Ali Mougharbel

• Polyoxometalates (POMs) are discrete metal-oxo clusters of early transition metals in high oxidation states. The compositional and structural diversity of POMs combined with their stability and redox activity render them attractive for applications in various fields such as material sciences, medicine, magnetism and especially catalysis. Chapter 1 consists of an introduction to the field of POMs and its most important aspects, as well as a bibliographic background for the various projects in this thesis. In Chapter 2 all experimental details are presented, such as the synthetic procedures of the starting materials (lacunary POMs, noble metal precursors, catalysts, supports, etc.) as well as the instrumentation used for materials characterization and applications. Chapter 3 introduces the background, motivation and objectives of the work conducted. Chapter 4 presents a new concept for the design and preparation of some sinter-resistant catalysts by grafting organo-rhodium and -iridium species in the cavity of the cyclic P8W48 POM host. These compounds were characterized in the solid state by single-crystal X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis (TGA) and in solution by 31P and 13C NMR spectroscopy. The actual catalysts prepared by supporting the novel POMs on the SBA15 support and these materials were then used for the hydrogenation of aromatics. In Chapter 5, the synthesis of the first examples of fully-inorganic Rh-, Ir-, Pd- and Pt derivatives of P8W48 is reported and these compounds were structurally characterized in the solid state and in solution. Chapter 6 describes the synthesis and characterization of novel RhCp*- and IrCp*-containing heteropolytungstates, which were characterized in the solid state and in solution. One highlight is the observation of W-Rh coupling in the 183W NMR spectra. Chapter 7 deals with the use of polyoxopalladates (POPs) as molecular precursors for catalysts used for the selective hydrogenation of alkynes a