Highly selective reactions of C60Cl6 with thiols for the synthesis of functionalized [60]fullerene derivatives

Chlorofullerene C(60)Cl(6) undergoes highly selective reactions with thiols forming compounds C(60)[SR](5)H with high yields. These reactions open up straightforward synthetic routes to many functionalized fullerene derivatives, e.g. water-soluble compounds showing interesting biological activities.     

Regio- and diastereo-controlled synthesis of bis(formylmethano)[60]fullerenes and their application to the formation of [60]fullerene pearl-necklace polyimines

The tether-directed method was firstly applied to the biscyclopropanation of [60]fullerene via the addition-elimination reaction of bis(sulfonium ylide)s to give bis(formylmethano)[60]fullerenes with satisfactory regio- and stereoselectivity. The equatorial-bisadduct thus obtained was used for the polycondensation with an aromatic diamine to afford the corresponding pearl-necklace polyimine with satisfactorily high degree of polymerization.     

New trifluoromethylated derivatives of [60]fullerene, C60(CF3)n with n = 12 and 14

New isomers of C(60)(CF(3))(12) and C(60)(CF(3))(14) have been isolated from mixtures obtained via reaction of C(60) or S(6)-C(60)(CF(3))(12) with CF(3)I; they were characterized by single crystal XRD study and investigated theoretically by means of DFT calculations.     

Facile fullerene modification: FeCl3-mediated quantitative conversion of C60 to polyarylated fullerenes containing pentaaryl(chloro)[60]fullerenes

A facile, one-step reaction using inexpensive reagents has been developed for functionalization of [60]fullerene, where the reaction of C(60) with FeCl(3) in chlorobenzene proceeded at 25 °C with 100% conversion, yielding a mixture of polyarylated products containing pentaaryl(chloro)[60]fullerene, C(60)(C(6)H(4)Cl)(5)Cl (up to 29%) and other polyarylated fullerenes (number of aryl groups is in a range from 5 to 10).     

Arbuzov chemistry with chlorofullerene C(60)Cl(6): a powerful method for selective synthesis of highly functionalized [60]fullerene derivatives

We report Arbuzov-type reactions of chlorofullerene C(60)Cl(6) with trialkyl phosphites producing highly functionalized fullerene derivatives C(60)[P(O)(OR)(2)](5)H with high yields. The designed family of [60]fullerene phosphonic acids and their esters showed unusual properties which might find valuable material science applications.     

Lewis acid promoted preparation of isomerically pure fullerenols from fullerene peroxides C60(OOt-Bu)6 and C60(O)(OOt-Bu)6

Fullerene mixed peroxides C60(t-BuOO)6 and C60(O)(t-BuOO)6 react with Lewis acids to form various fullerenols through the partial fragmentation of t-BuOO groups. Two monohydroxyl fullerenols with the general formula C60(OH)(t-BuOO)5 and six monohydroxyl fullerenols with the general formula C60(O)(OH)(t-BuOO)5 were prepared, which are essentially the same except the location of the OH group. An additional reaction of the monohydroxyl fullerenols gave bis- and trishydroxyl fullerenols. Single-crystal X-ray structures have been obtained for the two monohydroxyl fullerenols. Other compounds are characterized by chemical correlation and their spectroscopic data. Cuprous bromide could protect the most reactive t-BuOO group from being attacked by stronger Lewis acids. The proposed mechanism mainly involves Lewis acid induced heterolysis of the peroxo O-O bond.     

Optically active diastereomers of N-methyl-1??-(?)-myrtenylpyrrolidino[3??,4??:1,9](C60-J h)[5,6]fullerenes: synthesis, electrochemical and chiroptical properties

Novel optically active diastereomers of N-methyl-1??-myrtenylpyrrolidino[3??,4??:1,9]-(C₆₀-J _h)[5,6]fullerenes were synthesized. Reaction of the latter with methyl iodide yielded the corresponding quaternary ammonium salts. Individual diastereomers were isolated, their chiroptical and electrochemical properties were studied.     

Radical functionalization of [60]fullerene and its derivatives initiated by the C(CF3)2C6H4F radical

