Title:
Functionalized nanotubes
Document Type and Number:
Kind Code:
A1

Abstract:
Graphitic nanotubes, which includes tubular fullerenes (commonly called “buckytubes”) and fibrils, which are functionalized by chemical substitution or by adsorption of functional moieties. More specifically the invention relates to graphitic nanotubes which are uniformly or non-uniformly substituted with chemical moieties or upon which certain cyclic compounds are adsorbed and to complex structures comprised of such functionalized nanotubes linked to one another. The invention also relates to methods for introducing functional groups onto the surface of such nanotubes. The invention further relates to uses for functionalized nanotubes.
Representative Image:
Functionalized nanotubes
Inventors:
Fischer, Alan (Cambridge, MA, US)
Hoch, Robert (Hensonville, NY, US)
Moy, David (Winchester, MA, US)
Lu, Ming (Lanham, MD, US)
Martin, Mark (N. Bethesda, MD, US)
Niu, Chun Ming (Somerville, MA, US)
Ogata, Naoya (Tokyo, JP)
Tennent, Howard (Kennett Square, PA, US)
Dong, Liwen (Rockville, MD, US)
Sun, Ji (Potomac, MD, US)
Helms, Larry (Germantown, MD, US)
Jameison, Fabian (Gaithersburg, MD, US)
Liang, Pam (Alhambra, CA, US)
Simpson, David (N. Bethesda, MD, US)
Application Number:
10/837125
Publication Date:
10/14/2004
Filing Date:
04/30/2004
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Referenced by:
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Export Citation:
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Assignee:
Hyperion Catalysis International, Inc.
Primary Class:
423/447.200
International Classes:
(IPC1-7): D01F009/12; C07C063/333
Attorney, Agent or Firm:
INTELLECTUAL PROPERTY DEPARTMENT,KRAMER LEVIN NAFTALIS & FRANKEL LLP (919 THIRD AVENUE, NEW YORK, NY, 10022, US)
Claims:

What is claimed is:



1. A composition of matter of the formula [Rm wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube having a length to diameter ratio of greater than 5 and a diameter of less than 0.5 micron, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of R is the same and is selected from SO3H, COOH, NH2, OH, R′CHOH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′21 Hg—X, TlZ2 and Mg—X, y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, and Z is carboxylate or trifluoroacetate.

2. A composition of matter of the formula [Rm wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic fibril being substantially free of pyrolytically deposited carbon, the projection of the graphite layers on said fibrils extends for a distance of at least two fibril diameters, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of R is the same and is selected from SO3H, COOH, NH2, OH, R′CHOH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, and Z is carboxylate or trifluoroacetate.

3. A composition of matter of the formula [Rm wherein the carbon atoms, Cn, are surface atoms of a fishbone fibril, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of R is the same and is selected from SO3H, COOH, NH2, OH, R′CHOH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X. y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, and Z is carboxylate or trifluoroacetate.

4. A composition of matter of the formula [Rm wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube having a length to diameter ratio of greater than 5 and a diameter of less than 0.5 micron, n is an integer, L is a number less than 0.1 n and m is a number less than 0.5 n, each of R may be the same or different and is selected from SO3H, COOH, NH2, OH, R′CHOH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, y is an integer equal to or less than 3, R′ is selected from hydrogen, alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), R″ is a fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and further provided that where each of R is an oxygen-containing group COOH is not present.

5. A composition of matter of the formula [Rm wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic fibril being substantially free of pyrolytically deposited carbon, the projection of the graphite layers on said fibrils extends for a distance of at least two fibril diameters, n is an integer, L is a number less than 0.1 n and m is a number less than 0.5 n, each of R may be the same or different and is selected from SO3H, COOH, NH2, OH, R′CHOH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), R″ is a fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is a carboxylate or trifluoroacetate, and further provided that where each of R is an oxygen-containing group COOH is not present.

6. A composition of matter of the formula [Rm wherein the carbon atoms, Cn, are surface atoms of a fishbone fibril, n is an integer, L is a number less than 0.1 n and m is a number less than 0.5 n, each of R may be the same or different and is selected from SO3H, COOH, NH2, OH, R′CHOH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), R″ is a fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is a carboxylate or trifluoroacetate, and further provided that where each of R is an oxygen-containing group COOH is not present.

7. A composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube having a length to diameter ratio of greater than 5 and a diameter of less than 0.1 micron, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 19embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2OR′, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′, 20embedded image y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

8. The composition of claim 7 wherein A is 21embedded image R′ is H and Y is an amino acid selected from the group consisting of lysine, serine, threonine, tyrosine, aspartic acid and glutamic acid.

9. A composition of matter of the formula [CnHLAm wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic fibril being substantially free of pyrolytically deposited carbon, the projection of the graphite layers on said fibrils extends for a distance of at least two fibril diameters, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 22embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2OR′, R′—R″, R′—N—CO, (C2H4OwH, C3H6Ow, C2H4O)w—R′, (c3H6O)w—R′, and 23embedded image y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

10. The composition of claim 9 wherein A is 24embedded image R′ is H and Y is an amino acid selected from the group consisting of lysine, serine, threonine, tyrosine, aspartic acid and glutamic acid.

11. A composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface atoms of a fishbone fibril, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 25embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2OR′, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (c3H6O)w—R′, R′ 26embedded image y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

12. The composition of claim 11 wherein: A is 27embedded image R′ is H, and Y is an amino acid selected from the group consisting of lysine, serine, threonine, tyrosine, aspartic acid and glutamic acid.

