Speakers

Symposium 2020 ‘Exploring the Unknown’ the chemistry they didn't tell you about

The first speaker we would like to announce is:

  • Prof. dr. Stefanie Dehnen from the University of Marburg. Her research focuses on multinary, non-oxidic cluster and network compounds which are relevant in both inorganic and materials chemistry. We highly recommend that you come listen to her lecture titled “Multinary Clusters: From Uncommon Structures and Bonding to Potential Use”.

Abstract:

Multinary Clusters: From Uncommon Structures and Bonding to Potential Use

Stefanie Dehnen*

Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35032 Marburg, Germany.

*dehnen@chemie.uni-marburg.de

Multinary clusters comprising main group metal atoms and one or two further components – further (semi)metal atoms and/or chalcogen atoms and/or organic substituents – have attracted interest in recent times, owing to a number of uncommon properties. The most obvious feature is a large variety of different cluster compositions and architectures, but the materials do also show unexpected functionalities.1,2

Depending on the elemental composition, the clusters either belong to so-called intermetalloid clusters [Mx@E13/14yE15z]q– (E13/14 = Ga···Tl or Ge···Pb; E15 = As···Bi), hence comprising (semi)metal atoms in negative oxidation states,3 or they form chalcogenidometalate architectures of the general type [Mx(RE14)yE16z]q– (M = (transition) metal) with or without functional organic ligands R.4,5

While unsubstituted multinary clusters like [Co@Sn6Sb6]3–,6 [U@Bi12]3– 7 or [Au6(Ge3As)(Ge2As2)3]3− 8 mainly serve to study structural variations and to gain new insights into cluster formation and bonding,10 organic substituents on the cluster surfaces, as in [Mn4Sn4Se13(SeMe)4]6–,9 shed light on reactivities, and they may also cause extreme non-linear optical properties, rendering compounds like [(StySn)4S6],11 [(CySn)4Se6],12 or [{(CoMo)3S4Sn}(PhSn)3S6] 13  potentially useful, innovative materials.


References
[1] P. Feng, X. Bu, N. Zheng, Acc. Chem. Res. 2005, 38, 293. [2] S. Scharfe, F. Kraus, S. Stegmaier, A. Schier, T. F. Fässler, Angew. Chem. Int. Ed. 2011, 50, 3630. [3] R. J. Wilson, N. Lichtenberger, B. Weinert, S. Dehnen, Chem. Rev. 2019, 119, 8506. [4] S. Santner, J. Heine, S. Dehnen, Angew. Chem. Int. Ed. 2016, 54, 876. [5] E. Dornsiepen, E. Geringer, N. Rinn, S. Dehnen, Coord. Chem. Rev. 2019, 380, 136. [6] R. J. Wilson, F. Hastreiter, K. Reiter, P. Büschelberger, R. Wolf, R. Gschwind, F. Weigend, S. Dehnen, Angew. Chem. Int. Ed. 2018, 57, 15359. [7] N. Lichtenberger, R. J. Wilson, A. R. Eulenstein, W. Massa, R. Clérac, F. Weigend, S. Dehnen, J. Am. Chem. Soc. 2016, 138, 9033. [8] F. Pan, L. Guggolz, F. Weigend, S. Dehnen, Angew. Chem. Int. Ed. 2020, doi.org/10.1002/anie.202008108. [9] B. Peters, S. Santner, C. Donsbach, P. Vöpel, B. Smarsly, S. Dehnen, Chem. Sci. 2019, 10, 5211. [10] S. Mitzinger, L. Broeckaert, W. Massa, F. Weigend, S. Dehnen, Nat. Commun. 2016, 7, 10480. [11] N. W. Rosemann, J. P. Eußner, A. Beyer, S. W. Koch, K. Volz, S. Dehnen, S. Chatterjee, Science 2016, 352, 1301. [12] E. Dornsiepen, F. Dobener, S. Chatterjee, S. Dehnen, Angew. Chem. Int. Ed. 2019, 58, 17041. [13] E. Dornsiepen, F. Pieck, R. Tonner, S. Dehnen, J. Am. Chem. Soc. 2019, 141, 16494.

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The second speaker that we announce:

  • dr. ir. Bas Rosier, from the Institute for Complex Molecular Systems and Laboratory of Chemical Biology, Department of Biomedical Engineering, Eindhoven University of Technology, The Netherlands. He does research in antibody-based nanoswitches using DNA nanotechnology for continuous monitoring of analytes and biomarkers in organ-on-a-chip microfluidic devices. His title is "DNA nanotechnology meets chemical biology: precision assembly of biomolecules at the nanoscale".

Abstract:

DNA nanotechnology meets chemical biology: precision assembly of biomolecules at the nanoscale

Nanoscale organization of interacting molecules in the cell is a key regulatory principle in all major cell events, including apoptosis, metabolism, inflammation, and immunity. The co-localization of proteins in space and time plays a crucial role in dynamic enzymatic activation, to compartmentalize biochemical reaction cascades, and to trigger activation of signaling pathways. Nanostructures based on DNA can serve as programmable synthetic platforms onto which molecules can be assembled with full control over the number, position, and orientation of interacting components. Our laboratories focus on the bottom-up implementation of DNA nanotechnology in the fields of chemical biology and synthetic biology, which allows us to shed light on the molecular mechanisms behind nanoscale organization in the cell.

