Design and development of novel self-assembled luminescent lanthanide complexes in solution and in soft materials
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BRADBERRY, SAMUEL JOHN, Design and development of novel self-assembled luminescent lanthanide complexes in solution and in soft materials, Trinity College Dublin.School of Chemistry.CHEMISTRY, 2017Download Item:
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Abstract:
This thesis describes the design, synthesis and characterisation of naphthyl-dipicolylamide (naphthyl-dpa) ligands for sensitisation of lanthanide, Ln(III), emission. Chapter 1 provides an introduction to the fundamental physical and chemical properties of LnIII ions with particular focus on the photophysical properties. The features of emissive Ln(III) ions will be reviewed, an overview given to the mechanisms available to access this f-metal-centred luminescence and the key design features for ligands highlighted. This is followed by a review of current literature and the immediate prior art from the Gunnlaugsson laboratory.
Chapter 2 will describe the design and synthesis of naphthyl-dpa derivatives functionalised with sulfonate groups, ensuring aqueous solubility of these ligands. A pair of enantiomeric ligands will be presented, the photophysical properties of these ligands and their complexes with Eu(III) are probed in both aqueous and organic solutions, showing total quantum yield enhancements in the aqueous environment. The self-assembly behaviours of the ligands is investigated using spectroscopy. Chiral spectroscopy is exploited to analyse the photophysical properties and self-assembly in greater depth and global stability constants determined by non-linear regression analysis.This chapter concludes in the formation of gelled soft matter at higher concentration, using insights from dynamic light scattering (DLS), isothermal titration calorimetry (ITC) and scanning electron microscopy (SEM).
In Chapter 3, the extension of the naphthyl-dpa scaffold into responsive luminescent probes will be investigated. A family of chiral ligands and their complexes with Eu(III) are characterised in acetonitrile and methanol. The influence of the ligand substitution pattern and peripheral covalent structure is probed, revealing ?spectral fingerprints? and responsive behaviours in ligand- and metal-centred emissions. Self-assembly processes are probed in, showing similar processes between ligands, however differing significantly in their emission properties during self-assembly. A PET response is exploited in the development of acidity probes and one complex is calibrated in 5% methanol:water as a pH probe, showing a sensitive pH response in both ligand- and metal-centred emissions. This chapter concludes by describing the fabrication of a hydrogel-based pH sensor using Eu(III)-centred luminescence, clear spectroscopic and visual responses are demonstrated to both solution and vapour stimuli.
Chapter 4 focusses on the design of molecular logic gate mimics (MLGMs) in solution and polymer gels. This example represents one of the first soft materials-based MLGMs using Ln(III) luminescence. Firstly, a brief introduction will present the fundamentals of logical analysis and the limited examples of exploiting Ln(III) luminescence. A mixed Eu(III):Tb(III) system will be discussed showing luminescence responses to H+ and F-. These responses are characterised in methanol and organogels parameterised as logic functions; both clear logical and visual outputs are demonstrated to unambiguously identify input states.
Chapter 5 details the preliminary studies undertaken towards the covalent grafting of naphthyl-dpa binding sites to a bulk polymer chain and introduction of EuIII-based supramolecular crosslinks. Two naphthyl-dpa ligands with pendent methacrylamide moieties, and their Eu(III) complexes, are synthesised. The photophysical properties characterised spectroscopically. The self-assembly processes are characterised and particular attention is made to the luminescence lifetime distributions in a range of other solvents. Copolymers with p(HEMA-co-EGMDA) are synthesised and characterised thermally from which luminescent hydrogels are demonstrated. The emission properties characterised to elucidate the nature of the crosslinking complexes. The chapter concludes by presenting the preliminary mechanical analysis, showing inconclusive results; approaches to address, extend and exploit these preliminary results are presented. Finally, Chapter 6 outlines experimental details as well as compound characterisation. This is followed by literature references and Appendices containing relevant supplemental experimental data to that presented herein.
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Science Foundation Ireland (SFI)
Trinity College Dublin (TCD)
School of Chemistry, Trinity College Dublin
School of Chemistry and Chemical Biology
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http://people.tcd.ie/bradbersDescription:
APPROVED
Author: BRADBERRY, SAMUEL JOHN
Advisor:
Gunnlaugsson, ThorfinnuPublisher:
Trinity College Dublin. School of Chemistry. Discipline of ChemistryType of material:
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