Process of forming polysubstituted fullerenes

The present invention is directed toward the preparation of novel polysubstituted fullerenes. The method of forming polysubstituted fullerenes comprises contacting a fullerene with an electrophilic reagent selected from the group consisting of nitronium ion and organic peracid, provided that when the electrophilic reagent is nitronium ion, the fullerene is subsequently contacted with a nucleophilic reagent.

FIELD OF THE INVENTION 
The present invention is directed to polysubstituted fullerenes and the 
process of preparing such. 
BACKGROUND OF DISCLOSURE 
Fullerenes are hollow molecules composed of pure carbon atoms. Typically, 
fullerenes each have 12 pentagons, but differing numbers of hexagons. The 
pentagons are required in order to allow curvature and eventual closure of 
the closed surface upon itself. The most abundant species to date is the 
C.sub.60 molecule or Buckminster Fullerene. C.sub.60 consists of 12 
pentagons and 20 hexagons and is classified as an icosahedron, the highest 
symmetry structure possible. The second most abundant species, C.sub.70, 
contains 12 pentagons and 25 hexagons. To date, fullerenes containing up 
to 400 carbon atoms have been identified. Characteristic of fullerenes is 
their general formula C.sub.2n where n is greater than or equal to 25. 
Fullerenes are produced by high temperature vaporization of solid graphite 
rods by resistive heating or arc heating in the presence of a few to 
several torr of rare gas. The soot produced by the vaporization contains 
varying levels of fullerenes, depending on the vaporization conditions. 
However, the majority of the fullerenes produced are C.sub.60 and 
C.sub.70, with C.sub.60 being more abundant. 
The fullerenes are extracted from the soot by placing the soot into a 
solvent in which the fullerenes are soluble. The solution is then filtered 
and allowed to evaporate to yield fullerene powders. Alternatively, the 
fullerenes can be purchased commercially. 
SUMMARY OF THE INVENTION 
One embodiment of the present invention is directed to polysubstituted 
fullerene moieties having a plurality of substituents thereon, selected 
from the group consisting of hydroxy, oxide, nitro, amino, organocarboxy, 
amide, and/or mixtures thereof. 
Another embodiment is directed toward the preparation of the novel 
polysubstituted fullerenes. The method of forming polysubstituted 
fullerenes comprises contacting fullerenes with an electrophilic reagent 
such as nitronium ion or an organic peracid. When the electrophilic agent 
is nitronium ion, the fullerene is further contacted with a nucleophilic 
reagent. Polysubstituted fullerenes comprise a fullerene moiety selected 
from fullerenes or mixtures thereof having a plurality of substituents 
thereon. 
The polysubstituted fullerenes are particularly useful as cross-linking 
agents in polymers and/or as core building blocks of star polymers. 
Indeed, the polysubstituted fullerene molecules, with hydroxy or amino 
groups as the major components of substitutions, provide a unique 
three-dimensional multi-functional precursor suitable for utilization as 
polymer cross-linking agents and core building blocks of star polymers. 
Fully converted fullerenes, such as polyhydroxylated fullerenes, 
poly(amino) fullerenes, and poly(aminohydroxy) fullerenes, give a maximum 
number, about 10 to 15, of polymer arms on the fullerene molecules. 
Partially substituted fullerenes, such as poly(amino-hydroxyacetoxy) 
fullerenes, poly(aminohydroxytrifluoroacetoxy) fullerenes, 
poly(nitrohydroxy) fullerenes, and poly(aminoacetamino) fullerenes, can be 
used to produce a lesser number of polymer arms, about 3-10, on the 
fullerene molecule.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention employs either nitronium ion or organic peracid 
induced electrophilic substitutions on a fullerene molecule, followed by a 
sequence of chemical transformation to introduce hydroxy, nitro, 
organocarboxy, amide, oxide, and amino groups onto the fullerene. Contact 
with the electrophilic reagent requires from about 10 to about 30 hours. 
