Synthesis and Properties of New Luminescent Iridium and Platinum Complexes

A range of luminescent Ir(III) complexes [Ir(C^N)2(N^N)]n+ (n = 0, 1) and Pt(II) complexes [Pt(C^N)(N^N)]+ and [Pt(C^N)(O^O)] containing different cyclometallated (C^N) and ancillary (X^Y) ligands has been synthesised. All new compounds were fully characterised by 1H and 13C NMR spectroscopy, mass spectrometry and most compounds were structurally characterised by X-ray crystallography. Chapter one provides an introduction to luminescent transition metal complexes, in particular Ru(II) and Ir(III) and Pt(II) complexes and gives an overview of the factors controlling the emission wavelengths of cyclometallated Ru(II) and Ir(III) and Pt(II) complexes and their applications, particularly as sensors and probes. Chapter two discusses the synthesis and properties of [Ir(C^N)2(N^N)]n+ (n = 0, 1) and shows that that pH responsive Ir(III) bis cyclometallated complexes can be designed to have a pKa in the range which is relevant for biological imaging. Chapter three covers the synthesis and characterisation of cationic Ir(III) complexes [Ir(ppz)2(N^N)][PF6] (N^N = bidentate PYE ligands) an investigation of the donor properties and resonance structures of the ligands and on photophysical properties of the ligands and complexes. The study shows that there was no clear evidence from NMR spectroscopy that more polar solvents lead to an increase in the zwitterionic resonance structure for the complexed PYE ligands. In Chapter four the synthesis and characterisation of cyclometallated Pt(II) complexes [Pt(C^N)(X^Y)]n+ (n = 0, 1) with extra substituents that are free to rotate in solution to show EPESS activity is discussed. Chapter five describes the synthetic methodology and characterisation of a series of ligand and complexes.