Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.642120
Title: Studies of the hydrides of the heavier group 14 elements
Author: Brown, Daniel Hugh
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1998
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Abstract:
The chemistry of some simple tin hydrides (CH3)4-xSnHx(x=1-4) has been investigated with particular reference to their reactivity towards the reagents NaH, KH, alkyl lithium compounds, and the ylids Me3PCH2 and Ph3PCH2. It has been found that the reaction between the stannanes and alkali metal hydrides or the ylids produces salts containing the respective stannyl anions, [Sn(CH3)3-xHx]- (X=0-3). These salts have been characterised by low temperature infrared spectroscopy, the results of which are in good agreement with the results of ab initio calculations. In contrast, reactions involving alkyl lithium compounds proceed by transmetallation with elimination of LiH and alkylation of the tin centre. The technique of in situ crystal growth at low temperatures has been used to obtain X-ray crystal structures of Me3PCH2. Me2SnH2 and Me3SnH. The structure of the ylid in the solid phase has been shown to resemble the calculated structure of a transition state involving rotation of the CH2 group about the P-C axis. The reaction between monochlorostannane and sodium metal produced small quantities of Sn2H6, detected by mass spectrometry. Attempts to increase the scale of this preparation were unsuccessful. Gas phase electron diffraction data were recorded for monochlorostannane but subsequent refinement showed that some decomposition of the sample had occurred giving rise to SnH2Cl2. The structure of Me3PbH was investigated by powder neutron diffraction and gas phase electron diffraction. Rietveld refinement of the neutron diffraction data based on an extant single crystal structure of Me3PbH was unsuccessful owing to inconsistencies between the two data sets, most probably stemming from the different temperatures at which they were collected. The gas phase experiment was partially successful, but data collected at the short camera distance, and crucial to an accurate structural determination, could not reasonably be refined in conjunction with that collected at the long camera distance. No reliable gas phase structure of Me3PbH has yet been determined.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.642120  DOI: Not available
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