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Solubility of fullerenes

From Wikipedia, the free encyclopedia
C
60
in solution
C
60
in extra virgin olive oil showing the characteristic purple color of pristine C
60
solutions

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.

General considerations

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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
6
H6 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]

Solubility table

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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

See also

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References

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  1. ^ Guo, T.; Smalley, R.E.; Scuseria, G.E. (1993). "Ab initio theoretical predictions of C
    28
    , C
    28
    H4, C
    28
    F4, (Ti@C
    28
    )H4, and M@C
    28
    (M = Mg, Al, Si, S, Ca, Sc, Ti, Ge, Zr, and Sn)". Journal of Chemical Physics. 99 (1): 352. Bibcode:1993JChPh..99..352G. doi:10.1063/1.465758.
  2. ^ Talyzin, A.V. (1997). "Phase Transition C
    60
    C
    60
    *4C
    6
    H6 in Liquid Benzene". Journal of Physical Chemistry B. 101 (47): 9679–9681. doi:10.1021/jp9720303.
  3. ^ Talyzin, A.V.; Engström, I. (1998). "C
    70
    in Benzene, Hexane, and Toluene Solutions". Journal of Physical Chemistry B. 102 (34): 6477–6481. doi:10.1021/jp9815255.
  4. ^ Beck, Mihály T.; Mándi, Géza (1997). "Solubility of C
    60
    ". Fullerenes, Nanotubes and Carbon Nanostructures. 5 (2): 291–310. doi:10.1080/15363839708011993.
  5. ^ Bezmel'nitsyn, V.N.; Eletskii, A.V.; Okun', M.V. (1998). "Fullerenes in solutions". Physics-Uspekhi. 41 (11): 1091–1114. Bibcode:1998PhyU...41.1091B. doi:10.1070/PU1998v041n11ABEH000502.
  6. ^ Ruoff, R.S.; Tse, Doris S.; Malhotra, Ripudaman; Lorents, Donald C. (1993). "Solubility of fullerene (C
    60
    ) in a variety of solvents"
    (PDF). Journal of Physical Chemistry. 97 (13): 3379–3383. doi:10.1021/j100115a049.
  7. ^ Sivaraman, N.; Dhamodaran, R.; Kaliappan, I.; Srinivasan, T. G.; Vasudeva Rao, P. R. P.; Mathews, C. K. C. (1994). "Solubility of C
    70
    in Organic Solvents". Fullerene Science and Technology. 2 (3): 233–246. doi:10.1080/15363839408009549.
  8. ^ Semenov, K. N.; Charykov, N. A.; Keskinov, V. A.; Piartman, A. K.; Blokhin, A. A.; Kopyrin, A. A. (2010). "Solubility of Light Fullerenes in Organic Solvents". Journal of Chemical & Engineering Data. 55: 13–36. doi:10.1021/je900296s.