Nanometer metal—ligand coordination

For more practical purposes, therefore, one should take recourse to metal particles as produced by other means, in particular on supports or in matrices. The advantage is the availability of macroscopic amounts of sample the disadvantage is that interaction with the supporting medium must be assessed. A great variety of synthetic methods exists, of which we can mention only a few. Metal clusters can be produced by aerosol techniques, by vapor deposition, by condensation in rare-gas matrices, by chemical reactions in various supports, e.g. zeolites, SiOi, AI2O3, or polymer matrices. Many different metal-nonmetal composites, such as the ceramic metals (cermets) have been obtained with metal particles with sizes varying from nanometers upward. In alternative approaches, metal particles are stabilized by chemical coordination with ligand molecules, as in metal colloids and metal cluster compounds. 

Lehn has described supramolecular chemistry as an information science molecular subunits which contain the necessary information self-assemble into a larger specific structure. Complementary and explicit interaction of individual components with the appropriate symmetry and geometry generates the product assembly. In terms of coordination chemistry, astute ligand design and judicious choice of metal center allow one to access complex self-assembled architectures, many in the nanometer regime. 

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