Reaction of fullerene C60 with 2-azido-4,6-diphenylpyrimidine

The first representative of the pyrimidine-substituted [60]fullereno[1,2-b]aziridines was synthesized by the reaction of fullerene C₆₀ with 2-azido-4,6-diphenylpyrimidine. 2-(Azahomo[60]fullereno)-4,6-diphenylpyrimidine was found to be formed as a by-product. The electrochemical properties of the adducts were studied.     

Study of the factors determining the outcome of cycloaddition of isocyanurato-substituted azides to [60]fullerene

The final outcome of cycloaddition of isocyanuratoalkyl azides to C₆₀ depends on the temperature, the thermal stability of azides, the substituents in the isocyanurate ring, and the number of methylene groups in the alkyl radical. The thermal transformations of the monoadducts obtained were studied.     

Phosphorylated azahomo[60]fullerene: synthesis and electrochemical properties

A reaction of [60]fullerene with O,O-dibutyl azidophosphate affords a first representative of phosphorylated azahomo[60]fullerenes, which is easier to reduce electrochemically than the starting C₆₀.     

The synthesis of N-isocyanurato-substituted aziridino[1,2][60]fullerenes

N-Isocyanurato-substituted aziridino[1,2][60]fullerenes were synthesized for the first time as the main products by the reaction of isocyanurato-substituted azides with C₆₀. The thermal stability and the electrochemical behavior of the compounds synthesized were studied.     

Solvent and Concentration-Dependent Aggregation Study of C 60 Dyads and Multiads on Nonlinear Photonic Properties

We have studied the molecular self-assembly tendency of C₆₀(> DPAF-C₉) dyad, C₆₀(> DPAF-C₉)₂ triad, and C₆₀(> DPAF-C₉)₄ pentads in a solvent-dependent and concentration-dependent manner. The evaluation was performed by the particle-size measurements on molecular assemblies in either toluene or CS₂ using the dynamic light scattering technique. As a result, we observed a strong bimodal particle size distribution in most cases of the samples in both nonpolar solvents. In the instance of C₆₀(> DPAF-C₉) dyad, the first group of small nanoparticles exhibited a particle diameter size of 3.0–4.0 nm in good agreement with the estimated long axis length of C₆₀(> DPAF-C₉) (～ 2.7 nm), using 3D molecular modeling technique. Similar observation of a bimodal particle size distribution was detected on C₆₀(> DPAF-C₉)₄ pentads in toluene with a small nanoparticle diameter size of ～ 8.0 nm fitting well with the estimated dimension length of ～ 9.8 nm for loosely packed 3–6 C₆₀(> DPAF-C₉)₄ molecular assemblies. Furthermore, the tendency of forming large aggregation particles in a particle diameter of more than 4.0 μ m was significantly enhanced at a concentration of 1.0 × 10^–2 M.     

Electrochemical Studies of Calixarene-[60]Fullerene Inclusion Processes

[60]Fullerene (C₆₀)-calix[n]areneinteractions were studied in toluene:MeCN = 10:1 (v/v)using an electrochemical method. In the presence ofhomooxacalix[3]arenes and calix[5]arenes, bothE_pc and _pa shifted to the negativepotential, whereas they were scarcely affected by theaddition of calix[4]arenes. The₂values electrochemically determined forthe association with C₆₀ ^- are generallysmaller than the ₁ valuesspectroscopically determined for the association withC₆₀. The tendency indicates that thecharge-transfer-type interaction is one of thedriving forces for C₆₀ inclusion.thanks|Author for correspondence     

Ligand exchange reactions of fac -(dihapto-[60]fullerene) (dihapto-1,2- bis -(diphenylphosphino)ethane tricarbonyl chromium(0)

The complex fac-(η²-C₆₀)(η²-dppe)Cr(CO)₃ (dppe?=?1,2-bis(diphenylphosphino)ethane and C₆₀?=?[60]fullerene) reacts with piperidine (pip) to produce fac-(η²-C₆₀)(η¹-pip)₂Cr(CO)₃. The reactions are first order with respect to [?fac-(η²-C₆₀)(η²-dppe)Cr(CO)₃] under flooding conditions where [pip]???[?fac-(η²-C₆₀)(η²-dppe)Cr(CO)₃]. The pseudo-first order rate constant values (k _obsd) are [pip]-dependent. Curved (upward) plots of k _obsd versus [pip] and linear plots of k _obsd versus [pip]² indicate that the piperidine-assisted dppe displacement from fac-(η²-C₆₀) (η²-dppe)Cr(CO)₃ is second order with respect to [pip]. The proposed mechanism involves a [60]fullerene-stabilized intermediate.     

