Imidazolium- and triazolium-based interlocked structures for anion recognition and sensing

This thesis describes the synthesis and investigation of novel anion templated interlocked structures which incorporate the positively charged imidazolium and triazolium binding motifs for applications in anion recognition and sensing. Chapter One introduces the fields of anion supramolecular chemistry and mechanically interlocked structures, focusing on topics of particular relevance to this thesis, including anion recognition, anion sensing and the templated synthesis of interlocked architectures. Chapter Two details the incorporation of the imidazolium motif into the axle components of anion templated rotaxane hosts to achieve selective anion recognition by virtue of their interlocked binding cavities. The effects of exploiting imidazolium motifs with contrasting hydrogen bond donor arrangements and reducing the macro cycle size on the anion recognition properties of such systems were investigated using 'n NMR spectroscopy. Chapter Three reports the work undertaken to utilise fluorescent reporter groups as stoppers in the synthesis of anion sensing rotaxanes. Imidazolium- and triazolium-based systems containing either luminescent ruthenium(II) bipyridyl complexes or the organic fluorophore anthracene were prepared and their anion sensing behaviours explored using fluorescence spectroscopy. Synthetic efforts to construct suitable photo-active rotaxanes are detailed. Chapter Four describes investigations of the novel naphthalimide triazolium motif both for use in interlocked molecular motion systems, and for fluorescence sensing applications. The preparation of a naphthalimide triazolium rotaxane, capable of selective, anion-induced, uni-directional shuttling which was investigated extensively using 1 H NMR spectroscopy and optically signalled by perturbations in the DV Nis spectrum, is detailed. Preliminary research studies into the potential to exploit this motif for surface-based fluorescence sensing devices are also included. Chapter Five presents research into the utilisation of acyclic receptors displaying considerable binding-induced conformational changes for fluorescence anion sensing. The recognition properties of a series of imidazolium-based receptors were studied, whilst the ability of a pyrene-appended analogue to signal anion complexation via changes in excimer emission is reported. The control of interpenetrated assembly formation using anion-induced conformational changes within the threading component of a pseudorotaxane is also discussed. Chapter Six provides the experimental procedures and characterisation details for the compounds synthesised in this thesis. Chapter Seven is a summary of conclusions from Chapters Two, Three, Four and Five. Supplementary information relating to titration protocols, crystallographic data and surface studies is provided in the Appendices.EThOS - Electronic Theses Online ServiceGBUnited Kingdo