The solubility of fullerenes is generally low. Carbon disulfide dissolves 8g/L of C60, and the best solvent (1-chloronaphthalene) dissolves 53 g/L. up Still, fullerenes are the only known allotrope of carbon that can be dissolved in common solvents at room temperature. Besides those two, good solvents for fullerenes include 1,2-dichlorobenzene, toluene, p-xylene, and 1,2,3-tribromopropane. Fullerenes are highly insoluble in water, and practically insoluble in methanol.
Solutions of pure C60 (buckminsterfullerene) have a deep purple color. Solutions of C70 are reddish brown. Larger fullerenes C
76 to C
84 have a variety of colors. C
76 has two optical forms, while other larger fullerenes have several structural isomers.
Some fullerene structures are not soluble because they have a small band gap between the ground and excited states. These include the small fullerenes C
28, [1] C
36 and C
50. The C
72 structure is also in this class, but the endohedral version with a trapped lanthanide-group atom is soluble due to the interaction of the metal atom and the electronic states of the fullerene. Researchers had originally been puzzled by C
72 being absent in fullerene plasma-generated soot extract, but found in endohedral samples. Small band gap fullerenes are highly reactive and bind to other fullerenes or to soot particles.
Solubility of C
60 in some solvents shows unusual behaviour due to existence of solvate phases (analogues of crystallohydrates). For example, solubility of C
60 in benzene solution shows maximum at about 313 K. Crystallization from benzene solution at temperatures below maximum results in formation of triclinic solid solvate with four benzene molecules C
60·4C
6H6 which is rather unstable in air. Out of solution, this structure decomposes into usual face-centered cubic (fcc) C
60 in few minutes' time. At temperatures above solubility maximum the solvate is not stable even when immersed in saturated solution and melts with formation of fcc C
60. Crystallization at temperatures above the solubility maximum results in formation of pure fcc C
60. Millimeter-sized crystals of C
60 and C
70 can be grown from solution both for solvates and for pure fullerenes. [2] [3]
The following are some solubility values for C
60 and C
70 from the literature, in grams per liter. [4] [5] [6] [7] [8]
Solvent | C 60 | C 70 |
---|---|---|
1-chloronaphthalene | 51 | ND |
1-methylnaphthalene | 33 | ND |
1,2-dichlorobenzene | 24 | 36.2 |
1,2,4-trimethylbenzene | 18 | ND |
tetrahydronaphthalene | 16 | ND |
carbon disulfide | 8 | 9.875 |
1,2,3-tribromopropane | 8 | ND |
chlorobenzene | 7 | ND |
p-xylene | 5 | 3.985 |
bromoform | 5 | ND |
cumene | 4 | ND |
toluene | 3 | 1.406 |
benzene | 1.5 | 1.3 |
carbon tetrachloride | 0.447 | 0.121 |
chloroform | 0.25 | ND |
n-hexane | 0.046 | 0.013 |
cyclohexane | 0.035 | 0.08 |
tetrahydrofuran | 0.006 | ND |
acetonitrile | 0.004 | ND |
methanol | 4.0×10−5 | ND |
water | 1.3×10−11 | ND |
pentane | 0.004 | 0.002 |
heptane | ND | 0.047 |
octane | 0.025 | 0.042 |
isooctane | 0.026 | ND |
decane | 0.070 | 0.053 |
dodecane | 0.091 | 0.098 |
tetradecane | 0.126 | ND |
acetone | ND | 0.0019 |
isopropanol | ND | 0.0021 |
dioxane | 0.0041 | ND |
mesitylene | 0.997 | 1.472 |
dichloromethane | 0.254 | 0.080 |
ND = not determined | ||
A fullerene is an allotrope of carbon whose molecule consists of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecule may be a hollow sphere, ellipsoid, tube, or many other shapes and sizes. Graphene, which is a flat mesh of regular hexagonal rings, can be seen as an extreme member of the family.
Toluene, also known as toluol, is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group. As such, its systematic IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent.
A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell.
Solvation describes the interaction of solvent with dissolved molecules. Both ionized and uncharged molecules interact strongly with solvent, and the strength and nature of this interaction influence many properties of the solute, including solubility, reactivity, and color, as well as influencing the properties of the solvent such as the viscosity and density. In the process of solvation, ions are surrounded by a concentric shell of solvent. Solvation is the process of reorganizing solvent and solute molecules into solvation complexes. Solvation involves bond formation, hydrogen bonding, and van der Waals forces. Solvation of a solute by water is called hydration.
Buckminsterfullerene is a type of fullerene with the formula C60. It has a cage-like fused-ring structure (truncated icosahedron) that resembles a soccer ball, made of twenty hexagons and twelve pentagons. Each carbon atom has three bonds. It is a black solid that dissolves in hydrocarbon solvents to produce a violet solution. The compound has received intense study, although few real world applications have been found.
In chemistry, solubility is ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
Coronene is a polycyclic aromatic hydrocarbon (PAH) comprising seven peri-fused benzene rings. Its chemical formula is C
24H
12. It is a yellow material that dissolves in common solvents including benzene, toluene, and dichloromethane. Its solutions emit blue light fluorescence under UV light. It has been used as a solvent probe, similar to pyrene.
