Novel luminescent platinum (II) and lanthanide (III) complexes towards imaging, diagnostics and therapeutics

• Main Author: Stacey, Oliver J.
• Published: Cardiff University 2015
• Subjects: 546; QD Chemistry
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.646346

This thesis discusses the development and synthesis of ligands for coordination to dand f- block metal ions. The subsequent coordination chemistry to PtII and a range of LnIII metal ions is outlined, along with the photophysical properties of the resultant compounds towards bimodal imaging agents and probes for diagnostic and therapeutic applications. Chapter 2 presents the synthesis and characterisation of a range of PtII complexes using functionalised 2-phenylquinoline ligands. A range of products were synthesised by utilising a variety of ancillary ligands, including β-diketones, 8-hydroxyquinoline, 2,2′-bipyridine and pyridine, in order to investigate any effects on the photophysical properties. X-ray crystallography confirmed the anticipated structures of several compounds whilst 195Pt NMR was employed to probe the metal environment in the different complexes. Chapter 3 builds on the investigations in the previous chapter by altering the functionality of the 2-phenylquinoline ligand in order to tune the solubility. The second part of Chapter 3 exploits the facile coordination of pyridine, as found in Chapter 2, by introducing pendant pyridine-appended macrocycles encapsulating LnIII ions. This provided bimetallic complexes with good water solubility, which allowed relaxivity measurements to be carried out. Photophysical measurements also gave evidence of direct sensitisation of the LnIII ion by PtII based 3MLCT emission. Chapter 4 extends the 2-phenylquinoline functionality to incorporate naphthyl, anthracenyl and pyrenyl chromophores with suitable solubility in common organic solvents. The complexes were investigated to determine whether it was possible to observe interactions between the excited state of the chromophore and the metalcentred excited state. Low temperature and degassed steady state luminescence and lifetime measurements were obtained in order to build energy level diagrams to explain the interplay of excited states. Chapter 5 discusses the development of anthraquinone-based polypyridyl ligand scaffolds for the incorporation of LnIII ions. The ligands possess subtle differences that result in changes in the coordination sphere of the LnIII ion. This was confirmed by determining the inner-sphere hydration of the LnIII ions through observing the luminescence properties of the complexes.