Reactions of the electrochemically generated dianion of [60]fullerene with bulky secondary alky bromides

Reactions of the electrochemically generated dianion of [60]fullerene (C₆₀^2?) with bulky secondary alkyl bromides exhibit different reaction behaviors. Reaction of C₆₀^2? with diphenylbromomethane gives rise to 1,2-C₆₀HR or 1,4-C₆₀R₂ (R?=?CHPh₂) adducts, while reaction of C₆₀^2? with diethyl 2-bromomalonate unexpectedly affords methanofullerene C₆₀?>?CR₂ (R?=?CO₂Et). Plausible reaction mechanisms have been proposed to explain the formation of the observed products.     

Higher trifluoromethylated derivatives of C60, C60(CF3)16 and C60(CF3)18: Synthesis, structure, and theoretical study

Three isomers of C₆₀(CF₃)₁₆ and one isomer of C₆₀(CF₃)₁₈ have been isolated by HPLC from a mixture prepared by trifluoromethylation of C₆₀ with CF₃I in a glass ampoule at 380-400 °C. The molecular structures of the four new compounds have been determined by means of X-ray single crystal diffraction and discussed in terms of mechanistic pathways of their formation and relative stability according to the DFT calculations.     

Heterocycloaddition of thermally generated 1,2-diaza-1,3-butadienes to [60]fullerene

Stable C₆₀-fused tetrahydropyridazine derivatives were synthesized through the hetero-Diels-Alder cycloaddition of C₆₀ with 1,2-diaza-1,3-butadienes, which were generated in situ by the thermal extrusion of sulfur dioxide from 2,5-dihydro-1,2,3-thiadiazole-1,1-dioxides.     

[60]富勒烯[2＋2]环加成反应的研究进展

[2＋2]环加成反应是对C₆₀进行化学修饰的重要反应之一, 重点从[2＋2]环加成的典型反应、主要试剂及反应机理等方面进行了综述.     

Synthesis and properties of polyamides with [60]fullerene in the main chain

A novel series of polyamides having [60]fullerene moieties in the main chain were synthesized by a direct polycondensation of [60]fullerenobis(acetic acid) or [60]fullerenobis(acetic acid)/isophthalic acid mixture with a diamine in the presence of triphenyl phosphite and pyridine. Various properties of the polyamides were characterized by means of IR, GPC, TGA, DSC, UV–visible, and photoluminescence. The molecular weight M_w of the [60]fullerene-containing polyamides was observed in the range from about 300,000 to 3,000; upon the changing of the ratio of [60]fullerenobis(acetic acid)/isophthalic acid in the starting mixture, the resulting M_w decreased with increasing the ratio. Most of the thermal and optical properties gradually changed as the ratio changed; the major optical absorption band in visible range exhibited a significant tailing, which shifted toward a longer wavelength, while the photoluminescence spectrum red-shifted with increasing [60]fullerene content. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3139–3146, 1998     

Investigation of the electrocatalytic behavior of halogenated acids at a C60-p-tert-butylcalix[8]arene chemically modified electrode

The C₆₀-p-tert-butylcalix[8]arene (represented as C₆₀-L) chemically modified electrode has two redox wave couples in mixed solvents of MeCN and water (3:2, v/v), corresponding to C₆₀-L in the solution originating from partial film dissolution and from film reaction, respectively. Both the C₆₀-L in the solution state and in the film state exhibit catalytic activity towards the reduction of halogenated acids. Electronic Publication     

Conformational analysis and regioisomerism of mono- and diadducts of O,O-diisopropyl isoxazolinophosphonate with C60

Theoretically, cycloaddition of two molecules of phosphorylated nitrile oxide to C₆₀ can give rise to 22 regioisomers. A simple convenient nomenclature was proposed for their classification based on the well-known Hirsh nomenclature. A combination of HPLC, semiempirical quantum-chemical PM3 calculations, and the dipole moment method demonstrated that the equatorial, trans-4(tt), and trans-3(tt) adducts are most probable.     

