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Fullerene Fullerene is a hollow molecule composed entirely of carbon in the shape of spheres, ellipsoids, cylinders or tubes. Fullerene is very similar in structure to graphite, which is formed by stacking graphene layers composed of six-membered rings, and fullerene contains not only six-membered rings but also five-membered rings and occasionally seven-membered rings. In 1985, British chemist Dr. Harold Vortel Croto and American scientist Richard Smolley prepared the first fullerene at Rice University. That is, "C60 molecule" or "[60] fullerene", because this molecule is very similar to the architectural works of architect Buckminster Fuller, in order to show respect for him, it is named "Buckminster Fullerene" (buckyball). Iijima Chengnan observed this onion-like structure under transmission electron microscope as early as 1980. Fullerenes also exist in nature. In 2010, scientists discovered fullerenes also exist in outer space through Spitzer Space Telescope. "Perhaps fullerenes in outer space provide the seeds of life for the Earth". Before fullerenes were discovered, only graphite, diamonds and amorphous carbon (such as carbon black and carbon) were the allotropes of carbon. Its discovery greatly expanded the number of allotropes of carbon. The unique chemical and physical properties of fullerenes and carbon nanotubes and their potential applications in technology have aroused strong interest of scientists, especially in materials science, electronics and nanotechnology. Preparation and Purification Preparation The preparation of a large number of high-purity fullerenes at low cost is the basis of fullerenes research. Since Croto discovered C60, many preparation methods of fullerenes have been developed. At present, the more mature preparation methods of fullerenes mainly include arc method, thermal evaporation method, combustion method and chemical vapor deposition method. [2] Arc method Generally, the arc chamber is pumped into a high vacuum and then inert gas such as helium is introduced. The cathode and anode for preparing fullerene are arranged in the arc chamber. The cathode material of the electrode is usually spectral grade graphite rod, the anode material is generally graphite rod, and iron, nickel, copper or tungsten carbide are usually added to the anode electrode as catalysts. When the two high purity graphite electrodes are close to each other for arc discharge, the carbon rods gasify to form plasma. Under inert atmosphere, small carbon molecules collide, merge and close for many times to form stable C60 and high carbon fullerene molecules, which exist in a large amount of granular soot, deposit on the inner wall of the reactor, and collect soot for extraction. Arc method is very power-consuming and costly, and is a common method for preparing hollow fullerenes and metal fullerenes in laboratories. Combustion method There are C60 and C70 in the carbon black that benzene and toluene are not completely burned under the action of oxygen. The ratio of C60 to C70 can be controlled by adjusting the pressure and gas ratio, which is the main method for producing fullerenes in industry. Purification Purification of fullerenes is a process of obtaining impurity-free fullerenes. Crude products for fullerenes, i.e. Soot, are usually mixtures with C60 as the main component and C70 as the auxiliary component, and some homologues. The key to determine the price of fullerenes and their practical application is the purification of fullerenes. Fullerene purification steps commonly used in laboratories are: toluene Soxhlet extraction is first used from smoke dust rich in C60 and C70, and then paper funnel filtration is carried out. After evaporating the solvent, the remaining part (substances dissolved in toluene) is redissolved in toluene, and then crude purified by column chromatography mixed with alumina and activated carbon. The first effluent component is purple C60 solution and the second is reddish brown C70. At this time, the purity of C60 or C70 obtained by crude separation is not high, and high performance liquid chromatography is needed for fine separation. Nagata invented a kilogram purification technology for fullerenes. In this method, diazabicyclo is added to 1, 2, 3-trimethylbenzene solution of C60, C70 and other homologues. DBU will only react with C70 and higher homologues, and the reaction product will be separated by filtration, while fullerene C60 will not react with