Inclusion cyclotriveratrylene

Typically, the cumulative electron-withdrawing effect of metallating more than half of the arenes of the macrocycle is required in order to observe anion inclusion. Thus, we have focused on tetrametallated derivatives of calix[4]arene and di- or trimetalated derivatives of the related orr/io-cyclophane, cyclotriveratrylene (CTV). The X-ray crystal structure of the BF salt of the water soluble bear trap 51 demonstrates the suitability of the narrow calix[4]arene cavity for small tetra-... 

Cyclotriveratrylene/1180-60-5] (34) is a cyclocondensation product of veratrole with formaldehyde. It possesses a stable trigonal crown conformation and forms crystalline inclusion compounds with benzene, chlorobenzene, toluene, thiophene, decalin, chloroform, acetone, carbon disulfide, acetic acid, and butyric acid (101). Their structures consist of columns of cyclotriveratrylene molecules that are not amenable to close packing and provide channels into which the guests are accommodated. A number of modified host structures, derived from prototype (34) have been prepared. The hexaphenol analogue cyclotricatechylene also yields well-defined channel inclusions (101). They involve mosdy polar guests and the structures are held by hydrogen bonding. 

Ibragimov, B. T., Makhkamov, K. K., Beketov, K. M., Polymorphism of crystalline inclusion complexes and unsolvated hosts. Part 8. Endocyclic modification of the cyclotriveratrylene host-guest complex with acetone. J. Incl. Phenom. Macro-... 

The name cryptophane [23], which designates molecules made of two cyclotriveratrylene units assembled by three bridges in the way shown in Fig. 3, recalls the [l.l.ljorthocyclophane structure of CTV and underlines the presence of an enforced cavity in these compounds allowing the inclusion of suitable guest species (Sect. 3). 

Cyclotriveratrylene (1) and its hexademethylated derivative cyclotricatechylene (16) (Table 2) form crystalline inclusion compounds with a great variety of small to medium-sized molecules. These inclusion compounds have been described in a previous review [9] and will not be further considered here. 

An interesting example of the interplay between solid-state clathrands and solution-phase cavitands is provided by cyclotriveratrylene (CTV, 8). In the solid state, the saucer-shaped CTV molecules stack one on top of another in the two most common phases (x and and hence, while the molecules possess shallow molecular cavities, they do not include guests such as solvent molecules, which instead are located in voids between host stacks. However, larger guests such as buckminsterfuller-ene C6o, organometallic sandwich compounds,or carboranes form intracavity inclusion compounds, and the association persists in the solid state, with potential applications, for example, in the selective purification of fullerenes. Thus, CTV is both a cavitand and a clathrand. The cavitand behavior of CTV is highlighted by the chemistry of the double-CTV cryptophanes that form very stable solution complexes with a variety of halocarbon guests. 

Holman, K.T. Atwood, J.L. Steed. J.W. Intra cavity inclusion of [CpFe Varene)] guests by cyclotriveratrylene. Angew. Chem., Int. Ed. Engl. 1997. 36. 1736-1738. 

The number of papers reporting the role of CH/ti interaction is rapidly increasing. Only recent key papers are cited here. Chloroform interacts favorably with an arene n-oloud of fullerene complexes of calixarenes " and cyclotriveratrylene. Evidence for the role of CH/ti interaction in self-assembly was presented.The significance in molecular capsules " " and lattice- and cavity-inclusion type clathrates is well documented. 

Cyclotriveratrylene is a trimeric, bowl-shaped molecular skeleton, known to form solid-state inclusion compounds. A variety of cyclotriveratrylene derivatives, e.g. 96 and 97, resulted from r-complexation of the aromatic nuclei with one, two, or three Ru( / -arene) (arene = CeHe, p-MeC6H4Pr ) and Ir( -C5Me5) organometallic moieties [195-197], Some of their structures were established by X-ray diffraction. 

As a natural development of the successful molecular inclusion concept, which involved electrostatic as well as van der Waals forces between the interacting host and guest entities, an increasing interest has been shown in the systematic study of lattice-inclusion type systems. A considerable effort has been devoted to the design of new hosts for the formation of stable crystaUine clathrates and the improvement of selective complexations with potential guests. Suitable examples of clathrates studied in recent years include hosts such as Dianin s compounds , perhydrotriphenylene , cyclotriveratrylene triphenylmethane hexakis-(arylthio) and -(arylthiomethyl)benzenes tri-o-thymotide (TOT) and choleic acids (cf. Fig. 1 in Ch. 1 of Vol. 140). Selected series of such clathrate inclusion systems have particularly been useful in research of photochemical reactions in the solid state and of selective molecular complexation that is central to biological phenomena... 

Collet et al. (138-140) have recently reported the elegant syntheses of cavitands composed of two cyclotriveratrylene units connected by three di-or trimethylene bridges (Figure 2.61). These hollow host molecules have been named cryptophanes, and are suitable for inclusion of lipophilic guests in the interior of their three-dimensional enforced cavities. The cryptophanes (139)-(142) are chiral, and have been obtained in enantiomerically pure forms and their absolute configurations established. 

The macropolycyclic speleand (30 a) combines the [18]-N303 macrocyclic binding subunit with the cyclotriveratrylene shaping component [23]. Its tight intramolecular cavity allows inclusion of the CH3-NH3 ion yielding the speleate [CH3--NH3 c (30 a)] whose structure should be of the type shown schematically by (30 b). 

Similarly, cyclotriveratrylene forms an inclusion complex only with Cao, but not with Cvo- Again, the driving force is the creation of K-n charge transfer interactions. The X-ray structure is simplified in Figure 10 and shows that Ceo adopts a nesting position above the concave surface of cyclotriveratrylene, with close contacts between the two entities at the van der Waals limits (3.34 - 3.51 A). These short contacts compare well with the contacts in cubic close packed Ceo-... 

Matsubara, H. et al. Supramolecular inclusion complexes of fullerenes using cyclotriveratrylene derivatives with aromatic pendants. Chem. Lett. 27, 923-924,1998. 

Hardie, M. J. Raston, C. L. 2001. Alkali-metal - cyclotriveratrylene coordination polymers Inclusion of neutral C2B10H12 or anionic [CBnHi2] and DMF. Cryst. Growth Des., 1 53-8. 

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