One embodiment of the present invention is directed to fullerenes having a 
variety of substituents thereon. The fullerenes are referred to, according 
to the substituents, as follows: polyhydroxylated fullerenes are 
fullerenes having hydroxy (OH) groups thereon, fullerene oxides are 
fullerenes having an oxygen group thereon, fullerenes having a mixture of 
hydroxy and oxygen groups thereon are referred to as .alpha.-hydroxy 
hemiacetals, fullerenes having nitro (NO.sub.2) groups thereon are 
polynitro fullerenes, fullerenes having both hydroxy and nitro groups 
thereon are poly(nitrohydroxy) fullerenes, fullerenes having both an 
organocarboxy (RCO.sub.2) and OH group thereon are 
poly(hydroxyorganocarboxy) fullerenes, fullerenes having nitro, hydroxy, 
and acetoxy (CH.sub.3 CO.sub.2) groups from acetic acid being used as the 
nucleophile are referred to as poly(nitrohydroxyacetoxy) fullerenes, when 
the nitro group of poly(nitrohydroxyacetoxy) fullerenes is hydrogenated to 
an amino (NH.sub.2) group, the fullerene is referred to as 
poly(aminohydroxyacetoxy) fullerene, fullerenes having hydroxy and amino 
groups thereon are poly(aminohydroxy) fullerenes, fullerenes having nitro, 
hydroxy, and CF.sub.3 CO.sub.2 groups thereon are 
poly(aminohydroxytrifluoroacetoxy) fullerenes, fullerenes having nitro and 
CH.sub.3 CONH groups thereon are poly(nitroacetamino) fullerenes; 
fullerenes having amino and CH.sub.3 CONH groups thereon are 
poly(aminoacetamino) fullerenes, fullerenes having only NH.sub.2 groups 
thereon are polyamino fullerenes, fullerenes having nitro, hydroxy, and 
organocarboxy RCO.sub.2 groups thereon are poly(nitrohydroxyorganocarboxy) 
fullerenes, and fullerenes having a nitro and an organocarboxy group 
thereon are poly(nitroorganocarboxy) fullerenes. These names are not 
limiting; fullerenes having other groups thereon resulting from the 
selection of a particular nucleophile in accordance with the invention 
would be similarly named. 
The reaction of fullerenes, preferably C.sub.60 and C.sub.70 fullerenes and 
mixtures thereof, is carried out either in an aqueous medium in the 
presence of sulfuric acid and nitronium ion or in a non-aqueous medium 
with nitronium ion or organic peracid and various organic nucleophiles. 
The completion of reaction is easily determined by the reaction mixture 
turning clear brown or yellow. 
In the aqueous chemistry, several different mixtures of acidic medium can 
be employed to prepare polyhydroxylated fullerenes. Acidic mixtures 
include concentrated sulfuric acid with concentrated nitric acid, triflic 
acid (trifluoromethanesulfonic acid) with potassium nitrate, concentrated 
sulfuric acid with potassium nitrate, fuming sulfuric acid (oleum) with 
concentrated nitric acid, and fuming sulfuric acid with nitronium 
tetrafluoroborate. The first four acid mixtures generate nitronium ion, 
the electrophilic reagent, in-situ and therefore must be run at a reaction 
temperature of between about 90.degree.-115.degree. C. to activate the 
dehydrative conversion of nitric acid to nitronium ion. The fifth method 
employs the direct use of nitronium ion and, hence, proceeds at a 
temperature of about 20.degree.-50.degree. C. 
Once the reaction is complete, as evidenced by the formation of a clear 
brown solution, the reaction solution is diluted with water, followed by 
filtration, to remove unreacted fullerene particles. Neutralization with 
NaOH to precipitate product follows. The precipitation with NaOH can be 
achieved at a pH of aqueous solution higher than 9.0 and a low sulfate 
concentration (&lt;2% by Wt.). A brown solid results, which is moderately 
soluble in water and very soluble in acidic water. 
Removal of water from the partially hydrated product can be accomplished 
under vacuum at about 50.degree. C., affording a product with a slightly 
lower solubility in water. 
Upon completion of reaction, only trace amounts of starting C.sub.60 and 
C.sub.70 fullerenes are recovered. This is attributable to the fullerene 
intermediate, the partially substituted fullerene, having a higher 
solubility in acidic H.sub.2 O than the C.sub.60 and C.sub.70 fullerenes 
themselves. Thus, the reaction tends to continue on the intermediate until 
completion. Analysis has shown that the ratio of hydroxy groups to 
fullerene molecule is about 5-32. Higher substitution is possible for 
fullerenes having greater than 70 carbon atoms. 
The polyhydroxylated fullerenes often contain one to three sodium sulfate 
molecules per polyhydroxylated fullerene from the initial workup procedure 
using H.sub.2 SO.sub.4. They can be further purified by redissolving them 
in dilute hydrochloric acid, followed by reprecipitation after 
neutralization with NaOH. Purification reduces the level of sodium sulfate 
to less than 0.3 molecules per fullerene. Complete removal of sodium 
sulfate can be accomplished by reverse phase chromatography. 
