Supramolecular hydrogen bonded capsule

Figure 4.4 Supramolecular hydrogen bonded capsule developed by Rebek et ai (left) a dimeric structure and (right) various tetrameric structures.

The design and synthesis of supramolecular architectures with parallel control over shape and dimensions is a challenging task in current organic chemistry [13, 14], The information stored at a molecular level plays a key role in the process of self-assembly. Recent examples of nanoscopic supramolecular complexes from outside the dendrimer held include hydrogen-bonded rosettes [15,16], polymers [17], sandwiches [18, 19] and other complexes [20-22], helicates [23], grids [24], mushrooms [25], capsules [26] and spheres [27]. 

As one example, the observation of hydrogen bonding [7] in natural systems such as peptide helices and DNA base pairs led to a theoretical understanding of this phenomenon. This understanding has permitted the use of hydrogen bonding in synthesis, leading to the preparation of such diverse structures as Rebek s capsules [8], Lehn s supramolecular polymers [9], and Whitesides rosettes [10]. 

Hydrogen-bonded supramolecular capsule I compared with coordination capsule II. The external aliphatic groups are omitted for clarity. Note that a pair of intermolecular O—H O hydrogen bonds is replaced by four square-planar Cu-O coordination bonds in the metal-ion insertion process that generates the isostructural inorganic analog. From R. M. McKinley, G V. C. Cave and J. L. Atwood, Proc. Nat. Acad. Sci. 102, 5944-8 (2005). 

Strategies to Build up Supramolecular Cavities and Capsules Based on Hydrogen Bonds... 

Supramolecular self-assembly can be as simple as acetic acid dimerization through mutually complementary hydrogen bonds or as complex as supramolecule formation from multiple components as demonstrated by numerous examples of resorcin[4]arene and calix[4]arene capsules. One of the more interesting directions to have been taken has been the design and synthesis of self-complementary... 

Very Large Supramolecular Capsules Based on Hydrogen Bonding... 

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