Supramolecular Chemistry of Fullerenes

The interaction between host molecule and fullerene is mediated by the k-electrons of the carbon cage. Very efficient complex formation is thus achieved by Jt-Jt-donor—acceptor interactions. The fuUerene s distinct electrophiUcity further causes preferred interaction with electron donors. Fullerenes participating in supramolecular structures have been reported soon after the discovery of the element s new modification, and some examples shall be presented in the following. 

Chlathrates may, in a way, be regarded as supramolecular adducts in the crystalline state. C ) forms a series of these compounds which in most cases are obtained by simple cocrystallization of their constituents. Known examples are the inclusion compounds with hydrocarbons tike pentane or nonane, etc., but chlathrates of Qo or C70 have also been found with hydroquinone in the presence of benzene. In these cases the fullerene molecules occupy interstitial spaces within the crystal structure of hydroquinone and form donor-acceptor complexes. Further inclusion compounds with fuUerenes are known for ferrocene and other inorganic substances such as sulfur (Sg), white phosphorus (P4) or complexes hke (PhCN)2PdCl2 and PhsPAuCl (also refer to Section 2.5.3). For the complex of with ferrocene the crystal structure of the first is found with the latter inserted into the given gaps. The whole stracture can only exist because ferrocene is too weak a reducing agent to transform into Qo. 

A special host- est geometry is realized in the so-caUed peapods. These are single-waUed carbon nanotubes with fuUerenes enclosed in their irmer void so they are arranged tike peas in their pod (also refer to Section 3.5.6). The embedded fuUerenes can be as well as higher homologs. These may themselves contain endohedral guests, which turns peapod-formation reaUy into a super-supramo- 

FinaUy, certain long-chain molecules are able to bind fuUerenes by micelle formation and to finely disperse them in a medium. The examples reported for this kind of interaction mostly use surfactants like Triton X-100 or lecithin. The hydro-phobic fullerene is incorporated into the miceUe, partly in its center, but partly also in its periphery. Among other effects, this interaction leads to the solubility of such adducts in water. The embedding in long-chain, amphiphilic molecular units is also used to prepare artificial membranes holding fuUerenes. 

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Supramolecular chemistry of fullerenes linked or fused with heterocylic fragments 99CSR263. 

Just by comparing the number of publications on fullerenes (5500 until 1994 and 21500 between 1994 and now) it was immediately clear that the whole literature even that focussing on fullerene chemistry cannot be covered in a single monograph. We had to carefully select and condense the material, refer to the many excellent reviews of specific subjects such as chemistry of higher fullerenes and supramolecular chemistry of fullerenes. 

Hetero-arrays of porphyrins and phthalocyanines 07CCR2334. Metalloporphyrin hosts for supramolecular chemistry of fullerenes ... 

Supramolecular chemistry of fullerenes can be used to control the interplay of fullerenes in the solid state, for then covalently linking the fullerenes under high pressure and temperature. The pioneeringwork for the synthesis of dumbbell-shaped C120 w ai done by Iwasa et al. This was followed by Sun and Reed preparing a linear polymer o/ covalently linked Cgo molecules. 

Martin N. Nierengarten, J. F. Supramolecular Chemistry of Fullerenes and Carbon Nanotubes-, Wiley-VCH Verlag GmBH Weinheim,... 

Heterocyclic Supramolecular Chemistry of Fullerenes and Carbon Nanotubes... 

This review has described the supramolecular chemistry of fullerenes and CNTs. Although the non-covalent chemistry of heterocyclic molecules has been highlighted in this review, the supramolecular chemistry of other host molecules, as well as covalent chemistry, has also contributed enormously to the progress of this interdisciplinary field in science. One of the landmarks must be the application of the supramolecular interaction of Ceo with calix[8]arenes to the practical purification of fullerenes, which was reported independently by Shinkai et al. and Atwood et al. in 1994 [243,244]. Quite recently, the host-guest strategy has been successfully applied to structure-... 

The final chapter, Heterocyclic Supramolecular Chemistry of Fullerenes and Carbon Nanotubes by N. Komatsu presents an extremely unique review that focuses on the noncovalent chemistry of fullerenes and carbon nanotubes with nitrogen- and/or oxygen-containing heterocyclic molecules such as porphyrin, DNA, protein, peptide, and carbohydrate. Not only exohedral but also endohedral fimctionahzation is reviewed, because the above guest molecules can interact with both faces of the carbon nanotubes. The hurdles in structural separation, nanofabrication, and bioappHcations of carbon nanotubes will hopefully be addressed by the supramolecular strategy. 

Although the supramolecular chemistry of fullerene derivatives is a well explored and established field [53], surprisingly, fuUerene-containing supramolecular polymer systems have been scarcely studied. In fact, this family can be considered as the most recently explored among the other polyfullerenes, and it is now experiencing growing interest... 

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