Anionic copolymerization of [60]fullerene with styrene initiated by sodium naphthalene

The novel C₆₀–styrene copolymers with different C₆₀ contents were prepared in sodium naphthalene-initiated anionic polymerization reactions. Like the pure polystyrene, these copolymers exhibited the high solvency in many common organic solvents, even for the copolymer with high C₆₀ content. In the polymerization process of C₆₀ with styrene an important side reaction, i.e., reaction of C₆₀ with sodium naphthalene, would occur simultaneously, whereas crosslinking reaction may be negligible. ¹³C-NMR results provided an evidence that C₆₀ was incorporated covalently into the polystyrene backbone. In contrast to pure polystyrene, the TGA spectrum of copolymer containing ∼ 13% of C₆₀ shows two plateaus. The polystyrene chain segment in copolymer decomposed first at 300–400°C. Then the fullerene units reptured from the corresponding polystyrene fragments attached directly to the C₆₀ cores at 500–638°C. XRD evidence indicates that the degree of order of polymers increases with the fullerene content increased in terms of crystallography. Incorporation of C₆₀ into polystyrene results in the formation of new crystal gratings or crystallization phases. In addition, it was also found that [60]fullerene and its polyanion salts [C₆₀ⁿ⁻(M⁺)_n, M = Li, Na] cannot be used to initiate the anionic polymerization of some monomers such as acrylonitrile and styrene, etc.© 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2653–2663, 1998     

A biphasic displacement of [60]fullerene from fac-(dihapto-[60]fullerene)(dihapto-1,10-phenanthroline) tricarbonyl molybdenum (0)

The Lewis bases (=L) triphenylphosphine (PPh₃) and tricyclohexyl phosphine (P(Cy)₃) displace [60]fullerene (C₆₀) from the complex fac-(η²-C₆₀)(η²-phen)Mo(CO)₃ (phen = 1,10-phenanthroline). The progress of the reactions was followed observing the decrease of the absorbance values at 440 nm and by monitoring the stretching carbonyl region from 1700 to 2100 cm⁻¹. The plots of absorbance vs. time were biexponential, indicative of a biphasic behavior, for reactions under flooding conditions where [L] ? [fac-(η²-C₆₀)(η²-phen)Mo(CO)₃]. The plot of absorbance vs. time consisted of two consecutive segments: the first segment of the plot was a decrease of absorbance with time followed by a second segment where the absorbance increased with time. The first segment of the biphasic plot was ascribed to the solvent-assisted displacement of C₆₀ from fac-(η²-C₆₀)(η²-phen)Mo(CO)₃ and the second segment to decomposition of the complex fac-(η¹-L)(η²-phen)Mo(CO)₃ produced in the first of the two consecutive reactions. The rate constant values corresponding to the first segment of the biphasic plot are independent of the chemical nature of L, the molar concentration of L, and the molar concentration of C₆₀ but dependent on the chemical nature of the solvent.     

Synthesis, electrochemical properties, and thermal transformations of 1-(5-nitropyrimidin-2-yl)[60]fullereno[1,2-b]aziridine

The reaction of fullerene C₆₀ with 2-azido-5-nitropyrimidine afforded 1-(5-nitropyrimidin-2-yl)[60]fullereno[1,2-b]aziridine, whose electrochemical reduction proceeds more easily than the reduction of nonmodified C₆₀. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 484–488, March, 2006.     

Effective Mechanochemical Synthesis of [60]Fullerols

Abstract

[60]Fullerols which show an average composition of C₆₀(OH)_27.2 were synthesized effectively in high yield under the high-speed vibration milling (HSVM) conditions in air at room temperature.     

Addition reactions of fluoroalkanesulfonyl azides to [60] fullerene under thermal or microwave irradiation condition

The reactions of [60] fullerene with excess fluoroalkanesulfonyl azides R_fSO₂N₃ in o-dichlorobenzene under thermal or microwave irradiation condition afforded monoadduct opened [5,6]-bridged azafulleroids. While, similarly treatment of 2,2,2-trifluoroethyl azides CF₃CH₂N₃ with C₆₀ gave two monoadducts, i.e., opened [5,6]-bridged azafulleroids, closed [6,6]-bridged Aziridino-fullerene, and some multi-addition product. A general mechanism for these addition reactions was proposed.     

Synthesis of [60]fullerene-functionalized rotaxanes

Synthesis of [60]fullerene (C₆₀)-functionalized rotaxanes via Diels-Alder reactions with C₆₀ is described. Diels-Alder reaction of C₆₀ and sulfolene moiety as masked diene attached on the wheels of rotaxanes results in high yields of C₆₀ incorporation. Rotaxanes are prepared by tin-catalyzed urethane-forming end-capping reaction with isocyanate of pseudorotaxane having the wheel carrying C₆₀ functionality as introduced by the Diels-Alder reaction. The Diels-Alder reaction was accomplished as end-capping reaction between C₆₀ and pseudorotaxane bearing sultine moiety as masked diene on the axle terminal. A variety of C₆₀-containing [2]rotaxanes was prepared in moderate to good yields by these Diels-Alder protocols.