Novel chromophoric ligand scaffolds for d- and f- metal ions towards luminescent probes

• Main Author: Jones, Jennifer Elizabeth
• Published: Cardiff University 2011
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585250

This thesis discusses the development of chromophoric ligand scaffolds for application in d- and f- metal ion coordination chemistry, investigating the photophysical properties of the complexes towards bimodal agents and probes of biological application. Chapter 2 presents the synthesis and characterisation of four novel 3-picolyl functionalised amino-substituted anthraquinone chromophores, and their subsequent coordination chemistry with Re1. X-ray crystallography confirmed the predicted structure of three of the ligands and two of the mono-metallic complexes, confirming coordination via the axial pyridyl donor. The ligands have tuneable electronic properties depending on the functionalisation of the anthraquinone core, and are dominated by charge transfer characteristics, the assignment of which is supported by solvatochromic behaviour. The complexes are dual emissive following visible excitation, with emission assigned as ligand centred fluorescence and 3MLCT. Chapter 3 extends the use of ammc-anthraquinone chromophores for lanthanide sensitisation. Incorporation of two 1-amino anthraquinone chromophores into an aza-macrocyclic framework derived from cyclen, affords a chromophoric system for lanthanide coordination and subsequent near-IR sensitisated emission of Ybm, Ndm and Er"1 using visible light Chapter 4 investigates the functionalisation of bis-animo-anthraquinone chromophores as bridging units between two aza-macrocyclic frameworks, affording sensitised near-IR emission of Ybm, Ndm and Erm upon absorption of visible light. The complexes interact with calf thymus DNA and highlight the LI derivative with the strongest binding interaction. Theoretical docking studies are utilised for probing the nature of the DNA-AQ interaction and *H NMRD profiles examine relaxivity enhancements upon DNA binding. Finally, Chapter 5 discusses the functionalisation of the djroyrido 3,2-a:2',3'- cjphenazine ligand and its subsequent coordination chemistry with Cr11 Irm, Lnm and d-f hybrid systems. Low temperature phosphorescence spectra of the associated Cr complexes exhibit metal centred phosphorescence at ca. 730 nm, with substitution patterns affecting the wavelength of emission as well as the structure of the profile. Functionalised It111 complexes exhibit dual emission from *IL and 3MLCT as well as demonstrating solvent dependent and wavelength of excitation dependent emission. The dppz derived chromophores are suitable for sensitisation of near-IR emitting lanthanides including Ybm, Ndra and Er111 following visible light excitation. Functionalisation of the Ir111 and Crm chloroacetamides on the periphery of the complexes facilitates the formation of aza-macrocyclic complexes, and the corresponding Ybm and Gdffl complexes. Irradiation of the dppz derived chromophore prompts sensitised NIR emission off or both the Cr111 and Ir species, and low temperature steady state spectra of the CrIII-GdUI complexes demonstrating metal centred phosphorescence (2E 4A2) with vibronic structure.