Dean: Prof. Dr. Carsten Schmuck †

CRC “Supramolecular Chemistry on Proteins”

Led by its two spokespersons from the Faculty of Chemistry (Organic Chemistry), Collaborative Research Centre (CRC) 1093 “Supramolecular Chemistry on Proteins” entered its second funding period (2018–2021) after four very productive years. In this CRC, chemists and biologists work hand in hand to develop new tools that specifically bind to protein surfaces and influence their biological function. The tools are chemical ligands, which the chemists design and synthesise in the lab on the basis of innovative concepts. The biologists then attempt to answer some of biology’s hitherto unanswered questions by testing whether the tools bind specifically at a so-called hot spot on the surface of the target protein. In the first funding period up to 2017, they were able to show that the fundamental concept behind CRC 1093 is viable; working in close collaboration, they developed molecular tweezers that dock precisely onto the critical hot spot of Survivin, an apoptose-inhibiting protein produced by cancer cells, preventing it from binding to a receptor that is vital to cancer cell survival. The research team also synthesised and optimised synthetic ligands for the pores of the so-called 14-3-3 protein; the function of these pores is not known to this day. Ultimately, it was possible to refine the macromolecular methods so far that a self-assembling “molecular house” of DNA is built that contains and influences the function of a protein machine. Work in the second funding period aims to use such methods not only to block but also repair protein functions. The target surfaces on the protein also become more complex and not only single proteins but also protein complexes are addressed. Another aim is to be able to activate specific protein functions and ultimately use all these new tools to work in living cells. Important new research groups have joined the CRC for its second funding period, which will strengthen and expand the consortium’s portfolio.

CRC/Transregio “Heterogeneous Oxidation Catalysis in the Liquid Phase”

A second Collaborative Research Centre led by chemists from Essen (Inorganic Chemistry) was also launched in 2018. CRC/Transregio 247 “Heterogeneous Oxidation Catalysis in the Liquid Phase” has been set up with the neighbouring Ruhr University Bochum. The Max Planck Institute for Coal Research and for Chemical Energy Conversion in Mülheim a.d. Ruhr and the Fritz Haber Institute in Berlin are participating institutions. This consortium will now be exploring fundamental questions of catalytic reactivity at solid–liquid interfaces. The focus will be on oxidation reactions, which can be conducted thermally, electrochemically or by photoinduction. By studying structure-activity correlations in mixed cobalt-iron oxides, the project sets out to produce new fundamental knowledge that can be used for specific purposes, such as to develop new catalysts for beneficial and sustainable oxidation processes. An example is water electrolysis, which effectively stores electrical energy from renewable sources in the form of the chemical fuel hydrogen. In the preliminary stages the researchers were already able to show that partially replacing iron with vanadium in CoFe2O4 nanoparticles produces an especially active electrocatalyst for anodic water splitting with the composition CoFe0.5V1.5O4. CRC/TRR 247 will be working towards a deep understanding of this subject matter over the next four years.

Another key collaborative project in which the Faculty of Chemistry is playing a significant role is the Forschungskolleg FUTURE WATER, a research group funded since 2014 by the NRW State Ministry of Culture and Science. The focus of this doctoral training programme, which is coordinated by the Centre for Water and Environmental Research (ZWU) and has its spokesperson from the Faculty of Chemistry (Analytical Chemistry), is on sustainable water management. Important milestones towards this goal are the implementation of effective and efficient measures to reduce diffuse source pollutants and the associated task of establishing and safeguarding integrated rainwater management. The second cohort began its work at the end of 2017 and focuses precisely on this area in 12 inter- and transdisciplinary projects. In addition to necessary technical adjustments and questions relating to economics and social sciences, the researchers are primarily interested in methods of recording and analysing the cause and effect of diffuse source pollutants and their degradation in rainwater. As from January 2019, FUTURE WATER will be continuing its successful work for a further three and a half years in a second funding period. Important findings of the first cohort’s work were published jointly in a Virtual Special Issue of the peer-reviewed journal “Science of the Total Environment”.

