Supramolecular synthons crystal packing

It has been noted above that synthon VIII incorporates within it synthon VII. Which of these is the more useful representation The efficacy of a supramolecular synthon as an indicator of crystal pack-... 

Figure 8.3 Crystal packing using the nitro/iodo supramolecular synthon (a) antiparallel, centro-symmetric packing in 4-nitroiodobenzene, (b) non-linear optical active parallel arrangement of polar stacks in 4-iodo-4 -nitrobiphenyl.4...

A lot of information can be generated by analyzing the crystal packing in monocarboxylic acids and we confirm that the presence of centrosymmetric supramolecular synthon (i.e. the carboxylic acid dimer) affords centrosymmetric crystals. 

As outlined by Desiraju, crystal engineering strategies rely on the use of supramolecular synthons , or structural units within supermolecules that can be assembled using known synthetic operations , in order to achieve favourable erystal packings. Specifically, regarding organic-based moleeules, the supramolecular synthons can exist in two main types namely, homosynthons and heterosynthons (Scheme l). 

The supramolecular synthon concept combines the chemical elements of molecular recognition with the geometrical requirements of crystal packing. The seminal 1995 review paper of Desiraju introduced the formal Hterature definition of the supramolecular synthon, based on analogy with Corey s definition of synthons for covalent synthesis. The explicit link between eovalent synthesis and crystal engineering is stressed by this analogy, and co-erystal or... 

Creative concepts in crystal engineering make use of supramolecular synthons to define specific interactions in molecular solids, which may be employed to design crystal packings The synthon approach has been used to produce close packed structures, and, on the contrary, to build open network structures. In the packing motifs of high performance pigments several types of specific interactions (synthons) can be identified. 

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