Project

Discipline

Reactive Intermediates; Matrix Isolation Spectroscopy; Radical Ions; Quantum chemical modelling; Matrix Isolation; Quantum Chemical Calculations; Molecular Wires

Lead
Lay summary
The ability to predict and control the outcome of chemical reactions, be it in biology or technology, frequently requires knowledge of the key reaction intermediates. The present research project focusses on the study of such fleeting species (charged and uncharged radicals, nitrenes, carbenes) under conditions where they persist sufficiently long to be probed by conventional spectroscopic means. To this end, suitable precursors are embedded in frozen organic solvents at 77K or inert gas matrices at 10K where the targeted reactive intermediates are then generated by photolsis or radiolysis of these precursors. The electronic and vibrational spectra of the resulting species contain valuable information that is used to confirm or reject hypotheses with regard to the identity and the structure of reactive intermediates. In addition, their reactivity can be probed by allowing them to rearrange, either by slightly raising the temperature or by exposing them to light at selected wavelengths, or by letting them engage in bimolecular reactions with suitable small reactants with which the host material is doped. A common feature of all projects is, that the experimental work is invariably accompanied by quantum chemical model calculations which serve on the one hand to interpret the spectroscopic observations and on the other hand to shed light on the reactivity of the observed species. Much of the insight obtained in this project arises from a synergy betwen experimental and theoretical approaches.

Direct link to Lay Summary

Last update: 21.02.2013

Number	Title	Start	Funding scheme

The ability to predict and control the outcome of chemical reactions, be it in biology or technology, frequently requires knowledge of the key reaction intermediates. The present research project focusses on the study of such fleeting species (primarily charged and uncharged radicals and closed-shell cations) under conditions where they persist sufficiently long to be probed by conventional spectroscopic means. To this end, suitable precursors are embedded in inert solid media at low temperature where the targeted reactive intermediates are then generated by photolsis or radiolysis of these precursors. The electronic and vibrational spectra of the resulting species contain information that is used to confirm or reject hypotheses with regard to the identity and the structure of reactive intermediates. In addition, their reactivity can be probed by allowing them to rearrange, either by slightly raising the temperature or by exposing them to light at selected wavelengths, or by letting them engage in bimolecular reactions with suitable small reactants with which the host material is doped. A common feature of all projects is, that the experimental work is invariably accompanied by quantum chemical model calculations which serve on the one hand to interpret the spectroscopic observations and on the other hand to shed light on the reactivity of the observed species. Much of the insight obtained in this project arises from a synergy betwen experimental and theoretical approaches.