Dokument

Summary:
Silicone and Siloxane derivatives (e.g. (Me2SiO)n) are known to be chemically inert and hydrophobic materials. To bind cations thus requires sophisticated techniques to activate Si-O bonds for coordination. Central part of this thesis is therefor establishing Lewis acidic systems which allow effective Si-O bond activation. In addition, establishing suitable templates allow obtaining cation specific compounds in ring-opening oligomerization reactions. These reactions enable the synthesis of crown-ether analogues which formally resemble “inorganic” architectures of crown-ethers. So far, these ligands could not be synthesized by other means. Inorganic crown-ethers might show a reduced capability of binding cations but are remarkably stable in solution as long as a suitable metal ion is present which can act as a template. It could be shown that nine- and twelve membered cycles coordinate the cations Li+, Na+, Ca2+, Sr2+ and even H+ selectively. Hence, inorganic crown-ether analogues show an ion-selectivity towards chemically hard cations which has not been observed for their organic counterparts. In addition, templated synthesis has not yet been observed for conventional crown-ether analogues which is why a novel reactivity pattern is also presented here. The thesis does not only provide the synthesis of coordination compounds of inorganic crown-ether analogues but also that of related systems such as coordination compounds of hybrid disila-crown-ethers and cyclosiloxanes.

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