Fullerene chemistry is a field of organic chemistry devoted to the chemical properties of fullerenes ^{[1] [2] [3]}. Research in this field is driven by the need to functionalize fullerenes and tune their properties. For example fullerene is notoriously insoluble and adding a suitable group can enhance solubility. By adding a polymerizable group, a fullerene polymer can be obtained. Functionalized fullerenes are divided into two classes: exohedral with substituents outside the cage and endohedral fullerenes with trapped molecules inside the cage. Organic chemistry is a specific discipline within the subject of chemistry. ... The fullerenes, discovered in 1985 by researchers at Rice University, are a family of carbon allotropes named after Buckminster Fuller. ... Endohedral Fullerenes are fullerenes that have incorporated in their inner sphere atoms, ions or clusters. ...

Fullerene or C₆₀ is isocahedral or I_h with 12 pentagons and 20 hexagons. According to Euler's theorem these 12 pentagons are required for closure of the carbon network consisting of n hexagons and C₆₀ is the first stable fullerene because it is the smallest possible to obey this rule. In this structure none of the pentagons make contact with each other. Both C₆₀ and its relative C₇₀ obey this so-called isolated pentagon rule (IPR). The next homologue C₈₄ has 24 IPR isomers of which several are isolated and another 51,568 non-IPR isomers. Non-IPR fullerenes have thus far only been isolated as endohedral fullerenes such as Tb3N@C₈₄ with two fused pentagons at the apex of an egg-shaped cage ^[4] An icosahedron [ËŒaıkÉ™sÉ™hiːdrÉ™n] noun (plural: -drons, -dra [-drÉ™]) is a polyhedron having 20 faces, but usually a regular icosahedron is meant, which has faces which are equilateral triangles. ... It has been suggested that Vertex/Face/Edge relation in a convex polyhedron be merged into this article or section. ...

Due to its spherical shape the carbon atoms are highly pyramidalized with far reaching consequences for reactivity. It is estimated that strain energy constitutes 80% of the heat of formation. The conjugated carbon atoms respond to deviation from planarity by orbital rehybridization of the sp² orbitals and pi orbitals to a sp^2.27 orbital with a gain in p-character. The p lobes extend further outside the surface than they do into the interior of the sphere and this is one of the reasons a fullerene is electronegative. The other reason is that the empty low-lying pi^* orbitals also have high s character. The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 100 kPa... In chemistry, hybridisation is the mixing of atomic orbitals to form new orbitals suitable for bonding. ... The term orbital has several meanings: In physics and chemistry it is used to describe an atomic electron configuration, see also molecular orbital and atomic orbital. ... Electron atomic and molecular orbitals, showing a Pi-bond at the bottom right of the picture In chemistry, pi bonds (Ï€ bonds) are chemical bonds of the covalent type, where two lobes of one involved electron orbital overlap two lobes of the other involved electron orbital. ... It has been suggested that this article or section be merged with electronegativity. ...

The double bonds in fullerene are not all the same. Two groups can be identified: 30 so-called [6,6] double bonds connect two hexagons and 60 [5,6] bonds connect a hexagon and a pentagon. Of the two the [6,6] bonds are shorter with more double-bond character and therefore a hexagon is often represented as a cyclohexatriene and a pentagon as a pentalene or [5]radialene. In other words, although the carbon atoms in fullerene are all conjugated the superstructure is not a super aromatic compound. The X-ray diffraction bond length values are 135.5 pm for the [6,6] bond and 146.7 pm for the [5,6] bond. Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... The term aromatic compound may also refer to: any organic compound possessing a strong olfactory aroma aromatic hydrocarbons (originally named as a subset of the above; however, aromatic hydrocarbons do not necessarily possess any smell whatsoever) ... X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of x-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... In molecular geometry, bond length or bond distance is the distance between two bonded atoms in a molecule. ... Picometre (American spelling: picometer) is an SI measure of length that is equal to 10−12 of a metre. ...

