Fullerene derivative

The most important classes of functionalized [60]fullerene derivatives, e.g. methanofullerenes [341, pyrrolidinofullerenes [35], Diels-Alder adducts [34i] and aziridinofullerene [36], all give rise to a cancellation of the fivefold degeneration of their HOMO and tlireefold degeneration of their LUMO levels (figure Cl.2.5). This stems in a first order approximation from a perturbation of the fullerene s 7i-electron system in combination with a partial loss of the delocalization. 

This behaviour also stands for functionalized [60]fullerene derivatives, with, however, a few striking differences. The most obvious parameter is the negative shift of the reduction potentials, which typically amounts to -100 mV. Secondly, the separation of the corresponding reduction potentials is clearly different. Wlrile the first two reduction steps follow closely the trend noted for pristine [60]fullerene, the remaining four steps display an enlianced separation. This has, again, a good resemblance to the ITOMO-LUMO calculations, namely, a cancellation of the degeneration for functionalized [60]fullerenes [31, 116, 117]. 

Prato M and Maggini M 1998 Fulleropyrrolidines a family of full-fledged fullerene derivatives Accounts. Chem. Res. 31 519-26... 

Diederich F, Jonas U, Gramlich V, Herrmann A, Ringsdorf H and Thilgen C 1993 Synthesis of a fullerene derivative of benzo[18]crown-6 by Diels-Alder reaction complexation ability, amphiphilic properties, and x-ray crystal structure of a dimethoxy-1,9-(methano[1, 2]benzomethano)fullerene[60] benzene clathrate Helv. Chim. Acta 76 2445-53... 

Guldi D M and Asmus K-D 1997 Photophysical properties of mono- and multiply-functionalized fullerene derivatives J. Phys. Chem. A 101 1472-81... 

Guldi D M, Hungerbuhler H and Asmus K-D 1999 Inhibition of oluster phenomena in truly water soluble fullerene derivatives bimoleoular eleotron and energy transfer prooesses J. Phys. Chem. A 103 1444-53... 

Irie K, Nakamura Y, Ohigashi H, Tokuyama H, Yamago S and Nakamura E 1996 Photooytotoxioity of water-soluble fullerene derivatives Biosci. Biotech. Biochem. 60 1359-61... 

Friedman S H, DeCamp D L, Si]besma R, Srdanov G and WudI F 1993 Inhibition of HIV-1 protease by fullerene derivatives model building studies and experimental verifioation J. Am. Chem. See. 115 6506-9... 

Maggini M, Done A, Scorrano G and Prato M 1995 Synthesis of a [60]fullerene derivative covalently linked to a ruthenium (II) tris(bipyridine) complex J. Chem. Soc., Chem. Commun. 845-6... 

The structure-property relations of fullerenes, fullerene-derived solids, and carbon nanotubes are reviewed in the context of advanced technologies for carbon-hased materials. The synthesis, structure and electronic properties of fullerene solids are then considered, and modifications to their structure and properties through doping with various charge transfer agents are reviewed. Brief comments are included on potential applications of this unique family of new materials. 

Fig. 2. By rolling up a graphene sheet (a single layer of ear-bon atoms from a 3D graphite erystal) as a cylinder and capping each end of the eyiinder with half of a fullerene molecule, a fullerene-derived tubule, one layer in thickness, is formed. Shown here is a schematic theoretical model for a single-wall carbon tubule with the tubule axis OB (see Fig. 1) normal to (a) the 6 = 30° direction (an armchair tubule), (b) the 6 = 0° direction (a zigzag tubule), and (c) a general direction B with 0 < 6 < 30° (a chiral tubule). The actual tubules shown in the figure correspond to (n,m) values of (a) (5,5), (b) (9,0), and (c) (10,5).

Recently, there has been considerable interest in fullerene derivatives. Finding the lowest energy isomer among a variety of choices of attachment is always an interesting and important question. In C50, all carbons are equivalent, but there are two types of C-C bonds ... 

Fig. 8.11 and was, in fact, the first definitive X-ray structural determination of a fullerene derivative. 

