Synthesis, Characterization and Reactivity of Ylidyne and μ-Ylido Complexes Supported by Scorpionato Ligands

Abstract

The chemistry of compounds featuring triple bonds of the heavier Group-14 elements Si–Pb with transition metals is a very challenging research area, which combines modern molecular main-group element with transition-metal chemistry, and is of fundamental importance for the understanding of chemical bonding. During the last 15 years, the research in this area has witnessed considerable progress in isolating a series of closed-shell tetrylidyne complexes. However, despite numerous attempts, open-shell tetrylidyne complexes and heavier group 14 element congeners of metallacarbynes and carbide complexes remained inaccessible.<br /> This PhD thesis therefore focused on the development of first open-shell heavier tetrylidyne complexes featuring a tetrel-centered unpaired electron, and unprecedented metallatetrylidynes containing a multiply-bonded, linear-coordinated single heavier tetrel atom embedded between two metal centers. Initial reactivity studies of these novel complexes uncovered a plethora of exceptional products. Representative examples include a novel <em>m</em>₃-silicido complex, the first dimetallasilacumulene with a linear, two-coordinated single silicon atom and the first compounds of planar tetracoordinated silicon (ptSi) (Anti-van’t Hoff-Le Bell Silicon). Alongside, isolation and full characterization of the first room-temperature stable disilavinylidene (<em>Z</em>)-(SIdipp)Si=Si(Br)Tbb, a silicon analogue of the very reactive vinylidenes (R₂C=C:), is also reported in this thesis.<br /> The highly reactive and extremely air-sensitive compounds presented in this thesis were thoroughly analyzed by single-crystal X-ray diffraction and several spectroscopic techniques, which in combination with quantum chemical studies provided a comprehensive insight into the unusual electronic structures and properties of these novel compounds.