Cage structures, diagram

Valence bond (VB) formulas or Schlegel diagrams are useful for simple schematic representations of fullerenes and their derivatives. VB formulas are mostly used for parent fullerenes or for derivatives with a few modifications of the cage structure only. A Schlegel diagram shows each C-atom of the fullerene, which is flattened out in two dimensions. This model is suitable for considering polyadducts, for example, polyhydrofullerenes. 

Figure 7.20 (a) Schematic diagram showing the hydroquinone cage structure, (b) Structure of the... 

The mechanism leads clearly to the first drawing of the product but this is a cage structure and the second drawing is better. The new six-membered ring is outlined in black in both diagrams. Now a more elaborate example to show that quite complex molecules can be quickly assembled with this wonderful reaction. 

Structure diagrams of the synthesized cage-types are shown in Fig. 1 ... 

The water-NaCl dihydrate in Figure 11.14 has a simple molecular formula and forms regular-structure crystals, as do most such compounds. The cage-structure hydrates discussed here do not, because the guest molecules do not bind to host molecules in a stoichiometric way, like water and NaCl [14, p. 313]. The S-L equilibria in Figures 11.13 and 11.14 are practically independent of pressure. Because the G in G-L-S has a much larger specific volume than liquids or solids, gas hydrates phase diagrams are pressure-dependent. 

There are a number of other important boron cage compounds as well as structurally similar metal atom cluster molecules that are not closed polyhedra. Generally, these may be regarded as derived from closed polyhedra by removal of one or two vertices. The diagram below illustrates how removal of one or two vertices generates the so-called nido and arachno relatives of a closo octahedral structure. 

Fig. 6. A diagram showing the dynamic interconveision of solvent-separated ion pairs (SSIP, exdplexes, contact ion pairs (CIP), and free ions in solution. Electron transfer takes place within a cage of solvent molecules to generate a SSIP or more intimate charge-transfer complex, the latter being an exciplex or CIP. The nature of the charge-transfer intermediate generated may depend on the distance separating the reactants. The distance depends on the molecular structures of the reactants, i.e., their sizes, shapes, and steric features. Free ions are produced by ion dissociation from the solvent cage...

These structural details are emphasized in Figure 2.19, with, in the second and later rows Figures 2.19b-d, the local sets of 10, 6 and 4 vertices of the great rhombicosidodecahedron identified about a representative pole position on a face and, then, in the second column of diagrams, as fiilly decorated elliptical projections of the 120-vertex cage. 

Figure 3.23 Translation of the summary projection results of Figure 3.33 into motion diagrams, from which in conjunction with the Figure 3.24, all the distinct normal modes of vibration of the O4 orbit cage of a structure exhibiting T(j point symmetry can be identified.

The structures contain channels in one, two, or three directions. When one channel intersects another, there may be a larger cage. The channels contain the alkali or alkaline earth metal cations (i.e., the exchangeable cations and water). Diagram 6.2690 shows the channels of ZSM-5. Structure 6.2791 is in zeolites X and Y. Each corner represents a silicon or aluminum atom. There is an oxygen atom on each line between them. I and II indicate where cations might be. 

Figure 7.21 (a) The structure of unsolvated Dianin s compound (front and back of the central cavity omitted for clarity), (b) Schematic diagram of the host cavity the cage height is 11.0 A. (Reprinted with permission from [22]). 

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