Control of Dynamic Supramolecular Systems

Abstract

This thesis explores the control and application of complex dynamic system chemistry in the nanoscale by (1) manipulating interactions across lipid membranes and on the molecular level (2) through the manipulation of shapeshifting molecules. (1) This project involves the design and development of a library of artificial molecular carriers to be tested for successful bicarbonate targeting. These molecules are designed to instigate the active transport of ions across lipid membranes, 'pumping' ions from areas of low concentration to areas of higher concentration. These carriers can do this by consuming a fuel–redox energy supplied by the charge separation already present in photosynthetic apparatus. The preliminary data of our molecular artificial devices in the presence of plant cells suggest that these transporters have an influence on cell morphology due to possible cell membrane incorporation. Furthermore, emission studies revealed that molecular devices have an impact on the photosynthetic apparatus of the cell which is desired. These results are encouraging for the incorporation of molecular devices in plants. (2) In dynamic covalent chemistry, dynamic covalent rearrangements of fluxional carbon cages, such as bullvalenes and barbaralanes, impart shapeshifting molecular properties which have sparingly been studied. This research project focuses on developing methodologies to concretely control these dynamic fluxional carbon cages to simplify and analyse their structural complexity. Non-covalent control was achieved through the encapsulation of these fluxional molecules. This host-guest chemistry can control the dynamic regioisomerism & stereochemistry through molecular metal-organic cages and chiral macrocycles. For covalent control, the configuration of the cage is controlled by covalently tethered functional moieties. These methodologies involve incorporating phosphine-based ligands to control shapeshifting molecules through metal coordination. The development of such techniques will allow routine access to shapeshifting systems to explore their properties and application beyond synthetic, physical organic chemistry, and at the interfaces with materials chemistry and biology