C₆₀ fullerene has 60 pi electrons but a closed shell configuration requires 72 electrons. The fullerene is able to acquire the missing electrons by reaction with potassium to form first the K₆C₆₀^6- salt and then the K₁₂C₆₀^12- In this compound the bond length alternation observed in the parent molecule has vanished. General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ...

Fullerene reactions

Fullerenes tend to react as electrophiles. An additional driving force is relief of strain when double bonds become saturated. Key in this type of reaction is the level of functionalization i.e. monoaddition or multiple additions and in case of multiple additions their topological relationships (new substituents huddled together or evenly spaced). Some fullerene chemistry involves the opening of fullerenes by breaking several of the double bonds. The aim is to be able to insert small molecules through the hole, for instance hydrogen in endohedral hydrogen fullerene. In chemistry a molecule experiences strain when in a chemical conformation there exist unfavorable bond angles or bond distances. ...

• Fullerenes react as electrophiles with a host of nucleophiles in nucleophilic additions. The intermediary formed carbanion is captured an electrophile. Examples of nucleophiles are Grignard reagents and organolithium reagents. For example the reaction of C₆₀ with methylmagnesium chloride stops quantitatively at the penta-adduct with the methyl groups centered around a cyclopentadienyl anion which is subsequently protonated ^[5]. Another nucleophilic reaction is the Bingel reaction.
• The [6,6] bonds of fullerenes react as dienes or dienophiles in cycloadditions for instance Diels-Alder reactions. 4-membered rings can be obtained by [2+2]cycloadditions for instance with benzyne. An example of a [1,3-dipolar cycloaddition] to a 5-membered ring is the Prato reaction.
• Fullerenes are resistant to hydrogenation, the completely hydrogenated C60H60 is hypothetical because of large strain but hexahydrides are known
• Although more difficult than reduction, oxidation of fullerene is possible for instance with oxygen and osmium tetraoxide
• Fullerenes react in electrophilic additions as well. The reaction with bromine can add up to 24 bromine atoms to the sphere.
• Fullerenes react with carbenes to methanofullerenes

In chemistry, an electrophile (literally electron-lover) is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile. ... In organic chemistry, a nucleophilic addition reaction is an addition reaction where in a chemical compound a pi bond is removed by the creation of two new covalent bonds by the addition of a nucleophile. ... A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons. ... A Grignard Reagent is an alkyl- or aryl- magnesium halide. ... An organolithium reagent is an organometallic compound with a direct bond between a carbon and a lithium atom. ... A Grignard Reagent is an alkyl- or aryl- magnesium halide. ... Bingel reaction of fullerene with a malonate ester and a) sodium hydride or DBU in toluene at room temperature 45% yield The Bingel reaction in organic chemistry is a fullerene cyclopropanation reaction to a methanofullerene first discovered by C. Bingel in 1993 with the bromo derivative of diethyl malonate in... A Cycloaddition is a pericyclic reaction in which the net result is loss of two pi bonds and gain of two sigma bonds. ... The Diels-Alder reaction The Diels-Alder reaction is an organic chemical reaction (specifically, a cycloaddition) between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system. ... Benzyne is the parent molecule of aryne compounds. ... The Prato reaction in organic chemistry describes the functionalization of fullerenes and nanotubes with azomethine ylides in a 1,3-dipolar cycloaddition . ... Hydrogenation is a chemical reaction in which unsaturated bonds between carbon atoms are reduced by attachment of a hydrogen atom to each carbon. ... In organic chemistry, an electrophilic addition reaction is an addition reaction where in chemical compound a pi bond is removed by the creation of two new covalent bonds. ... General Name, Symbol, Number bromine, Br, 35 Chemical series halogens Group, Period, Block 17, 4, p Appearance gas/liquid: red-brown solid: metallic luster Atomic mass 79. ... In chemistry a carbene is a short-lived and highly reactive organic molecule with a divalent carbon atom with only six valence electrons and the general formula: R1R2C: . The carbon atom is sp2 hybridised with an empty p-orbital extending above and below a plane containing R1 and R2 and...