DBU, so the pure product of C60 will be finally obtained. Other amine compounds, such as DABCO, do not have this selectivity. C60 can react with cyclodextrin at a ratio of 1: 2, but C70 is not. A method for separating fullerenes is based on this principle. Cyclodextrin is fixed to gold particle colloid through S-S bridge. The water-soluble gold/cyclodextrin complex [Au/CD] is very stable, and C60 can be selectively extracted by refluxing with water-insoluble soot in water for several days, while C70 components can be obtained by simple filtration. The separation of C60 from the [Au/CD] complex is realized by adding adamantanol with high affinity for the inner cavity of cyclodextrin to the cyclodextrin aqueous solution to separate C60 from the [Au/CD] complex. After separation, ethanol is added to the [Au/CD/ADA] complex and then distilled to realize the recycling of reagents. 50 mg of [Au/CD] can extract 5 mg of fullerene C60. The latter two methods only stay in the laboratory stage and are not practical.

Category Edit Since the discovery of fullerenes in 1985, fullerenes with new structures have been predicted or discovered, surpassing the single cluster itself. Bucky spherical clusters: the smallest is C20 (unsaturated derivative of eicosane) and the most common is C60; Carbon nanotubes: very small hollow tubes, divided into single-walled and multi-walled; Potential applications in the electronics industry; Megatubes: Larger than nanotubes, the tube walls can be prepared into different thicknesses and have potential value in transporting molecules of different sizes; Polymer: "Chain, two-dimensional or three-dimensional polymer" formed under high temperature and pressure. Nano "onion": multi-walled carbon layer is wrapped outside Bucky ball to form spherical particles, which may be used as lubricant; Bat-connected dimer: two Bucky balls are connected by carbon chains; Fullerene ring. Buckyball Nanotubes are hollow fullerene tubes. These carbon tubes are usually only a few nanometers wide, but their length can reach 1 micron or even 1 millimeter. Carbon nanotubes are usually closed at the end, there are also openings at the end, and some are not completely sealed at the end. The unique molecular structure of carbon nanotubes leads to its peculiar macro properties, such as high tensile strength, high electrical conductivity, high ductility, high thermal conductivity and chemical inertia (because it is cylindrical or "planar" and no bare atoms are easily replaced). One potential application is to make paper batteries, which was a new discovery by Rensselaer Institute of Technology in 2007. Another possible application is the high-strength carbon cable used as a space elevator. The nano "bud" structure formed by adsorbing fullerenes outside carbon nanotubes through covalent bonds is called nano bud. Fullerites are the solid forms of fullerenes and their derivatives, which are not specifically referred to in Chinese. The word superhard fullerene is generally used to describe fullerene obtained under high pressure and high temperature. Under such conditions, ordinary fullerene solids will form nanocrystals in the form of diamonds, which have quite high mechanical strength and hardness. Embedded fullerenes are a new type of embedded fullerenes formed by embedding some atoms into fullerene carbon cages, such as hydrogen, carbon, scandium, nitrogen, etc. Most of them are formed in the process of producing fullerenes by arc method, and some atoms or molecules can also be loaded into fullerenes after opening pores by chemical methods. Structure Edit Mathematically, fullerene structures are convex polyhedrons composed of pentagonal and hexagonal faces. The smallest fullerene is C20 and has a dodecahedral structure. There are no fullerenes with 22 vertices, and then there are C2n fullerenes, n=12, 13, 14... The number of pentagons and hexagons of all fullerenes is 12 and n-10 respectively. C60 C60 and C70 cyclic voltammetry curve testing machine: Chi660d, working electrode: glassy carbon, counter electrode: platinum wire; Reference electrode: silver wire; Supporting electrolyte: tetrabutylammonium hexafluorophosphate; Scanning speed: 50mV/s; Room Temperature Because C60 is the most easily obtained, purified and cheapest type in fullerene families, C60 and its derivatives are the fullerenes that have been studied and applied most. Through mass spectrometry analysis and X-ray analysis, it is proved that the molecular structure of C60 is spherical 