Excellent Chemistry Lecture
Excellent Chemistry Lecture (ECL) series focuses on emerging topics related to the three IChF Clusters of Excellence
2024
-
14 Nov 2024
-
NMR in Photo- and Organocatalysis – Pushing the Limits
- Prof. Dr. Ruth M. Gschwind, University of Regensburg
- Excellent Chemistry Lecture - Cluster 3, IChF Aula
Excellent Chemistry Lectures- See more
NMR in Photo- and Organocatalysis – Pushing the Limits
- Date: 14 Nov 2024, 10:00
- Lecturer: Prof. Dr. Ruth M. Gschwind, University of Regensburg
- Institution: Excellent Chemistry Lecture - Cluster 3, IChF Aula
- Abstract:
The detection and characterization of intermediates in catalytic reactions is crucial for the rational optimization of reaction conditions. However, in many rapidly expanding fields of asymmetric catalysis, mechanistic studies as well as structural investigations on intermediates or intermolecular interactions are scarce. In this talk I will present techniques and methods to extend the application of NMR in photocatalysis and ion pair catalysis and explain their impact on examples. First our LED based NMR illumination device [1] will be introduced together with the new triple combination illumination/NMR/UV [2] and an NMR access to intermediates below the detection limit [3]. These methods allow for new insights into one- versus two-electron processes usually inaccessible to UV/Vis [4], the inclusion of radical species into NMR reaction profiles [2], the structure elucidation of thermally labile photoswitches [2], the sequencing of tiny intermediates [5], and even insights into photosteps in photocatalysis [6]. Last, the structure elucidation, H-bond analysis, reactivity/selectivity understanding and experimental transition state combination analysis of chiral phosphoric acids in ion pair catalysis is demonstrated [7]. Here, the NMR time scale could be extended so far that even the switching of a single hydrogen bond can be detected experimentally [8]. The translation of structural insights to synthetic applications is shown at two examples: Higher stereoselectivities were obtained for a whole bundle of ion pair catalysts combining ground- and transition state analysis with dispersion donor effects [9]. Furthermore, accelerated photochemical reactions at oil-water interface exploiting melting point depression are presented [10].
[1] C. Feldmeier, H. Bartling, E. Riedle, R.M. Gschwind, J. Magn. Res., 2013, 232, 39.
[2] A. Seegerer, P. Nitschke, R.M. Gschwind, Angew. Chem. Int. Ed. 2018, 57, 7493.
[3] L. Nanjundappa, A. Seegerer, J. Hioe, R.M. Gschwind, JACS 2018, 140, 1855.
[4] C. Feldmeier, H. Bartling, K. Magerl, R.M. Gschwind, Angew. Chem. Int. Ed., 2015, 54, 1347.
[5]. S. Wang, L. Nanjundappa, J. Hioe, R. M. Gschwind, B. König, Chem. Sci., 2019, 10, 4580. [6] N. Berg, S. Bergwinkl, P. Nuernberger, D. Horinek, R.M. Gschwind, JACS 2021, 143, 724. [7] JACS, 2016, 138, 15965; JACS, 2016, 138, 16345; JACS 2017, 139, 6752; Chem. Sci. 2019, 10, 5226; Chem. Sci. 2019, 10, 10025; Chem. Sci. 2020, 11, 4381; Chem. Sci. 2021, 12, 15263; JACS, 2022, 144, 19861.
[8] L. Nanjundappa, J. Hioe, J. Gramueller, R. M. Gschwind, JACS 2019, 141, 16398.
[9] J. Gramüller, M. Franta, R. M. Gschwind, JACS 2022, 144, 1986.
[10] Y. Tian, W. Silva, R.M. Gschwind, B. König, Science 2024, 383, 750.
