Highly dispersed transition metal ions

Investigations of Highly Dispersed Transition Metal Ions in Oxides or Zeotype-Systems by PL Spectroscopy... 

In this chapter, the progress being made in the development of highly dispersed transition metal oxides (Ti, V, Cr, Mo) or ions (Ag ) as single-site heterogeneous photocatalysts within the frameworks or cavities of zeolites and mesoporous materials will be reviewed. 

Highly dispersed surface species, with the limiting form of single-site active centers, play a primary role in a number of catalytic materials because of their peculiar features in terms of activity and selectivity. Both oxo-species and transition metal ions supported on oxides (or in zeotype materials) belonging to these types... 

A growing interest in the possibility of metal-cation and metal-metal bond formation is evident in the recent literature. One application of this concept is in the stabilization of species on a given support. For example, it has been demonstrated that Rh (171) can be effectively anchored to a NaY support by the use of transition-metal ions such as Fe2+ or Cr3+. The observed high metal dispersions and high stabilities under HTR conditions were attributed to the formation of direct Rh-Cr"+ cation bonds. It has been suggested that this bonding would involve an electron transfer from Rh to Cr"+ ions. A similar metal-cation bonding was proposed by... 

The most dramatic reactions of coordinated ligands occur in complexes of transition metals, because of the inherent stability of these complexes and also the relatively high charge on the metal ion. The overall charge on cationic complexes is dispersed onto the ligands, which are consequently... 

Macromolecular conformations and reversible order-disorder and disorder-order transitions are highly sensitive to solvent, temperature, pressure, pH, water activity, and metal ions. Polyanions are distinguished from neutral molecules by their sensitivity to electrolytes. Whereas synthetic polymers do not normally dissolve or disperse spontaneously, some polysaccharides may do so in water (hydration), given their strong hydrophilicity. 

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