The goal of our research is establishing the reactivity of systems involving paramagnetic stages, particularly organic radicals and radical ions and transition metal ions.
The work is based on magnetic resonance spectroscopy (NMR, CIDNP, EPR, time-resolved EPR, ENDOR), UV-VIS spectroscopy, laser-flash photolysis, cyclic voltammetry, and theoretical calculations.
Most importantly, however, we rely on collaborations with several colleagues around the world.

Photoinitiated Radical Polymerization

We have been involved in the investigation of innovative photoinitiators for many years. In this context, we have indicated a useful approach for obtaining kinetic data from time-resolved EPR. We have also shown that photoinitiated polymerization proceed reversibly even at the starting phase and that hydrogen-transfer reactions take place. We are currently studying several new phosphorus- and germanium-based photoinitiators. Moreover we are pursuing the conversion of end-groups in photoinitiated radical polymerizations.

Working on the topic: P. Frühwirt, G. Glotz, M. Schmallegger, D. Neshchadin

Collaborations: C. Barner-Kowollik (QUT, Australia / KIT, Germany), H. Grützmacher & K. Dietliker (ETHZ, Switzerland), R. Liska (TU Wien, Austria), M. Haas & H. Stüger (TU Graz, Austria), N. Moszner (Ivoclar Vivadent, Liechtenstein)

Link to Photoinitiator Efficiencies Calculator: http://ptc-pc-139.tugraz.at/cgi-bin/index.pl

Recent Publications:

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Combining Photochemistry with NMR

Coming from our NMR setup with modified probe-heads allowing laser irradiation inside the NMR spectrometer, we seek to apply NMR detection to all kinds of photo reactions. Various light sources can be coupled to the spectrometer, including lasers, LEDs and high intensity UV-lamps. This so called in-situ irradiation enables us to observe numerous photoreactions in a quick and facile manner; e.g. intramolecular rearrangements, polymerizations, initiator cleavage etc. The collected data can be used to extract kinetic parameters like quantum yields or to identify photoproducts. A specific focus lies on method development for light induced sensitivity enhancement with the aid of switchable inorganic complexes.

Working on the topic: P. Frühwirt, M. Schmallegger, D. Neshchadin

Collaborations: R. Herges (University of Kiel, Germany), K. Zangger (University of Graz, Austria)

Recent Publications:

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Antioxidants

Antioxidants usually act at a rather rapid time scale, at the diffusion-controlled limit. We have been investigating the reactivity of several types of antioxidants at real time (ns time scale) and establishing the nature and the structure of species formed in the very early stages of antioxidative processes.

Working on the topic: D. Neshchadin, M. Schmallegger

Recent publications: 

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Radical Processes in Biomimetic Systems

Oxidative stress by radical species is one of the main causes of alterations of the structure of biological membranes and is often associated with negative physiological consequences. One possibility to study these processes is the use of biomimetic systems like liposomes. We are currently studying radical processes across biomimetic membranes establishing the structure and properties of species formed in the early stages of oxidative stress.

Working on the topic: M. Schmallegger

Recent publications:

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Novel Organic Materials

Molecules consisting of efficient donor and acceptor moieties possess intriguing chemical and physical properties. Also the synthetic pathways for obtaining such compounds involves rather subtle reaction steps. We have been investigating such reactions together with the characterization of the target molecules.

Working on the topic: D. Neshchadin

Collaborations: F. Diederich (ETHZ, Switzerland)

Recent publications:

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Contact
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Univ.-Prof. Mag. Dr. Georg Gescheidt-Demner Stremayrgasse 9, room CE01506
+43 316 873 32220
g.gescheidt-demnernoSpam@tugraz.at