Title:
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Synthesis and catalytic applications of ruthenium- and iron-based nanoparticles from the pyrolysis of metal-containing homopolymers and block copolymers
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This Thesis is concerned with the synthesis of new Fe- and Rucontaining
homopolymers and block copolymers and their applications as
precursors for the fabrication of catalytically active nanoparticles upon
pyrolysis (NPs). The strained sila[l]ferrocenophane (T]-CSH4) Fe(T]-CsH4)SiMeRc
has been synthesised. Two different routes for its synthesis Were
employed and compared. The compound was polymerised via thermal ringopening
polymerisation (ROP), which afforded insoluble polymeric material.
Photo controlled ROP. was used to afford narrowly dispersed, high molecular .
weight (Mn between 10,000 and 53,000 Da) air and moisture stable [(T]CsH4)
Fe(T]-CsH4)-SiMeRc]n. Electrochemical characterisation of (T]-CsH4)Fe(T]CsH4)-
SiMeRc revealed unusual, concentration dependent behaviour
associated with the pendant Rc substituent. We postulate a dimerisation
pathway based on Ru-Ru bond formation upon oxidation of the Rc side
. groups. The synthesis of the block copolymer PSm-b-[(T]-CsH4)Fe(T]-CsH4)SiMeRc]
n was carried out and afforded narrowly dispersed block copolymers
of high molecular weight (Mn between 28,000 and 36,000 Da).
The synthesis of Fe(T]-CsH4)zSi(Me)(C=CSiMe3) and its
photocontrolled polymerisation to yield high molecular weight (Mn between
13,000 and 45,500 Da) [Fe(T]-CsH4)zSi(Me)(C=CSiMe3)]n is also presented.
Deprotection and clusterisation with RU3(CO)12 yielded the highly metalen,
riched compound [Fe( T]-CsH4)zSiCH3{(Il-H)Ru3(CO)9Cz}]n. UV -irradiation
was utilised for cross-linking reactions, which proceeded readily. The block
copolymers PSm-h-[Fe(T]-CsH4)zSi(Me)(C=CSiMe3)]n and PSm~h-[Fe(T]CsH4)
zSiCH3{(Il-H)Ru3(CO)9CZ}]n were prepared.
The fabrication of metal-containing nanoparticles (NPs) via pyrolysis
of the metallopolymers was carried out via bulk' and thin film pyrolysis
between 500 and 1000°C. Analysis of the resulting materials revealed the
formation of RuSi, RuzFeSi, RU4Fe and/or Ru NPs, depending on the material
and pyrolysis temperature. The particles were embedded in a carbonaceous
matrix. The catalytic activity towards hydrogenation of cyclohexene by the
particles formed via pyrolysis of thin films was investigated and showed
some catalytic activity.
The synthesis of a metallopolymer for the fabrication of
monometallic Ru NPs is also discussed.
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