| dc.description.abstract | The debate surrounding climate change and global resource consumption has stimulated
discussion within the chemical community about sustainable methods for enabling
chemical transformations. Among the various avenues of research, photocatalysis has
been identified as an attractive sustainable option as it would allow society to make use
of light as an abundant resource that is not environmentally damaging. Current state of
the art photocatalysts tend to be based on iridium and ruthenium polypyridyl complexes.
However, the cost and low natural abundance of the metals they contain is not compatible
with the long term environmental sustainability that modern photocatalysis is striving
towards. Organophotocatalysts have been identified as a promising solution to this
problem as they are derived from more abundant chemical feedstocks, making them far
cheaper to synthesise and allowing for better long-term sustainability.
In addition to natural pigments and organic dyes, various organic π-conjugated
electron donor-acceptor (D-A) systems, comprising of electron-rich donor and electron-deficient acceptor groups connected through delocalised π-conjugated structures, have
been investigated as organophotocatalysts. The benzo[c][1,2,5]thiadiazole (BTZ) group
is an example of a strongly electron withdrawing group that has mainly been researched
for photovoltaic systems although some promising photocatalysis has already been
investigated with this moeity.
Four different methods for utilising BTZ photocatalysts are presented in this
thesis. The first of these was a conventional homogeneous approach to photocatalysis,
whereby a series of structurally similar molecular BTZ photocatalysts were synthesised
to optimise their photophysical and optoelectronic properties towards a test photoredox
reaction. Secondly, photocatalysts were appended to the upper-rim of calix[4]arenes to
investigate using their ability to form host-guest complexes to facilitate photocatalysis.
The third and fourth regimes involve the use of two different polymer systems by either
chemically incorporating the BTZ group into conjugated porous polymers or by trapping
molecular photocatalysts within solution cast thin films of intrinsically microporous
polymers. | en |
