AbstractsChemistry

This thesis deals with the synthesis and characterization of novel polychoride salts. The synthetic approach of conducting the reactions involving neat halogens, was adapted to fit the requirements of using chlorine as a gaseous reactant. Several previously unknown polychlorides were synthesized and characterized by means of vibrational spectroscopy and X-ray single crystal structure determination. This includes [Cl8]2– the first polychloride dianion to be reported in literature as well as the first higher polychloride network [Et4N]2[(Cl3)2·Cl2]. Additionally two new structures of trichloride salts were found. One of which (N,N’-dimethyl-2-chloro-imidazolinium trichloride) containing the most regular trichloride anions to be reported so far. Under the use of different ionic liquids a convenient way to synthesize and crystallize higher polychloride salts was developed. Furthermore a broad variety of substances were tested towards their ability to chemically withstand treatment with elemental chlorine. The polychloride monoanions [Cl5]– and [Cl9]– were successfully synthesized and characterized by Raman spectroscopy. All preparative work was accompanied by quantum-chemical calculations confirming and helping to interpret the results allowing insights to the bonding situation. Having prepared a couple of polychloride salts it was possible to compare polychloride chemistry to that of polybromides and polyiodides, showing similarities as well as differences. Although not as manifold as polybromides and especially polyiodides, polychlorides exhibit similar structural motives and similar thermodynamic stability could be predicted. Major differences arise from the weaker bond energies enabling even higher polychlorides to form structures involving discrete anions that do not show any tendency to form networks as well as compounds that – very similar to known heavier polyhalides – form networks which are held together by halogen bonding as the driving force and main factor of their stability. Finding a way to prove the existence of higher polychlorides in substances certainly cleared the way to attain a deeper understanding of polyhalide chemistry now being able to compare structures of all polyhalides except polyfluorides. Die vorliegende Arbeit behandelt die Synthese und Charakterisierung neuartiger Polychloridsalze. Der Ansatz die Synthese mittels elementarer Halogene durchzuführen, wurde erfolgreich an die Anforderungen angepasst, die die Arbeit mit gasförmigem Chlor mit sich bringt. Mehrere unbekannte Polychloride konnten dargestellt und spektroskopisch, sowie strukturell charakterisiert werden. Dies beinhaltete [Cl8]2–, das bisher erste und einzige Polychloriddianion, sowie das erste Polychloridnetzwerk [Et4N]2[(Cl3)2·Cl2]. Des Weiteren konnten zwei neue Trichloridsalze strukturell aufgeklärt werden, darunter N,N’-dimethyl-2-chloroimidazoliniumtrichlorid, welches das regelmäßigste bislang bekannte Trichloridanion enthält. Durch den Einsatz verschiedener ionischer Flüssigkeiten…