Inclusion adamantane

Figure 30 Lateral stereo views of adamantane derivative thiacalix[4]arene top) presented in Fig. 29. A CHCI3 molecule has been entrapped inside the inclusion compound. The bottom view left bottom) and top view right bottom) are also shown. H atoms have been removed from the inclusion compound for more clarity [128].

Capping of inclusion complex with adamantane amine... 

Nakajima et al. (1) prepared liquid crystalline polyrotaxane derivatives containing the mesogenic group 4-cyano-4 -hydroxybiphenyl attached to the a-cyclodextrin component of linear polyethylene glycol containing an a-cyclodextrin inclusion complex with an adamantane termini. 

These data thus provide evidence of specific interactions between grafted adamantane groups and (3- CD with no influence of the polyether chain in the inclusion process [23], And at the same time was confirmed by H NMR spectra the selective interaction between the pendant hydrophobic adamantyl groups and (3 - cyclodextrin. 

Fig. 1. Topographies of cyclodextrin inclusion complexes a-CD - nitromethane (75) (top), p-CD - adamantane-carboxylate (76, 77) (center), and y-CD - 12-crown-4 (76, 78). The striking correspondence of hydrophobic surface regions of guest and CD-host at their interfaces may be viewed in color on the Internet (79).

Figure 11.9. Crystal structure of the [Ag4(3)4]4+ cage with the inclusion of one guest adamantane molecule inside the cage. 2,4,6-Tri-p-tolyl groups, hydrogen atoms, and anions have been omitted for clarity.

FIGURE 4 Schematic representation of P-CD-adamantane inclusion complex formation and immobilization of CD nanoparticles on adamantine-modified surface. (Reprinted with permission from ref. 44. Copyright 2006 by the American Chemical Society.)... 

Preparation B. Ault and Kopet2 describe as an introductory organic experiment a procedure for the preparation of adamantane by isomerization of endo-tetrahydrodicyclopentadiene by the method of Schleyer but the product is isolated from a hexane extract of the reaction mixture as the beautifully crystalline inclusion complex with thiourea.3 As noted in 1, 1164, the ratio in this complex is 3.4 molecules of host per molecule of guest hydrocarbon. Although the reaction time is only 1 hour, the yield (15%) is about the same as that reported for a reaction time of 8-12 hours. 

Selenourea, like urea and thiourea, can form inclusion compounds with a variety of hydrocarbons. Its inclusion properties were studied by van Bekkum and coworkers in 1969 [79], well over 20 years after the discovery of the analogous urea [54] and thiourea [55] inclusion compounds. The 1 3 adduct of adamantane with... 

To the best of our knowledge, there is only one example in the literature of a photoaddition reaction influenced by CD and involving two different molecules, that is, the photocycloaddition of 5-X-adamantan-2-ones (X = F, Cl, Br, OH, phenyl, ferf-butyl) with fumaronitrile (Scheme 31) [319]. The reaction performed in p-CD aqueous solution led to a remarkable change in product distribution with respect to that found in isotropic solvent. The syn/anti ratio of the frans-oxetane formed was reversed (Table 23). The effect was maximum with the bulkier substituents and was not observed on addition of a- and y-CD. The rationale is that deep inclusion in the P-CD... 

Weickenmeier and Wenz [84] investigated the inclusion complex formation of poly[(N-vinyl-2-pyrrolidone)-co-(maleic acid)] modified with j8-CD moieties with 1-adamantanamine and with 1-adamantanecarboxylic acid by isothermal titration calorimetry. They reported 1 1 inclusion complexes between -CD moieties and adamantane derivatives with relatively large binding constants (ca. 3-5 x 10 M ). 

Two main reasons guided this choice. On one hand, the reactions of these compounds under classical conditions are already known. This facilitates to find out, how nitrene reactivity has been modified by inclusion. On the other hand, as has been shown earlier in this chapter, the adamantane skeleton is a good fit for the cavity of a- and j8-cyclodextrins leading to high association constants upon complexation. 

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