32-hedron. It is a football-like hollow symmetrical molecule with 30 carbon-carbon double bonds formed by connecting 60 carbon atoms through 20 six-membered rings and 12 five-membered rings. Therefore, fullerenes are also called football alkenes. C60 is highly Ih symmetrical and highly delocalized conjugate, but it is not a super aromatic system. Its nuclear magnetic resonance carbon spectrum has only one spectral line, but there are two kinds of double bonds. It has 30 bonds at the junction of six-membered ring and six-membered ring, called [6, 6] bonds, and 60 bonds at the junction of five-membered ring and six-membered ring, called [5, 6] bonds. The [6, 6] bond is shorter than the [5, 6] bond. X-ray single crystal diffraction data of C60 show that the [6, 6] bond length is 135.5 picometres and the [5, 6] long bond is 146.7 picometres. Therefore, [6, 6] has more double bond properties, is easier to be added, and the addition product is more stable. Moreover, the six-membered ring is often regarded as benzene ring, and the five-membered ring is regarded as cyclopentadiene or five-membered axene. C60 has 1812 isomers. C60 and its associate C70 both satisfy this so-called isolated pentagon rule (IPR). While 24 of the C84 isomers satisfy the isolated pentagonal rule, However, the other 51568 isomers do not meet the isolated pentagonal rule. These 51568 are non-pentagonal isolated isomers, while only a few fullerenes that do not meet the isolated pentagonal rule have been separated so far, such as an egg-shaped cage-shaped embedded metal fullerene Tb3NaC84 with two pentagons fused at the top of the molecule. Or stable fullerenes with extrspherical chemical modification such as C50Cl10 and C60H8. Theoretical calculation shows that the lowest unoccupied orbit (LUMO) orbit of C60 is a triple degenerate orbit, so it can obtain at least six electrons, and only four reduction potentials can be obtained by conventional cyclic voltammetry and differential pulse voltammetry, while the spectrum of six reduction potentials can be obtained by using a 1: 5 mixed solvent of acetonitrile and toluene under vacuum conditions. C70 Theoretical calculations show that the LUMO orbital of C70 is a double degenerate orbital, However, the energy level difference between its LUMO+1 orbit and LUMO orbit is very small, so it can obtain at least six electrons. Conventional cyclic voltammetry and differential pulse voltammetry can only obtain four reduction potentials, while the spectrum of six reduction potentials can be obtained by using a 1: 5 mixed solvent of acetonitrile and toluene under vacuum conditions. Low symmetry fullerene The bond lengths of fullerenes with low symmetry are different, although they are also delocalized bonds. It can be clearly seen from the nuclear magnetic resonance carbon spectrum that there are many carbon signals. Chirality Some fullerenes are D2 symmetrical, so they are inherently chiral, such as C76, C78, C80 and C84. Scientists have been committed to developing special sensors to recognize and separate their enantiomers. Nature Solubility C60 solution Fullerenes dissolve poorly in most solvents and are usually dissolved in aromatic solvents such as toluene, chlorobenzene, or non-aromatic solvent carbon disulfide. The solution of pure fullerene is usually purple, and the solution of C70 is slightly redder than that of C60 because it has absorption at 500nm. Other fullerenes, such as C76 and C80, have different purple colors. Fullerenes are the only isotropic carbon found so far dissolved in conventional solvents at room temperature. Some fullerenes are insoluble because their ground state and excited state bandwidths are very narrow, such as C28, C36 and C50. C72 is also almost insoluble, but the embedded fullerenes of C72, such as La2 @ C72, are soluble due to the interaction between metal elements and fullerenes. Early scientific scientists were puzzled that C72 was not found, but there were embedded fullerenes of C72. Fullerenes with narrow bandwidth are highly active and often combine with other fullerenes. The solubility of chemically modified fullerene derivatives is greatly enhanced, for example, the solubility of PC61BM in chlorobenzene is 50mg/mL at room temperature. The solubility of C60 and C70 in some solvents is listed in the left table, where the solubility is usually an estimate of saturation concentration. Hydrated fullerene (HyFn) Aqueous solution of C60HyFn, the concentration of C60 is 0.22 mg/mL Hydrated fullerene C60HyFn