In the present invention, when nitronium ion is the electrophilic reagent, 
it is probably the major active attacking species which reacts with the 
fullerene. When the present invention is carried out in the presence of 
sulfuric acid in aqueous solution, nitronium ion is formed by an acid-base 
reaction in which nitric acid acts as the base. The nitronium ion 
conversion is most effective above 90.degree. C. Therefore, most reactions 
using sulfuric acid and nitric acid or potassium nitrate as reagents must 
be performed above that temperature. Alternatively, for the reaction to be 
carried out at a lower temperature of about 20.degree.-50.degree. C., 
nitronium tetrafluoroborate(NO.sub.2 +BF.sub.4 -) as a solid, or in 
tetramethylene sulfone can be used. 
Probably, the electrophilic attack of nitronium ion on the olefin moiety of 
the fullerene is accomplished by the removal of a pair of electrons from 
the sextet in the benzene-like structure to give a carbocation as a 
resonance hybrid of arenium ions. Such carbocations are highly reactive. 
They can be reacted in the presence of nucleophilic reagents, such as 
water or organic acid, to afford a mixture of hydroxynitro or 
nitroalkylcarboxy fullerenes. 
Probably, in the presence of strong acid such as sulfuric acid, the nitro 
functionality can be protonated and behave as an excellent leaving group 
that generates a new carbocation center adjacent to the hydroxy 
substitution. This carbocation intermediate can either react with water to 
give 1,2-diol product, rearrange with 1,4-shift and then react with water 
to afford 1,4-diol product, or form epoxide with the .alpha.-hydroxy 
group. The rearrangement of epoxide intermediate readily occurs to give 
fullerene oxide. Further reaction of fullerene oxide with nitronium ion 
and water in a similar mechanism, as discussed above, gives a product of 
.alpha.-hydroxy hemiacetal. Spectroscopic analysis shows that these 
.alpha.-hydroxy hemiacetal products are major components in the product 
mixture. 
When nitronium ion is used as the electrophile in nonaqueous chemistry, the 
fullerene, preferably C.sub.60, C.sub.70, and mixtures thereof, is 
contacted with NO.sub.2 BF.sub.4, either in solid form or in sulfolane 
solution, or another source of nitronium ion in the presence of a 
nucleophile. Suitable nucleophiles have the general formula 
##STR1## 
where R is a substituted or nonsubstituted alkyl or aryl group and wherein 
the substituent groups include OR', halides, --NO.sub.2, --CN, and 
--NHCOR'. R' may be any aliphatic group. Examples of such nucleophiles 
include, but are not limited to, acetic acid and trifluoroacetic acid. 
When the carbocation intermediate, formed by reaction of the fullerene 
with nitronium ion, is allowed to react with water or acetonitrile as the 
nucleophile, a poly(nitrohydroxy) fullerene or poly(nitroacetamino) 
fullerene, respectively, can be obtained. The ratio of the nucleophilic 
substituent added to C.sub.60 or C.sub.70 is about 4 to about 15, though 
higher substitutions are possible for other fullerenes. 
Catalytic hydrogenation of poly(nitrohydroxy) fullerenes, fullerenes having 
both NO.sub.2 and OH groups thereon, converts the nitro group to the 
corresponding amino functionality. The reaction is carried out using 
palladium on carbon as a catalyst under a hydrogen pressure of about 50 
psi for about 6 hours affording poly(aminohydroxy) fullerenes. Catalytic 
hydrogenation can be used to convert the NO.sub.2 group on any 
polysubstituted fullerene to an amino group. 
Polyhydroxylated or polyhydroxyorganocarboxy fullerenes can be prepared via 
the epoxidation method by reacting fullerenes, preferably C.sub.60, 
C.sub.70, and mixtures thereof, with organic peracids having the general 
formula 
##STR2## 
where R is a substituted or nonsubstituted alkyl group containing 1-20 
carbon atoms or a substituted or nonsubstituted aryl group wherein the 
substituted groups include OH, halides, NO.sub.2, and CN. For example, 
C.sub.60, C.sub.70 and mixtures thereof can be reacted with 
m-chloroperbenzoic acid in chloroform at 50.degree.-90.degree. C. to give 
a poly(hydroxyorganocarboxy) fullerene. The ratio of the organocarboxy 
substituent to C.sub.60 or C.sub.70 fullerene will be about 4 to about 10, 
though higher substitutions are possible for fullerenes containing greater 
than 70 carbon atoms. Hydrolysis, for example, with NaOH in methanol at 
about 50.degree.-85.degree. C. will yield polyhydroxylated fullerenes. 