Fullerene derivatives such as CgoH, (p. 283), C60H2 (p. 287), and C61H2 (p. 287), and hyperco-ordinated non-classical carbonium ions (p. 290) have already been briefly mentioned. 

Electrochemistry of fullerene derivatives with heterocyclic fragments 98ACR593. 

Diels-Alder reactions of butadienes 13 and 2,3-di-w-propylbutadiene 14 with [60]-fullerene 15 led to several fullerene derivatives [15-17] (Scheme 2.10). Dienes 13 and 14 bore electron-donating groups, but the reactions also occurred with electron-withdrawing substituents due to the sufficiently low-energy LUMO of Ceo-... 

The ability of a dendritic shell to encapsulate a functional core moiety and to create a specific site-isolated microenvironment capable of affecting the molecular properties has been intensively explored in recent years [19]. A variety of experimental techniques have been employed to evidence the shielding of the core moiety and to ascertain the effect of the dendritic shell [19, 20]. Dendrimers with a fullerene core appear to be appealing candidates to evidence such effects resulting from the presence of the surrounding dendritic branches. Effectively, the lifetime of the first triplet excited state of fullerene derivatives... 

The dendritic effect evidenced for 1-8 might be useful to optimize the optical hmiting properties characteristic of fullerene derivatives. Effectively, the intensity dependant absorption of fuUerenes originates from larger absorption cross sections of excited states compared to that of the ground state [32], therefore the... 

Fullerene derivative 34 substituted with two long alkyl chains (solubilizing groups) and a carboxylic function was used as peripheral subunit for the constructions of the dendrons (Fig. 14). 

A review9 with more than 37 references includes an examination of symmetry groups and chirality conditions for C60 and C70 bonded to one or two metals in rf and/or rf fashion. Palladium and platinum rf complexes of C6o and C70 are described (novel synthesis, NMR spectra, electrochemistry) as well as first optically active organometallic fullerene derivatives. 

Itoh and coworkers [223] have shown that fullerene derivatives as 6/2-113, which to date have been prepared in a stepwise procedure, can be obtained in a three-component domino process by treatment of diynes 6/2-109, dimethylphenylsilane 6/2-110 and fullerene (C60) in the presence of a Rh-catalyst [223]. Interestingly, using maleic anhydride as dienophile failed to give the desired cycloadduct, whereas Cso -in spite of its strong tendency to form complexes with various transition metals [224] - never suppressed the catalytic silylative cyclization step to give the diene 6/2-112 (Scheme 6/2.24). 

Compound 318 used as dipolarophile with ylide 315 (Ar = 2,4,6-Me3C6H2) gives spiro compound 319 (Equation 46) <2001HCA3403>. The 1,3-dipolar cycloaddition of 3-oxo-2-pyrazolidinium ylide 315 (Ar = Ph) with buckminsterfullerene Cgo yields new heterocyclic fullerene derivatives <1995TL2457>. 

T. Da Ros and M. Prato, Medicinal chemistry with fullerenes and fullerene derivatives, Chem. Commun. (1999) 663-669. 

S. Marchesan, T. Da Ros, G. Spalluto, J. Balzarini, and M. Prato, Anti-HIV properties of cationic fullerene derivatives, Bioorg. Med. Chem. Lett., 15 (2005)... 

H. Ito, T. Tada, M. Sudo, Y. Ishida, T. Hino, and K. Saigo, [60]Fullerenoacetyl chloride as a versatile precursor for fullerene derivatives Efficient ester formation with various alcohols, Org. Lett., 5 (2003) 2643-2645. 

In addition, the use of appropriate hydrophilic constituents on the aldehyde or glycine reactants can result in excellent water solubility of the (To derivative. Two such modification arms can be added simultaneously to the pyrrolidine ring, thus providing a functional group for further conjugation and a hydrophilic arm for increased water solubility. PEG derivatives have been formed in this manner, which create highly soluble fullerene derivatives. 

Various commercial suppliers now offer fullerene derivatives with functionalities available for bioconjugation, including carboxylic and poly-hydroxylic derivatives, which are very hydrophilic and water-soluble (BuckyUSA, NanoLab, NanoNB, Nano-C, and Aldrich). 

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