It was found that the 2-(p-fluorophenyl)hexafluoroisopropyl radical produced by thermal dissociation of the Polishchuk dimer [C(CF₃)₂C₆H₄F]₂ can withdraw, under mild conditions, the H atom from the methyl group of toluene and mesitylene to form the corresponding radicals, whose addition to [60]fullerene occurs more selectively than in the case of photochemical production of these radicals. Dynamics of the step-by-step multiaddition of the radicals to C₆₀ was studied by ESR. It was found that the addition of benzyl radicals affords adducts containing from 3 to 5 benzyl groups, whereas no spin-adducts with five addends were observed for more bulky 3,5-dimethylphenylmethyl radicals. The interaction of 3,5-dimethylphenylmethyl radicals with the metal complexes (η²-C₆₀[IrH(CO)(PPh₃)₂] and (η²-C₆₀[Pd(PPh₃)₂] was studied for the first time. It was shown that the palladium derivative undergoes only demetallation. In the case of the Ir complex, up to 3 radicals add to the fullerene ligand in the same hemisphere where the transition metal is coordinated. The reaction rates are ∼5 times lower than those for C₆₀. The ability of 2-(p-fluorophenyl)hexafluoroisopropyl radicals to dehydrogenate C₆₀H₃₆ was found. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1119–1123, June, 1999.     

Regioselective synthesis of [60]fullerene eta 5-indenide R3C60- and eta 5-cyclopentadienide R5C60- bearing different R groups

Treatment of a 1,7-diorgano[60]fullerene with Grignard reagents or organocopper reagents affords a [60]fullerene indenide or a [60]fullerene cyclopentadienide regioselectively in good to excellent yields. These reactions gave an insight into the reaction mechanism of the organocopper penta-addition reaction of [60]fullerene, giving [60]fullerene cyclopentadienide in quantitative yield.     

(C26H40N2O4)[Ln(NO3)5H2O]的合成及其铕缔合物的晶体结构

合成了4个新型的稀土化合物(C₂₆H₄₀N₂O₄)[Ln(NO₃)₅H₂O](Ln=Pr,Nd,Sm,Eu),采用元素分析和红外光谱表征,用四圆衍射仪测定了其中(C₂₆H₄₀N₂O₄)[Eu(NO₃)₅H₂O]的晶体结构,属三斜晶系,P1空间群,晶胞参数:α=0.9100(4)nm,b=1.3560(3)nm,c=1.6463(4)nm;α=68.62(2)°,β=74.84(3)°,γ=87.50(2)°;Z=2.中心铕离子由5个硝酸根的10个氧原子和1个水分子中的氧原子配位,配位数是11.1,7,10,16-四氧-4,13-二氮杂-N,N'-二苄基环十八烷(N,N'-二苄基穴醚(2,2))未参与配位.     

Ring-opening reaction of tetrahydrofuran on the penta(organo)[60]fullerenes: synthesis of hydroxybutyl, methacrylate, and norbornene derivatives

Ring-opening reaction of tetrahydrofuran takes place on penta(methyl)- and penta(n-butylphenyl)[60]fullerenes in the presence of chlorotrimethylsilane giving penta(organo)fullerene hydroxybutyl derivatives, C₆₀R₅(C₄H₈OH) (R = Me, ⁿBuC₆H₄). The hydroxyl groups were further transformed into methacrylate and norbornylcarbonyloxy groups via esterification with the corresponding acid chlorides. The methacrylate derivative, penta(methyl)[60]fullerenylbutyl methacrylates was crystallographically characterized.     

(C_2H_(10)N_2)[H_3As_3O_(10)]的水热合成与晶体结构

采用中温水热方法合成了新化合物(C2H10N2)[H3As3O10].利用X射线粉末衍射仪、红外光谱仪、热重分析仪及X射线单晶衍射仪表征了产物的结构.结果表明:该化合物属于单斜晶系,P2(1)/n空间群;晶胞参数为a=0.808 3(6)nm,b=1.446 9(9)nm,c=0.892 0(8)nm,β=98.16°,V=1.032 7(14)nm3,Z=4,F(000)=864,R1=0.025 3,wR2=0.093 4.其化学式为C2H13As3N2O10,分子量Mr=449.90.该化合物是由有机胺阳离子支撑的第一个具有一维链状结构的砷酸盐化合物,相邻的砷酸盐链通过AAAA堆积方式形成三维拓扑扩展结构.     

New low-temperature method for joint synthesis of C60 fullerene and new carbon molecules in the form of C3-C15 and quasi-fullerenes C48, C42, C40

Method for joint synthesis of C₆₀ fullerene and new carbon molecules in the form of C₃-C₁₅ and quasifullerenes C₄₈, C₄₂, and C₄₀, alternative to arc-discharge technique, was developed for the first time. The process of fullerenization of benzene molecules into carbon molecules is performed at comparatively low (～1000°C) temperatures. It is shown that C₃-C₁₈ nanoclusters are generated as main components of a monoatomic carbon vapor under conditions that rule out sublimation of carbon. Crystalline substances containing exceedingly active small carbon molecules were synthesized for the first time. The products of benzene fullerenization were studied by methods of mass-spectrometric analysis, electron-probe X-ray microanalysis, and optical microscopy.     