Such polyhydroxylated fullerenes have IR spectrum closely resembling those 
of polyhydroxylated fullerenes obtained from the aqueous nitronium 
ion/acid reaction. 
Polysubstituted fullerenes having at least three hydroxy or amino groups 
thereon and/or mixtures of such groups and oxide, nitro, organocarboxy, 
and amide substituent on the fullerene moiety can be used as cross-linking 
reagents in polymers. When used as such, about 0.2 to about 6% by weight 
of such cross-linking reagent to diacid chloride is required. 
The polysubstituted fullerene is heated at about 50.degree. C. to about 
90.degree. C. in the presence of a diacid chloride for about 10 to about 
20 hours, followed by polymerization by adding a mixture of a diol and the 
same diacid chloride and continuing to heat for about 10 to about 20 
hours. The diol selected contains about 4 to about 20 carbon atoms. 
The following examples are intended to demonstrate the invention and are 
not limiting. 
EXAMPLE 1 
A reaction flask (50 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (500 mg) in a ratio of 4:1 and distilled water (3.0 ml) was 
treated with concentrated sulfuric acid (15 ml) dropwise at 5.degree. C. 
while vigorously stirring. A slow addition rate of acid is necessary to 
avoid a sharp increase in temperature. To this acid suspension, 
concentrated nitric acid (5.0 ml) was added dropwise at 5.degree. C. The 
mixture was slowly heated to 115.degree. C. and stirred at 115.degree. C. 
for 4 hrs. The mixture was cooled to room temperature and added slowly 
into ice (50 g). The resulting aqueous acid solution was filtered through 
celite under vacuum to remove insoluble particles. The clear brown-orange 
filtrate was basified by an aqueous sodium hydroxide solution (2N) until 
the pH of the product solution reached 9.0 or higher. During the base 
neutralization, the color of solution slowly turned dark with a fine brown 
precipitate. The solution was allowed to stand at room temperature for 5 
hrs to complete the precipitation. The precipitate was separated from 
solution by centrifugation. It was then washed and centrifuged three times 
with a dilute NaOH solution (1N), twice with methanol, and dried in vacuum 
at 50.degree. C. to afford brown solids of polyhydroxylated fullerene (450 
mg). IR (KBR).upsilon..sub.max 3416 (s), 1598 (s), 1396 (s), and 1088 
cm.sup.-1. Mass spectrum of polyhydroxylated fullerene: m/e 758, 772, 790, 
802, 814, 818, 832, 846, 860, 878, 894, 910, 926, 942, 956, 966, 1012, 
1028, 1038, 1044, 1054, 1068, 1076, 1084, 1092, 1106, 1118, 1136, 1150, 
1176, and 1188. 
The combined aqueous solutions obtained from the above separation procedure 
were diluted with water to a total volume of 800 ml and allowed to stand 
at room temperature overnight to cause the further precipitation of fine 
brown solids. The solids were separated from solution and repeatedly 
washed with 1N NaOH (aq.) and methanol. After drying in vacuum at 
50.degree. C., a second crop of polyhydroxylated fullerenes (80 mg) was 
obtained as a brown solid. 
EXAMPLE 2 
A reaction flask (25 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (200 mg) and distilled water (0.5 ml) was treated dropwise with 
triflic acid (trifluoromethanesulfonic acid, 5 ml) at 5.degree. C. while 
vigorously stirring. A slow addition rate of acid is necessary to avoid a 
sharp increase of temperature. To this acid suspension potassium nitrate 
(1 g) was added portionwise at 5.degree. C. The mixture was slowly heated 
to 110.degree. C. and stirred at 110.degree. C. for 4 hrs. The mixture was 
cooled to room temperature and added slowly into ice (20 g). The resulting 
aqueous acid solution was filtered through celite under vacuum to remove 
insoluble particles. The clear brown-orange filtrate was basidified by an 
aqueous sodium hydroxide solution (2N) until the pH of the product 
solution reached 9.0 or higher. During the base neutralization, the color 
of solution slowly turned to dark with a fine brown precipitate. The 
solution was allowed to stand at room temperature for 5 hrs to complete 
the precipitation. The precipitate was separated from solution by 
centrifuge action. It was then washed and centrifuged three times with a 
dilute NaOH solution (1N), twice with methanol, and dried in vacuum at 
50.degree. C. to yield brown solids of polyhydroxylated fullerene (90 mg). 
The insoluble solids remaining on the celite were extracted with toluene 
(100 ml) and filtered under vacuum. The toluene solution was dried on the 
rotary evaporator to remove all the solvent. The resulting dark brown 
solid (150 mg) was identified to be a mixture of carbon 60 and carbon 70 
fullerenes. 
