Strukturbestimmung von Catecholato-Silanen in verschiedenen Phasen und mit unterschiedlichen Methoden
Zusammenfassung der Projektergebnisse
Catecholates play a unique role in the structural, bio- and geochemistry of silicon. A wealth of information exists for hypercoordinated catecholato silicates, but the structure of the parent, tetracoordinated bis(catecholato)silane, Si(cat H)2 1, or any derivative, is unknown. The claim of a squareplanar coordinated silicon(IV) in 1 triggered a prominent debate in 1979, which remains unsettled to this day. Herewith, we present a comprehensive structural study on 1 and derivatives in the gas phase by electron diffraction, in a neon matrix by IR spectroscopy, in solution by diffusion NMR spectroscopy, and in the solid-state by X-ray diffraction and MAS NMR spectroscopy; complemented by quantum-chemical computations. The study comprises a multitude of insights, among: 1) silicon catecholates display rapid dynamic covalency by Si−O bond metathesis; 2) in the condensed phase, bis(catecholato)silanes are metastable towards oligomerization to a degree depending on the type of catechol, temperature, and concentration; 3) the monomeric bis(catecholato)silane contains tetrahedral coordinate silicon. Our findings disclose the origins of a long-lasting debate and help to understand of the role of catechols for mineralization and distribution of silica in our geo- and biosphere.
Projektbezogene Publikationen (Auswahl)
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The Structure of Bis(catecholato)silanes: Phase Adaptation by Dynamic Covalent Chemistry of the Si–O Bond. Journal of the American Chemical Society, 143(44), 18784-18793.
Hartmann, Deborah; Thorwart, Thaddäus; Müller, Rosa; Thusek, Jean; Schwabedissen, Jan; Mix, Andreas; Lamm, Jan-Hendrik; Neumann, Beate; Mitzel, Norbert W. & Greb, Lutz