Photoelectron spectroscopy and electronic structures of fullerene oxides: C60Ox- (x = 1-3)

We report a photoelectron spectroscopy (PES) study on a series of fullerene oxides, C60Ox- (x = 1-3). The PES spectra reveal one isomer for C60O-, two isomers for C60O2, and multiple isomers for C60O3-. Compared to C60, the electronic structures of C60Ox are only slightly perturbed, resulting in similar anion photoelectron spectra. The electron affinity of C60Ox was observed to increase only marginally with the number of oxygen atoms, x, from 2.683 eV for C60, to 2.745 eV for C60O, and 2.785 eV/2.820 eV for C60O2 (two isomers). We also carried out theoretical calculations, which confirmed the observed isomers and showed that all the fullerene oxides are in the form of epoxide. The PES and theoretical calculations, as well as molecular orbital analysis, indicate that addition of oxygen atoms to the C60 cage only modifies the local carbon network and leave the rest of the fullerene cage largely intact geometrically and electronically.     

Multiple Adducts of C60 by Tether-Directed Remote Functionalization and synthesis of soluble derivatives of new carbon allotropes Cn(60+5)

A comprehensive series of multiple adducts of C₆₀ was prepared by tether-directed remote functionalization. When the tether-reactive-group conjugates 2 and 10 were attached to methano[60]fullerenecarboxylic acid ( = cyclopropafullerene-C₆₀-I_h-carboxylic acid) and C₆₀, respectively, the e-bis-adducts 4 and 9 (Schemes 1 and 2) were obtained with complete regioselectivity as predicted by semi-empirical PM3 calculations (Fig. 2). Attachment of the anchor-tether-reactive-group conjugate 13 to C₆₀ by Bingel reaction, followed by double intramolecular Diels-Alder cycloaddition afforded the tris-adduct 12 (Scheme 3). Starting from 12 , a series of selective e-additions led to the tetrakis-adducts 16 and 19 (Scheme 4), pentakis-adducts 20 – 23 (Scheme 5), and, ultimately, to hexakis-adducts 24 and 25 (Scheme 6), and 29 and 30 (Scheme 7) with a pseudo-octahedral addition pattern on the fullerene core. Oxidative cyclization of diethynylmethanofullerene 30 under Eglinton-Glaser conditions afforded the trimeric and tetrameric acetylenic macrocycles 26 , with three, and 27 , with four appended C₆₀ moieties, respectively (Scheme 8). These multinanometer-sized compounds are the first soluble derivatives of C₁₉₅ and C₂₆₀, two members of a new class of fullerene-acetylene hybrid C-allotropes with the general formula C_{n(60 + 5)}. The matrix-assisted laser-desorption time-of-flight mass spectra of 26 and 27 showed a remarkable fragmentation; the sequential loss of fullerene spheres led to the formation of ions corresponding to mono-fullerene adducts of the cyclocarbons cyclo-C₁₅ and cyclo-C₂₀ (Fig. 4). Large solvent effects were observed in the Bingel addition of 2-bromomalonates to higher adducts of C₆₀, with the use of polar solvents enhancing the reaction rate without loss of regioselectivity. Experimental evidence for the enhanced reactivity of e_face over e_edge bonds was obtained, which had previously been predicted in computational studies. The correlated series of mono- to hexakis-adducts of C₆₀ allowed identification of the changes in reactivity and physical properties that occur, when the conjugated π-electron chromophore of the fullerene is reduced as a result of increasing functionalization; this analysis is the subject of the directly following paper.     

The synthesis of 2-chloro-1-β-D-ribofuranosyl-5,6-dimethylbenzimidazole and (certain related derivatives

The synthesis of 2-chloro-1-(β-D -ribofuranosyl)-5,6-dimethylbenzimidazole (3b) has been accomplished by a condensation of 1-trimethylsilyl-2-chloro-5,6-dimethylbenzimidazole (1) with 2,3,5-tri-O-acetyl-D -ribofuranosyl bromide (2) followed by subsequent deacetylation. Nucleophilic displacement of the 2-chloro group from 3b has furnished several interesting 2-substituted-1-(β-D -ribofuranosyl)-5,6-dimethylbenzimidazoles. 1-(β-D -Ribofuranosyl)-5,6-dimethylbenzimidazole (5) and 1-(β-D -ribofuranosyl)-5,6-dimethylbenzimidazole-2-thione (4) were prepared from 3b. Alkylation of 4 furnished certain 2-alkylthio-1-(β-D -ribofuranosyl)-5,6-dirnethylbenzimidazoles and oxidation of 4 with alkaline hydrogen peroxide produced 1-(β-D -ribofuranosyl)-5,6-dimethylbenzimidazole-2-one D The assignment of anomeric configuration for all nucleosides reported is discussed.