The main theme of this thesis is the catalytic oxidation of CO, which we have investigated on several model catalyst surfaces at atmospheric pressures and elevated temperatures with the combination... Show moreThe main theme of this thesis is the catalytic oxidation of CO, which we have investigated on several model catalyst surfaces at atmospheric pressures and elevated temperatures with the combination of Scanning Tunneling Microscopy and Mass Spectrometry.The study of CO oxidation on low-index and vicinal palladium surfaces has shown that when exposed to ambient pressures of oxygen at elevated temperature, these surfaces oxidize irrespective of their orientation. In this pressure regime the oxides were shown to have a higher reactivity than the metallic surfaces.In a certain window of partial pressure combinations of O2 and CO reaction rate oscillations were observed on Pd(100) and on its vicinal surface Pd(1.1.17). ). CO adsorption on Pt(111) was found to lead to the formation of a regular overlayer structure, identified as (√19 x √19) R23.4°-13CO. The stability of this structure under different reaction conditions was discussed. These results were further used to illustrate the importance of temperature in a catalytic system.Spectacularly high conversion rates could be achieved during CO oxidation at atmospheric pressure on metallic Pt(100) surface. Show less
The research described in this Ph.D. Thesis has been devoted to the design and development of polynuclear polypyridyl ruthenium and ruthenium-platinum complexes in search of new anticancer agents.... Show moreThe research described in this Ph.D. Thesis has been devoted to the design and development of polynuclear polypyridyl ruthenium and ruthenium-platinum complexes in search of new anticancer agents. A variety of polynuclear ruthenium and ruthenium-platinum complexes has been synthesized with a long and flexible linker. The complexes are characterized and have been studied for anticancer activity. The ruthenium unit of the dinuclear complexes varies in molecular structure, which may result in different interactions with DNA, the target of anticancer platinum and ruthenium antitumor compounds. The monofunctional ruthenium unit coordinates to the DNA-model base 9-ethylguanine. Variable temperature 1H NMR experiments prove that the base is hindered in its free rotation at room temperature. The crystal structure of a dinuclear ruthenium-platinum complex shows that the platinum unit is capable of intercalation and coordination (in)to DNA. Trinuclear and tetranuclear ruthenium and ruthenium-platinum complexes show higher activity than the dinuclear derivatives. A tetranuclear ruthenium complex displays interesting biological features. Human ovarian cisplatin sensitive carcinoma cells adhere together and form clots upon incubation of the complex. The effect possibly indicates antimetastatic activity. Dinuclear and trinuclear ruthenium-platinum complexes of short and semi-rigid linkers do not show significant activity against different cancer cell lines. Show less