is a stable and highly hydrophilic supramolecular compound. As of 2010, the maximum C60 concentration in the form of hydrated fullerenes is 4mg/mL. Electrical conductivity Many properties of C60 were discovered after it could be produced in large quantities. Soon Haddon et al. Discovered that alkali metal doped C60 had metal behavior. In 1991, potassium doped C60 had superconducting behavior at 18K, which was the highest molecular superconducting temperature so far. Later, superconducting properties of a large number of metal doped fullerenes were discovered. The results show that the superconducting conversion temperature increases with the cell volume of alkali metal doped fullerenes. Cesium can form the largest alkali metal ions, so cesium doped fullerene materials have been widely studied. Recently, it has been reported that Cs3C60As has superconducting properties at 38K, but at high pressure. Cs2RbC60 has the highest superconducting conversion temperature at 33K under normal pressure. According to the BCS theory of C60 solid superconductivity, The superconducting transition temperature increases with the increase of cell volume, because the interval between C60 molecules is related to the increase of the density of states of Fermi level N (F), so scientists have done a lot of work to try to increase the distance between fullerene molecules, especially inserting neutral molecules into A3C60 lattice to increase the interval while keeping the valence state of C60 unchanged. However, this ammoniation technology unexpectedly obtains special properties of novel fullerene insertion complexes: Mott-Hubbard transition and the relationship between orientation/orbital order and magnetic structure of C60 molecules. C60 solids are composed of weak interaction forces, so they are molecular solids and retain molecular properties. The discrete energy level of a free C60 molecule is only weakly dispersed in the solid, resulting in a narrow non-overlapping band gap of only 0.5 eV. For undoped C60 solid, 5 times Hu band is its HOMO energy level and 3 times t1u band is its empty LUMO energy level. This system is band forbidden. However, when C60 solid is doped with metal atoms, the metal atoms will be occupied by T1U band electrons or part of T1G band electrons three times that, sometimes showing metallic properties. Although its t1u band is partially occupied, according to BCS theory, the t1u band of A4C60 is partially occupied and should have metal properties, but it is an insulator. This contradiction may be explained by Jahn-Teller effect. The spontaneous deformation of highly symmetric molecules leads to the splitting of its merger orbitals and thus obtains electron energy. This Jahn-Teller type electron-phonon interaction is so strong in C60 solid that it can destroy the valence band pattern of the special valence state. Narrow band gap or strong electron interaction and degenerate ground state are very important to understand and explain the superconductivity of fullerene solids. When the repulsion ratio of electrons to each other is large, the simple Mott-Hubbard model will produce an insulating local electron ground state, which explains that cesium doped C60 solid has no superconductivity at normal pressure. Mott insulators will be generated when the localization of T1U electrons driven by electron interaction exceeds the critical point, while high voltage can reduce the spacing between fullerenes. At this time, cesium doped C60 solid shows metallicity and superconductivity. There is no complete theory about the superconductivity of C60 solid, but BCS theory is a widely accepted theory, because strong electron interaction and Jahn-Teller electron-phonon coupling can generate electron pairs, thus obtaining higher insulator-metal transition temperature. Thermodynamic properties Differential scanning calorimetry (DSC) shows that C60 undergoes phase transition at 256K with an entropy of 27.3 J. K. Mol, which is attributed to its glass morphology-crystal transition, which is a typical directed disorder transition. Similarly, C70 also undergoes disorder transformation at 275K, 321K and 338K, with a total entropy of 22.7 J.K.mol. The wide disorder transition of fullerenes is related to the gradual change from the quasi-jump rotation at the initial lower temperature to the isotropic rotation. Chemical properties Fullerenes are stable, but not completely unreactive. The SP hybrid orbital in graphite is planar, while in fullerene it is curved in order