Fullerene ligands

Fullerene is a ligand in organometallic chemistry. The [6,6] double bond is electron-deficient and forms metallic bonds with η = 2 hapticity. C₆₀ fullerene reacts with tungsten hexacarbonyl W(CO)₆ to the (η²-C₆₀)W(CO)₅ complex in a hexane solution in direct sunlight ^[6]. In chemistry, a ligand is an atom, ion, or molecule (see also: functional group) that generally donates one or more of its electrons through a coordinate covalent bond to, or shares its electrons through a covalent bond with, one or more central atoms or ions (these ligands act as a... It has been suggested that Organometallic compounds be merged into this article or section. ... // η-bonding The Greek letter η (eta) is used to denote the number of atoms of a ligand that bind to a metal center. ... Tungsten hexacarbonyl (also called tungsten carbonyl) is the chemical compound with the formula W(CO)6. ... the 3rd ingredient in big mac ...

Nanotube chemistry

Carbon nanotubes, also part of the fullerene family, consist of graphene sheets rolled up into a cylinder. Unlike the spherical fullerenes made up of hexagons and pentagons, nanotubes only have hexagons present but in terms of reactivity both systems have much in common. Due to electrostatic forces nanotubes have a nasty tendency to cluster together in large bundles and many potential applications require an exfoliation process. One way to do this is by chemical surface modification. 3D model of three types of single-walled carbon nanotubes. ... Figure 1. ... Exfoliation has several meanings: Dead skin cells? No: geological exfoliation of granite at Enchanted Rock State Natural Area, Texas, USA Exfoliation (cosmetology), is a cosmetic technique aimed at removing dead skin cells from the face and body. ...

A useful tool for the analysis of derivatised nanotubes is Raman spectroscopy which shows a G-band (G for graphite) for the native nanotubes at 1580 cm^-1 and a D-band (D for defect) at 1280 cm^-1 when the graphite lattice is disrupted with conversion of sp² to sp³ hybridized carbon. The ratio of both peaks I_D/I_G is taken as a measure of functionalization. Other tools are UV spectroscopy where pristine nanaotubes show distinct Van Hove singularities where functionalized tubes do not and simple TGA analysis. Raman spectroscopy is a spectroscopic technique used in condensed matter physics and chemistry to study vibrational, rotational, and other low-frequency modes in a system. ... Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ... In chemistry, hybridisation is the mixing of atomic orbitals to form new orbitals suitable for bonding. ... A van Hove singularity is a kink in the density of states (DOS) of a solid. ... Thermogravimetric Analysis or TGA is a type of testing that is performed on samples to determine changes in weight in relation to change in temperature. ...

In one type of chemical modification an aniline is oxidized to a diazonium intermediate which after expulsion of nitrogen forms a covalent bond as an aryl radical ^{[7] [8]}: Aniline, phenylamine or aminobenzene (C6H5NH2) is an organic chemical compound which is a primary aromatic amine consisting of a benzene ring and an amino group. ... Phenyldiazonium cation Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group with the characteristic structure of R-N2+ X- where R can be any organic residue such alkyl or aryl and X is an inorganic or organic anion such as a halogen. ...

Also known are protocols for Diels-Alder reactions, one assisted by chromium hexacarbonyl and high pressure ^[9]. The I_D/I_G ratio for reaction with Danishefsky’s diene is 2.6. The Diels-Alder reaction The Diels-Alder reaction is an organic chemical reaction (specifically, a cycloaddition) between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system. ... Chromium carbonyl, which is also known as chromium hexacarbonyl is a zerovalent homoleptic compound which has the formula Cr(CO)6. ...

References