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.     

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.     

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     

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     

Reactions of [60]fullerene with 2-azidopyrimidines

The reaction of [60]fullerene with 2-azidopyrimidines affords fullerenoimidazopyrimidines, whose electron affinity is higher than that of nonmodified C₆₀.     

Energies of Charge Transfer for the Supramolecular Complexes of [60]- and [70]Fullerenes with a Series of meso-Tetraphenylporphyrins in the Solution State

Supramolecular complexes of [60]- and [70]fullerenes with various meso-tetraphenylporphyrins in toluene solutions have been studied by electronic absorption spectroscopy. Charge transfer (CT) absorption bands are observed in the visible region. Vertical ionization potentials (I _D ^V) of the meso-tetraphenylporphyrins are reported from a study of EDA interaction of these porphyrins with a number of electron acceptors like o-chloranil, p-chloranil, 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) and vitamin K. The dependence of the CT transition energy on the donor ionization potential has been utilized to estimate the vertical electron affinities (E _A ^V) of [60]- and [70]fullerenes in solution. The value of E _A ^V for [60]fullerene is found to be 0.10 eV lower in magnitude than that of [70]fullerene. We have extracted degrees of CT, and oscillator and transition dipole strengths of the fullerenes/meso-tetraphenylporphyrins complexes. The experimental results show that the CT complexes studied here have a neutral character in their ground states. Electronic coupling elements have been determined for fullerene/meso-tetraphenylporphyrin complexes. Values of the solvent reorganization energy indicate that the electron transfer process takes place at a faster rate in the case of [70]fullerene/meso-tetraphenylporphyrin complexes.     

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.     

Direct Formation of Cycloadducts Between Fullerenes and Amino Acids Through Electron-Transfer Processes

Abstract

The reactions of [60]fullerene and amino acids in the absence of aldehyde in o-dichlorobenzene (ODCB) at 150 °C have been investigated. Fulleropyrrolidines 1 [C₆₀(CH₂N(CH₃)CHC₆H₂(NO₂)₃)], 2 [C₆₀(CH₂N(CH₃)CH₂)], 3 [C₆₀(CH₂NHCH₂)], and 5a–b [C₆₀(RCHNHCHR), R?CH₃ (5a), R?CH₂Ph (5b)] were obtained in moderate yields from the reactions of C₆₀ and corresponding amino acids. The reaction of C₇₀ and N-methylglycine in the absence of aldehyde was also studied and was found to give the positional isomers of N-methyl[70]fulleropyrrolidines 6 (1,9-isomer) and 7(7,8-isomer). All products were fully characterized by ultraviolet–visible, Fourier transform–infrared (FT-IR), NMR, and mass spectrometry. The reactions were also carried out in the dark to exclude the possible interference of the photoinduced reactions, and almost the same yields of products were obtained.     

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     

Photophysical Properties and Photoinduced Electron Transfer between[60]Fullerene—containing Cyclic Sulphoxide [C60—C60H8SO]and Tetrathiafulvalene（TTF） by Laser Flash Photolysis

Photoinduced electron transfer(PET) processes between C60-C6H8SO and Tetrathiafulvalene(TTF) have been studied by nanosecond laser photolysis.Quantrm yiekds(φet) and rate constants of electron transfer(ket) from TTF to excited triplet state of[60] fullerene-containing cyclic sulphoxide in benzonitrile(BN) have been evaluated by observing the transient absorption bands in the NIR region.With the decay of excited triplet state of [60]fullerene-containing cyclic suplhoxide,the rise of radical anion of [60]fullerene-containing cyclic sulphoxinde is observed.     

Synthesis of a single isomer of the bis-adduct of isocyanurato-substituted azide with [60]fullerene

A single di(azahomo)[60]fullerene isomer was prepared for the first time by the reaction between [60]fullerene and isocyanurato-substituted azide. The structure of the product was established by ¹H and ¹³C NMR, UV, and IR spectroscopy.     

单加成环丙烷富勒烯膦酸酯衍生物的合成与电化学性能

在Mn(OAc)₃•2H₂O催化下, C₆₀分别和亚甲基二膦酸四乙酯、氰基亚甲基膦酸二乙酯或乙氧羰基亚甲基膦酸二乙酯在氯苯中回流, 生成3个单加成环丙烷富勒烯膦酸衍生物C₆₀C(R)PO(OEt)₂ [1, R＝PO(OEt)₂; 2, R＝COOEt; 3, R＝CN]. 与以前报道的Bingel反应法相比, 该方法副产物少并且缩短了反应时间. 采用循环伏安法发现1, 2的还原电位相对于C₆₀发生负移, 而3的还原电位相对于C₆₀却正移40 mV, 表明引入象氰基一样具有很强吸电子能力的取代基团, 可以改善富勒烯球的电化学性能, 合成电子接受能力较强的富勒烯衍生物.     

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.     