13. A composition of matter of the formula [[R′-A]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube having a length to diameter ratio of greater than 5 and a diameter of less than 0.5 micron, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of R′ is alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), A is selected from 28embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2OR′, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4Ow—R′, (C3H6O)w—R′, 29embedded image y is an integer equal to or less than 3, R′ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

14. The composition of claim 13 wherein A is 30embedded image R′ is H, and Y is an amino acid selected from the group consisting of lysine, serine, threonine, tyrosine, aspartic acid and glutamic acid.

15. A composition of matter of the formula [[R′-A]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic fibril being substantially free of pyrolytically deposited carbon, the projection of the graphite layers on said fibrils extends for a distance of at least two fibril diameters, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of R′ is alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), A is selected from 31embedded image Y is an appropriate functional group of a protein, a peptide, an enzyme, an amino acid, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—NR′2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2OR′, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′, 32embedded image y is an integer equal to or less than 3, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

16. The composition of claim 15 wherein: A is 33embedded image R′ is H, and Y is an amino acid selected from the group consisting of lysine, serine, threonine, tyrosine, aspartic acid and glutamic acid.

17. A composition of matter of the formula [[R′-A]m wherein the carbon atoms, Cn, are surface atoms of a fishbone fibril, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of R′ is alkyl., aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkyether), A is selected from 34embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R—)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2OR′, R′—R″, R′—N—CO, (c2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′ 35embedded image y is an integer equal to or less than 3, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

18. A composition of matter of the formula [[X′-Aa]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube having a length to diameter ratio of greater than Sand a diameter of less than 0.5 micron, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, a is an integer less than 10, each of A is selected from 36embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiOR′3, R′SiOR′yR′3−y, R′SiO—SiR′2yOR′, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (c3H6O)w—R′, R′ 37embedded image y is an integer equal to or less than 3, R′ is alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, X′ is a polynuclear aromatic, polyheteronuclear aromatic or metallopolyheteronuclear aromatic moiety, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

19. A composition of matter of the formula [[X′-Aa]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic fibril being substantially free of pyrolytically deposited carbon, the projection of the graphite layers on said fibrils extends for a distance of at least two fibril diameters, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, a is an integer less than 10, each of A is selected from 38embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2R′, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′ 39embedded image y is an integer equal to or less than 3, R′ is alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, X′ is a polynuclear aromatic, polyheteronuclear aromatic or metallopolyheteronuclear aromatic moiety, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

20. A composition of matter of the formula [[X′-Aa]m wherein the carbon atoms, Cn, are surface atoms of a fishbone fibril, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, a is an integer less than 10, each of A is selected from 40embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′O—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′N+(R′)3X−, R′SiR′3, R′SiOR′yR′3−y, R′SiO—SiR′2OR′, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′ 41embedded image y is an integer equal to or less than 3, R′ is alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, X′ is a polynuclear aromatic, polyheteronuclear aromatic or metallopolyheternuclear aromatic moiety, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200.

21. A method of forming a composition of matter of the formula [CH(R′)OH]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkylether), comprising the step of reacting the surface carbons with a compound having the formula R′CH2OH in the presence of a free radical initiator under conditions sufficient to form functionalized nanotubes having the formula [CH(R′)OH]m.

22. The method of claim 21 wherein said free radical initiator is benzoyl peroxide.

23. A method of forming a composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 42embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′SiR′3R′—N+(R′)3X−, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′ and 43embedded image R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the steps of: (a) reacting the surface carbons with at least one appropriate reagent under conditions sufficient to form substituted nanotubes having the formula [Rm, wherein each of R is the same and is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3; and (b) reacting the substituted nanotubes [CnHLRm with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula [Am.

24. A method of forming a composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube having a length to diameter ratio of greater than 5 and a diameter of less than 0.1 micron, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 44embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R′—N+(R′)3X−, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (c3H6O)w—R′, R′ and 45embedded image R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the steps of: (a) reacting the surface carbons with at least one appropriate reagent under conditions sufficient to form substituted nanotubes having the formula [Rm, wherein each of R is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3; and (b) reacting the substituted nanotubes [Rm with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula. [Am.

25. A method of forming a composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube being substantially free of pyrolytically deposited carbon, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 46embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R′—N+(R′)3X−, R′—R″, R′—N—CO, (c2H4OwH, C3H6OwH, C2H4O)w—R′, (c3H6O)w—R′, R′ and 47embedded image R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the steps of: (a) reacting the surface carbons with at least one appropriate reagent under conditions sufficient to form substituted nanotubes having the formula (CnHLRm, wherein each of R is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3; and (b) reacting the substituted nanotubes (CnHLRm with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula [Am.

26. A method of forming a composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 48embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R′—N+(R′)3X−, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (c3H6O)w—R′, R′ and 49embedded image R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the step of reacting substituted nanotubes [Rm with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula [Am, where each of R is the same and is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3.

27. A method of forming a composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube having a length to diameter ratio of greater than 5 and a diameter of less than 0.1 micron, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 50embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R—N+(R′)3X−, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′ and 51embedded image R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the step of reacting substituted nanotubes [Rm with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula [Am, where each of R is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′wR′3−y, SiSiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3.

28. A method of forming a composition of matter of the formula [Am wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube being substantially free of pyrolytically deposited carbon, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of A is selected from 52embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—N(R′)2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R′—N+(R′)3X−, R′—R″, R′—N—CO, (c2H4OwH, C3H6OwH, C2H4O)w—R′, (c3H6O)w—R′, R′ and 53embedded image R′ is alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the step of reacting substituted nanotubes [Rm with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula [Am, where each of R is selected from SO3H, COOH, NH2, OH, CH(′R)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3.