EXAMPLE 3 
A reaction flask (50 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (500 mg) and distilled water (3.0 ml) was treated with 
concentrated sulfuric acid (15 ml) dropwise at 5.degree. C. while 
vigorously stirring. A slow addition rate of acid is necessary to avoid a 
sharp increase in temperature. To this acid suspension potassium nitrate 
(3.5 g) was added dropwise at 5.degree. C. The mixture was slowly heated 
to 90.degree. C. and stirred at 90.degree. C. for 24 hrs. It was cooled to 
room temperature and added slowly into ice (50 g). The resulting aqueous 
acid solution was filtered through celite under vacuum to remove insoluble 
particles. The clear brown-orange filtrate was basidified by an aqueous 
sodium hydroxide solution (2N) until the pH of the product solution 
reached 9.0 or higher. During the base neutralization, the color of 
solution slowly turns to dark with a fine brown precipitate. The solution 
was allowed to stand at room temperature for 5 hrs to complete the 
precipitation. The precipitation was separated from solution by 
centrifugation. It was then washed and centrifuged three times with a 
dilute NaOH solution (1N), twice with methanol, and dried in vacuum at 
50.degree. C. to afford brown solids of polyhydroxylated fullerene (550 
mg). 
The combined aqueous solution obtained from the above separation procedure 
was diluted with water to a total volume of 800 ml and allowed to stand at 
room temperature overnight to cause the further precipitation of fine 
brown solids. The solids were separated from solution and repeatedly 
washed with 1N NaOH (aq.) and methanol. After drying in vacuum at 
50.degree. C., a second crop of polyhydroxylated fullerene (150 mg) was 
obtained as a brown solid. 
EXAMPLE 4 
A reaction flask (50 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (500 mg) and fuming sulfuric acid (oleum, 15 ml) was allowed to 
stir for 3 hrs to give a green suspension. The mixture was treated with 
distilled water (3.0 ml) dropwise at 5.degree. C. while vigorously 
stirring. A slow addition rate of water is necessary to avoid a sharp 
increase in temperature. To this acid suspension concentrated nitric acid 
(5.0 ml) was added dropwise at 5.degree. C. The mixture was slowly heated 
to 115.degree. C. and stirred at 115.degree. C. for 4 hrs. The mixture was 
cooled to room temperature and added slowly into ice (50 g). The resulting 
aqueous acid solution was filtered through celite under vacuum to remove 
insoluble particles. The clear brown-orange filtrate was basidified by an 
aqueous sodium hydroxide solution (2N) until the pH of the product 
solution reached 9.0 or higher. During the base neutralization, the color 
of solution slowly turns to dark brown with a fine brown precipitate. The 
solution was allowed to stand at room temperature for 5 hrs to complete 
the precipitation. The precipitate was separated from solution by 
centrifugation. It was then washed and centrifuged three times with a 
dilute NaOH solution (1N), twice with methanol, and dried in vacuum at 
50.degree. C. to afford brown solids of polyhydroxylated fullerene (610 
mg). 
The combined aqueous solutions obtained from the above separation procedure 
were diluted with water to a total volume of 800 ml and allowed to stand 
at room temperature overnight to cause the further precipitation of fine 
brown solids. The solids were separated from solution and repeatedly 
washed with 1N NaOH (aq.) and methanol. After drying in vacuum at 
50.degree. C., a second crop of polyhydroxylated fullerene (160 mg) was 
obtained as a brown solid. 
EXAMPLE 5 
A reaction flask (25 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (200 mg) and fuming sulfuric acid (oleum, 8 ml) was allowed to 
stir for 2 hrs to give a green suspension. To this acid suspension water 
(2 ml) and nitronium tetrafluoroborate (480 mg) were added portionwise at 
ambient temperature. The mixture was heated to 50.degree. C. and stirred 
at 50.degree. C. for a period of 16 hrs. It was cooled to room temperature 
and added slowly into ice (30 g). The resulting aqueous acid solution was 
filtered through celite under vacuum to remove insoluble particles. The 
clear brown-orange filtrate was basidified by an aqueous sodium hydroxide 
solution (2N) until the pH of the product solution reached 9.0 or higher. 
During the base neutralization, the color of solution slowly turns to dark 
with a fine brown precipitate. The solution was allowed to stand at room 
temperature for 5 hrs. to complete the precipitation. The precipitate was 
separated from solution by centrifugation three times with a dilute NaOH 
solution (1N), twice with methanol, and dried in vacuum at 50.degree. C. 
to afford brown solids of polyhydroxylated fullerene (320 mg). 
