different models of momentum transport by shallow convection will be developed to represent its impact on winds. Last, evidence of global relationships between winds and shallow cumulus are traced in Aeolus and additional satellite data and the impact of momentum transport on circulations in a control and warmer climate is tested in a general circulation model. This project exploits my expertise in observing and modeling clouds and convection focused on a hypothesis which, if true, will strongly influence our understanding of the sensitivity of circulations and the sensitivity of climate. It will increase the predictability of low-level winds and convergence patterns, which are important to many disciplines, including climate studies, numerical weather prediction and wind-energy research.

1 867 120 €

Start date: 2017-01-01, End date: 2021-12-31

The Greenland ice sheet (GrIS) is losing mass at an increasing pace, in response to atmospheric and ocean forcing. The mechanisms leading to the observed mass loss are poorly understood. It is not clear whether the current trends will be sustained into the future, and how they are affected by regional and global climate variability. In addition, the impacts of Greenland deglaciation on the local and global climate are not well known. This project aims to explain the relationship between GrIS surface melt trends and climate variability, to determine the timing and impacts of multi-century deglaciation of Greenland, and to explain the relationship between ongoing and previous deglaciations during the last interglacial and the Holocene. For this purpose, we will use the Community Earth System Model (CESM), the first full-complexity global climate model to include interactive ice sheet flow and a realistic and physical-based simulation of surface mass balance (the difference between surface accumulation and losses from runoff and sublimation). This tool will include for the first time a large range of temporal and spatial scales of ice sheet-climate interaction in the same model. Previous work has been done with oversimplified and/or uncoupled representations of ice sheet and climate processes, for instance with simplified ocean and/or atmospheric dynamics in Earth System Models of Intermediate Complexity, with fixed topography and prescribed ocean components in Regional Climate Models, or with highly parameterized snow albedo and/or melt schemes in General Circulation Models. This project will provide new insights into the coupling between the GrIS and climate change, will lead widespread integration of ice sheets as a new and indispensable component of complex Earth System Models, and will advance our understanding of present and past climate dynamics.

1 677 282 €

Start date: 2016-06-01, End date: 2021-05-31