Polythiophenes (PTs) are polymerized thiophenes, a sulfur heterocycle. The parent PT is an insoluble colored solid with the formula (C4H2S)n. The rings are linked through the 2- and 5-positions. Poly(alkylthiophene)s have alkyl substituents at the 3- or 4-position(s). They are also colored solids, but tend to be soluble in organic solvents.
Lithium diisopropylamide (commonly abbreviated LDA) is a chemical compound with the molecular formula [(CH3)2CH]2NLi. It is used as a strong base and has been widely utilized due to its good solubility in non-polar organic solvents and non-nucleophilic nature. It is a colorless solid, but is usually generated and observed only in solution. It was first prepared by Hamell and Levine in 1950 along with several other hindered lithium diorganylamides to effect the deprotonation of esters at the α position without attack of the carbonyl group.
Terephthalic acid is an organic compound with formula C6H4(CO2H)2. This white solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several million tonnes are produced annually. The common name is derived from the turpentine-producing tree Pistacia terebinthus and phthalic acid.
In chemistry, an atom cluster is an ensemble of bound atoms or molecules that is intermediate in size between a simple molecule and a nanoparticle; that is, up to a few nanometers (nm) in diameter. The term microcluster may be used for ensembles with up to couple dozen atoms.
Endohedral fullerenes, also called endofullerenes, are fullerenes that have additional atoms, ions, or clusters enclosed within their inner spheres. The first lanthanum C60 complex was synthesized in 1985 and called La@C60. The @ (at sign) in the name reflects the notion of a small molecule trapped inside a shell. Two types of endohedral complexes exist: endohedral metallofullerenes and non-metal doped fullerenes.
In chemistry, a phase-transfer catalyst or PTC is a catalyst that facilitates the migration of a reactant from one phase into another phase where reaction occurs. Phase-transfer catalysis is a special form of heterogeneous catalysis. Ionic reactants are often soluble in an aqueous phase but insoluble in an organic phase in the absence of the phase-transfer catalyst. The catalyst functions like a detergent for solubilizing the salts into the organic phase. Phase-transfer catalysis refers to the acceleration of the reaction upon the addition of the phase-transfer catalyst.
18-Crown-6 is an organic compound with the formula [C2H4O]6 and the IUPAC name of 1,4,7,10,13,16-hexaoxacyclooctadecane. It is a white, hygroscopic crystalline solid with a low melting point. Like other crown ethers, 18-crown-6 functions as a ligand for some metal cations with a particular affinity for potassium cations (binding constant in methanol: 106 M−1). The point group of 18-crown-6 is S6. The dipole moment of 18-crown-6 varies in different solvent and under different temperature. Under 25 °C, the dipole moment of 18-crown-6 is 2.76 ± 0.06 D in cyclohexane and 2.73 ± 0.02 in benzene. The synthesis of the crown ethers led to the awarding of the Nobel Prize in Chemistry to Charles J. Pedersen.
The Prato reaction is a particular example of the well-known 1,3-dipolar cycloaddition of azomethine ylides to olefins. In fullerene chemistry this reaction refers to the functionalization of fullerenes and nanotubes. The amino acid sarcosine reacts with paraformaldehyde when heated at reflux in toluene to an ylide which reacts with a double bond in a 6,6 ring position in a fullerene via a 1,3-dipolar cycloaddition to yield a N-methylpyrrolidine derivative or pyrrolidinofullerene or pyrrolidino[[3,4:1,2]] [60]fullerene in 82% yield based on C60 conversion.
Endohedral hydrogen fullerene (H2@C60) is an endohedral fullerene containing molecular hydrogen. This chemical compound has a potential application in molecular electronics and was synthesized in 2005 at Kyoto University by the group of Koichi Komatsu. Ordinarily the payload of endohedral fullerenes are inserted at the time of the synthesis of the fullerene itself or is introduced to the fullerene at very low yields at high temperatures and high pressure. This particular fullerene was synthesised in an unusual way in three steps starting from pristine C60 fullerene: cracking open the carbon framework, insert hydrogen gas and zipping up by organic synthesis methods.
Fullerene chemistry is a field of organic chemistry devoted to the chemical properties of fullerenes. 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 fullerenes with substituents outside the cage and endohedral fullerenes with trapped molecules inside the cage.
In chemistry, recrystallization is a technique used to purify chemicals. By dissolving both impurities and a compound in an appropriate solvent, either the desired compound or impurities can be removed from the solution, leaving the other behind. It is named for the crystals often formed when the compound precipitates out. Alternatively, recrystallization can refer to the natural growth of larger ice crystals at the expense of smaller ones.
C70 fullerene is the fullerene molecule consisting of 70 carbon atoms. It is a cage-like fused-ring structure which resembles a rugby ball, made of 25 hexagons and 12 pentagons, with a carbon atom at the vertices of each polygon and a bond along each polygon edge. A related fullerene molecule, named buckminsterfullerene (C60 fullerene), consists of 60 carbon atoms.
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