29. A method of forming a composition of matter of the formula [[R′-A]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is an integer, L is a number less than 0.4 n, m is a number less than 0.5 n, R′ is alkyl, aryl, cycloalkyl, aralkyl, cycloaryl, or poly(alkyether), X is a halide, each of A is selected from 54embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—NH2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′ and 55embedded image R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, and Z is carboxylate or trifluoroacetate, comprising the step of reacting substituted nanotubes having the formula [[R′—R]m with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula [[R′A]m, where each of R is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3.

30. A method of forming a composition of matter of the formula [[X′Ra]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, a is zero or an integer less than 10, each of R is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, y is an integer equal to or less than 3, R′ is alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, X is a halide, X′ is a polynuclear aromatic, polyheteronuclear aromatic or metallopolyheteronuclear aromatic moiety, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, and Z is carboxylate or trifluoroacetate, comprising the step of adsorbing at least one appropriate macrocyclic compound onto the surface of the graphitic nanotube under conditions sufficient to form a functionalized nanotube having the formula [[X′—Ra]m.

31. A method of forming a composition of matter of the formula [[X′-Aa]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, a is an integer less than 10, each of A is selected from 56embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—NH2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH, C2H4O)w—R′, (C3H6O)w—R′, R′ and 57embedded image R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, X′ is a polynuclear aromatic, polyheteronuclear aromatic or metallopolyheteronuclear aromatic moiety, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the steps of: (a) adsorbing at least one appropriate macrocyclic compound onto the surface of the graphitic nanotube under conditions sufficient to form a substituted nanotube having the formula [[X′—Ra]m, where each of R is selected from SO3H, COOH, NH2, OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2—OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3; and (b) reacting the substituted nanotubes [[X′—Ra]m with at least one appropriate reagent under conditions sufficient to form a functionalized nanotube having the formula [[X′-Aa]m.

32. A method of forming a composition of matter of the formula [[X′-Aa]m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, wherein n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, a is an integer less than 10, each of A is selected from 58embedded image Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, an oligonucleotide, a nucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—NH2, R′SH, R′CHO, R′CN, R′X, R′SiR′3, R′—R″, R′—N—CO, (C2H4OwH, C3H6OwH c2H4O)w—R′, (C3H6O)w—R′, R′ and 59embedded image R′ is alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, X′ is a polynuclear aromatic, polyheteronuclear aromatic or metallopolyheteronuclear aromatic moiety, Z is carboxylate or trifluoroacetate, and w is an integer greater than one and less than 200, comprising the step of reacting the substituted nanotubes [[X′—Ra]m with at least one appropriate reagent under conditions sufficient to form a functionalized nanotube having the formula [[X′-Aa]m, where each of R is selected from SO3H, COOH, NH2, OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3, SiOR′yR′3−y, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, and y is an integer equal to or less than 3.

33. A method for forming a composition of matter of the formula 60embedded image wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is an integer, L is a number less than 0.1 n and m is a number less that 0.5 n, R′ is alkyl, aryl, cycloalkyl or cycloaryl, comprising the steps of: reacting the surface carbons with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes having the formula [COOH)m; and reacting the functionized nanotubes with a compound having two or more amino groups under conditions sufficient to form functionalized nanotubes having the formula 61embedded image

34. A method of forming a composition of matter of the formula [Rm wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n in an integer, L is a number less than 0.1 n, m is a number less than 0.5 n, each of R is the same and is selected from SO3H, COOH, NH2, OH, CH(R′)OH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′3′, SiOR′yR′3−y′, SiO—SiR′2OR′, R″, Li, AlR′2, Hg—X, TlZ2 and Mg—X, y is an integer equal to or less than 3, R′ is hydrogen, alkyl, aryl, cycloalkyl, aralkyl or cycloaryl, R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl or fluoroaralkyl, X is a halide, and Z is carboxylate or trifluoroacetate, comprising the step of reacting the surface carbons with at least one enzyme capable of accepting the nanotube as a substrate and of performing a chemical reaction resulting in a composition of matter of the formula [Rm, in aqueous suspension under conditions acceptable for the at least one enzyme to carry out the reaction.

35. The method of claim 34 wherein Rm is —OH and the enzyme is a cytochrome p450 enzyme or a peroxidase.

36. A method for forming a composition of matter of the formula [NH2)m wherein the carbon atoms, Cn, are surface carbons of a substantially cylindrical, graphitic nanotube, n is in an integer, L is a number less than 0.1 n and m is a number less than 0.5 n, comprising the steps of: reacting the surface carbons with nitric acid and sulfuric acid to form nitrated nanotubes; and reducing the nitrated nanotubes to form [NH2)m.

37. A method of uniformly substituting the surface of carbon nanotubes with a functional group comprising contacting carbon nanotubes with an effective amount of reactant capable of uniformly substituting a functional group onto the surface of said carbon nanotubes.

38. The method of claim 37, wherein the reactant is a phthalocyanine.

39. The method of claim 38, wherein the reactant is nickel (II) phthalocyaninetetrasulfonic acid (tetrasodium salt) or 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine.

40. A surface-modified carbon nanotube made by the method comprising contacting carbon nanotube with an effective amount of a reactant for substituting a functional group onto the surface of said carbon nanotube.

