Supramolecular, generally networks

Although the cyclic dimers are connected by additional H-bonds, the authors did not observe a super-tetrahedral network. Notably, a 2 1 alcohol-amine complex 14 15, was also observed [41] between 4-methoxyphenol (15) and methylhydrazine (14) (Scheme 5). Thus, a dimer formed by a primary amine and a secondary amine in such cases does not have the general requisites to generate a supramolecular architecture. 

The third section describes the hierarchy and supramolecular chirality of molecular assemblies in the crystalline state. The steroidal molecules construct hierarchical assemblies on the basis of sequential information, as in the case of proteins. The notable feature is that each hierarchical assembly exhibits supramolecular chirality, such as three-axial, tilt, helical, and bundle chirality. On the other hand, the primary ammonium salts construct hierarchical hydrogen bonding networks which, in some cases, create supramolecular chirality from achiral components. The creation of chirality can be interpreted from a topological viewpoint, leading us to define the handedness of the supramolecular chirality. At the end of this section we present the general concept that molecular-level information on organic substances can be expressed by their assemblies through non-covalent interactions. 

To continue, the crystal structure of fefraA i -(4-iodophenyl)methane (16) is isomorphous with 17 having an I---I distance of 3.95 and 4.16 A in the corresponding 14-synthon. In this family of halo-substituted tetraphenylmethanes with S4- or pseudo-S4-symmetry, the molecules exhibit similar colunmar packing in the solid state [14]. In summary, if a supramolecular strucUire is defined as a network and analysed retrosynthetically, general connectivity strategies can be systematically derived. 

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