| Although the interest in scandium has increased significantly in the past fifteen years, a scandium-element double bond (Sc=E) had not been successfully isolated. The work that is presented in this thesis focuses on the various attempts to synthesize and isolate a Sc=E complex. The bulky, monoanionic beta-diketiminato ligand system provided the support framework for scandium and the two elements that were employed in the attempts to produce the Sc=E moiety were tellurium and nitrogen.; The research regarding tellurium employed scandium dialkyl complexes and the tellurium transfer agent, TePnBu3. Tellurium readily inserted into the scandium-carbon bonds of the scandium dialkyls to generate scandium ditellurolates. Upon exposure to light, the scandium ditellurolates cleanly eliminated dialkyl tellurides to produce bridging scandium telluride complexes. A cross-over experiment was performed which indicated that the bridging scandium tellurides formed via an intermolecular pathway.; Since the scandium tellurides were forming by means of an intermolecular pathway, the focus of the project shifted to nitrogen in order to synthesize a Sc=E species. Several scandium amido alkyl complexes were synthesized and characterized. The thermolysis of a scandium amido methyl compound was undertaken and a scandium amido metallate complex was produced. As thermolysis attempts were unsuccessful, several bases of varying strengths and nucleophilicity were introduced to the neutral scandium amido species and the ion pair (that formed after the addition of a borane activator) in an attempt to deprotonate the amido proton. If the base was too small, nucleophilic attack proceeded at the metal center and if the base was too large, then it deprotonated the ligand. In addition to deprotonation, the elimination of FSiMe3 from a scandium amido(silyl) compound was undertaken in an attempt to generate a Sc=E species.; Due to the thermal instability of the beta-diketiminato ligands at elevated temperatures, a novel derivative was synthesized. The thermal stability of this new species was assessed by generating a scandium dialkyl complex supported by this ligand and monitoring its rate of decomposition by NMR spectroscopy. |
