Purification of endohedral and other fullerenes by chemical methods
AssigneeTDA Research, Inc.
InventorsRobert D. Bolskar, J. Michael Alford
Life of this patent
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Abstract
The invention provides a method of separating a first and a second set of fullerenes in a fullerene mixture. In the method of the invention, a stable fullerene cation is formed of one of the first or the second set of fullerenes. The fullerene cation is then separated from the other set of fullerenes. Optionally, the fullerene cation may be returned to its neutral state. The method of the invention is particularly useful for the purification and separation of endohedral fullerenes from empty fullerenes. However, the method may be applied to the purification of a broad range of endohedral and empty fullerene materials.
Claims51
A method of separating a first and a second fullerene in a fullerene material comprising the steps of:
- (c) introducing the fullerene material into a solvent;
- (d) forming a stable fullerene cation from the first fullerene, wherein the solvent is selected so that at least one of the fullerene cation or the second fullerene is soluble therein;
- and
- (c) separating the fullerene cation or a salt thereof from the second fullerene.
A method of purifying a selected fullerene from a fullerene material containing the selected fullerene and an undesired fullerene comprising the steps of:
- (a) introducing the fullerene material into a solvent;
- (b) forming a stable fullerene cation from one of the selected fullerene or the undesired fullerene;
- (c) decreasing the polarity of the solvent to precipitate a salt of the fullerene cation;
- and
- (d) separating the solvent from the precipitated fullerene cation salt.
A method for separating C60 and C70 fullerenes from a fullerene material containing a first fullerene and C60 and C70 fullerenes comprising the steps of:
- (a) introducing the fullerene material into a solvent;
- (b) forming a stable fullerene cation from the first fullerene, wherein the fullerene cation and the C60 and C70 fullerenes are all soluble in the solvent;
- (c) decreasing the polarity of the solvent to precipitate a salt of the fullerene cation;
- and
- (d) separating the solvent containing the C60 and C70 fullerenes from the fullerene cation salt precipitate.
A method for preparing an endohedral fullerene substantially free of C60 and C70 fullerenes comprising the steps of:
- (a) introducing the fullerene material into a solvent, the fullerene material containing C60 and C70 fullerenes and an endohedral fullerene;
- (b) forming a stable fullerene cation from the endohedral fullerene wherein the endohedral fullerene cation and the C60 and C70 fullerenes are all soluble in the solvent;
- (c) decreasing the polarity of the solvent to precipitate a salt of the endohedral fullerene cation;
- and
- (d) separating the solvent containing the C60 and C70 fullerenes from the endohedral fullerene cation salt.
A method for separation of soluble and easily oxidizable M@C2n from a fullerene material comprising the steps of:
- (a) subliming the fullerene material, thereby separating the M@C2, from any giant fullerenes and nonfullerenes;
- (b) contacting the sublimed fullerene material with an oxidizing agent in a first solvent, thereby forming a first solution containing a M@C2n cation, wherein the first solvent is selected so that the M@C2n cation and any soluble fullerenes are soluble therein;
- (c) filtering the first solution to remove any solids, thereby separating the M@C2n cation from any fullerenes insoluble in the first solvent;
- (d) precipitating the M@C2n cation from the first solution to form a first precipitate containing a salt of the M@C2n cation, thereby separating the M@C2n cation from any fullerenes that remain in the first solution;
- (e) dissolving the first precipitate in a second solvent thereby forming a second solution containing the M@C2n cation, wherein the second solvent is selected so that the M@C2n cation is soluble and that any soluble fullerenes are substantially insoluble therein;
- thereby separating the M@C2n cation from any fullerenes which did not dissolve in the second solvent;
- (f) reacting the filtered second solution with an anion metathesis agent, thereby forming a second precipitate containing a salt of the M@C2n cation, thereby separating the M@C2n cation salt from any fullerenes remaining in the second solution;
- (g) dissolving the second precipitate in a third solvent, wherein the third solvent is selected so that the M@C2n cation and any soluble fullerenes are soluble therein;
- (h) contacting the third solution with an oxidant thereby forming the M@C2, cation in solution;
- (i) precipitating the M@C2n cation from the third solution to form a third precipitate containing a salt of the M@C2n cation, thereby separating the M@C2n cation from any fullerenes remaining in the third solution.
A method for separation of soluble and easily oxidizable M@C2n from a fullerene material comprising the steps of:
- (a) subliming the fullerene material, thereby separating the M@C2n from any giant fullerenes and nonfullerenes;
- (b) contacting the sublimed fullerene material with AgSbF6 in ODCB, thereby forming a first solution containing a M@C2n cation;
- (c) filtering the first solution to remove any solids, thereby separating the M@C2n cation from any fullerenes insoluble in ODCB;
- (d) precipitating the M@C2n cation from the first solution to form a first precipitate containing a salt of the M@C2n cation, thereby separating the M@C2n cation from any fullerenes that remain in the first solution;
- (e) dissolving the first precipitate in CH2Cl2, thereby forming a second solution containing the M@C2n cation and separating the M@C2n cation from any fullerenes which did not dissolve in the CH2Cl2;
- (f) reacting the filtered second solution with n-Bu4NCl, thereby forming a second precipitate containing a salt of the M@C2n cation, thereby separating the M@C2n cation salt from any fullerenes remaining in the second solution;
- (g) dissolving the second precipitate in ODCB, thereby forming a third solution;
- (h) contacting the third solution with AgSbF6 thereby forming the M@C2n cation in solution;
- I (i) precipitating the M@C2n cation from the third solution to form a third precipitate containing a salt of the M@C2n cation, thereby separating the M@C2n cation from any fullerenes remaining in the third solution.
A method for the separation of insoluble M@C2n from a fullerene material comprising the steps of:
- (a) subliming the fullerene material, thereby separating the M@C2n from any giant fullerenes and non-fullerenes;
- (b) contacting the sublimed fullerene material with an oxidizing agent in a solvent, thereby forming a solution containing soluble C2N+M@C2N and C2N;
- (c) filtering the solution to remove any solids, thereby separating the insoluble M@C2n from any fullerenes and any fullerene cations soluble in the solvent.
A method for the separation of soluble M@C2n cations from a fullerene material comprising the steps of:
- (a) contacting the fullerene material with an oxidizing agent in a solvent, thereby forming a solution containing M@C2n cations;
- (b) filtering the solution to remove any solids, thereby separating the soluble M@C2n cations from any insoluble M@C2n and empty fullerenes soluble in the solvent.
A method for the separation of empty small bandgap fullerenes from a fullerene material containing insoluble M@C2n comprising the steps of:
- (a) subliming the fullerene material, thereby separating the M@C2n and small bandgap fullerenes from any giant fullerenes and non-fullerenes;
- (b) contacting the sublimed fullerene material with a oxidizing agent in a solvent, thereby forming a solution containing empty small bandgap fullerene cations;
- (c) filtering the solution to remove the insoluble M@C2n from the soluble small bandgap fullerene cations.
Dependencies are inferred from the claim text.