Synthesis of a novel [60]fullerene pearl-necklace polymer,poly(4,4′-carbonylbisphenylene trans-2-[60]fullerenobisacetamide)

A novel [60]fullerene pearl-necklace polymer, poly(4,4′-carbonylbisphenylene trans-2-[60]fullerenobisacetamide), was synthesized by a direct polycondensation of trans-2-[60]fullerenobisacetic acid with 4,4′-diaminobenzophenone in the presence of large excesses of triphenyl phosphite and pyridine. In the present polymer, [60]fullerene pearls and diamine linkers were attached to each other by methano-carbonyl connectors. The molecular weight M_w of the polymer was determined to be 4.5 × 10⁴ on the basis of the TOF-MS, and a GPC analysis of the polymer using polystyrene standards showed a weight-average molecular weight of 5.3 × 10⁴. The UV-vis spectrum of the resultant polymer in N,N-dimethylacetamide (DMAc) exhibited a broad absorption (λ_max 310 nm, ε 2.1 × 10⁴ L · mol⁻¹ · cm⁻¹), tailing to longer wavelengths, and a fluorenscence peak centered at 550 nm was observed in DMAc. There was observed a large downfield-shift of the cyclopropane methyne proton in the ¹H-NMR spectra from 4.57 ppm of the ethyl ester to 5.78 ppm of the polyamide. These observations indicate that the present polyamide is a high-molecular-weight [60]fullerene pearl-necklace polymer and that the cyclopropane rings are efficient to make the [60]fullerene cages and the diamine components conjugatable. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3632–3637, 1999     

Influence of alkali and alkaline earth ions on the O -alkylation of the lower rim phenolic-OH groups of p-tert -butyl-calix[4]arene to result in amide-pendants: Template action of K+ and the structure of K+ bound tetra-amide derivative crystallized with a p-tert -butyl-calix[4]arene anion

Role of alkali and alkaline earth ions on the formation of calix[4]arene-amide derivatives through O-alkylation of the lower rim phenolic-OH groups in general and template action of K⁺ in particular have been explored. Na⁺ and K⁺ ions among alkali, and Ca²⁺ and Sr²⁺ ions among alkaline earth have shown tetra-amide derivatives bound to metal ion species. Among all these, potassium salts act as template and yields a K⁺ bound tetra-amide derivative where the charge is counter balanced by a calix[4] arene-monoanion and the product is crystallographically characterized. Change in the amide precursor used in these O-alkylation reactions has no effect on the type of the amide derivative formed. Also demonstrated is a direct one-step reaction for the preparation of 1,3-di-amide derivative in high yield and low reaction period using CsHCO₃.     

Exploring the photoinduced electron transfer reactivity of aza[60]fullerene iminium cation

Photolysis of (C₅₉N)₂ solutions in the presence of neutral π-donors, such as arenes and electron-rich alkenes leads to a series of novel aza[60]fullerene monoadducts. The key step of the reaction involves a photoinduced electron transfer from the donor molecule to the iminium cation of aza[60]fullerene, followed by radical coupling of the resulting aza[60]fullerenyl radical with an intermediate stabilized radical derived from the substrate. This type of reactivity has been proven efficient with arenes having oxidation potential higher than about 1.5 V. Simple olefins, such as tri- and tetra-methylethylene, as well as cyclohexene, can also participate in this kind of photoinduced electron transfer-initiated reaction with C₅₉N⁺, affording the corresponding aza[60]fullerene derivatives. In the case of 2-methoxyprop-1-ene, 2,4-hexadiene, and β,β-dimethylstyrene, [2+2] cycloaddition reactions with the aza[60]fullerene carbon shell dominate, leading to a mixture of unidentified multiadducts.     

Modification of fullerene C60 by phosphorylated diazo compounds

New representatives of phosphorylated methanofullerenes were prepared by the reactions of [60]fullerene with O,O-diethyl -diazoethyl- and O,O-diethyl -diazobenzylphosphonates. Electrochemical reduction of the above-mentioned products proceeded stepwise and reversibly.     

Charge Transfer in the Electron Donor-Acceptor Complexes of [60]Fullerene/PM567 and [70]Fullerene/PM567

UV-Vis spectroscopic investigations of electron donor-acceptor complexes of [60]- and [70]fullerenes with a well-known laser dye, viz., 4,4-difluoro-1,3,5,7,8-pentamethyl-2,6-diethyl-4-bora-3a,4a-diaza-s-indecene (PM567), are reported in toluene solutions. Absorption bands due to charge transfer (CT) transitions have been located in the visible region. The vertical ionization potential of PM567 has been determined utilizing Mulliken’s equation. A possible mechanism for the interaction between the electronic subsystems of [60]- and [70]fullerenes with PM567 is discussed. Oscillator strengths, resonance energies and electronic coupling elements of the CT complexes were estimated. Formation constant data and ab initio calculations suggest that PM567 binds more tightly with [60]fullerene compared to [70]fullerene.     

Oxidation of fullerene C<Subscript>60</Subscript> with the system aluminum tri-<Emphasis Type="Italic">tert</Emphasis>-butoxide—<Emphasis Type="Italic">tert</Emphasis>-butyl hydroperoxide

Oxidation of fullerene C₆₀ with the system aluminum tri-tert-butoxide-tert-butyl hydroperoxide, in which electron-excited dioxygen is generated, gave a complex mixture of fullerene oxides C₆₀O _x (x = 1–6). The pathways of their formation were proposed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 296–300, February, 2008.     

Synthesis of Starburst Oligoanilino[60]fullerene and Poly(Dimethylsiloxane) Triblock Copolymers

Abstract

A new synthetic approach for the fabrication of core‐shell like conducting elastomers was described. The approach utilized the facile intermolecular self‐assembly of poly(dimethylsiloxane) (PDMS) in DMSO leading to formation of a core particle, while soluble oligoaniline (A _x ) segments dispersed in the solution phase resembling a shell overlayer for building the morphology. This morphology was demonstrated by bis[penta(tetraanilinofullereno)] bis(aminopropyl)poly(dimethylsiloxane) [PDMS‐(F5A₄)₂] triblock co‐oligomers synthesized using a functionalized C₆₀ derivative as a linker. Observation of ¹H NMR spectroscopic responses on the PDMS particle formation in DMSO‐d ₆ is consistent with the proposed core‐shell geometry with oligoaniline moieties located at the shell overlayer.