41. The surface-modified carbon nanotube of claim 40, wherein the reactant is a phthalocyanine.

42. The surface-modified carbon nanotube of claim 41, wherein the reactant is nickel (II) phthalocyaninetetra-sulfonic acid (tetrasodium salt) or 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine.

43. A method for linking a protein to a nanotube comprising the steps of: contacting a nanotube bearing an NHS ester group with a protein under conditions sufficient to form a covalent bond between the NHS ester and the amine group of the protein.

44. An electrode comprising functionalized nanotubes.

45. The electrode of claim 44 wherein the electrode is a porous flow through electrode.

46. An electrode as recited in claim 45, wherein the functionalized nanotubes are phthalocyanine substituted nanotubes.

47. A porous material comprising a multiplicity of functionalized nanotube networks, wherein said functionalized nanotube network comprise at least two functional fibrils linked at functional groups by at least one linker moiety, wherein said linker moiety is either bifunctional or polyfunctional.

48. A method for separating a solute of interest from a sample comprising the steps of: physically or chemically modifying the surface carbons of a graphitic nanotube with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes; immobilizing a substance capable of binding the solute of interest on the functionalized nanotubes; and exposing the substituted nanotubes to the fraction containing the solute of interest under conditions sufficient for the solute of interest to bind the substance immobilized on the functionalized nanotubes.

49. The method of claim 48 wherein the solute of interest is a protein.

50. The method of claim 49, further comprising the step of recovering the functionalized nanotubes.

51. The method of claim 48, wherein the functionalized nanotubes are in the form of a porous mat.

52. The method of claim 48, wherein the functionalized nanotubes are in the form of a packed column.

53. The method of claim 48, wherein the binding is reversible.

54. The method of claim 48, wherein the binding is an ionic interaction.

55. The method of claim 48, wherein the binding is a hydrophobic interaction.

56. The method of claim 48, wherein the binding is through specific molecular recognition.

57. A polymer bead comprising an essentially spherical bead with a diameter of less than 25 Åto which is linked a plurality of functionalized nanotubes.

58. The polymer bead of claim 57 wherein the bead is magnetic.

59. A method for catalyzing a reaction wherein at least one reactant is converted to at least one product comprising the steps of: physically or chemically modifying the surface carbons of a graphitic nanotube with at least one appropriate reagent under conditions sufficient to form functionalized nanotubes; immobilizing a biocatalyst capable of catalyzing a reaction on the functionalized nanotubes; and contacting the functionalized nanotubes with the reactant(s) under conditions sufficient for the reactants(s) to be converted to the product(s).

60. The method of claim 59, further comprising the step of recovering the functionalized nanotubes after the reaction is complete.

61. The method of claim 59 wherein the functionalized nanotubes are in the form of a porous mat.

62. The method of claim 59 wherein the functionalized nanotubes are in the form of a packed column.

63. A method for synthesizing a peptide comprising the step of attaching the terminal amino acid of the peptide to a nanotube via a reversible linker.

64. The method of claim 63 wherein the linker is 4-(hydroxymethyl)phenoxyacetic acid.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part of U.S. application Ser. No. 08/352,400, filed Dec. 8, 1994, the contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

[0002] The invention relates broadly to graphitic nanotubes, which includes tubular fullerenes (commonly called “buckytubes”) and fibrils, which are functionalized by chemical substitution or by adsorption of functional moieties. More specifically the invention relates to graphitic nanotubes which are uniformly or non-uniformly substituted with chemical moieties or upon which certain cyclic compounds are adsorbed and to complex structures comprised of such functionalized fibrils linked to one another. The invention also relates to methods of introducing functional groups onto the surface of such fibrils.

BACKGROUND OF THE INVENTION

[0003] This invention lies in the field of submicron graphitic fibrils, sometimes called vapor grown carbon fibers. Carbon fibrils are vermicular carbon deposits having diameters less than 1.0μ, preferably less than 0.5μ, and even more preferably less than 0.2μ. They exist in a variety of forms and have been prepared through the catalytic decomposition of various carbon-containing gases at metal surfaces. Such vermicular carbon deposits have been observed almost since the advent of electron microscopy. A good early survey and reference is found in Baker and Harris, Chemistry and Physics of Carbon , Walker and Thrower ed., Vol. 14, 1978, p. 83, hereby incorporated by reference. See also, Rodriguez, N., J. Mater. Research , Vol. 8, p. 3233 (1993), hereby incorporated by reference.

[0004] In 1976, Endo et al. (see Obelin, A. and Endo, M., J. of Crystal Growth , Vol. 32 (1976), pp. 335-349, hereby incorporated by reference) elucidated the basic mechanism by which such carbon fibrils grow. There were seen to originate from a metal catalyst particle, which, in the presence of a hydrocarbon containing gas, becomes supersaturated in carbon. A cylindrical ordered graphitic core is extruded which immediately, according to Endo et al., becomes coated with an outer layer of pyrolytically deposited graphite. These fibrils with a pyrolytic overcoat typically have diameters in excess of 0.1 Å, more typically 0.2 to 0.5μ.

[0005] In 1983, Tennent, U.S. Pat. No. 4,663,230, hereby incorporated by reference, succeeded in growing cylindrical ordered graphite cores, uncontaminated with pyrolytic carbon. Thus, the Tennent invention provided access to smaller diameter fibrils, typically 35 to 700 Å (0.0035 to 0.0701μ) and to an ordered, “as grown” graphitic surface. Fibrillar carbons of less perfect structure, but also without a pyrolytic carbon outer layer have also been grown.

