Cage Inclusion Compounds

Fig. 7. Schemes of crystalline cyclodextrin inclusion compounds (a) channel type (b) cage herringbone type (c) cage brick type (58).

Figure 3. The shape and size of the cavity/channel of Dianin s compound, (a) The cage formed by two sets of hexamers. (b) The top or bottom half of the cage, hexamers are held together by hydrogen bonds, (c) Schematic illustration of the cage/channel. The stacking is along the c axis. (Reproduced with permission from D. D. MacNicol in Inclusion Compounds, Vol. 2, J. L. Atwood, J. E. D. Davies, and D. D. MacNicol, Eds., Academic Press, New York, 1984, p. 1.)...

Figure 8. A stereoscopic view of the packing in the inclusion compound of 1,1,6,6-tetraphenylhexa-2,4-dyne-1,6-diol, 2, with (a) chalcone and (b) 9-anthraldehyde. 9-Anthraldehyde gives cage-type and chalcone gives channel-type structures. [Reproduced with permission from F. Toda, Topics Curr. Chem. 140, 43 (1987).]...

There are many other types of inclusion compounds of undefined stoichiometry in which the guest molecules are confined in tunnels and cages... 

Packing of the cyclodextrin molecules (a, p, p) within the crystal lattice of inclusion compounds (58,59) occurs in one of two modes, described as cage and channel structures (Fig. 7). In channel-type inclusions, cyclodextrin molecules are stacked on top of one another like coins in a roll producing endless channels in which guest molecules are embedded (Fig. 7a). In crystal structures of the cage type, the cavity of one cyclodextrin molecule is blocked off on both sides by neighboring cyclodextrin molecules packed crosswise in herringbone fashion (Fig. 7b), or in a motif reminiscent of bricks in a wall (Fig. 7c). 

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