The Influence of Ir and Pt Addition on the Synthesis of Fullerenes at Atmospheric Pressure

The addition of metallic Ir and Pt to a fullerene-forming, atmospheric-pressure plasma reactor was found to influence the generation of carbonaceous products. It was observed that the added metals were efficiently dispersed into the plasma and that their presence increased the yield of fullerenes. The addition of Ir led to a noticeable shift in the fullerene distribution towards C₆₀, whereas the addition of Pt increased the proportion of C₆₀ oxides and decreased the proportion of higher fullerenes. Addition of Ir also caused a reduction of the soot particle size and the formation of a considerable quantity of carbon nanotubes.     

Synthesis and characterization of a new water-soluble endohedral metallofullerene for MRI contrast agents

Water-soluble amino acid derivatives of gadolinium (Gd) endohedral metallofullerenes (AAD-EMFs), Gd@C₈₂O_m(OH)_n(NHCH₂CH₂COOH)_l (m ≈ 6, n ≈ 16 and l ≈ 8) are synthesized by a direct reaction of the pure endohedral metallofullerene Gd@C₈₂ with an excess of alkaline solution of β-alanine. The structure of the AAD-EMFs is characterized by FTIR, XPS and laser-desorption time-of-flight (LD-TOF) mass spectrometries. Water proton relaxivity analysis indicates that the longitudinal relaxivity R₁ (the effect on 1/T₁, 9.1 mM⁻¹ s⁻¹) of AAD-EMFs is higher than that of the commercial MRI contrast agent, Magnevist (gadolinium-diethylenetriaminepentaacetic acid, Gd-DTPA, 5.6 mM⁻¹ s⁻¹). The MRI phantom studies are performed to confirm the high efficiency of this sample as MRI contrast agents.     

Self-assembly of C60 containing poly(methyl methacrylate) in ethyl acetate/decalin mixtures solvent

[60]Fullerene (C₆₀) was mono-substituted with well-defined poly(methyl methacrylate) (PMMA-b-C₆₀) using the atom transfer radical polymerization (ATRP) technique. The self-assembly behaviors of PMMA-b-C₆₀ in ethyl acetate (EA) and decalin mixtures were studied using laser light scattering (LLS) and transmission electron microscopy (TEM). Homogeneous solutions of PMMA-b-C₆₀ can be obtained in the solvent mixtures containing more than 40 wt% EA, where the molar ratio of decalin to EA is close to 1. For each solvent mixture, unimers coexist with micelles and large aggregates. The sizes of PMMA-b-C₆₀ micelles and aggregates are independent of polymer concentration, confirming that they are produced via the closed association mechanism. For the various solvent mixtures, the weight-averaged molecular weights, M_w of the PMMA-b-C₆₀ aggregates range from 4.1×10⁷ to 12.5×10⁷ g/mol. The hydrodynamic radii of the large aggregate, R_h, vary from 90 to 136 nm, while the z-averaged radii of gyration, R_g, range from 210 to 311 nm. The R_g/R_h value for each solvent mixture is ∼2.3, which is independent of decalin contents in the mixed solvents. The morphological study using the transmission electron microscope suggests that the large aggregates are composed of porous large compound micelles (LCM) in solution.     

The bipartite edge frustration of graphs under subdivided edges and their related sums

The bipartite edge frustration of a graph G, denoted by φ(G), is the smallest number of edges that have to be deleted from G to obtain a bipartite spanning subgraph of G. This topological index is related to the well-known Max-cut problem, and has important applications in computing stability of fullerenes. In this paper, the bipartite edge frustration of an infinite family of fullerenes is computed. Moreover, this quantity for four classes of graphs arising from a given graph under different types of edge subdivisions is investigated.     

