Functionalized fullerenes

Diels-Alder reactions have been used to synthesize and functionalize polymers, as reported by several groups. Rotello and coworkers112, for example, covalently attached [60]fullerene to furan and cyclopentadiene substituted resins. The reaction with the furan substituted resin proved reversible. The resin was recovered by heating the fullerene functionalized resin. 

The second way to prepare water soluble fullerenes is by adding functional groups to the molecules exterior (Brettreich and Hirsch, 1998 Foley et al., 2002b Guldi et al., 1999 Nakajima et al., 1996 Rajagopalan et al., 1996 Sayes et al., 2004 Wang et al., 1999). Numerous efforts have pushed for fullerene functionalization to be the most useful way to make water soluble fullerenes. Fullerene functionalization... 

These cycloadditions with o-quinodimethanes provide a broad variety of useful fullerene functionalizations, since o-quinodimethanes can be prepared using several routes and the resulting cycloadducts are thermally stable [42], There exist several alternatives to the iodide-induced bromine 1,4-elimination of 1,2-bis (bromomethyl)-benzenes [44-47]. o-Quinodimethanes have been prepared by thermolysis of 3-isochromanone (42) [43], benzocyclobutenes (43) [48-50], isobenzothiophene 2,2-dioxides (44) [42] and sultines [51,52] or by photolysis of o-alkylphenones such as 45 [53-55] and could be added to Cjq in good yields (Scheme 4.7). Indene, thermally rearranged to isoindene, also adds to Cjq in similar fashion to quinodimethanes [56]. 

As mentioned previously, photocycloaddition reactions are a useful method for obtaining fullerene derivatives fused directly to heterocycles. Such compounds have attracted much interest because they might have interesting properties, e.g., amino acid fullerene derivatives as biologically active compounds or pyrrolidino-fullerenes as key precursors for a great number of fullerenes donor-acceptor bridged dyads and triads. Fullerenes functionalized with silicon compounds are of great interest in materials science. The synthesis of these compounds will be described in this section. 

AFM investigations of unmodified and C60-functionalized PVFA-co-PVAm layers on a flat silica layer-deposited on a silicon wafer-are shown in Fig. 10. The fullerene functionalized PVFA-co-PVAm/silica layer causes holes with a diameter of 10 nm and depth of 2 nm. The former PVFA-co-PVAm layer has a thickness of about 1.2 nm. This shows the strong influence of reacted C6o molecules on the conformation of the adsorbed polymer layer. These holes observed are also an indication that fullerene aggregates are encapsulated in the PVFA-co-PVAm layer on silica. 

The Bingel-Hirsch reaction is an important tool in fullerene functionalization. It yields cyclopropanated fullerenes by means of deprotonated bromomalonates. 

An application of microwave irradiation in the synthesis of fullerene-functionalized polycarbonates has recently been reported. The process is based on direct reaction of Ceo (1) and polycarbonate (62) in the presence of AIBN under the action of microwave irradiation [66]. The resulting Ceo-PC (63) material can be dissolved in common organic solvents and has optical limiting properties similar to those of C o itself. This material can be used for optical applications. 

Fig. 8. CD spectra of a 52a with chiral side chains, hut an achiral fullerene addition pattern, and b the diastereoisomeric 48a and 49a having enantiomeric, inherently chiral fullerene functionalization patterns in addition to the (S)-configured side chains...

H-Bond-assembled supramolecular architectures of fullerenes functionalized by various heterocyclic fragments 07CJO153. 

Photoinduced electron transfer in supramolecular systems of fullerenes functionalized with ligands capable of binding to zinc porphyrins and zinc phthalocyanines 05CCR(249)1410. 

Oligothiophenes containing redox active groups Fullerene-functionalized oligothiophenes... 

Using a copper phenanthroline complex as a core, Armaroli et al. synthesized a dendritic compound with fullerene-functionalized branches. Electrochemical... 

Fullerenes have been used as cores for redox dendrimers, and a system of fullerenes functionalized with poly(arylacetylene) dendritic branches has been studied. However, electrochemical experiments indicated no significant interaction between the dendrimers and the fullerene core [57]. 

A range of fullerenes functionalized with long alkyl chains was synthesized and inserted into SWCNTs... 

Sudeep PK, Ipe BI, Thomas KG, George MV (2002) Fullerene-functionalized GNPs. A self-assembled photoactive antenna-metal nanocore assembly. Nano Lett 2 29-35... 

When a better electrofugal group is present in a position, the reaction is particularly convenient. This is the case for the fullerene functionalization of C-60 fullerene that has been now patented. 

Mikami, K., Matsumoto, S., Tonoi, T, and Okubo, Y, Solid state photochemistry for fullerene functionalization solid state photoinduced electron transfer in the Diels-Alder reaction with anthracenes, Tetrahedron Lett., 39, 3733, 1998. 

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