[0006] The fibrils, buckytubes and nanofibers that are functionalized in this application are distinguishable from continuous carbon fibers commercially available as reinforcement materials. In contrast to fibrils, which have, desirably large, but unavoidably finite aspect ratios, continuous carbon fibers have aspect ratios (L/D) of at least 104 and often 106 or more. The diameter of continuous fibers is also far larger than that of fibrils, being always >1.0 and typically 5 to 7μ.

[0007] Continuous carbon fibers are made by the pyrolysis of organic precursor fibers, usually rayon, polyacrylonitrile (PAN) and pitch. Thus, they may include heteroatoms within their structure. The graphitic nature of “as made” continuous carbon fibers varies, but they may be subjected to a subsequent graphitization step. Differences in degree of graphitization, orientation and crystallinity of graphite planes, if they are present, the potential presence of heteroatoms and even the absolute difference in substrate diameter make experience with continuous fibers poor predictors of nanofiber chemistry.

[0008] Tennent, U.S. Pat. No. 4,663,230 describes carbon fibrils that are free of a continuous thermal carbon overcoat and have multiple graphitic outer layers that are substantially parallel to the fibril axis. As such they may be characterized as having their c-axes, the axes which are perpendicular to the tangents of the curved layers of graphite, substantially perpendicular to their cylindrical axes. They generally have diameters no greater than 0.1μ and length to diameter ratios of at least 5. Desirably they are substantially free of a continuous thermal carbon overcoat, i.e., pyrolytically deposited carbon resulting from thermal cracking of the gas feed used to prepare them.

[0009] Tennent, et al., U.S. Pat. No. 5,171,560, hereby incorporated by reference, describes carbon fibrils free of thermal overcoat and having graphitic layers substantially parallel to the fibril axes such that the projection of said layers on said fibril axes extends for a distance of at least two fibril diameters. Typically, such fibrils are substantially cylindrical, graphitic nanotubes of substantially constant diameter and comprise cylindrical graphitic sheets whose c-axes are substantially perpendicular to their cylindrical axis. They are substantially free of pyrolytically deposited carbon, have a diameter less than 0.1μ and a length to diameter ratio of greater than 5. These fibrils are of primary interest in the invention.

[0010] Further details regarding the formation of carbon fibril aggregates may be found in the disclosure of Snyder et al., U.S. patent application Ser. No. 149,573, filed Jan. 28, 1988, and PCT Application No. US89/00322, filed Jan. 28, 1989 (“Carbon Fibrils”) WO 89/07163, and Moy et al., U.S. patent application Ser. No. 413,837 filed Sep. 28, 1989 and PCT Application No. US90/05498, filed Sep. 27, 1990 (“Fibril Aggregates and Method of Making Same”) WO 91/05089, all of which are assigned to the same assignee as the invention here and are hereby incorporated by reference.

[0011] Moy et al., U.S. Ser. No. 07/887,307 filed May 22, 1992, hereby incorporated by reference, describes fibrils prepared as aggregates having various macroscopic morphologies (as determined by scanning electron microscopy) in which they are randomly entangled with each other to form entangled balls of fibrils resembling bird nests (“BN”); or as aggregates consisting of bundles of straight to slightly bent or kinked carbon fibrils having substantially the same relative orientation, and having the appearance of combed yarn (“CY”) e.g., the longitudinal axis of each fibril (despite individual bends or kinks) extends in the same direction as that of the surrounding fibrils in the bundles; or as aggregates consisting of straight to slightly bent or kinked fibrils which are loosely entangled with each other to form an “open net” (“ON”) structure. In open net structures the degree of fibril entanglement is greater than observed in the combed yarn aggregates (in which the individual fibrils have substantially the same relative orientation) but less than that of bird nests. CY and ON aggregates are more readily dispersed than BN making them useful in composite fabrication where uniform properties throughout the structure are desired.

[0012] When the projection of the graphitic layers on the fibril axis extends for a distance of less than two fibril diameters, the carbon planes of the graphitic nanofiber, in cross section, take on a herring bone appearance. These are termed fishbone fibrils. Geus, U.S. Pat. No. 4,855,091, hereby incorporated by reference, provides a procedure for preparation of fishbone fibrils substantially free of a pyrolytic overcoat. These fibrils are also useful in the practice of the invention.

[0013] Carbon nanotubes of a morphology similar to the catalytically grown fibrils described above have been grown in a high temperature carbon arc (Iijima, Nature 354 56 1991). It is now generally accepted (Weaver, Science 265 1994) that these arc-grown nanofibers have the same morphology as the earlier catalytically grown fibrils of Tennent. Arc grown carbon nanofibers are also useful in the invention.

[0014] McCarthy et al., U.S. patent application Ser. No. 351,967 filed May 15, 1989, hereby incorporated by reference, describes processes for oxidizing the surface of carbon fibrils that include contacting the fibrils with an oxidizing agent that includes sulfuric acid (H 2 SO 4 ) and potassium chlorate (KClO 3 ) under reaction conditions (e.g., time, temperature, and pressure) sufficient to oxidize the surface of the fibril. The fibrils oxidized according to the processes of McCarthy, et al. are non-uniformly oxidized, that is, the carbon atoms are substituted with a mixture of carboxyl, aldehyde, ketone, phenolic and other carbonyl groups.