Priority Programme “Materials for Additive Manufacturing”

Technical Chemistry was successful in initiating another major consortium project, which will be coordinated in the coming years from Essen. It is the nationwide DFG Priority Programme 2122 “Materials for Additive Manufacturing”. The lasers that are used in production are becoming increasingly powerful, but the available materials are often entirely inadequate for today’s laser processing purposes. With lasers set over the long term to dominate key production processes on account of their production rate and precision, there is an urgent need to adapt materials to these widespread production methods. This calls for fundamental research that addresses the beginning of the process chain, the material. The coordinated Priority Programme offers precisely this approach by combining material development and photonics research and starting with material synthesis. The research questions are formulated for a range of materials and with a focus on the photonic process of additive laser manufacturing of polymer and metal powders. This will be used to develop the first chemical, metallurgical and additive-based modifications specifically for photonic production.

Inorganic Chemistry

In addition to the activity described above in heterogeneous catalysis, another focus of solid-state chemical research in Inorganic Chemistry in Essen is in Nanosciences. Here, for example, the researchers have synthesised metallic and bimetallic nanoparticles of noble metals (silver, gold, platinum). Examination of their intrinsic structure using crystallographic and electron microscopy techniques revealed the internal facets (domains) and different elemental distribution inside bimetallic nanoparticles. A practical application of this research is in controlling silver ion release in antibacterial materials. If a covalent surface chemistry (binding of receptor molecules) is established on ultrasmall gold nanoparticles (2 nm), it is possible to specifically target epitopes on protein surfaces. Synthesis of covalent functionalised calcium phosphate nanoparticles charged with biomolecules makes it possible to trigger specific biological functions in vitro and in vivo. Work with colleagues in medicine led to successful inoculation against viruses and the ability to selectively trigger genes in cells by transfection with DNA and to deactivate them by genetic silencing. Synthesis of protein-functionalised nanoparticles meanwhile made it possible to elucidate the journey and fate of nanoparticles after they enter the cell, which delivered important insights for nanomedical applications. Further studies on inorganic material synthesis concentrated on the field of thermoelectric materials, which were manufactured either as nanoparticle powder in solution-based methods, especially in ionic liquids, or as thin, in some cases epitaxial, films using different gas-phase-based deposition methods, such as atomic layer deposition (ALD), chemical vapor deposition (CVD) or physical vapor deposition (PVD). This made it possible for the first time to determine the thermal conductivity in cross-plane direction on epitaxial Sb2Te3 films. The main focus of research in organometallic molecular chemistry was on establishing low-valency main group element compounds, especially Mg(I), Zn(I), and Ga(I) compounds, as potent reduction agents that are soluble in organic solvents. In the course of this work, the researchers chiefly produced organometallic group-13/15 compounds with unusual electronic states and determined their structures with spectroscopic techniques in solution and with x-ray crystallography in solid state. The general methods that were established in this research for producing new homo- and heterobimetallic compounds with a double bond component and open-shell Sb- and Bi-centered radicals deserve special mention in this context.

A strong area of research for the groups in Organic Chemistry is supramolecular chemistry (cf. CRC 1093 above). Their research in this area is mainly in the fields of chemical biology, the development of new materials, and construction of molecular machines. There are also three junior research groups/junior professorships with their own research interests in the field of liquid crystals, new luminophores, and organocatalysis. Numerous new receptor molecules have been developed for biological applications over the past two years, for example, and it was here that the breakthrough to “molecular tweezers” was made, which can be used in what is known as “click chemistry” to bind to all possible additional functional elements. The researchers also synthesised a peptide amphiphile that forms amyloid fibrils which gold nanoparticles can break into fragments. These bind strongly to DNA, thus enabling gene transfection. An old dream of the chemists was meanwhile fulfilled in the form of molecular machines powered by light and electricity, and the researchers also succeeded for the first time in using catenanes – single molecules that are mechanically connected to one another as if in a chain – in asymmetric organocatalysis. Other examples to complete the portfolio of fascinating highlights of recent research in Organic Chemistry are a highly variable building block system for supramolecular construction of innovative liquid crystals using hydrogen bridges, and completely new fluorescent dyes that light up when they reach their target molecule (e.g. a protein) (which is known as aggregation-induced emission).