EXAMPLE 6 
A reaction flask (25 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (70 mg) in methylene chloride (dried over molecular sieve) was 
treated with nitronium tetrafluoroborate (0.5 m in sulfolane solution), 
NO.sub.2 BF.sub.4 (200 mg) and acetic acid (1.0 ml). The mixture was 
stirred at 23.degree. C. for a period of 14 hrs. The resulting orange 
solution was neutralized with potassium carbonate (1.5 g) and filtered 
through celite. The filtrate was evaporated to dryness and the residue was 
stirred with ether for 5 min. The ether insoluble solid was collected by 
the centrifuge technique and dried under vacuum to afford yellow-brown 
solids of poly(nitrohydroxy acetoxy) fullerene (90 mg). Elemental analysis 
indicated that the composition of the compound is best fit with a unit 
formula (C.sub.74 H.sub.24 N.sub.3.8 O.sub.25) of C.sub.60 (CH.sub.3 
CO.sub.2).sub.7 (NO.sub.2).sub.3.8 (OH).sub.3.2. Found: C, 59.91; H, 2.14; 
N, 3.47; O, 28.18; S, 2.08 (from sulfolane residue). IR (KBr) 
.upsilon..sub.max 3439, 2940, 1816, 1753, 1829, 1567, 1372, 1337, 1220, 
1080, 1052, and 807 cm.sup.-1. .sup.1 H NMR (THF-d.sub.8) .delta.2.0-2.2 
(bs, CH.sub.3). .sup.13 C NMR (THF-d.sub.8) .delta.20 (CH3), 150, 170 
(carbonyl). Mass spectrum of the compound using pure carbon 60 as a 
starting material: m/e 720, 737, 753, 769, 780, 787, 797, 813, 829, 840, 
845, 857, 861, 873, 889, 901, 919, 933, 949, 965, 978, 990, 1009, 1023, 
1035, 1052, 1058, 1065, 1069, 1081, 1085, 1099, 1105, 1114, 1128, 1153, 
1231, 1289, 1306, 1347, 1362, and 1394. 
To a thick-wall reactor (25 ml) connected with a hydrogen cylinder was 
charged the poly(nitrohydroxyacetoxy) fullerene (50 mg), palladium on 
carbon (Pd/C, 20 mg), and tetrahydrofuran (10 ml). The mixture was stirred 
and maintained under a hydrogen pressure of 50 psi for 6 hrs. At the end 
of reaction, the resulting suspension was filtered through celite to 
remove catalyst residues. The filtrate was then dried by solvent 
evaporation to give brown solids of poly(aminohydroxyacetoxy) fullerene 
(35 mg). IR (KBr) .upsilon..sub.max 3618 (NH.sub.2), 3415 (w), 2948, 2863, 
1637 (w), 1431, 1310, 1228, 1154, 1111, 868, 769, and 581 cm.sup.-1. 
To a reaction flask (25 ml) charged with the poly(aminohydroxyacetoxy) 
fullerene (50 mg) and methanol (10 ml) was added sodium hydroxide (150 
mg). The mixture was heated at 60.degree.-70.degree. C. overnight with 
stirring. At the end of reaction, water (50 ml) and NaOH (200 mg) was 
added to cause the precipitation of poly(aminohydroxy) fullerene (40 mg). 
EXAMPLE 7 
A reaction flask (25 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (70 mg) in methylene chloride (dried over molecular sieve) was 
treated with nitronium tetrafluoroborate (0.5 m in sulfolane solution), 
NO.sub.2 BF.sub.4 (200 mg) and trifluoroacetic acid (1.0 ml). The mixture 
was stirred at 23.degree. C. for a period of 14 hrs. Water was added to 
the resulting yellow-orange solution to cause the precipitation of solids. 
The solid was collected by the centrifuge technique, washed with water, 
and dried under vacuum to afford yellow-orange solids of 
poly(nitrohydroxytri-fluoroacetoxy) fullerene (93 mg). Elemental analysis 
indicated that the composition of the compound was: C, 57.17; H, 1.98; N, 
2.41; O, 27.17; F, 9.21. IR (KBr) .upsilon..sub.max, 3441, 1629, 1567, 
1333, 1290, 1138, 1084, and 815 cm.sup.-1. 
