Multimetallic nanoscale assemblies based on bifunctional linkers
File(s)
Author(s)
McArdle, James
Type
Thesis
Abstract
The intermediate size of nanoscale materials with respect to bulk materials and discrete molecular species affords them unique physical and chemical properties. Since the seminal work of Nord in 1943 the use of nanoparticles as heterogeneous catalysis has gathered significant interest and has led to their application in alkene hydrogenation, photocatalysis, aerobic oxidation and Heck cross-coupling to name a few.
Due to improvements in the synthesis, stabilisation and characterisation of nanoparticles it is now possible to functionalise the surface of nanoparticles with traditional molecular transition metal catalysts. These species may bridge the gap between homogeneous and heterogeneous catalysts where the nanoparticule support provides excellent recyclability yet maintains high activity and selectivity due to the essentially molecular nature of the catalyst on its surface
In chapter 1 the development of functionalised nanoparticles and their application as catalysts will be discussed in broad terms with a focus on the functionalisation of gold nanoparticles with novel alkanethiol ligands. The investigation of novel ligands that provide superior stability and potential for functionalisation will then be introduced.
Chapter 2 details the synthesis of a novel unsymmetrical dithiocarbamate with propargyl functionality and the subsequent experiments in which the reactivity of both groups was tested. Novel Ru(II), Ni(II) and Pd(II) complexes were synthesised despite the ligand exhibiting unanticipated intramolecular reactivity. In chapter 3 the synthesis of an unsymmetrical ferrocene linker is detailed and its use in the synthesis of multimetallic complexes given. This linker proved amenable to the synthesis of two novel group 8 hexa- and hepta-metallic complexes. Finally, chapter 4 details the work carried out on thioctic acid and its use as an alternative to both alkanethiols and dithiocarbamates. A novel Ru(II) complex was synthesised and used to functionalise the surface of AuNPs which were characterised fully.
Due to improvements in the synthesis, stabilisation and characterisation of nanoparticles it is now possible to functionalise the surface of nanoparticles with traditional molecular transition metal catalysts. These species may bridge the gap between homogeneous and heterogeneous catalysts where the nanoparticule support provides excellent recyclability yet maintains high activity and selectivity due to the essentially molecular nature of the catalyst on its surface
In chapter 1 the development of functionalised nanoparticles and their application as catalysts will be discussed in broad terms with a focus on the functionalisation of gold nanoparticles with novel alkanethiol ligands. The investigation of novel ligands that provide superior stability and potential for functionalisation will then be introduced.
Chapter 2 details the synthesis of a novel unsymmetrical dithiocarbamate with propargyl functionality and the subsequent experiments in which the reactivity of both groups was tested. Novel Ru(II), Ni(II) and Pd(II) complexes were synthesised despite the ligand exhibiting unanticipated intramolecular reactivity. In chapter 3 the synthesis of an unsymmetrical ferrocene linker is detailed and its use in the synthesis of multimetallic complexes given. This linker proved amenable to the synthesis of two novel group 8 hexa- and hepta-metallic complexes. Finally, chapter 4 details the work carried out on thioctic acid and its use as an alternative to both alkanethiols and dithiocarbamates. A novel Ru(II) complex was synthesised and used to functionalise the surface of AuNPs which were characterised fully.
Version
Open Access
Date Issued
2017-05
Date Awarded
2017-09
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Long, Nicholas
Wilton-Ely, James
Publisher Department
Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)