Xiang Ma

• Polyoxometalates (POMs) are a class of discrete, anionic and soluble polynuclear metal oxides, which are generally constructed through the connectivity between early d-block metal ions and oxo linkers. The class of polyoxopalladates(II) (POPs) as a new member of POMs were discovered in 2008. In the last 14 years, around 80 POPs of various shapes, sizes and compositions have been prepared and various properties studied, with a focus on catalysis. The focus of this thesis lies in the discovery of novel POPs and their structural as well as catalytic characterization. Chapter 1 is an introduction of POMs and metal-organic frameworks (MOFs) including the history, structural properties, analytical techniques, properties and applications. In Chapter 2, the class of POPs and polyoxometalate-based metal organic frameworks (POM-MOFs) are presented. Chapter 3 represents the information on the instruments used for the characterization. In Chapter 4, the discovery of the large, neutral 40-palladium(II)-oxo cluster (POC) is presented and their solid state and solution characterization. In Chapter 5, tetranuclear and hexanuclear Pd-oxo units are discovered in the vanado- and chromo(V) capped-4-palladates(II), one dimeric 4-palladium-oxo cluster and a 4-Mn4(IV)O4-capped-6-palladate(II) as well as 10-vanado-14-palladate(II) were isolated and structurally characterized. Their catalytic semi-hydrogenation of 1-octyne and phenylacetylene was investigated as supported catalysts. In Chapter 6 Pd(IV)-containing POP and POM compounds were synthesized, which represents the first mix-valence POP and the tungsten analogue of the known molybdenum specie. In the second part of the work, the (4-triazole-phenyl)- arsonic acid functionalized POM like inverted-Keggin and hexamolybdates and their trasition-metals mediated extended network are discussed in Chapter 7 and Chapter 8 respectively.