-
6 Nov 2024
-
Weak and strong coupling: potential for controlling energetics and relaxation in molecular based systems
- Prof. Karl Borjesson, University of Gothenburg, Sweden
- Excellent Chemistry Lecture - Cluster 2, IChF Aula
Excellent Chemistry Lectures- See more
Weak and strong coupling: potential for controlling energetics and relaxation in molecular based systems
- Date: 6 Nov 2024, 10:00
- Lecturer: Prof. Karl Borjesson, University of Gothenburg, Sweden
- Institution: Excellent Chemistry Lecture - Cluster 2, IChF Aula
- Contact person:
dr Sylwester Gawinkowski
- Abstract:
Coupling of the transition dipole moment of an organic chromophore can create new photophysical relaxation pathways and/or change the energetics of the excited states. I will give a selection of examples using three different coupling scenarios. The first scenario deals with weak exciton coupling, which enables energy transfer between chromophores. I will discuss how the energy transfer, commonly referred to as FRET, can be used as a multiplicity converter. The second scenario deals with strong exciton coupling, which results in new delocalized states with distinctly different energies than the uncoupled chromophore (so-called J-aggregates). I will start by showing that such systems can not only be used to red shift the absorption, but the delocalized nature results in a breakdown of the so-called energy gap law, giving a surprisingly high emission quantum yield in the NIR region of the electromagnetic spectrum. I will then continue with highlighting the benefit of strong exciton coupling for decreasing energy losses for triplet sensitizers. The third and last scenario deals with strong light-matter coupling. Here the molecular transition dipole moment is strongly coupled to the electromagnetic field inside an optical cavity, producing so-called polaritonic states. This phenomenon opens a plethora of options for manipulating the properties of molecules, with a broad range of applications in physics, chemistry, and materials science. In this presentation, I will discuss on the possibility to modify energetic driving forces and to efficiently harvest the excitation energy in planar heterojunctions by utilizing the delocalized nature of hybrid light-matter states.
-
30 Oct 2024
-
Advanced human heart models and gene therapies. Are they connected? - R&D dualism
- Tomasz Kolanowski, MD, PhD, Institute of Human Genetics, Polish Academy of Sciences
- Excellent Chemistry Lecture - Cluster 1, IChF Aula
Excellent Chemistry Lectures- See more
Advanced human heart models and gene therapies. Are they connected? - R&D dualism
- Date: 30 Oct 2024, 11:30
- Lecturer: Tomasz Kolanowski, MD, PhD, Institute of Human Genetics, Polish Academy of Sciences
- Institution: Excellent Chemistry Lecture - Cluster 1, IChF Aula
- Place:
IChF Aula
- Contact person:
prof. Agnieszka Michota-Kamińska
-
12 Sept 2024
-
Coupling chemistry and cavitation bubbles: an emerging mode of activation boosted by the electrification of our society
- Prof. Dr. François JEROME, Affiliation: Institut de Chimie des Milieux et Matériaux de Poitiers, Poitiers (FRANCE)
- Excellence cluster 3: “Catalysis and materials for sustainable transformations”
Excellent Chemistry Lectures- See more
Coupling chemistry and cavitation bubbles: an emerging mode of activation boosted by the electrification of our society
Excellence cluster 3: “Catalysis and materials for sustainable transformations”
- Date: 12 Sept 2024, Thursday, 10 am, Aula IChF PAN
- Lecturer: Prof. Dr. François JEROME, Affiliation: Institut de Chimie des Milieux et Matériaux de Poitiers, Poitiers (FRANCE)
- Institution: Excellence cluster 3: “Catalysis and materials for sustainable transformations”
- Place:
Aula IChF PAN
- Contact person:
Contact person at IChF: Prof. Dr. Juan Carlos Colmenares Q., jcarloscolmenares@ichf.edu.pl
- Abstract:
The massive defossilization of our society is now offering new prospects to activate chemicals in a potentially more sustainable way, for instance with the help of electric and magnetic fields, photons, electrons, mechanical forces, etc. In this context, we are exploring the use of cavitation bubbles, formed by the application of an ultrasonic wave in a liquid, to activate and convert chemicals without assistance of any catalyst. If excited species generated at the bubble collapse time can induce nearly barrier-less reactions, the control of the selectivity of induced reactions remains a scientific challenging task, which we (partly) address in this conference. In particular, we will highlight that NH3 can be advantageously activated without any catalyst, “just” by the application of ultrasonic wave at 550 kHz. This ultrasonic activation was exploited in the direct conversion of NH3 to N2H4 and its subsequent oxidation to a diimide for promoting the hydrogenation of alkenes to alkanes. The confinement of cavitation bubbles on the surface of solid catalysts (here CuO) will be also discussed to demonstrate that the energy stored in cavitation bubbles can be selectively transferred to a catalytic surface. It thus opens a mean to locally heat the surface of a catalyst rather than the complete bulk solution which is a much more energy consuming path.
Short CV
François JEROME got his PhD in 2000 from the University of Burgundy (France). Then he moved to UC-Davis (USA) for a one-year postdoctoral position, and then he returned back to France (Rennes) for a second postdoctoral position. In 2002, he was recruited as a permanent CNRS researcher at the laboratory of catalysis in organic chemistry at the University of Poitiers. In 2011, he was promoted CNRS research director at the Institute of Chemistry of Poitiers. His research largely concerns the conversion of renewable feedstocks to fine chemicals. In this field, he developed an expertise on catalysis and more particularly on the coupling of catalysis with auxiliary promotional tools. His research was awarded by the French Chemical society (prize from the catalysis division), the CNRS (national medal on innovation) and EFCATS (Francois Gault lectureship award). He is now leading a public/private network working on the catalytic conversion of renewable feedstocks, he is in the editorial board of the green chemistry journal and he is chairman of the International Symposium on Green Chemistry organized each two years at La Rochelle (France, > 700 attendees).