to form tubes or spheres, which forms a larger bond angle tension. When some of its double bonds are saturated through the reaction, the bond angle tension is released. For example, the [6, 6] bond of fullerene is electrophilic, and the bond tension is reduced by changing the sp hybrid orbital to the sp hybrid orbital. The change in the atomic orbital makes the bond from about 120 ° of sp to about 109.5 ° of sp, thus reducing the Gibbs free energy of C60 sphere and stabilizing it. Fullerenes can form either single addition products or multiple addition products. Fullerene chemistry is a science that studies the chemical properties of fullerenes. The need to functionalize fullerenes to adjust their properties has prompted people to carry out a lot of research in this field. For example, fullerenes have poor solubility, and adding appropriate functional groups can improve their solubility. Fullerene polymers can be obtained by adding a functional group that can polymerize. Functionalization of fullerenes can be divided into two categories: chemical modification outside the cage of fullerenes; Binding molecules into fullerene spheres is an opening reaction. Because the spherical structure of this molecule makes carbon atoms highly pyramidal, this has a profound impact on its reactivity. It is estimated that its strain energy is equivalent to 80% of the reaction heat energy. The parallelism of conjugated carbon atoms affects the hybrid orbital SP ², a SP orbital that obtains P electrons. The expansion of the interconnection of P orbitals in the outer sphere is better than that in the inner sphere (carbon atoms are connected by SP hybrid orbitals, the other P electrons form PI bonds in pairs, and the PI electrons form a complex PI-PI conjugated system similar to spheres), which is one reason why fullerenes are electron donors. Another reason is that in the empty low-level PI orbit. The double bonds in fullerenes are not exactly the same and can be roughly divided into two types: [6, 6] bonds, bonds connecting two hexagons, and [5, 6] bonds connecting a hexagon and a pentagon. The [6, 6] bond in the two is shorter than the [6, 6] bond in the cyclohexatriene molecule and the double bond in the axene and dicyclopentadiene molecule. In other words, although the carbon atoms in fullerene molecules are hyperconjugated, fullerene is not a super-large aromatic compound. C60 has 60 pi electrons, but the enclosed shell architecture requires 72 electrons. Fullerenes can obtain deletion electrons through reaction with potassium, such as K6C60 salt synthesized first and K12C60 salt synthesized next; In this compound, the phenomenon of bond length alternation in molecules disappears. According to IUPAC, methylene fullerene (also called cyclopropane fullerene) refers to closed-loop (cyclopropane) fullerene derivatives, while fulleroid refers to ring-opening fullerene derivatives (methanoannulene) fullerenes often undergo electrophilic reactions. The key of such reactions is functional monoaddition or multiple addition. Nucleophilic addition Fullerenes react with nucleophilic reagents as an electrophilic reagent in nucleophilic addition, and carbon anions formed by fullerenes are captured by nucleophilic reagents such as Grignard reagents or organolithic reagents. For example, methylmagnesium chloride and C60 are protonated to form (CH3) 5HC60 after quantitatively forming a pentaaddition product with methyl in the middle of cyclopentadiene. Binger reaction is also an important fullerene cycloaddition reaction to form methylene fullerene. Fullerenes can undergo Fourier alkylation reaction under the action of chlorobenzene and aluminum trichloride. The product of hydroaromatization is 1, 2 addition (Ar-CC-H). Pericyclic reaction The [6, 6] bond of fullerenes can react with dienes or dienophiles, such as D-A reaction. [2 +2] Cycloaddition can form a quaternary ring, such as phenylene. The 1, 3-dipolar cycloaddition reaction can produce a five-membered ring, which is called Prato reaction. Fullerene reacts with carbene to form methylene fullerene. Hydrogenation (reduction) reaction Hydrogenated fullerene products such as C60H18 and C60H36. However, the fully hydrogenated C60H60 is only a hypothetical product because the molecular tension is too large. The highly hydrogenated fullerenes are unstable, and the direct reaction between fullerenes and hydrogen at high temperature will lead to the collapse of cage structure and the formation of polycyclic aromatic