Physical Chemistry

The Faculty of Chemistry is exploring another entirely different fundamental research question – “Where did life originate?” – in Physical Chemistry. When it comes to the origin of life, to this day there is still no real understanding of how the first self-replicating molecules and more complex systems like cells came into being. The chemists in Essen succeeded in developing a model for formation and self-optimization of vesicles under dynamic environmental conditions. The Essen model consists in interaction between two cyclic processes: a process of periodic vesicle formation and a process in which peptides are in equilib­rium with their basic building blocks, amino acids. The structures that develop out of the combination of these two processes undergo their own structural and chemical evolution, which can have parasitic and symbiotic effects and even lead to the creation of new functions. The temporal evolution of interconnected cyclic processes not only represents an important aspect of living systems, it also provides a relevant model for the earliest processes that could have led to the creation of life on Earth. In cooperation with Analytical Chemistry and Geology at the UDE, the researchers have recently succeeded in a long-term study in simulating the process of molecular evolution described above in a high-pressure cell. Over a number of days, it is possible under periodic pressure variations to induce the formation of several hundred generations of vesicles, with a mixture of twelve amino acids simultaneously producing a statistical mixture of short-chain peptides. In each successive generation, the peptides that contributed most to the stability and life-prolonging function of the vesicles are gradually selected. Precisely these peptides accumulate as the process goes on and lead to a population of particularly stable and functional vesicles. One of these selected peptides, an octapeptide, was sequenced, synthesised and added in sizeable quantities to pure membrane vesicles. We were able to establish here that this peptide has three functions: a) it increases the thermal stability of the vesicles, b) it reduces the size of the vesicle and therefore the risk that it will be destroyed, and c) it leads to increased permeability of the vesicle membrane and thereby to faster relaxation of the osmotic pressure. All three influences can be regarded as survival mechanisms for the vesicles. These observations confirm successful evolution of the vesicle structures, which could possibly be a model for the development of a protocell. From vesicles it is only a small step to systems that can be controlled in their behaviour through their surface. The research in this area is situated at the UDE and its affiliated institute DTNW in Krefeld. Among the things the researchers here are exploring is how liquids influence friction and adhesion between surfaces in a strongly bound liquid layer. These thin lubricating films are fixed in place with tethered polymers. We work on fundamental questions of the chemistry and structure of the molecular functional layers at the UDE in Essen and put them in a more applied context at the DTNW. The resulting findings on how molecules are fixed on surfaces then gives us a base technology for use in other research projects, such as on attaching new flame retardants to textiles or making optical methods of analysis more efficient.

Technical Chemistry

In water research, Technical Chemistry contributes to the Faculty’s work primarily by developing improved or new materials for water cleansing and purification. They take the form either of membranes that filter unwanted substances out of water or materials that bind such substances to their surface or can catalytically convert them (porous adsorbers or catalysts). An example of a major innovation in this area are microstructure thin-film composite membranes for water desalination by reverse osmosis. New methods were established to manufacture membranes with microchannels on the selectively permeable surface, and the researchers were able to demonstrate that these membranes can achieve permeabilities up to five times higher than those of conventional, non-structured membranes, under the same pressure and with identical retention, for dissolved salts. This can be explained by a combination of an increase in the surface area of the active membrane and improved mixing directly at the membrane surface. Larger-scale implementation of this concept is a very attractive prospect, as it can significantly cut the cost of seawater desalination by reverse osmosis or similar applications. Another example with a connection to the Nanosciences research focus is direct processing of the biopolymer cellulose with the aid of ionic liquids as “green solvents” to produce porous materials with adsorber or catalytic properties for water purification. These hybrid materials gain their special activity through the integration of functional nanoparticles directly in the same processing step. The combination of renewable resources as the base material and very effective processing is expected to produce major sustainability and cost benefits for applications.