To a thick-wall reactor (25 ml) connected with a hydrogen cylinder was 
charged the poly(nitrohydroxytrifluoroacetoxy) fullerene (50 mg), 
palladium on carbon (Pd/C, 20 mg), and tetrahydrofuran (10 ml). The 
mixture was stirred and maintained under a hydrogen pressure of 50 psi for 
6 hrs. At the end of reaction, the resulting suspension was centrifuged to 
remove catalyst residues. The solution was then dried by solvent 
evaporation to give yellow-brown solids of 
poly(aminohydroxytrifluoroacetoxy) fullerene (27 mg). 
To a reaction flask (25 ml) charged with the 
poly(aminohydroxytrifluoroacetoxy) fullerene (25 mg) and methanol (5 ml) 
was added sodium hydroxide (80 mg). The mixture was heated at 
60.degree.-70.degree. C. for overnight with stirring. At the end of 
reaction, water (30 ml) and NaOH (100 mg) was added to cause the 
precipitation of poly(aminohydroxy) fullerene (40 mg). 
EXAMPLE 8 
A reaction flask (25 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (50 mg) in methylene chloride (dried over molecular sieve) was 
treated with nitronium tetrafluoroborate (0.5 m in sulfolane solution), 
NO.sub.2 BF.sub.4 (150 mg). The mixture was stirred at 23.degree. C. for a 
period of 14 hrs. Water was added to the resulting solution to cause the 
precipitation of solids. The solid was collected by the centrifuge 
technique, washed with water, and dried under vacuum to afford brown 
solids of poly(nitrohydroxy) fullerene (63 mg). Elemental analysis 
indicated that the composition of the compound was: C, 60.76; H, 1.73; N, 
3.06; O, 26.28. IR (KBr) .upsilon..sub.max 3450, 1656, 1567, 1337, 1092, 
and 815 cm.sup.-1. 
To a thick-wall reactor (25 ml) connected with a hydrogen cylinder was 
charged the poly(nitrohydroxy) fullerene (40 mg), palladium on carbon 
(Pd/C, 15 mg), and tetrahydrofuran (10 ml). The mixture was stirred and 
maintained under a hydrogen pressure of 50 psi for 8 hrs. At the end of 
reaction, the resulting suspension was centrifuged to remove catalyst 
residues. The solution was then dried by solvent evaporation to give 
yellow-brown solids of poly(aminohydroxy) fullerene (25 mg). 
EXAMPLE 9 
A reaction flask (50 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (100 mg) was treated with concentrated nitric acid (10 ml) while 
vigorously stirring. The suspension was heated at 75.degree. C. for 2 
days. At the end of reaction, water (20 ml) was added to cause the 
precipitation of poly(nitrohydroxy) fullerene (110 mg). IR (KBr) 
.upsilon..sub.max 3410 (s, br), 1629, 1566 (s), 1341, 1084, and 816 
cm.sup.-1. 
To a thick-wall reactor (25 ml) connected with a hydrogen cylinder was 
charged the poly(nitrohydroxy) fullerene (40 mg), palladium on carbon 
(Pd/C, 5 mg), and tetrahydrofuran (10 ml). The mixture was stirred and 
maintained under a hydrogen pressure of 50 psi for 6 hrs. At the end of 
reaction, the resulting suspension was filtered through celite to remove 
catalyst residues. The filtrate was then dried by solvent evaporation to 
give brown solids of poly(aminohydroxy) fullerene (33 mg). 
EXAMPLE 10 
A reaction flask (25 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (70 mg) in methylene chloride (1 ml, dried over molecular sieve) 
was treated with nitronium tetrafluoroborate (0.5 m in sulfolane 
solution), NO.sub.2 BF.sub.4 (100 mg) and acetonitrile (1.0 ml). The 
mixture was stirred at 23.degree. C. for a period of 15 hrs. Water was 
added (0.5 ml) and the stirring continued for another 2 hrs. Organic 
solvents were evaporated under reduced pressure and more water was added 
to cause the precipitation of brown solids. The solid was collected by the 
centrifuge technique, washed with water, and dried in vacuum to obtain 
poly(nitroacetamino) fullerene (82 mg). IR (KBr) .upsilon..sub.max 1656, 
1563, 1330, 1076, and 807 cm.sup.-1. 
To a thick-wall reactor (25 ml) connected with a hydrogen cylinder was 
charged the poly(nitroacetamino) fullerene (40 mg), palladium on carbon 
(Pd/C, 5 mg), and tetrahydrofuran (10 ml). The mixture was stirred and 
maintained under a hydrogen pressure of 50 psi for 6 hrs. At the end of 
reaction, the resulting suspension was filtered through celite to remove 
catalyst residues. The filtrate was then dried by solvent evaporation to 
give brown solids of poly(aminoacetamino) fullerene (28 mg). 
