Fullerenes preparation route

Another route to the preparation of Cgo derivatives involves the reaction of a halogen derivative of diethylmalonate in the presence of a strong base with fullerenes, which results in a... 

There have been several developments in this area since this manuscript was prepared. The heat of combustion of corannulene was determined by microbomb combustion calorimetry and its gas-phase enthalpy of formation was estimated at 110.8 kcal/mol. All anionic oxidation states of corannulene were observed by optical absorption, EPR, and NMR spectroscopies. More support for the an-nulene-within-annulene model of the corannulene tetraanion was presented. An alternative pyrolysis route to corannulene was reported, as well as some attempts toward the synthesis of bowl-shaped subunits of fullerenes. And in contrast with previous semiempirical studies," ab initio calculations predicted a general concave preference for the metal cation binding to semibuckminsterfullerene 2%. ... 

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]. 

In this edition, we have incorporated new material in all the chapters and updated references to the literature. New sections dealing with porous solids, fullerenes and related materials, metal nitrides, metal tellurides, molecular magnets and other organic materials have been added. Under preparative strategies, we have included new types of synthesis reported in the literature, specially those based on soft chemistry routes. We have a new section covering typical results from empirical theory and electron spectroscopy. There is a major section dealing with high-temperature oxide superconductors. We hope that this edition of the book will prove to be a useful text and reference work for all those interested in solid state chemistry and materials science. 

Other methanofullerenes (not of the Bingel-type) were also found to be unstable after several reduction processes (68-70, Figure 23), [9-11] and under CPE they led to the isolation of [60]fullerene. A more recent study was conducted in THF to avoid the well-known reactivity of CH2CI2 towards the polyanions of C60 [72] and to explore the mechanisms involved during adduct removal [9b,10], Surprisingly, an electrochemically induced intermolecular adduct transfer was observed for the spiromethanofullerenes studied, and the regio-isomer distribution found in THF differed significantly from that obtained when the compounds are prepared by a direct synthetic route [10], The proposed mechanism for the formation of... 

In addition to C60, many other higher homologs have been prepared and characterized. Several synthetic routes to fullerenes have yielded gram quantities of pure C60 and C70, whereas C76, C78, Cso, Cs2, Cs4 and other fullerenes have been isolated as minor products. Figure 14.1.5 shows the structures of the following fullerenes C20, C50, C70, and two C78-isomers. 

Work on clusters also had its origin in this decade. Initial work led in following years to the production of the well-known Stuttgart pseudopoten-tials, which enables the realistic calculation of systems containing heavier elements. It also prepared the route to many studies on magic numbers in cluster chemistry and eventually to fullerenes and nanotubes. 

The [2-1-1] fragmentation of the precursors shown in Figure 6.2 also provides a potential route to monocyclic carbon clusters. Thus cyclic dehydro oligomers of diethynyl[4.4.1]propellatetraenes 6a,b incorporated in a fullerene structure have been prepared and their fragmentation was investigated by mass spectrometry [7]. MALDI TOF mass spectra of 6a,b exhibited peaks due to the stepwise loss of the fullerene fragments, leading to the formation of mono-fullerene adducts of C15 and C20. However, the... 

An alternative route to the pyrazolino[60]fullerenes involves use of nitrile imines as dipoles - these are prepared in a one-pot procedure starting from hydrazones. 

Formation of several pyrazolyl-pyrazolino[60]fullerene adducts (45a-c) from nitrile imines by use of this procedure has been described (Scheme 21.17) [53, 54]. The nitrile imines are generated in situ from the corresponding hydrazone 42a-c and NBS in the presence of EtsN and then reacted with Ceo (1) under the action of microwave irradiation, using a focused microwave oven. The route is simpler than the previously described method, which involved cycloaddition of Qo to nitrile imines prepared from the corresponding N-chlorobenzylidene derivatives [55]. 

Fullerene Nano-Composites Prepared via Soft-Chemistry Routes... 

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. 

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