Dinuclear ruthenium and platinum complexes: Design, synthesis, characterization and potential applications

Near infra-red electrochromes find many applications, especially in the telecommunication industry as optical attenuators in fiber optic networks at the 1550, 1310 and 980 nm bands. Dinuclear ruthenium complexes based on the diacylhydrazide (DCH) or oxamide bridging ligands are NIR electrochromic materials that are well known.;This research project involved the preparation macromolecular materials containing dinuclear ruthenium complex moieties by polymerization of functionalized complexes that could be processed into free standing, transparent thin films which were then evaluated in prototype devices for potential applications.;Firstly, second-generation dendrimers were investigated. Unfortunately, the devised synthetic routes proved unsuccessful and only first-generation dendrimers were obtained. Subsequently, linear and hyperbranched polyurethane polymers were prepared from diol ruthenium complexes and suitable isocyanates. Crosslinked DCH ruthenium complex films were insoluble in common organic solvents and demonstrated the promising NIR electrochromic properties. Moreover, when these films were probed at 1550 nm in a reflective configuration, an optical attenuation of 17.5 dB/mum was recorded, which corresponds to a three fold increase when compared to similar devices operating in a transmissive configuration. Biurea complex analogues absorb near 1200 nm, and films were prepared. However, due to lower electrochromic material loading and incomplete crosslinking, the optical attenuation at both the 980 and 1310 nm bands only reached 5 dB/mum. Another aspect of this project was to investigate the potential of a glucose biosensor application using glucose oxydase while monitoring the NIR absorption. The response time of an all-solution configuration was rather slow, relying only on slow diffusion dynamics. Response time was even slower with previously prepared thin films.;Finally, the same DCH ligand system was used to prepare a series of dinuclear platinum complexes to investigate their emissive properties. It was found that the bridging ligand had negligible effects on the photoluminescence of the complex. Increasing the electron donating potential of the peripheral ligand did promote a bathochromic shift, its magnitude dependant on the ligand. Contrary to the ruthenium complexes, the platinum complexes did not exhibit a mixed valence state. While emission at 600 nm was achieved, NIR phosphorescence could be attained by using other peripheral ligands.