Null, eins oder drei? Die Rolle von Au0‐, AuI‐ und AuIII‐Zentren im Heterogenkatalysator Au/CeO2 wurde anhand der kupferfreien Sonogashira‐Kreuzkupplung von Iodbenzol und Phenylacetylen untersucht (siehe Bild). Heterogen‐ und homogenkatalytische Reaktionen mit definierten Au0‐, AuI‐ und AuIII‐Verbindungen entlarvten AuI als aktive Spezies bei der Kreuzkupplung.

People who emigrate to westernised countries have a higher risk for developing IBD, especially UC. Environmental factors related with industrialization seem to play an important role in the pathogenesis of these diseases.

No abstract

The well-known layered double hydroxides (LDHs) and their thermal-treatment products, which are used as adsorbents, drug-delivery vehicles, polymer stabilizers, and catalysts, [1][2][3][4][5][6][7] are generally based on brucite-like materials doped with dblock elements, although studies on a Li + -Al 3+ LDH [8] and on ionic europium and gadolinium complexes intercalated in pillared LDHs have recently been reported. [9] Compounds of the type presented herein, which are formed by pure cationic rare-earth hydroxide layers, have not yet been reported; they represent a new generation of pillared materials, in which the properties of intercalation materials are combined with those of rare-earth elements. [R 4 (OH) 10 (H 2 O) 4 ] n A n (R = rare-earth ions, A = intercalated organic anions, 2,6-naphthalenedisulfonate (NDS 2À) and 2,6-anthraquinonedisulfonate (AQDS 2À )) is the first family of layered rare-earth hydroxides (LRHs). In these LRHs, the positive charge of the inorganic layer is created only by trivalent rare-earth hydroxocations, which arises from the high and variable coordinative capability of the rare-earth centers and to the tendency of the hydroxide ion to form m n connections in structures that contain these rare-earth centers. Rigid organic anions are intercalated to neutralize the positive charge. Apart from their potential as ion exchangers, these new materials contain a great number of active metal centers with the capability of varying the coordination number in catalytic processes, which confers to them great possibilities in the field of green chemistry. In fact, the performed tests in hydrodesulfurization (HDS), sulfide oxidation, and redox reactions reveal these new LRHs to be high-quality heterogeneous catalysts. Other interesting physical properties emerging from both the f-f interactions and those of intercalated organic anions are also to be expected.