C_(60)衍生物的放射性碘标记

富勒烯Ｃ6 0 是由 60个碳原子组成的球型分子 ,包含 1 2个五元环和 2 0个六元环 ,直径为0 .71ｎｍ。独特的结构赋予了它特殊的物理、化学和生物性质。Ｃ6 0 是一个优良的电子接受体 ,通过光诱导产生单重态氧的效率高达 1 0 0 % ,被喻为“单重态氧的发生器”。它极易与游离基反应 ,又被喻为“吸收游离基的海绵”。它具有 3 0个双键 ,可以发生许多有机反应 ,连接各种化学药物 ,是药物设计的理想载体[1] 。Ｃ6 0 仅溶于一些非极性和弱极性的有机溶剂 ,在水等极性溶剂中不溶。富勒烯作为药物载体 ,首先要制成水溶性衍生物。更为重要的是还必须了…     

C60 Dimers Revisited

Abstract

Several dimers: C₁₂₀, C₁₄₀, C₁₃₀ and their oxygen‐containing derivatives as well as some oligomers or polymers of the well known spherical fullerenes have been synthesized so far. Some of the formulas attributed to such compounds represent the first steps in a more complex fate leading to trivalent capped tubulenes. Such a way could even be followed by functionalized fullerenes. A detailed network transformation is given for C₆₀ and its mono‐ and di‐epoxy derivatives. Semiempirical calculations support the presented findings.     

Application of fullerene C60 nano-oil for performance enhancement of domestic refrigerator compressors

In this work, the fullerene C₆₀ nano-oil is proposed as a promising lubricant to enhance the performance of domestic refrigerator compressors. The stability of fullerene C₆₀ nanoparticles dispersed in a mineral oil and the lubrication properties of the nano-oil were investigated experimentally. It was confirmed that the nanoparticles steadily suspend in the mineral oil at stationary conditions for a long period of time. The friction coefficients of the nano-oil significantly decrease with increasing the concentration of nanoparticles in the mineral oil, especially at the lower applied loads. The friction coefficients of the nano-oil with the concentration of 1–3 g L⁻¹ are 12.9–19.6% lower than that of pure mineral oil. The applications of the nano-oil with the specific concentration of 3 g L⁻¹ to two domestic refrigerator compressors were examined by compressor calorimeter experiments. The results shows the COPs of two compressors were improved by 5.6% and 5.3%, respectively, when the nano-oil was used instead of pure mineral oil.     

Theoretical study of charge transfer mechanism in fullerene-phenyl-phenothiazine compound: A real-space analysis

Quantum chemistry methods as well as two-dimensional (2D) and three-dimensional (3D) real-space analysis have been conducted to study the photo-induced intramolecular charge-transfer (ICT) and excited state properties of fullerene-phenylphenothiazine, which has recently been developed for solar cells. Firstly, we obtained the energy levels and spatial distributions of HOMO/LUMO, energy gap (ΔEH-L) and excitation energies on the basis of quantum chemistry study. Secondly, two-dimensional (2D) and three-dimensional (3D) real-space analysis were used to visualize the CT process and to reveal the nature of the excited states. In the above analyses, the 2D real-space analysis of the transition density matrix provided information about the electron-hole coherence, and the 3D real-space analysis of charge difference density enabled the visualization of the orientation and result of the ICT. The results of real-space analysis directly indicate that some states are ICT states, and others belong to locally excited states. Moreover, according to the generalized Mulliken Hush theory, we calculated the electronic coupling matrix elements and predict that electron transfer for some ICT states more easily takes place than that for some locally excited states.     

Low‐Frequency Phonons in High‐Pressure High‐Temperature C60 Polymers

Abstract

Inelastic neutron scattering investigations of the orthorhombic (O), tetragonal (T), and rhombohedral (R) pressure‐polymerized phases of C₆₀ as well as the pressure‐dimerized state give evidence for differences in the responses of low‐energy excitations between these phases. These differences are assigned to changes in low‐energy interball modes dynamics as a function of the structure of pressure‐polymerized phases. Far‐infrared transmittance measurements complete the information of the low‐frequency vibrational dynamics of these phases. The temperature dependence of these low‐frequency excitations reveals a strong anharmonicity and possible phase transitions.