Crystal engineering, diamondoid

Since diamondoids possess the capability for derivatization, they can be used to achieve suitable molecular geometries needed for MBBs of nanotechnology. Functionalization by different groups can produce appropriate reactants for desired reactions, microelectronics, and optics, by employing polymers, films, and crystal engineering. 

The approach in crystal engineering is to learn from known crystalline structures of, for example, minerals in order to design compounds with desired properties. Crystal engineering is considered to be a key new technology with applications in pharmaceuticals, catalysis, and materials science. The structures of adamantane and other diamondoids have received considerable attention in crystal engineering due to their molecular stiffness, derivatization capabilities, and their six or more linking groups [114-117]. 

We saw in the preceding section the crystal engineering of diamondoid arrays arising via halogen bonding, from the use of tetrahedral building blocks. We complete this chapter by a brief discussion of what constitutes a diamondoid array and why they are not just interesting from a materials point of view but also very beautiful. 

The three-dimensional network structure of diamond can be considered as constructed from the linkage of nodes (C atoms) with rods (C-C bonds) in a tetrahedral pattern. From the viewpoint of crystal engineering, in a diamondoid network the node can be any group with tetrahedral connectivity, and the linking rods (or linker) can be all kinds of bonding interactions (ionic, covalent, coordination, hydrogen bond, and weak interactions) or molecular fragment. 

Robson s early work yielded some elegant examples of crystal engineering in which 3-D networks of simple, known structure types, such as the diamondoid and Re03 structures, were built from suitable combinations of metal ions and rigid linkers. Fig. 6 shows a simple example based upon the PtS structure.19 Others have exploited the same concept, including Carlucci el al.,20 who reported some remarkable open-frame-work structures based upon silver in combination with ligands such as pyrazine (Fig. 7). Some of the most striking examples... 

Diamondoid networks represent just one example of the types of architecture that can be generated in a rational manner using the modular self-assembly approach. The remainder of this chapter will focus upon the diversity of simple architectures that are accessible using crystal engineering strategies, many of which have no precedent in minerals yet are afforded via one-pot reactions and commercially available components. 

Desiraju. G.R. Diamondoid and square grid networks 30. in the same structure. Crystal engineering with the iodonitro supramolecular synthon. Cryst. Growth Des. 

Another interesting case in crystal engineering is the one of interpenetrated cyano-bridged diamondoid networks. Zinc(II) easily adopts a tetrahedral geometry, so the solid-state structure of Zn(CN)2 is quite predictable tetrahedral zinc ions are connected by cyano groups generating a diamond-like net, with double interpenetration (Schemel). The cadmium derivative. 

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