Kemifaglige foredrag 2015

Supramolecular Systems at Work

Prof. Stefan Matile

Prof. Stefan Matile
Department of Organic Chemistry
University of Geneva, Geneva, Switzerland

This lecture will describe some synthetic supramolecular systems with interesting functions.  All functions covered emerged from an original interest to learn how to transport ions or molecules across lipid bilayer membranes.  From there, sensors, photosystems and detectors for more “exotic” interactions evolved as main lines of research.  Topics of current interest include the integration of these exotic interactions into functional supramolecular systems.  Lessons from transport with anion-π interactions are applied to catalysis, with examples reaching from Kemp elimination to unpublished highlights on enolate chemistry.[1]  The existence of ionpair-π interactions on push-pull surfaces are probed with spectral tuning.[2]  The construction of functional surface architectures of highest possible sophistication will be achieved with up to three orthogonal dynamic covalent bonds used in concert.[3]  Ring tension is applied to dynamic covalent disulfide-exchange chemistry to find new ways to enter into cells.[4]  Mechanosensitive bonds, finally are introduced to build fluorescent probes that change color like lobsters during cooking and feel central characteristics of lipid bilayer membranes such as tension, potential and disorder.[5]

References:

1.   Y. Zhao, C. Beuchat, J. Mareda, Y. Domoto, J. Gajewy, A. Wilson, N. Sakai, S. Matile, “Anion-π Catalysis,” J. Am. Chem. Soc.2014, 136, 2101-2111.

2.   K. Fujisawa, C. Beuchat, M. Humbert-Droz, A. Wilson, T. A. Wesolowski, J. Mareda, N. Sakai, S. Matile, “Anion-π and Cation-π Interactions on the Same Surface,” Angew. Chem. Int. Ed.2014, 53, 11266-11269.

3.   H. Hayashi, A. Sobczuk, A. Bolag, N. Sakai, S. Matile, “Antiparallel Three-Component Gradients in Double-Channel Surface Architectures,” Chem. Sci.2014, 5, 4610-4614.

4.   G. Gasparini, E.-K. Bang, G. Molinard, D. V. Tulumello, S. Ward, S. O. Kelley, A. Roux, N. Sakai, S. Matile, “Cellular Uptake of Substrate-Initiated Cell-Penetrating Poly(disulfide)s,”J. Am. Chem. Soc.2014, 136, 6069-6074.

5.   M. Dal Molin, Q. Verolet, A. Colom, R. Letrun, E. Derivery, M. Gonzalez-Gaitan, E. Vauthey, A. Roux, N. Sakai, S. Matile, “Fluorescent Flippers for Mechanosensitive Membrane Probes,” J. Am. Chem. Soc.2015, 137, 568-571.

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Host: Kurt Gothelf, Institut for Kemi & iNANO, Aarhus Universitet

Foredraget bliver afholdt d. 26. marts kl. 15.15 i Aud I (1514-213)

Peptide-inspired ligands for the modulation of biological function

Dr. Tom Grossmann

Dr. Tom N. Grossmann
Chemical Genomics Centre of the Max Planck Society

University of Dortmund

Abstract:

Ligands that selectively bind to biomolecular targets are a prerequisite for most strategies aiming at the elucidation or modulation of biological processes. The discovery of these ligands can be very challenging. Giving the huge amount of available structural data, peptide binding epitopes provide a rich source of inspiration for novel ligands. Preorganization of such peptides into their bioactive conformation or the use of rigid peptidomimetic scaffolds have been applied to ensure binding affinity and bioactivity. Notably, there is a lack of approaches for the stabilization of irregular and complex peptide structures. In addition, the design of peptide-derived bioactive compounds is often hampered by their low cellular uptake and biostability. Addressing these challenges, my lab focuses on the design of peptide-inspired ligands for an application in proximity-induced chemical reactions and as inhibitors of protein‒protein interactions.

Host: Thomas B. Poulsen, Institut for Kemi, Aarhus Universitet

Foredraget bliver afholdt d. 12. marts kl. 15.15 i Aud I (1514-213)

Gas Phase Advanced Oxidation for Emissions Control: Fra Forskning til Faktura

Matthew S. Johnson

Prof. Matthew S. Johnson 
Kemisk Institut
Københavns Universitet

Abstract:

Gas-phase advanced oxidation (GPAO) is a new method for pollution control building on the photooxidation and particle formation chemistry occurring in the atmosphere. The process uses ozone and UV-C light to produce in situ radicals to oxidize pollution, generating particles that are removed by a filter. This combination of in situ processes removes a wide range of pollutants with a comparatively low specific energy input. GPAO is the basis of commercial emissions control systems installed by the cleantech spin-out company Infuser at European Protein in Jelling and Jysk Miljørens in Aarhus, and we are working on systems for Madsen Biogas and Volkswagen. Prototype tests show removal efficiencies of >95% for propane, cyclohexane, benzene, isoprene, aerosol particle mass, and ozone for mole fractions in the range of 0.4−6 ppm and exposure times up to 0.5 min. The laboratory prototype generated a OH• concentration of (2.5 ± 0.3) × 1010 cm−3 at a volumetric energy input of 3 kJ/m3. Based on these results, in situ gas-phase advanced oxidation is a viable control strategy for most volatile organic compounds, specifically those with a OH• reaction rate higher than ca. 5 × 10−13 cm3 s-1. Secondary pollution including carbon monoxide and ultrafine particles are generated under some conditions and can be controlled given additional treatment

Host: Merete Bilde, Institut for Kemi, Aarhus Universitet 

Fordraget bliver afholdt d. 19. januar kl. 15.15 i Aud I (1514-213)