Tubular inclusion compounds

Figure 17 The hydrogen-bonded supramolecular synthon present in all helical tubulate inclusion compounds formed by diol 11 (and its family of hosts). The molecules hydrogen bond together O-H O-H O-H to form the threefold screw axis structure illustrated. Identical arrangements subtended by the second diol hydroxy groups give rise to the chiral tubular lattice structure shown in Figure 16. Hydrogen atoms are omitted for clarity.

Several diols form inclusion compounds.67 The bicyclic one shown (7.10) contains tubular canals that guests can fit into.68 The crystals form inclusion compounds with the vapor of 1,2-dimethoxyethane, 1,2-dichloroethane, 1,4-diox-ane, ethyl acetate, toluene, chlorobenzene, and others. The tetrols (7.11 and 7.12) also form inclusion compounds with various guests. 

A striking feature of the cellular effects of bismuth compounds in animals (and one shared only by lead) is the production of intranuclear inclusion bodies of up to 5 ixm in diameter (87), for example, in the tubular epithelial cells of the kidney. Electron probe microanalysis shows that these contain both Bi and S, and so could be a complex with a Cys-rich protein such as metallothionein. Bismuth is known to be a potent inducer of renal metallothionein synthesis, and pretreatment of animals with bismuth salts can prevent some of the toxic side effects induced by cisplatin (88). The role of metallothionein in the pharmacology of bismuth remains to be established, but the strong involvement of zinc, also an inducer of metallothionein synthesis, in the metabolism of skin cells, for example, may be related. Like several other elements of Group V, the development of the biological chemistiy of Bi is hampered by the lack of good physical properties, in particular of a well-behaved NMR isotope. 

The corannulenes are the simplest examples of compounds with a curved surface. They include fluoranthenes that are important synthetic intermediates in the construction of corannulenes and their derivatives. Indenofluoranthenes have a curvature of a higher order due to the inclusion of two 5-membered rings. Methods for the synthesis of fluoranthenes from naphthalene and indenocorannulenes from corannulenes offer approaches to the formation of high-order spherical and tubular structures. 

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