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Title: Probing the interactions of gold(I) cations with multiple bonds
Author: Sanguramath, Rajashekharayya A.
ISNI:       0000 0004 2723 5109
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2012
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Abstract A major part of this thesis is devoted to studies on the interaction of gold(I) cations with 1,3- dienes, arenes and allyl- and vinylsilanes. There are two self contained chapters, one on the synthesis of a simple Ag(I)-enyne cation and the other on the attempted synthesis of the cyaphide anion. Synthesis and characterisation of four cationic gold(I)-l ,3-diene complexes are described. In the solid state, gold(l) cations bind to only one of the double bonds of the 1,3-diene unit. Depending upon the substituents on the diene, the gold adopts either a 112- or 11'- bonding mode. Solution VT-NMR spectroscopy indicated fluxionality via an intramolecular pathway. With regard to acyclic 1,3-dienes a low energy pathway for gold(I) cations migration along the diene backbone has been suggested based on calculations. Cyclic 1,3-dienes were readily polymerised when treated with gold(I) catalysts under mild conditions. A detailed characterisation of isolated polymers has been carried out. Four gold(I)-arene complexes of the type [(112-arene)Au(P(But)2(o-biphenyl»][SbF6] were synthesised and characterised. Solution VT NMR spectroscopy indicated fluxionality in the interaction. The solid state UV -Vis absorption spectra of naphthalene, anthracene and pyrene displayed a large red-shift upon coordination to the gold(I) cation. The solid-state fluorescence emissions of the complexes have been studied. The interaction of gold(I) cations with allyl- and vinylsilanes has been studied by the synthesis and characterisation of five new complexes of the type [(112- allylsilane/vinylsilane)Au(P(But)2(o-biphenyl»][SbF6]. The influence of p-silyl effect has been highlighted in terms of metal fragment slippage across the C=C bond. Binding energies for all the complexes have been calculated. A simple Ag(I)-(l ,3-enyne) cation has been synthesised and structurally characterised. Both in solid state and solution silver binds exclusively to the alkyne moiety. A greater insight into , binding has been obtained oy calculating binding energies for alkyne coordination vs. alkene coordination. Synthesis of the cyaphide anion CC=P) has been attempted. The precursor phosphaalkyne complex, [Ru(IMe4)4(Me3SiC=P)H][BAl4], has been synthesised and characterised. 3'p NMR spectroscopy evidence for the formation of the cyaphide anion has been obtained. The interaction of gold(I) cations with phosphaalkyne was studied with the isolation and characterisation of the complex, [(ButC=P) Au(P(But)2(o-biphenyl»][SbF6]'.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available