Macrocycles, incorporating carboranes

Figure 3.18. Macrocycles incorporating carboranes related to cyclophenylenes.

Hawthorne and co-workers have also produced a series of macrocyclic Lewis acid hosts called mercuracarborands (156, 157, and 158) (Fig. 84) with structures incorporating electron-withdrawing icosahedral carboranes and electrophilic mercury centers. They were synthesized by a kinetic halide ion template effect that afforded tetrameric cycles or cyclic trimers in the presence or absence of halide ion templates, respectively.163 These complexes, which can bind a variety of electron-rich guests, are ideal for catalytic and ion-sensing applications, as well as for the assembly of supramolecular architectures. 

Figure 84 Macrocyclic mercuracarborands (156, 157, and 158) with structures incorporating electron-withdrawing icosahedral carboranes and electrophilic mercury centers. (Adapted from ref. 163.)... 

The supramolecular chemistry of carborane clusters received significant impulses in the 1990s with the development of two types of compounds the arene-coupled macrocyclic systems incorporating ctoio-carboranes, and the mercuracarborands. 

Arene-Coupled Macrocyclic Systems Incorporating c/oso-Carboranes... 

FIGURE 27.2 (a) Arene-coupled macrocyclic systems incorporating meto-carboranes, (b) Cyclooctaphane assembling ortho- and meto-carborane units, and (c) xylyl-linked tetramer. 

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