hydrocarbons. Oxidation reaction Fullerenes and their derivatives will be slowly oxidized in the air, which is also the reason why fullerenes need to be stored in light or low temperature under normal circumstances. Reactions of fullerenes with osmium trioxide and ozone; The reaction with ozone is very fast and intense, and fullerenol mixture with hydroxyl polyaddition can be formed, because the addition number and addition position have a wide distribution. Hydroxylation reaction Fullerenes can be hydroxylated to obtain fullerenols, and their water solubility depends on the number of hydroxyl groups in the molecule. One method is to react fullerenes with dilute sulfuric acid and potassium nitrate to produce C60 (OH) 15, and the other method is to increase 24 to 26 hydroxyl groups from TBAH under the catalysis of dilute sodium hydroxide solution. Hydroxylation reactions have also been reported with solvent-free sodium hydroxide reacting with hydrogen peroxide and fullerenes. C60 (OH) 8 is synthesized by the reaction of hydrogen peroxide and fullerene. The maximum number of hydroxyl groups can reach 36 to 40. Electrophilic addition Fullerenes can also undergo electrophilic reactions, for example, 24 bromine atoms are added to fullerene spheres, and the record holder for electrophilic addition is C60F48. Coordination reaction The five-membered ring and six-membered ring of fullerenes can be used as ligands of metal complexes, especially the five-membered ring, which can form various metallocene complexes. [6, 6] Double bonds are electron-deficient and are usually bonded to metals at = 2 (Hapto number in coordination chemistry). The bonding mode such as = 5 or = 6 is related to spherical fullerene ligands. The cyclohexane solution of fullerene and tungsten thiocarbonyl W (CO) 6 was directly irradiated by sunlight to form (²-C 60) 5W (CO) 6. Opening reaction Opening reaction refers to the reaction of selectively cutting off carbon-carbon bonds on fullerene skeleton by chemical means to prepare open fullerene. After opening, some small molecules, such as hydrogen molecules, helium, lithium, etc., may be packed into carbon spheres. The first open-porous fullerene was reported by Wood et al. In 1995. Supramolecular chemistry Fullerenes and other functional groups are effectively linked together through non-covalent interaction to form supramolecular systems with specific structures, and then their functionalization is realized by regulating the electronic interaction between various groups, which has aroused great interest of researchers. Host and Guest Chemistry of Naked C60 Because of the unique rigid spherical structure of C60 molecule, Developing specific subjects with which they can be efficiently integrated is a meaningful task, For more than 20 years, scientists have been happy to wrap them up with novel compounds and interesting ways to obtain inclusions and chimeric compounds. They have conducted a great deal of research and made great progress in the host and guest chemistry of fullerenes and developed a series of host compounds, which can be roughly divided into electron-rich compounds and macrocyclic hosts. The former has derivatives of ferrocene, porphyrin, phthalocyanine, tetrathiafulvalene, perylene, bowlene and banded polyconjugated systems, while the latter has derivatives of cyclodextrins, calixarene, azacalixarene, long chain alkanes and oligomers. So far, the porphyrin cage molecule synthesized by Professor Xiangtian Zhuo has the strongest binding force to fullerene molecule supramolecular. The binding constant of porphyrin cage molecule to C60 in o-dichlorobenzene is Log Ka = 8.11. Self-assembly of Supramolecules of C60 Derivatives Modified fullerenes can obtain more action sites, so the research on supramolecular self-assembly of fullerene derivatives has always been a hot topic, far more than the assembly of unmodified fullerenes, especially in many research fields such as fullerene-based functional materials, photoinduced electron transfer, artificial photosynthesis systems, photonic devices, etc. Method for preparing ordered aggregation state of C60 and its derivatives The self-assembled precursor produced after fullerene functionalization forms an ordered aggregated structure through supramolecular action, which not only improves the understanding of fullerene intrinsic characteristics and the construction level of single molecular devices, but also is the need for fullerene high-tech functionalized materials. Over the past