Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.796205
Title: The synthesis and reactivity of some platinum group clusters
Author: Ewing, Paul Nicholas
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1989
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Abstract:
This thesis describes the synthesis, characterisation and reactivity of several M3Pt, (M = Os,Ru) clusters. Chapter 1 contains a brief survey of the chemistry of unsaturated clusters together with an account of commonly applied electron counting schemes. Catalytically activated cluster transformations and the reactivity of lightly stabilised clusters are also considered. In Chapter 2, the chemistry of the unsaturated 58 electron closo-tetrahedral cluster Os3Pt(mu-H)2(CO)10(PCy3 ), 1, is described. The 60 electron adducts of 1, Os3Pt(mu-H)(CO)(PCy3)(L), are known to adopt butterfly (L = CO) or closo-tetrahedral (L = CH 2) metal core geometries. A molecular orbital analysis of the interactions of mu-CO and mu-CH2 fragments with the closo-tetrahedral complex [Ru3Pt(CO)10(PH3)2- , which models 1, is presented. This analysis suggests that the symmetry of the frontier orbitals of the incoming ligand is important in defining the framework geometry of the 60 electron adducts. With this in mind, the reactivity of Os3Pt(mu-H)2-(CO)10(PCy3) towards CO and CH2 analogues (CNR; and SO2, SnCl2) is reported. CNR and SO2 give rise to the expected butterfly and tetrahedral adducts respectively. However, with SnCl2 a more complex cluster transformation takes place. The CNR adduct readily decarbonylates to give the first CO substituted derivative of 1. The protonation of several Os3Pt systems is reported. All the clusters examined protonate at Os-Os edges. In the final sections of this chapter the reactivity of 1 towards heterocumulene and anionic acetylide species is described. Chapter 3 describes the synthesis and reactivity of the spiked triangular complex Ru3Pt(mu-H)(mu4-eta2 -C=Ct-Bu)(cod)(CO) 9, 2. The cod ligand of 2. is readily displaced by dppe giving the analogous substituted complex Ru3 Pt(mu-H)(mu4-eta2 -C=Ct-Bu)(dppe)(CO9), 3 and the tautomeric vinylidene butterfly species Ru3Pt(mu4-eta2-C=C(H)t-Bu)(dppe)-(CO9) , 4.3 and 4 interconvert via an intramolecular hydride migration. 4 protonates at the hinge Ru-Ru vector. The reaction of 2 with Os3(mu-H)2(CO) 10 results in scission of the Pt-Ru bond of and formation of Os3Pt(mu-H)2(mu-CO)(cod)(CO)9. In Chapter 4 the X-ray structure determinations of OS3Pt(mu-H)(mu4-eta2-C=CPh)(CO)10(PCy3); Ru3Pt(mu-H)(mu4-eta2-C=Ct-Bu)(cod)(CO)9; and [Ru3Pt(mu-H)(mu4-eta2-C=C(H)t-Bu)(dppe)(CO)9]+BF4 are reported. These analyses were performed by the author. Chapter 5 details the experimental procedures used in this work.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.796205  DOI: Not available
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