[0015] Fibrils have also been oxidized non-uniformly by treatment with nitric acid. International Application PCT/US94/10168 discloses the formation of oxidized fibrils containing a mixture of functional groups. Hoogenvaad, M. S., et al. (“Metal Catalysts supported on a Novel Carbon Support”, Presented at Sixth International Conference on Scientific Basis for the Preparation of Heterogeneous Catalysts, Brussels, Belgium, September 1994) also found it beneficial in the preparation of fibril-supported precious metals to first oxidize the fibril surface with nitric acid. Such pretreatment with acid is a standard step in the preparation of carbon-supported noble metal catalysts, where, given the usual sources of such carbon, it serves as much to clean the surface of undesirable materials as to functionalize it.

[0016] In published work, McCarthy and Bening (Polymer Preprints ACS Div. of Polymer Chem. 30 (1)420(1990)) prepared derivatives of oxidized fibrils in order to demonstrate that the surface comprised a variety of oxidized groups. The compounds they prepared, phenylhydrazones, haloaromaticesters, thallous salts, etc., were selected because of their analytical utility, being, for example, brightly colored, or exhibiting some other strong and easily identified and differentiated signal. These compounds were not isolated and are, unlike the derivatives described herein, of no practical significance.

[0017] While many uses have been found for carbon fibrils and aggregates of carbon fibrils, as described in the patents and patent applications referred to above, many different and important uses may be developed if the fibril surfaces are functionalized. Functionalization, either uniformly or non-uniformly, permits interaction of the functionalized fibrils with various substrates to form unique compositions of matter with unique properties and permits fibril structures to be created based on linkages between the functional sites on the fibrils' surfaces.

OBJECTS OF THE INVENTION

[0018] It is therefore a primary object of this invention to provide functionalized fibrils, i.e. fibrils whose surfaces are uniformly or non-uniformly modified so as to have a functional chemical moiety associated therewith.

[0019] It is a further and related object of this invention to provide fibrils whose surfaces are functionalized by reaction with oxidizing or other chemical media.

[0020] It is a further and related object of this invention to provide fibrils whose surfaces are uniformly modified either by chemical reaction or by physical adsorption of species which themselves have a chemical reactivity.

[0021] It is a further object to provide fibrils whose surfaces have been modified e.g. by oxidation which are then further modified by reaction with functional groups.

[0022] It is still a further and related object of this invention to provide fibrils whose surfaces are modified with a spectrum of functional groups so that the fibrils can be chemically reacted or physically bonded to chemical groups in a variety of substrates.

[0023] It is still the further and related object of this invention to provide complex structures of fibrils by linking functional groups on the fibrils with one another by a range of linker chemistries.

[0024] It is still a further and related object of this invention to provide methods for chemical modification of fibril surfaces and methods for physically absorbing species on the surfaces of fibrils so as to provide, in each case, a functional moiety associated with the surface of the fibril.

[0025] It is yet a further object of this invention to provide new compositions of matter based upon the functionalized fibrils.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a graphical representation of an assay of BSA binding to plain fibrils, carboxy fibrils, and PEG-modified fibrils.

[0027] FIG. 2 is a graphical representation of an assay of β-lactoglobulin binding to carboxy fibrils and PEG-modified fibrils prepared by two different methods.

[0028] FIG. 3 is a graphical representation of the elution profile of bovine serum albumin (BSA) on a tertiary amine fibril column.

[0029] FIG. 4 is a graphical representation of the elution profile of BSA on a quaternary amine fibril column.

[0030] FIG. 5 is the reaction sequence for the preparation of lysine-based dendrimeric fibrils.

[0031] FIG. 6 is a graphical representation of cyclic voltammograms demonstrating the use of iron phthalocyanine modified fibrils in a flow cell.

[0032] FIG. 7 is the reaction sequence for the preparation of bifunctional fibrils by the addition of NE-(tert-butoxycarbonyl)-L-lysine.

[0033] FIG. 8 is a graphical representation of the results of the synthesis of ethyl butyrate using fibril-immobilized lipase.

[0034] FIG. 9 is a graphical representation of the results of separation of alkaline phosphatase (AP) from a mixture of AP and β-galactosidase (βG) using AP inhibitor-modified fibrils.

[0035] FIG. 10 is a graphical representation of the results of separation of βG from a mixture of AP and βG using βG-modified fibrils.

DETAILED DESCRIPTION OF THE INVENTION

[0036] The invention is directed to compositions which broadly have the formula

[R m

[0037] where n is an integer, L is a number less than 0.1 n, m is a number less than 0.5 n,

[0038] each of R is the same and is selected from SO 3 H, COOH, NH 2 , OH, R′CHOH, CHO, CN, COCl, halide, COSH, SH, COOR′, SR′, SiR′ 3 , SiOR′ y R′ 3−y , SiO—SiR′ 2 OR′, R″, Li, AlR′ 2 , Hg—X, TlZ 2 and Mg—X,

[0039] y is an integer equal to or less than 3,

[0040] R′ is hydrogen, alkyl, aryl, cycloalkyl, or aralkyl, cycloaryl, or poly(alkylether),

[0041] R″ is fluoroalkyl, fluoroaryl, fluorocycloalkyl, fluoroaralkyl or cycloaryl,

[0042] X is halide, and

[0043] Z is carboxylate or trifluoroacetate.

[0044] The carbon atoms, C n , are surface carbons of a substantially cylindrical, graphitic nanotube of substantially constant diameter. The nanotubes include those having a length to diameter ratio of greater than 5 and a diameter of less than 0.5μ, preferably less than 0.1. The nanotubes can also be substantially cylindrical, graphitic nanotubes which are substantially free of pyrolytically deposited carbon, more preferably those characterized by having a projection of the graphite layers on the fibril axis which extends for a distance of at least two fibril diameters and/or those having cylindrical graphitic sheets whose c-axes are substantially perpendicular to their cylindrical axis. These compositions are uniform in that each of R is the same.