In this lecture I will highlight our efforts of using 75×100 nm2 DNA origami nanostructures to investigate proximity-induced activation of enzymes involved in programmed cell death. By tethering both wildtype and mutant enzymes to DNA nanostructures we demonstrated that enzymatic activity is induced by proximity-driven dimerization with half-of-sites reactivity, and revealed a multivalent activity enhancement in oligomers of three and four enzymes1. Additionally, I will discuss a modular strategy developed in our laboratory for the synthesis of well-defined antibody-DNA conjugates via radical-based photochemistry using protein adapters carrying the unnatural amino acid p-benzoylphenylalanine2,3. With this strategy, we were able to demonstrate assembly of antibodies onto DNA nanostructures with nanometer precision, detection of subcellular targets using super-resolution microscopy, controlled activation of cellular receptors, and the construction of antibody-DNA nanoswitches for in situ monitoring of biomarkers.

References

B.J.H.M. Rosier, A.J. Markvoort, B. Gumí Audenis, J.A.L. Roodhuizen, A. den Hamer, L. Brunsveld, T.F.A. de Greef, Proximity-induced caspase-9 activation on a DNA origami-based synthetic apoptosome. Nature Catal 3, 295 (2020).
B.J.H.M. Rosier*, G.A.O. Cremers*, W. Engelen, M. Merkx, L. Brunsveld, T.F.A. de Greef, Incorporation of native antibodies and Fc-fusion proteins on DNA nanostructures via a modular conjugation strategy. ChemComm 53, 7393 (2017).
3 G.A.O. Cremers*, B.J.H.M. Rosier*, R. Riera Brillas, L. Albertazzi, T.F.A. de Greef, Efficient small-scale conjugation of DNA to primary antibodies for multiplexed cellular targeting. Bioconjugate Chem 30, 2384 (2019).

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The third speaker that we announce:

  • Prof. dr. Gert-Jan Gruter, currently a part-time professor at the university of Amsterdam and the CTO of Avantium, a pioneer in the emerging industry of sustainable chemistry, whose vision is a fossil free world. Let’s Go!

Gert-Jan (1963) has a background in Polymer Chemistry (DSM 1993-2000) and has been Professor of Polymer Catalysis at Eindhoven University of Technology. In 2000 he transferred to Avantium and in 2004 he was appointed as Chief Technology Officer (CTO). He initiated the YXY/Synvina technology which includes novel processes from carbohydrates to FDCA monomer and 100% bio-based PEF polyester for bottles, fibers and film. In addition Gruter is involved in the development of the “DAWN Biorefinery Technology” for the production of pure glucose from agro and forestry lignocellulosic residues, the “RAY MEG Technology” for the 1-step hydrogenolysis of sugars to Mono Ethylene Glycol and the “Volta Technology” for the electrochemical reduction of CO2 to polyester monomers such as oxalic acid and glycolic acid. Gert-Jan is inventor on more than 100 patent applications; he was elected “2014 European CTO of the year” and nominated for European inventor of the year in 2017. Gert-Jan is currently part-time professor Industrial Sustainable Chemistry at the University of Amsterdam (UvA), where he is working on novel high Tg sustainable materials for re-use, on biodegradation, consumer psychology and on ocean plastics.

Abstract:

The Future of Plastics. Materials from biomass and CO2

The future of plastics will be determined by four main factors: (1) climate change will require a transition from fossil feedstock to renewable feedstock (biomass, CO2 and recycling are the only alternatives for fossil feedstock); (2) the 3-5% annual growth of polymer materials will lead by 2050 to a tripling of the 350 million tons of plastics produced in 2018, which creates a feedstock challenge as well as a feedstock opportunity; (3) the 8 million tons of plastics leaking into the environment every year may overtake climate change as the #1 challenge of humanity in the coming decades; (4) the limited amount of closed-loop recycling (less than 2% of packaging). In the presentation some of the Avantium and UvA developments that will address these three main factors will be presented.

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The fourth speaker that we announce:

  • dr. Kasia Tych: she has recently joined our university and thus can show us what new science is to be explored right here! Her research involves single molecule characterisation of proteins using force spectroscopy by optical tweezers combined with fluorescence. These single molecule techniques allow studying structures and function-related motions of biomolecules that would otherwise be inaccessible.

Abstract:

Using optical tweezers to learn about how biological molecules function

Since Dr. Arthur Ashkin first demonstrated the use of optical tweezers to manipulate biological objects such as viruses and bacteria in 1987, an experiment which won him the Nobel Prize in Physics in 2018, this experimental technique has developed to the extent that it is now possible to use them to measure forces acting on a single molecule. In my lecture, in addition to describing the principles behind the technique, I will explain why this is useful and important in the context of studying the function of biological molecules. I will give examples from the current literature and my own research of what is possible to achieve and how, alongside elegant chemical functionalization strategies, structural studies and functional measurements, optical tweezers are providing us with access to otherwise inaccessible information about the function-related motions of these molecules. Finally, I will give a brief overview of what it will be possible to do with optical tweezers in the future.

