Construction of porous supramolecular frameworks assembled from covalent cage compounds

Abstract

This thesis describes the synthesis of cage molecules using covalent and non-covalent interactions and approaches to covalently modify the organic cages to form frameworks. Chapter 1 is an introduction to the field of supramolecular chemistry discussing the types of non-covalent interactions that can be used for self-assembly. It details the types of porous materials that are known with a focus on porous organic solids relevant to the thesis. Chapter 2 details the synthesis of covalent organic cages via threefold Eglinton coupling reactions and crystal packing studies of the resulting cages. The synthesis of the cage precursors via convergent and divergent synthetic approaches are detailed. Work includes the optimisation of synthetic conditions for a Si-centred unfunctionalised organic cage and examines the gas adsorption properties of this cage. To further expand the library, Si-centred nitrile and bromo functionalised cages are reported. Additionally, a hexanitrile functionalised organic cage formed from a tripodal C-centred building block and its crystal packing are described. Chapter 3 explores the synthesis of asymmetric organic cages via irreversible reactions. This chapter reports the synthesis and characterisation of unsymmetrical organic cages via Sonogashira coupling and CuAAC reactions. Chapter 4 investigate the preparation of organic cages via non-covalent interactions such as hydrogen and coordination bonds. Two new hydrogen bonding receptors are reported and the outcomes of self-assembly experiments with ditopic hydrogen bond acceptors are discussed. A novel tripodal tris-pyridyl ligand is prepared and the self-assembly of this ligand with Pd(II) and Ag(I) salts is studied. Chapter 5 details the post-synthetic modification of the covalent organic cages described in the previous chapters. The unfunctionalised silicon-centred cage is post-synthetically modified using cobalt octacarbonyl. The silicon and carbon centred hexanitrile cages are converted to hexakis(amidinium) cages and their assembly with carboxylate anions is explored. Chapter 6 contains the experimental procedure and characterisation data for the novel compounds synthesised in chapters 2-5. Spectral data for new compounds are provided in an Appendix. Chapter 7 summarises the major conclusions and future works of this thesis.