Molecular encaged clusters

In the pages that follow, we summarize methods for the synthesis of clusters in cages, their structural characterization, reactivity, and catalytic and other properties. The literature of encaged clusters is limited to clusters in zeolites, and thus little is included here about other molecular sieves or potential cluster hosts. The literature dtations are not comprehensive rather, examples are dted to illustrate prindples and to emphasize the unique properties of encaged clusters and the... 

Elemental semiconductor clusters encaged in zeolites provide a valuable opportunity for gaining a fundamental understanding of semiconductor clusters because stoichiometry is not a concern in the synthesis. Selenium is of interest because it has an intermediate electrical conductivity and a negative coefficient of resistivity in the dark hence it is markedly photoconductive. It has uses in, for example, photoelectric devices and xerography. When Se is sorbed into a molecular sieve, it gives markedly different optical absorption spectra from those of the bulk material. 

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