[0045] Non-uniformly substituted nanotubes are also prepared. These include compositions of the formula

[R m

[0046] where n, L, m, R and the nanotube itself are as defined above, provided that each of R does not contain oxygen, or, if each of R is an oxygen-containing group COOH is not present.

[0047] Functionalized nanotubes having the formula

[R m

[0048] where n, L, m, R and R′ have the same meaning as above and the carbon atoms are surface carbon atoms of a fishbone fibril having a length to diameter ratio greater than 5, are also included within the invention. These may be uniformly or non-uniformly substituted. Preferably, the nanotubes are free of thermal overcoat and have diameters less than 0.5μ.

[0049] Also included in the invention are functionalized nanotubes having the formula

[[R′—R] m

[0050] where n, L, m, R′ and R have the same meaning as above. The carbon atoms, C n , are surface carbons of a substantially cylindrical, graphitic nanotube of substantially constant diameter. The nanotubes have a length to diameter ratio of greater than 5 and a diameter of less than 0.5μ, preferably less than 0.1. The nanotubes may be nanotubes which are substantially free of pyrolytically deposited carbon. More preferably, the nanotubes are those in which the projection of the graphite layers on the fibril axes extends for a distance of at least two fibril diameters and/or those having cylindrical graphitic sheets whose c-axes are substantially perpendicular to their cylindrical axis.

[0051] In both uniformly and non-uniformly substituted nanotubes, the surface atoms C n are reacted. Most carbon atoms in the surface layer of a graphitic fibril, as in graphite, are basal plane carbons. Basal plane carbons are relatively inert to chemical attack. At defect sites, where, for example, the graphitic plane fails to extend fully around the fibril, there are carbon atoms analogous to the edge carbon atoms of a graphite plane (See Urry, Elementary Equilibrium Chemistry of Carbon , Wiley, New York 1989.) for a discussion of edge and basal plane carbons).

[0052] At defect sites, edge or basal plane carbons of lower, interior layers of the nanotube may be exposed. The term surface carbon includes all the carbons, basal plane and edge, of the outermost layer of the nanotube, as well as carbons, both basal plane and/or edge, of lower layers that may be exposed at defect sites of the outermost layer. The edge carbons are reactive and must contain some heteroatom or group to satisfy carbon valency.

[0053] The substituted nanotubes described above may advantageously be further functionalized. Such compositions include compositions of the formula

[A m

[0054] where the carbons are surface carbons of a nanotube, n, L and m are as described above,

[0055] A is selected from 1 embedded image

[0056] Y is an appropriate functional group of a protein, a peptide, an amino acid, an enzyme, an antibody, a nucleotide, an oligonucleotide, an antigen, or an enzyme substrate, enzyme inhibitor or the transition state analog of an enzyme substrate or is selected from R′—OH, R′—NR′ 2 , R′SH, R′CHO, R′CN, R′X, R′N + (R′) 3 X − , R′SiR′ 3 , R′SiOR′ y R′ 3−y R′SiO—SiR′ 2 OR′, R′—R″, R′—N—CO, (C 2 H 4 O w , C 3 H 6 O w H, C 2 H 4 O) w —R′, (C 3 H 6 O) w —R′, 2 embedded image

[0057] and w is an integer greater than one and less than 200. The carbon atoms, C n , are surface carbons of a substantially cylindrical, graphitic nanotube of substantially constant diameter. The nanotubes include those having a length to diameter ratio of greater than 5 and a diameter of less than 0.1μ, preferably less than 0.051μ. The nanotubes can also be substantially cylindrical, graphitic nanotubes which are substantially free of pyrolytically deposited carbon. More preferably they are characterized by having a projection of the graphite layers on the fibril axes which extends for a distance of at least two fibril diameters and/or they are comprised of cylindrical graphitic sheets whose c-axes are substantially perpendicular to their cylindrical axes. Preferably, the nanotubes are free of thermal overcoat and have diameters less than 0.5μ.

[0058] The functional nanotubes of structure

[[R′—R] m

[0059] may also be functionalized to produce compositions having the formula

[[R′-A] m

[0060] where n, L, m, R′ and A are as defined above. The carbon atoms, C n , are surface carbons of a substantially cylindrical, graphitic nanotube of substantially constant diameter. The nanotubes include those having a length to diameter ratio of greater than 5 and a diameter of less than 0.51, preferably less than 0.1 g. The nanotubes can also be substantially cylindrical, graphitic nanotubes which are substantially free of pyrolytically deposited carbon. More preferably they are characterized by having a projection of the graphite layers on the fibril axes which extends for a distance of at least two fibril diameters and/or by having cylindrical graphitic sheets whose c-axes are substantially perpendicular to their cylindrical axis. Preferably, the nanotubes are free of thermal overcoat and have diameters less than 0.5μ.

[0061] The compositions of the invention also include nanotubes upon which certain cyclic compounds are adsorbed. These include compositions of matter of the formula

[[X—R a ] m

[0062] where n is an integer, L is a number less than 0.1 n, m is less than 0.5 n, a is zero or a number less than 10, X is a polynuclear aromatic, polyheteronuclear aromatic or metallopolyheteronuclear aromatic moiety and R is as recited above. The carbon atoms, C n , are surface carbons of a substantially cylindrical, graphitic nanotube of substantially constant diameter. The nanotubes include those having a length to diameter ratio of greater than 5 and a diameter of less than 0.5μ, preferably less than 0.1μ. The nanotubes can also be substantially cylindrical, graphitic nanotubes which are substantially free of pyrolytically deposited carbon and more preferably those characterized by having a projection of the graphite layers on said fibril axes which extend for a distance of at least two fibril diameters and/or those having cylindrical graphitic sheets whose c-axes are substantially perpendicular to their cylindrical axes. Preferably, the nanotubes are free of thermal overcoat and have diameters less than 0.5μ.

