Resorcarene-calixarene carcerand

Fig. 1 Molecular architecture two fascinating nanometer-scale supramolecular species and the corresponding macroscopic counterparts, (a) Resorcarene-calixarene carcerand [7] and the Battistero of Pisa (Italy), (b) Norbomylogous-type compound [8] and the Olina medieval bridge, Modena (Italy). The geometries of the molecules are constructed by molecular mechanics calculations...

Fig. 4 Exemplary cases of enforced cavity hosts and their supramolecular compounds (guests symbolized in broken rings) (a) Cleft-type (b) tweezer-type (c) spherand (d) cyclophane (monocyclic) (e) cyclophane ibicyclic) (f) cavitand (g) carcerand (h) calixarene (calix[4]arene) (i) resorcarene (j) cryptophane (k) cyclodextrin (P-cyclodextrin) and (1) cucurbituril.

Calixarenes, for example, 2.120, have already been discussed as hosts for cations and both cation and neutral molecules simultaneously in Sections 2.3.6 and 2.5.5, respectively. Resorcarenes e.g. 2.121) are very closely related to calixarenes and are sometimes referred to as calixresorcarenes. They are prepared from the acid-catalysed condensation of resorcinol (1,3-dihydroxybenzene) with aldehydes, a reaction first carried out by Baeyer in 1872. This macrocycle is arguably one of the most important molecules in the field, as resorcarenes serve as the basic building blocks for many cavitands and (hemi)carcerands. Both calixarenes and resorcarenes posses a shallow bowl-shaped conformation in their most stable forms. However, [4]resorcarenes (the [4] prefix refers to the ntimber of resorcinol units that make up the molecule, just as in calix[n]arenes) tend to produce a... 

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