Structure Determinations of the Sulfonic Acid Monofluoromethylesters FSO2OCH2F and CF3SO2OCH2F in the Solid and Gaseous Phases

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We propose to study the structures of the sulfonic acid monofluoromethylesters FSO2OCH2F and CF3SO2OCH2F in the solid and gaseous phases. These compounds are small sulfonic acid esters and simple representatives of an important class of compounds and thus of fundamental interest. We expect to get achieve a detailed under¬standing of the structures of simple fluoromethyl sulfonates, their reactivity and chemistry within this class of compounds. The variation of electron-withdrawing substituents from F to CF3 and the comparative study of the changes in structure and conformational behaviour will allow new insights into the nature of bonding and electronic influences of substituents. This should help to guide further research into new and hitherto unknown fluoromethylating agents and to explain the difference in reaction behaviour between methyl and fluoromethylating agents. A possible relation between structure and stability properties of these potentially strong fluoro¬methylating agents is a further target of this research. We plan to elucidate the crystal structures of the sulfonic acid monofluoromethylesters FSO2OCH2F and CF3SO2OCH2F by applying suitable crystallization techniques to these liquid substances in order to gain crystals for X-ray diffraction that lead to resolvable structures of the solid state. If possible, we also plan to determine the electron density topologies by high angle X-ray diffraction for a detailed analysis of the electronic effects within the compounds. By making use of the X-ray crystallographic results we hope to receive more accurate computational data of their inter- and intramolecular interactions in the system. Central part of the project is to explore the experimental gas phase structures of these compounds by electron diffraction experiments and analysis of the diffraction data – if necessary with sophisticated dynamic descriptions of the molecules. The sample preparation and purification will be performed in Munich, the samples transferred to Bielefeld and structural studies in gas and solid performed in the core facility GED@BI (Centre of Gas Electron Diffraction and Small Molecule Structures) in Bielefeld. These experimental studies will be accompanied by high level quantum-chemical methods.