Analytical Chemistry

The focus of work in the Analytical Chemistry research groups in Essen can be found on the one hand in the field of development and application of methods of automated sample preparation, chromatographic separation and detection using quantitative and isotope-ratio mass spectrometry for food and environmental samples. Another focus is on the development of multidimensional separation techniques and new ion sources for mass spectrometry. These kinds of analytical platforms are used in the analysis of complex samples such as the metabolome or lipidome. “Effect-based analysis” is another area of interest and the subject of successful international cooperation with researchers from Essen University Hospital, Ruhr University Bochum, Tsinghua University in Bejing and the National University Hanoi (Vietnam). Analytical Chemistry is also responsible for many of the activities relating to water research. It explores water chemistry processes and technologies, primarily relating to oxidation processes for disinfection and trace substance removal. These processes are used both in drinking water purification and wastewater treatment. The high visibility of water research in Essen is also apparent from the numerous conferences and meetings organised here, including annual water conventions and the Mülheimer Wasseranalytisches Seminar, which is held every two years (with IWW Water Centre) for 250 to 300 participants. A two-week spring school on industrial analytical chemistry was also organised for the first time in Essen in 2017 in collaboration with Merck and attended by around 40 participants from all over Germany. Another highlight of the ongoing outreach activities is undoubtedly an experimental lecture to over 600 children, which was held as part of the 2017 “UNI Kids” programme and asked the question “Water builds bridges, but does it remember?”. Research-related training is another area in which Analytical Chemistry in Essen was able to report a number of successes. In 2018, for example, cooperation with Agilent Technologies was launched and the Teaching and Research Center for Separation (TRC) set up. The TRC is the fifth world-class Center of Excellence funded by Agilent worldwide. This support means that ultramodern analytical instruments are available for the training. Every year, the TRC also offers six five-day, fee-paying courses for those interested from the university community and industry.

Theoretical Chemistry

An example of the research in Theoretical Chemistry in Essen is the successful model development and simulation of interfaces between one-dimensional oxidic nanotubes and liquid water. This makes it possible to also test nanotubes with diameters that are actually too big for direct simulation. The resulting models make it possible to explore photocatalytic processes at these interfaces.

Biofilm Centre

Among the research of the Biofilm Centre in Essen is work on microorganisms, many new species of which have been discovered in the CO2-rich water of a cold-water geyser in Utah/USA. Working with cooperation partners from the University of California, Berkeley/USA, and the University of Calgary/CAN, the researchers were able to analyse the genetic material and show how hydrogeology and microbiology influence each other. Above all in the deeper layers, microorganisms were found that live in symbiosis with other organisms on which they are entirely dependent for their existence.

The work of the Biofilm Centre sets out to understand the ecology and the biochemical principles of microbial processes in the environment. The systems explored range from groundwater and drinking water supply to extreme habitats, such as natural oil reservoirs or hot springs. Research is conducted on subjects such as the assembly of ecosystems and their nutrient cycles, with a special focus on pollutant degradation, as well as on parasitic and symbiotic relationships in bacteria, archaea and viruses, an area which is becoming increasingly central to work at the Biofilm Centre.

Chemistry Education

Another of the Faculty’s main interests is in empirical educational research in Chemistry Education. This covers the entire breadth of institutional teaching and learning, from general studies as a primary school subject to the tertiary education sector with science-related degrees or training and continuing education for teachers. In the DFG-funded research consortium “Studying and academic success in the initial phase of scientific and technical degree courses” (ALSTER), researchers are working - in view of the high dropout rates in scientific and technical degree programmes - to explain what academic success depends on in these subjects. In its second funding period, the consortium, with the Faculty of Chemistry playing a significant role, is turning its attention in five sub-projects to exploring funding and support options, in particular to address the deficits that have been identified in prior subject knowledge or understanding of iconic models. Taking place alongside the consortium is the BMBF-funded project “Chemistry, social sciences and engineering: academic success and dropout phenomena” (CASSIS), in which different types of higher education institutions and degree subjects are compared to identify institution- and subject-specific reasons behind dropout phenomena. The aim is to improve the initial stages of studying and thereby academic success as a whole. It is not least on account of the BMBF Teacher training quality campaign that the work on the conditions for success specifically in teacher training is also important in other research projects. The quality of teacher education is also the focus of the ProViel project (“Professionalisation for diversity”), in which the Faculty of Chemistry is also taking part. In future, the research programme will also include the research training group GK QL on “Querschnittsaufgaben in Lehrerbildung sowie Schul- und Unterrichtsentwicklung” (Cross-disciplinary tasks in teacher education and school and teaching development). In addition, the DFG project “Feedback during in-service teacher education regarding multiple external representations” (FiRe2) focuses as well on improving the quality of in-service teacher training and the connections between the different phases of teacher education.