ten years, many research groups have done a lot of research on obtaining stable C60 nanomaterials such as nanoparticles, nanotubes, nanowires, nanobelts and highly ordered two-dimensional structures. Classical self-assembly methods, template methods, vapor deposition methods, chemical adsorption and LB film technologies have been developed to construct organic nanomaterials with specific morphology. Safety and Toxicity Moussa et al. Conducted toxicological studies after injecting large doses of C60 into the abdominal cavity of organisms and found that there was no evidence that mice were poisoned after injecting 5000mg/kg (body weight) of C60. Mori et al. Also found no poisoning, genotoxicity or mutagenicity after oral administration of 2000mg/kg of C60 and C70 mixture to rodents, Other studies have also proved that C60 and C70 are non-toxic, while Gharbi et al. Found that injection of C60 suspension will not cause acute or sub-acute toxicity to rodents, on the contrary, a certain dose of C60 will protect their liver from free radical damage. The latest research in 2012 showed that oral fullerenes can double the life span of mice without any side effects. Professor Moussa has studied the nature of C60 for 18 years and wrote the article "Continuous Feeding of Mice C60 to Prolong Their Life". In October 2012, he declared in a video interview that pure C60 was not toxic. Kolosnjaj wrote a complex and detailed review on the toxicity of fullerenes in 2007. Reviewing the toxicity research work of all fullerenes from the early 1990s to the present, it is believed that there is no obvious evidence that C60 is toxic since the discovery of fullerenes, while asbestos-like lesions were found when carbon nanotubes were injected into the abdominal cavity of mice by Poland et al. It is worth noting that this study is not an inhalation study. Although there have been toxicological experiments on the inhalation of nanotubes before this, this study cannot confirm that carbon nanotubes have asbestos-like toxicological characteristics. Saye et al. Found that inhaling C60 (OH) 24 or nano C60 in mice had no toxic or side effects, while injecting Shi Ying particles into mice under the same circumstances caused strong inflammation. As mentioned above, nanotubes are very different from C60 in chemical and physical properties (solubility) such as molecular weight, shape and size, so from a toxicological point of view, there is no correlation between C60 and the differences in different toxicological properties of carbon nanotubes. When analyzing toxicity data, different molecules of fullerenes must be distinguished: (C60, C70 …); Fullerene derivatives: C60 or other chemically modified fullerene derivatives; Fullerene complexes (e.g., surfactant-assisted water-soluble fullerenes, such as C60-polyvinylpyrrolidone; Host and guest complexes, such as cyclodextrins or porphyrins), in which case fullerenes are linked to other molecules through supramolecular interaction; C60 nanoparticles Application [https://www.hemorrhoids.shop/ '''Skin care products Because fullerenes can affinity free radicals, individual merchants disperse water-soluble fullerenes in cosmetics. Fullerenes have antioxidant effects.'''] Multivariate body research Fullerene derivatives form polymers covalently or noncovalently with electron-rich groups such as porphyrins and ferrocene, which are used to study intramolecular energy, charge transfer, photoinduced energy and charge transfer. Organic solar cell Main Entry: Organic Solar Cells Since Dr. Yu Gang used fullerene derivative PCBM ([6, 6]-phenyl-c61-butyric acid method ester, abbreviated as PC61BM or PCBM) in bulk heterojunction organic solar cells in 1995, organic solar cells have made great progress. Among them, three companies have commercially doped PCBM organic solar cells. Up to now, most organic solar cells use fullerene as electron acceptor material. Popular culture Edit There are many fullerenes in popular culture and they appeared before scientists paid attention to them. In New Scientist magazine, David E. H. Jones once wrote a weekly column called "Daedalus" to describe various interesting but difficult science and technology. In 1966, he suggested that a hollow carbon sphere molecule could be obtained by doping heteroatoms to distort a network of planar hexagons. On September 4, 2010, Google's home page replaced the second "O" in the GOOGLE pattern with a rotating C60 fullerene to celebrate the 25th anniversary of fullerene discovery.