Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597417
Title: The chemistry of the hypersilyl and related ligands
Author: Chan, W. T. K.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2009
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Abstract:
This thesis is mainly focused on the investigation of the chemistry and reactivity of the hypersilyl ligand {[(Me3Si)3Si]-}, and the rationalisation of the use of siloxanes as precursors ([(R2SiO)n]). A total of ten new compounds have been prepared from these studies, and X-ray crystallography forms a central basis of the analysis of these species, along with NMR spectroscopy and various other analytical techniques. The first novel compound described is [(Ph3Si)(Me3Si)2SiK.18-crown-6] (3). Despite isolating 3 in pure both crystalline and powder form the difficulty in synthesising the compound in large scale meant that its reactivity could not be investigated fully. A series of Si-M complexes was made in the form of [(Me3Si)3Si.MX3]-[K.18-crown-6]+ (4-6, M = Al or Ga, X = Cl or Br), as well as [(Ph3Si)(Me3Si)2Si.GaCl3]-[K.18-crown-6]+ through the reaction of the respective silyl anion with the corresponding group 13 halides. Due to yield considerations, 6 was chosen as a precursor to study the thermal decomposition behaviour of this type of compounds. The reaction between (Me3Si)3SiK.18-crown-6 (1a) with (P4) led to the formation of the unusual {P8[(Me3Si)3Si]2.K.18-crown-6}-[K.18-crown-6.(THF)2]+ (8). The discovery of 8 allows an investigation into the relatively poorly understood mechanism for this type of reaction, and a proposed mechanism, supported by computational calculations, is discussed. The reaction between hypersilyl potassium (1a) and mesityl nitrile gave 6,8-dimethyl-1-amino-3-mesityl-isoquinoline. Finally, the unexpected formation of [2-PySi(Me)2LiO]6 and {[18-crown-6.]GaCl4} are also described.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.597417  DOI: Not available
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