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Fifth speaker: dr. Markus Kärkäs, an assistant professor at the KTH Royal Institute of Technology in Sweden! His research interests include organic electrosynthesis, artificial photosynthesis and photoredox catalysis. At the symposium, he will delve into the chemistry of radical-based reactions, and discuss the development of photoredox- and electrochemically-based methods for stereoselective synthesis of unnatural alfa-amino acids and lignin fragmentation.

Abstract:

Leveraging Radicals in Catalysis

Markus D. Kärkäs 

Department of Chemistry, KTH Royal Institute of Technology, Teknikringen 30, SE-100 44 Stockholm,  Sweden 

E-mail: karkas@kth.se

Free radicals are ubiquitous intermediates in biological systems and can be leveraged to drive reactions  that would otherwise be difficult to achieve with classical ionic/polar transformations. The perception that  radicals are uncontrollable species and that reactions involving free radicals are nonselective has  historically discouraged scientists from applying radicals in synthetic settings. However, this viewpoint is  gradually shifting, mainly because of the advances that have been made feasible due to the gained insight  into the principal factors that govern radical processes. Radical-based reactions are now frequently being  considered and incorporated in contemporary organic syntheses as these radical routes offer advantages  compared to classical polar methods.1 This talk will detail the development of photoredox- and  electrochemically-based methods for stereoselective synthesis of unnatural α–amino acids2 as well as  lignin fragmentation.3

References 

(1) For selected reviews, see: (a) Kärkäs, M. D.; Porco, Jr., J. A.; Stephenson, C. R. J., Chem. Rev. 2016, 116,  9683–9747. (b) Kärkäs, M. D. Chem. Soc. Rev. 2018, 47, 5786–5865. (c) Shatskiy, A.; Lundberg, H.;  Kärkäs, M. D. ChemElectroChem 2019, 6, 4067–4092. 

(2) Shatskiy, A.; Axelsson, A.; Blomkvist, B.; Liu, J.-Q.; Dinér, P.; Kärkäs, M. D. ChemRxiv 2020, DOI:  10.26434/chemrxiv.12084672. 

(3) (a) Bosque, I.; Magallanes, G.; Rigoulet, M.; Kärkäs, M. D.; Stephenson, C. R. J. ACS Cent. Sci. 2017, 3,  621–628. (b) Yang, C.; Kärkäs, M. D.; Magallanes, G.; Chan, K.; Stephenson, C. R. J. Org. Lett. 2020, 22,


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The sixth speaker we would like to announce:

  • Prof. Stephen Liddle, professor and head of inorganic chemistry, and co-director of the Centre for Radiochemistry Research. He currently holds an EPSRC Established Career Fellowship at The University of Manchester. He is a native of the north east of England and obtained his BSc(Hons) and PhD degrees from Newcastle University. After postdoctoral stints at Edinburgh, Newcastle, and Nottingham universities he  was awarded a Royal Society University Research Fellowship in 2007, which he held at Nottingham. He was promoted to Associate Professor and Reader in 2010, Professor of Inorganic Chemistry in 2013, and he moved to his present position in 2015. He has published around 200 papers, reviews, and book chapters/books, and has received a number of awards including most recently an Alexander von Humboldt Foundation Friedrich Wilhelm Bessel Research Award in 2019 and the RSC Tilden Prize in 2020. He was elected a Fellow of the Royal Society of Chemistry in 2011 and is Vice President to the Executive Committee of the European Rare Earth and Actinide Society (2012-now). He was Chairman of COST Action CM1006, a 22 country 120 research group network for f-block chemistry (2011-2015), and he has been active in outreach activities, most notably on YouTube.

Abstract:

Adventures in Early Actinide Chemistry

Prof. Stephen T. Liddle

Department of Chemistry and Centre for Radiochemistry Research, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.

steve.liddle@manchester.ac.uk

When compared to the chemistry of the transition metals, it is unarguably the case that even after a burst of momentum over the past ten to fifteen years the chemistry of the actinides, largely for historical reasons, still lags quite some way behind. This is a problem, not only because there are deficiencies in our fundamental knowledge and understanding, but also because after being in a nuclear age for around eighty years there are a number of nuclear legacy issues that might better addressed with a superior understanding of these elements.

Fortunately, studying actinides is actually not an insurmountable challenge, and this lecture will provide some contextualisation of the history and background of the field, then discuss some of our contributions to the area, and hopefully convey just how cool elements like uranium are! I thank the Royal Society, Engineering and Physical Sciences Research Council, European Research Council, Marie Curie Fellowship, National Nuclear Laboratory, and The University of Manchester for funding and support, and a host of talented co-workers for working magic with ridiculously sensitive actinide complexes.

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