Amines fullerenes

Another route to fabricate fullerene doped monoliths has been shown by Peng et al. (2001), which successfully prepared crack free, transparent fullerene glasses oflarge dimensions (up to 60 mm) from sol-gel mixtures of aminated Cgo derivatives and tetraethyl orthosilicate (TEOS). The aminated fullerene derivatives have been synthesized by amination reactions of Ceo with 6-amino-l-hexanol, cyclohexylamine, 2-(2-aminoethoxy)ethanol, and 3-aminopropyltriethoxysilane to prepare derivatives with the molecular structures H C6o[NH(CH2)6oH]jt, H C6o(NH-cyc/o-C6Hn)je, Hjj,C6o[NH(CH2CH2o)2H], and H (C6o[NH(CH2)3Si(OCH2CH3)3]i . A silica network with covalently bonded amine fullerene derivatives has been obtained, as shown in Figure 23-3. 

Several studies have demonstrated the successful incoriDoration of [60]fullerene into polymeric stmctures by following two general concepts (i) in-chain addition, so called pearl necklace type polymers or (ii) on-chain addition pendant polymers. Pendant copolymers emerge predominantly from the controlled mono- and multiple functionalization of the fullerene core with different amine-, azide-, ethylene propylene terjDolymer, polystyrene, poly(oxyethylene) and poly(oxypropylene) precursors [63,64,65,66,62 and 66]. On the other hand, (-CggPd-) polymers of the pearl necklace type were fonned via the periodic linkage of [60]fullerene and Pd monomer units after their initial reaction with thep-xy y ene diradical [69,70 and 71]. 

Nakamura Y, Suzuki KO-kawa M, Konno T, Nishimura J (2005) Photoreactions between [60] Fullerene and various aromatic tertiary amines. J Org Chem 70(21) 8472-8477... 

Figure 15.5 A trityl-protected pyrrolidine derivative of Cgg can be prepared by the reaction of N-trityl-oxazolidinone with a fullerene. Deprotection of the trityl group using methanesulfonic acid gives the secondary amine, which can be used in further conjugation reactions.

Figure 15.9 The reaction of the amine-blocked derivative of 3-hydroxypropylamine with ethylmalonyl chloride gives an ethylmalonate-protected-amine compound, which can be used in the Bingel reaction to create an amine group on a fullerene surface. Reaction with Cfl in the presence of I2 and DBU gives the cyclopropanation product that can be deprotected with TFA to yield the free amine.

The PCBM methyl ester can be used for coupling amine-containing ligands after removal of the methyl group and activation of the carboxylate using a number of different reaction strategies. Hummelen et al. (1995) successfully coupled cholestanol and histamine to the fuller-ene-PCBM derivative (after acid chloride formation) for use in fabrication of photodetectors and biological studies, respectively. For specific applications of PCBM-fullerenes, see Shaheen et al. (2001), Brabec et al. (2001), Yu et al. (1995), Mecher et al. (2002), Meijer et al. (2003), van Duren et al. (2004), and Anthopoulos et al. (2004). 

Metal-free initiators, 14 258-259 Metal fullerenes, 2 718-719 Metal-halogen exchange, in pyridine chemistry, 22 107-108 Metal hydrazides, 23 567 Metal hydrides, 23 611-613 amines by reduction, 2 493 hydrogen storage and, 23 851 nitriding, 27 206-207 storage of, 23 786... 

Hirayama J, Abe H, Kamo N, Shinbo T, Ohnishi-Yamada Y, Kurosawa S, Ikebuchi K, Sekiguchi S (1999) Photoinactivation of vesicular stomatitis virus with fullerene conjugated with methoxy polyethylene glycol amine. Biol Pharm Bull 22 1106-1109. 

Water colloid solutions of fullerenes C60 (10 4 M) were prepared as described in Scharff et al. (2004). Fullerene-aminopropylaerosyl (fullerene C60-composite-l) was synthesized (Golub et al., 2003) by the introduction of aminopropyl chains oriented ad extra by amine groups (0.9 mM/g), to the surface layer of sihcon dioxide nanoparticles that were bound to fullerene C60 (0.12 mM/g) (Fig. 6.1). Fullerene-anthracenaliminopropylaerosyl (fullerene C60-composite-2) was composed also from anthraccnaliminc (0.2mM/g) that was introduced via azomethine condensation of aldehyde group of anthracenal with surface amino group. 

As well as the Bingel reaction and its modifications some more reactions that involve the addition-elimination mechanism have been discovered. 1,2-Methano-[60]fullerenes are obtainable in good yields by reaction with phosphorus- [44] or sulfur-ylides [45,46] or by fluorine-ion-mediated reaction with silylated nucleophiles [47]. The reaction with ylides requires stabilized sulfur or phosphorus ylides (Scheme 3.9). As well as representing a new route to l,2-methano[60]fullerenes, the synthesis of methanofullerenes with a formyl group at the bridgehead-carbon is possible. This formyl-group can be easily transformed into imines with various aromatic amines. 

Figure 3.10 Surfaces of e g. ITO or gold can be functionalized with Cg via amine addition to the fullerene.

The CgQ surface coverage was determined to be 2.0 10 mol cm . The monolayer can be further modified with monomeric amine reagents, which demonstrates the potential of the self-assembly process for growing three-dimensional fullerene structures. Different surfaces such as quartz. Si-oxide [105] or ITO [102] were coated with multilayers of fullerene up to stacks of 9 layers. An imidirectional electron transfer is possible across the fullerene mulhlayers [102]. Not only can multiple layers of fullerenes be connected to a certain surface but amino-functionalized can also serve as a linker between two different surfaces. 3-Aminopropyl-tethered glass plates could be linked via a Cgg layer to 3-aminopropyl covered zeolite crystals [106]. 

The facile addition of primary and secondary amines to Cjq has been used to synthesize polymer-bound Cjq [126-133]. Solutions of precursor polymers containing primary amino groups in the side chain or secondary amino groups in the main chain [132] were allowed to react with CgQ in a "buckybalT fishing process. Fullerene end capped polymers (type V) are accessible by reaction of amino-terminated polystyrene [128], poly(ethylene glycol) or poly(propylene glycol) [129] with Cgo. 

Reaction of 217 with Cjq leads to the amino-protected porphyrin-fulleropyrroli-dine, which can easily be deprotected to the corresponding amine [229, 277]. By further functionalization via amide coupling an easy access to extended donor-acceptor systems is possible. A carotene-porphyrin-fullerene triad was prepared by reaction of the amine with the appropriate carotene acid chloride. The motivation for the synthesis of all these donor-acceptor systems is the attempt to understand and imitate the photosynthetic process. On that score, a model for an artificial photosynthetic antenna-reaction center complex has been achieved by attaching five porphyrin cores in a dendrimer-like fashion to the fullerene [242]. 

A water-soluble Cj-symmetrical trisadduct of Cjq showed excellent radical scavenging properties in vitro and in vivo and exhibits remarkable neuro-pro tective properties [7,8]. It is a drug candidate for the prevention of ALS and Parldnsoris disease. Concerning the reaction mechanism, nucleophilic additions and radical additions are closely related and in some cases it is difficult to decide which mechanism actually operates [92]. For example, the first step in the reaction of f-eo with amines is a single electron transfer (SET) from the amine to the fullerene. The resulting amines are finally formed via a complex sequence of radical recombinations, deprotonations and redox reactions [36]. 

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