Building inorganic clusters

A few considerations about possible schemes of relationships between inorganic crystal structures based on a systematic construction of complex structural types by means of a few operations (symmetry operations, topological transformations) applied to some building units (point systems, clusters, rods, sheets), have been previously reported in 3.9.1, following criteria suggested, for instance, by Hyde and Andersson (1989) and by Zvyagin (1993). 

The paramount advantage of molecular solids over their more classical inorganic counterparts is that their constituents, the building blocks, are molecules or clusters that can be designed and synthesized in other words they can be intentionally modified. Therefore, we can talk about molecular and crystal engineering and the goal is to be able to produce materials with predetermined physical properties. We are not yet at this desired level but the scientific and technical bases are certainly at hand. 

Molecular electron transfer is the basis for many important natural and commercial processes. During the past decade photochemists have relied upon supramolecular arrays of molecules to facilitate their understanding of the chemical and physical basis for this fundamentally important process. It therefore seems appropriate that several chapters in this volume examine thermally and photo-chemically induced electron transfer in supramolecular assemblies consisting of inorganic molecular building blocks such as covalently linked donor-acceptor dyads, transition metal clusters, and nanocrystalline semiconductor particles. 

A.N. Alexandrova, A.I. Boldyrev, H.-J. Zhai, L.S. Wang, All-boron aromatic clusters as potential new inorganic ligands and building blocks in chemistry, Coord. Chem. Rev. 250 (2006) 2811. 

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