-
18 Jun 2024
-
Wireless electrochemistry for chirality detection
- Prof. Dr Serena Arnaboldi, University of Milan, Italy
- Excellence cluster 2: “Photonics and light driven processes”
Excellent Chemistry Lectures- See more
Wireless electrochemistry for chirality detection
- Date: 18 Jun 2024, 10:00
- Lecturer: Prof. Dr Serena Arnaboldi, University of Milan, Italy
- Institution: Excellence cluster 2: “Photonics and light driven processes”
- Place:
Aula IChF PAN
- Contact person:
Dr Sylwester Gawinkowski
- Abstract:
Prof. Serena Arnaboldi is a faculty member at the University of Milan, where she also obtained her PhD in 2015. She has continued her scientific journey by spending time in various laboratories in Italy (Rome, Genoa) and abroad at the Institute of Polymer Chemistry in Stuttgart, Germany, and the University of Bordeaux in France. In 2022, she was appointed Associate Professor of Analytical Chemistry at the University of Milan, where she leads her research group. Her scientific interests focus on electrochemistry, particularly chiral electroanalysis. She publishes in renowned scientific journals such as Chemical Science, Angewandte Chemie, and Nature Chemistry. She is also the recipient of an ERC Starting Grant.
-
6 Jun 2024
-
Compartmentalized Biohybrid Photocatalysis
- Prof. Lars Jeuken, Leiden University, Leiden, Netherlands
- Excellence cluster 3: “Catalysis and materials for sustainable transformations”
Excellent Chemistry Lectures- See more
Compartmentalized Biohybrid Photocatalysis
- Date: 6 Jun 2024, Thursday, 10 am
- Lecturer: Prof. Lars Jeuken, Leiden University, Leiden, Netherlands
- Institution: Excellence cluster 3: “Catalysis and materials for sustainable transformations”
- Place:
Aula IChF PAN
- Contact person:
dr hab. Adam Kubas, akubas@ichf.edu.pl
- Abstract:
In nature, charge recombination in photosystems is minimised by efficient charge separation across the thylakoid membrane. In a semi-artificial photosynthetic approach, we aim to mimic this principle by coupling light-harvesting or photocatalytic nanoparticles (NPs) to lipid vesicles. Key to this approach has been an icosahaem membrane protein, MtrCAB from Shewanella oneidensis MR-1. In this protein, twenty haems form a ~15 nm long molecular wire, which efficiently transfer electrons across lipid membranes. Interaction and photo-induced electron transfer between light-harvesting NPs and MtrCAB is studied, among others, with life-time fluorescence, X-ray footprinting mass spectrometry and photoelectrochemistry. Transmembrane photoreduction is observed in liposomes loaded with redox-active dyes. Finally, by encapsulating biocatalysts like hydrogenase in the liposomes, a compartmentalized biohybrid photocatalytic system has been realised. We envision that these approaches can ultimately be used to develop whole-cell biophotocatalysis in the future.
Short CV
After studying Biology in Utrecht, Lars Jeuken started his PhD studies in 1995 in Leiden on the structure-function relationship of copper proteins. After a Post-Doc in Oxford (1999-2002), where he learned bioelectrochemistry, he was awarded a BBSRC David Phillips fellowship, which he took to Leeds to study respiratory membrane enzymes with electrochemistry. In Leeds, he received an ERC consolidator grant and became professor in 2017 while studying novel hybrid nanoparticle-biocatalytic system for solar fuel production. In 2021, he moved to Leiden where he continues his research.
-
27 May 2024
-
One- and two-photon excited surface-enhanced Raman scattering of biological samples
- Prof. Dr Janina Kneipp, Humboldt-Universität zu Berlin
- Excellent Chemistry Lecture - Cluster 1, IChF Aula
Excellent Chemistry Lectures- See more
One- and two-photon excited surface-enhanced Raman scattering of biological samples
- Date: 27 May 2024, 13:00
- Lecturer: Prof. Dr Janina Kneipp, Humboldt-Universität zu Berlin
- Institution: Excellent Chemistry Lecture - Cluster 1, IChF Aula
- Place:
IChF Aula
- Contact person:
prof. Agnieszka Michota-Kamińska