Ordered solid-state structure

Molecular Recognition-Directed Self-Assembly of Ordered Solid-State Structures... 

Molecular recognition directed self-assembling of organized phases has been described recently in the formation 1) of mesophases by association of complementary molecular component, as in 13 (23) 2) of supramolecular liquid crystalline polymers of type 14 (24) and 3) of ordered solid state structures, such as that represented by 15 (25). In all these cases, the incorporation of NLO active groups may be expected to produce materials whose SHG properties would depend on molecular recognition induced self-organization. 

The defects we have discussed in this chapter are largely microscopic and cannot be observed from the macroscopic structure of the materials. However, there are various sorts of macroscopic defect which can be examined using electron microscopy, and which explain certain physical characteristics. For example, metals are generally malleable and ductile but their ordered solid state structure implies that they should be rigid. Sometimes heating metals makes them more brittle in a process known as work hardening . These characteristics indicate that the structures of the metals are not perfect. The malleability of metals is an indication that the structure contains defects which occur in lines and planes, allowing the atoms to slip over each other. As the temperature rises or the metal is worked (as by a blacksmith), the metal becomes harder as the defects are removed. 

Ordered solid state structures are formed through molecular recognition-directed self-assembly of complementary hydrogen bonding components (Figure 4) [25]... 

In order to specify the structure of a chemical compound, we have to describe the spatial distribution of the atoms in an adequate manner. This can be done with the aid of chemical nomenclature, which is well developed, at least for small molecules. However, for solid-state structures, there exists no systematic nomenclature which allows us to specify structural facts. One manages with the specification of structure types in the following manner magnesium fluoride crystallizes in the rutile type , which expresses for MgF2 a distribution of Mg and F atoms corresponding to that of Ti and O atoms in rutile. Every structure type is designated by an arbitrarily chosen representative. How structural information can be expressed in formulas is treated in Section 2.1. 

The solution structures of cyano-Gilman cuprates and lower-order cyanocuprates have been studied by cryoscopic measurements in THF [141]. The results of this study have in several cases shown ways to obtain useful single crystals of several higher- and lower-order cyanocuprates and consequently to determine their structures in the solid state. It appears that a number of these cyanocuprates retain their observed solid-state structure when dissolved in THF. 

The solid-state structure of WOF4 determined by X-ray crystallography has been questioned again. Bonding requirements and bond order-bond length... 

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