Scientific Exchange at lunchtime on every first friday of the month!

Our next Lunchtalk Sessions, always from 12 - 13 PM:

and many more to come!

 Apply for a talk!

Do you want to present your research at our lunchtalks? Submit an abstract at https://forms.gle/pajNcEuZuRnHqhZ66

Certificates for all speakers will be provided!

Get in touch with us on Instagram @jcf_lunchtalks

or through mail Diese E-Mail-Adresse ist vor Spambots geschützt! Zur Anzeige muss JavaScript eingeschaltet sein.

Next Session

Photochemistry@Noon

This March we are lighting up the dark in cooperation with the GDCh division for Photochemistry.

Date: 06 March 2026

Time: 12 PM

Via Zoom: https://zoom.us/j/99558437022

 Matthias Schmitz (Johannes Gutenberg University Mainz)

"Strategies for Enhanced Efficiency and Performance in Photocatalysis"

Photochemical energy and electron transfer catalysis have become powerful tools for achieving particularly mild reaction conditions and enabling syntheses that are difficult to perform thermally. However, photocatalytic processes often suffer from very low quantum yields, which means that much of the incoming light is not used for the desired reaction and is usually lost as heat. This energy loss reduces their economic viability, which is why strategies to increase quantum yields are highly relevant in the context of larger-scale reactions. Ruthenium complexes are among the best-known photocatalysts, but they show only limited quantum yields. These are increased by covalently binding them to a purely organic chromophore, resulting in molecular dyads with longer excited state lifetimes and lower spin-orbit coupling effects during electron transfer events. However, covalently linking both chromophores is very time- and resource-consuming, which in turn reduces economic viability. A significant simplification of the preparation can be achieved by linking the chromophores via Coulombic interactions leading to Coulombic dyads, which only requires the mixing of commercially available salts. The combination of laboratory-scale as well as mechanistic irradiation experiments with detailed spectroscopic investigations via transient absorption spectroscopy provided deep mechanistic insights into this easy-to-use dyad class.

Sandra Merin Sebastian (University of Duisburg-Essen)

"How Polymer Architecture Controls Phthalocyanine Aggregation and ROS Generation in Antimicrobial Photodynamic Therapy"

Antimicrobial photodynamic inactivation (aPDI) is a promising light-triggered strategy to address drug-resistant infections and biofilm persistence, but its efficiency is often limited by the formulation of hydrophobic photosensitizers (PS) in water. In our recent work, we investigated how the hydrophilic-hydrophobic balance of cationic amphiphilic diblock copolymers (prepared via RAFT polymerization) governs the loading, aggregation state, excited-state dynamics, and ROS pathways of functionalized zinc phthalocyanines (ZnPc) in polymeric micelles. By systematically varying the length of the quaternized hydrophilic block, we observed pronounced changes in fluorescence lifetimes (sub-ns to ~2 ns), shifts between Type II and Type I ROS signatures depending on carrier architecture, and strong light-activated antibacterial performance against both Gram-positive and Gram-negative bacteria. Importantly, fluorescence lifetime analysis in bacterial suspensions and FLIM in mature biofilms revealed that the local microenvironment can reorganize the PS within the carrier, complicating “from-structure-to-function” prediction.

Building on these insights, my current work addresses a key limitation of simple PS-loaded micelles: dye leakage and the resulting loss of photophysical control and bioactivity. I will also present our ongoing strategy using terpolymers where ZnPc units are covalently integrated into the polymer backbone, aiming to suppress leakage, stabilize the emissive/photoreactive state, and improve reproducibility in complex biological environments.

Shubham Tiwari (Albert Ludwigs University Freiburg)

"Surface Engineering via Hydrogel Transfer Printing"

Coating materials with hydrogel layers is important for the performance of many modern biomedical materials, but it often proves difficult on substrates with complex, non-planar topologies. Additionally, achieving permanent adhesion to the substrate can be challenging, particularly when water is present, as it causes the hydrogel to swell. We introduce a hydrogel transfer printing technique that uses special paper as a substrate and a C-H insertion reaction. The paper acts as a flexible transfer agent and has a controlled hydrophobic and a hydrophilic side. A photoreactive hydrogel precursor is deposited on its hydrophobic side, which is then placed on the target surface. Adding a small amount of water to the hydrophilic side releases the hydrogel precursor and enables smooth transfer to the desired substrate. After removing the transfer paper, brief UV illumination activates the deposited photopolymer, leading to crosslinking and covalent attachment of the layer to the substrate surface via CHic.

An emerging advancement in glaucoma, a leading cause of blindness, has been achieved by transfer printing, which demands innovative and effective treatments that surpass the limitations of current drug and surgical interventions to lower intraocular pressure. This approach employs cell-repellent patches deposited via transfer printing, composed of a hydrophilic, protein-repellent prepolymer hydrogel based on a copolymer of dimethylacrylamide and a comonomer bearing anthraquinone moieties. Upon transferring the hydrogel patch to the desired location, brief irradiation with UV light with the wavelength of 365 nm simultaneously induces crosslinking and covalent attachment to the ocular surface via C–H insertion reactions, resulting in robust and stable integration.

We also demonstrate the handling and attachment of these hydrogels to substrates with varying, complex topologies along with cellulose and biological, with brief UV irradiation which allows the deposition of hydrogel layers with high accuracy and uniformity, as well as excellent underwater adhesion.

Thanks to our previous speakers!

13 February 2026: Organic Chemistry

Zhengyang Dong (Johannes Gutenberg University Mainz)

"Flavin-based electron-bifurcation: From cell to flask"

Dr. Marvin Wenninger (Otto von Guericke University Magdeburg)

"(+)-Neosorangicin A: Synthetic Access to a Promising Natural Product Lead"

05 December 2025: Physical Chemistry

Abha Valavalkar (Friedrich Schiller University Jena)

"Photophysics of biologically relevant molecules"

07 November 2025: Macromolecular Chemistry

Anna-Lisa Poser (Fraunhofer Institute for Applied Polymer Research IAP // University of Potsdam)

"The Shape Memory Effect in Polyurethane Foams"

07 October 2025: Electrochemistry 

Franziska Kühling (Carl von Ossietzky Universität Oldenburg)

"New Insights on the Fundamentals of Bipolar Electrochemistry"

Alena Neudert (Universität Bayreuth) 

"Hybrid all-Fe Redox Flow Battery: Coupling Theory and Experiment"