Complexes of Platinum(II) and Iridium(III) with Liquid Crystal and Luminescent Properties

Abstract This thesis is concerned with the search for luminescent metallomesogens, a class of materials that presents the combination of two different properties, luminescence (triplet emission) and liquid crystallinity. The motivation is two-fold. One possibility is that these materials could be used as polarised back-light emitters in liquid crystal displays, which would mean that the back polariser could be removed, so improving light throughput through the device. The other is that, owing to the order inherent in liquid crystal phases, the use of liquid-crystalline components will lead to better charge-carrier mobilities, this enhancing the overall efficiency of the devices in which they are used. The research is based around cyclometallated 2-phenylpyridine complexes of two metals, platinum(II) with its square planar geometry, and iridium(III) with its octahedral geometry, and the aim is to modify the ligand structures so that, in combination with the metal, liquid-crystalline complexes result that retain the emissive properties of the 2-phenylpyridine-metal chromophore.. All the complexes have been characterise using different technique. Chemical characterisation used NMR spectroscopy, elemental analysis, mass spectrometry and in some cases single crystal X-ray diffraction. Liquid crystal phases were characterised using combinations of polarised optical microscopy, differential scanning calorimetry and powder X-ray diffraction.