Title:
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Molecular tweezers and their binding properties in solution and on surfaces
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This work aimed to develop novel molecular tweezers and to study the interactions involved
in their binding with IT-electronically complementary receptors in solution and in the solid
state. The tweezers were then tested as "reader" molecules for information-bearing
copolymers.
In the development of novel tweezer-molecules, this thesis highlights the importance of the
choice of the spacer-unit. In some cases the nature of the spacer prevented binding
altogether; while in others it gave new properties to the tweezers such as responsiveness to
external stimuli. In more detail, novel pH-sensitive tweezers showed markedly different
binding activities and fluorescent properties in various pH environments.
For the determination of the binding constant, a new 1H-NMR-based method involving the
dilution of a fixed-ratio solution was developed. This method was implemented for strongly
binding tweezer-macrocycle complexes, as titration methods proved incompatible with such
systems.
A new kind of tweezer-molecule was developed by covalent inclusion of a Pd centre in a
pyrene-armed tweezer-molecule. This metal centre enhanced the complexation strength of
nitrile- and heterocycle-based ligands via a synergistic mechanism of binding in which both
IT-IT stacking and Pd-coordination occur. The strong binding ability of t his new class of
receptors provides opportunities for binding studies of complementary Pt-complexes, new
information-bearing systems, and bio-receptors.
Model compounds for a new class of copolyimide have been synthesized and their binding
properties investigated. These copolymers have shown information-bearing properties.
The interactions between model compounds for the tweezer-copolyimide systems were
investigated at the metal/vacuum interface. The intermolecular interactions of macrocycles
were explored as well as t heir interactions with Au{111} surface. The pie-pie stacking
interactions of pyromellitic moieties and pyrene derivatives were studied on Cu{ll0}. These
studies showed the ability of these molecules to arrange in ordered superstructures and
demonstrated the existence of IT-IT stacking interactions at the solid/vacuum interface.
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