Building metal-containing

Currently the main interest in template reactions lies in their key role in the controlled synthesis or the self-assembly of a variety of supramole-cular entities (449). One needs a combination of intuition, conjecture, and serendipity (450) a recent example of successfully combining serendipity and rational design is provided by the silver(I)-promoted assembly of one-dimensional stranded chains (451). One also needs an understanding of mechanism in order to optimize the selection and design of building blocks and templates for the generation of yet more sophisticated supramolecular structures references cited in this present review contain at least some kinetic or mechanistic information or speculation. Template routes to interlocked molecular structures have been reviewed (452), while a discussion of switching by transition metal contains a little about the kinetics and mechanisms of this aspect of template... 

There are a wide variety of inorganic and metal-containing polymers. The potential uses are many and include the broad areas of biomedical, electrical, optical, analytical, catalytic, building, and photochemical applications. 

On oxidation of mononuclear complexes in the potential window <+1.6 V, only one metal-based process is observed. The oxidation potential depends strongly on the nature of the metal ion (Os is oxidized at less positive potentials compared to Ru ) and, less dramatically, on the nature of the coordinated ligands. Because of the previously discussed electronic properties of the isolated components and of the stabilization of the LUMO of 2,3-dpp and 2,5-dpp on coordination to a second metal center, it can be expected that the oxidation potential of the metal-containing building blocks increases in the order ... 

Perhaps the most difficult inherent problem in metal remediation is that metals, although they may be released in the breakdown of a metal-containing compound, are not degradable in the same sense as carbon-based molecules. The metal atom is not the major building block for new cellular components, and while a significant amount of carbon is released to the atmosphere as C02, the metal atom is often not volatilized. Both incorporation into cell mass and volatilization facilitate carbon removal from environmental systems. In contrast, metals, unless removed completely from a system through intervention, will persist indefinitely. 

Carbon and metal sulfide deposits are the two main causes of deactivation of residue hydrodemetallization (HDM) catalysts. During a catalytic test, the metals contained in the feed (Ni, V) are slowly deposited on the catalyst surface leading to the build up of large particles of metal sulfides which ultimately plug the catalyst pores. Carbon, on the other hand, is known to accumulate quickly on the catalyst surface within the first days of a run until a steady state is reached (1-20). At the beginning of a run, a strong deactivation of the residue HDM catalyst rapidly occurs to which both types of deposits may contribute. However at the present time it is not clear whether this initial deactivation is mainly due to coke or metal sulfide deposits. 

Successful stabilization/solidification of cadmium in the concentration 50,000 mg l1 of Cd2+, and lead in the concentration 10,000 mg T1 of Pb2+, in the cement matrix, was obtained. Low concentrations during leaching pointed out that the heavy metal containing waste could be successfully stabilized and immobilized on this way and landfilled, or safely utilized as the building material. 

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