[0063] Preferred cyclic compounds are planar macrocycles as described on p. 76 of Cotton and Wilkinson, Advanced Organic Chemistry . More preferred cyclic compounds for adsorption are porphyrins and phthalocyanines.

[0064] The adsorbed cyclic compounds may be functionalized. Such compositions include compounds of the formula

[[X-A a ]m

[0065] where m, n, L, a, X and A are as defined above and the carbons are surface carbons of a substantially cylindrical graphitic nanotube as described above.

[0066] The carbon fibrils functionalized as described above may be incorporated in a matrix. Preferably, the matrix is an organic polymer (e.g., a thermoset resin such as epoxy, bismaleimide, polyamide, or polyester resin; a thermoplastic resin; a reaction injection molded resin; or an elastomer such as natural rubber, styrene-butadiene rubber, or cis-1,4-polybutadiene); an inorganic polymer (e.g., a polymeric inorganic oxide such as glass), a metal (e.g., lead or copper), or a ceramic material (e.g., Portland cement). Beads may be formed from the matrix into which the fibrils have been incorporated. Alternately, functionalized fibrils can be attached to the outer surface of functionalized beads.

[0067] Without being bound to a particular theory, the functionalized fibrils are better dispersed into polymer systems because the modified surface properties are more compatible with the polymer, or, because the modified functional groups (particularly hydroxyl or amine groups) are bonded directly to the polymer as terminal groups. In this way, polymer systems such as polycarbonates, polyurethanes, polyesters or polyamides/imides bond directly to the fibrils making the fibrils easier to disperse with improved adherence.

[0068] The invention is also in methods of introducing functional groups onto the surface of carbon fibrils by contacting carbon fibrils with a strong oxidizing agent for a period of time sufficient to oxidize the surface of said fibrils and further contacting said fibrils with a reactant suitable for adding a functional group to the oxidized surface. In a preferred embodiment of the invention, the oxidizing agent is comprised of a solution of an alkali metal chlorate in a strong acid. In other embodiments of the invention the alkali metal chlorate is sodium chlorate or potassium chlorate. In preferred embodiments the strong acid used is sulfuric acid. Periods of time sufficient for oxidation are from about 0.5 hours to about 24 hours.

[0069] In a further preferred embodiment, a composition having the formula [CH(R′)OH] m , wherein n, L, R′ and m are as defined above, is formed by reacting R′CH 2 OH with the surface carbons of a nanotube in the presence of a free radical initiator such as benzoyl peroxide.

[0070] The invention is also in a method for linking proteins to nanotubes modified by an NHS ester, by forming a covalent bond between the NHS ester and the amino group of the protein.

[0071] The invention is also in methods for producing a network of carbon fibrils comprising contacting carbon fibrils with an oxidizing agent for a period of time sufficient to oxidize the surface of the carbon fibrils, contacting the surface-oxidized carbon fibrils with reactant suitable for adding a functional group to the surface of the carbon fibrils, and further contacting the surface-functionalized fibrils with a cross-linking agent effective for producing a network of carbon fibrils. A preferred cross-linking agent is a polyol, polyamine or polycarboxylic acid.

[0072] Functionalized fibrils also are useful for preparing rigid networks of fibrils. A well-dispersed, three-dimensional network of acid-functionalized fibrils may, for example, be stabilized by cross-linking the acid groups (inter-fibril) with polyols or polyamines to form a rigid network.

[0073] The invention also includes three-dimensional networks formed by linking functionalized fibrils of the invention. These complexes include at least two functionalized fibrils linked by one or more linkers comprising a direct bond or chemical moiety. These networks comprise porous media of remarkably uniform equivalent pore size. They are useful as adsorbents, catalyst supports and separation media.

[0074] Although the interstices between these fibrils are irregular in both size and shape, they can be thought of as pores and characterized by the methods used to characterize porous media. The size of the interstices in such networks can be controlled by the concentration and level of dispersion of fibrils, and the concentration and chain lengths of the cross-linking agents. Such materials can act as structured catalyst supports and may be tailored to exclude or include molecules of a certain size. Aside from conventional industrial catalysis, they have special applications as large pore supports for biocatalysts.

[0075] The rigid networks can also serve as the backbone in biomimetic systems for molecular recognition. Such systems have been described in U.S. Pat. No. 5,110,833 and International Patent Publication No. WO93/19844. The appropriate choices for cross-linkers and complexing agents allow for stabilization of specific molecular frameworks.

Methods of Functionalizing Nanotubes

[0076] The uniformly functionalized fibrils of the invention can be directly prepared by sulfonation, electrophilic addition to deoxygenated fibril surfaces or metallation. When arc grown nanofibers are used, they may require extensive purification prior to functionalization. Ebbesen et al. (Nature 367 519 (1994)) give a procedure for such purification.

[0077] Preferably, the carbon fibrils are processed prior to contacting them with the functionalizing agent. Such processing may include dispersing the fibrils in a solvent. In some instances the carbon fibrils may then be filtered and dried prior to further contact.

1. Sulfonation

[0078] Background techniques are described in March, J. P., Advanced Organic Chemistry, 3rd Ed. Wiley, New York 1985; House, H., Modern