To a reaction flask (25 ml) charged with the poly(aminoacetamino) fullerene 
(30 mg) and methanol (10 ml) sodium hydroxide (100 mg) was added. The 
mixture was heated at 60.degree.-70.degree. C. for overnight with 
stirring. At the end of reaction, water (50 ml) and NaOH (100 mg) were 
added to cause the precipitation of poly(amino) fullerene (19 mg). 
EXAMPLE 11 
A reaction flask (25 ml) charged with a fullerene mixture of carbon 60 and 
carbon 70 (200 mg), m-chloroperbenzoic acid (MCPBA, 800 mg), and 
chloroform (50 ml) was maintained under an atmospheric pressure of inert 
gas (N.sub.2). The mixture was heated to 70.degree. and stirred at that 
temperature for a period of 16 hrs. Another portion of chloroform (50 ml) 
was then added and centrifuged to isolate the chloroform-insoluble brown 
solids. After washing the solid with more chloroform, it was redissolved 
in acetone (40 ml), filtered through celite, and the solvent evaporated to 
afford poly(.alpha.-hydroxy m-chlorobenzocarboxy) fullerene (350 mg). 
Elemental analysis gives C, 65.81; H, 1.97; 0, 20.21; Cl, 8.56. IR (KBr) 
.upsilon..sub.max 3424 (s, broad), 1734 (carbonyl), 1626, 1286 (w), 1251, 
1078 (broad), and 745 cm.sup.-1. Mass spectrum yields: m/e 720, 765, 769, 
793, 817, 841, 853, 857, 869, 889, 901, 919, 933, 941, 951, 977, 995, 
1023, 1037, 1071, 1085, 1127, 1143, 1159, 1193, 1211, 1239, 1255, 1333, 
1359, and 1381. 
To a reaction flask (25 ml) charged with poly(.alpha.-hydroxy 
m-chlorobenzocarboxy) fullerene (100 mg) and methanol (10 ml) sodium 
hydroxide (150 mg) was added. The mixture was heated at 
60.degree.-70.degree. C. for overnight with stirring. At the end of 
reaction, water (50 ml) and NaOH (200 mg) were added to cause the 
precipitation of polyhydroxylated fullerene (45 mg). (KBr) 
.upsilon..sub.max 3416 (s, broad), 1586, 1391, 1068, and 550 (w, broad) 
cm.sup.-1. 
EXAMPLE 12 
In a typical reaction, a finely divided polyhydroxylated fullerene prepared 
in accordance with Example 1 (1 to 6% by weight of total acid chloride 
used) was suspended in pyridine (100 parts), which was dried over 
molecular sieve, and stirred at ambient temperature for 30 min. Sebacoyl 
chloride [ClCO(CH.sub.2).sub.8 COCl, 2 parts] was added slowly and the 
mixture was heated at 75.degree. C. for a period of 16 hours. 
1,6-hexanediol (5 parts) and sebacoyl chloride (3 parts) was then added 
slowly. The reaction was allowed to continue for an additional 16 hrs at 
75.degree. C. At the end of reaction, diethyl ether (500 parts) was added 
to cause the precipitation of polymer products. The precipitates were 
filtered, washed with diethyl ether and water, and dried to afford brown 
solids of polyester. The solid was further suspended and stirred in dilute 
HCl solution (1N) for 2 hrs to remove the unreacted polyhydroxylated 
fullerene from the polyester. 
In a separated reaction, an equal molar quantity of sebacoyl chloride and 
1,6-hexanediol were allowed to polymerize in pyridine under similar 
conditions as described above to give a control polyester. The comparison 
of physical properties between polyester (containing bonded 
polyhydroxylated fullerene) and polyester (containing no polyhydroxylated 
fullerene) was carried out by differential scanning calorimetry (DSC) and 
thermogravimetry analysis (TGA) measurements. As a result, we observed a 
significant improvement of thermal stability of the polyester containing 
the polyhydroxylated fullerene than that without at high temperatures 
above 200.degree. C. with much less weight loss (50% for polyester 
containing 1.5% of polyhydroxylated fullerene and 27% for the polyester 
containing 3% of the polyhydroxylated fullerene as compared to 64% for the 
polyester without the polyhydroxylated fullerene at 360.degree. C.) as 
shown in their TGA data. The comparison between DSC data taken for the 
polyesters indicated a shift of T.sub.g in the polyester containing 
polyhydroxylated fullerene (below ambient temperature) from 130.degree. C. 
for the polyester without polyhydroxylated fullerene.