A
mixture consisting of 0.3125 mL of toluene and 4.6 mg of C60 was
made. This solution was prepared in a conical vial and set on an electric
stirrer for 30 minutes. The black C60 solution dissolved to yield a
purple solution after 15 minutes.
13 mL of cyclopentadiene were distilled for one hour at 44o C in a
fractional distillation system. 0.14 mL of the "cracked" cyclopentadiene were
then added to .625 mL of toluene in a micro-vial. The contents of this
container were then transferred dropwise to the stirred C60
solution. The resulting solution was stirred for 30 minutes. During this
time, a color change from a purple to purple-brown hue was observed.
0.0249
g C60 and 2.7 mL of toluene were combined in a conical vial and
placed on an electronic stirrer for an hour. A solution consisting of 0.11
mL piperylene and 1 mL toluene was added to the vial. This solution
was set to stir for 3 days. After stirring, the solution was black. The
solution was transferred to a round-bottom microflask and a fractional
distillation was run to remove the toluene. After one hour at a pressure of
3.6 mm Hg, a water temperature of 70oC and a system temperature of
290C, toluene evaporated, leaving a grayish-black solid in the
bottom of the flask. Spectra were taken of the solid.
To increase the extent of reaction, this experiment was performed again with a
higher piperylene concentration. 0.6 mL of piperylene were added to a solution
of 0.0252 g C60 in 3 mL of toluene in a conical vial. This solution
was then stirred for 4 hours. The solution was transferred to a round-bottom
microflask and was then distilled under 35 mm Hg of pressure. After 25 minutes
and total evaporation of solvent had occurred, water temperature was observed
to be 62oC and system temperature was 30o C. Analysis
was performed on the greyish-black solid remaining in the flask.
The
second type of reaction that was performed was a fullerenation reaction.
First, 5.1 mg of the C60 was placed a 4 mL conical vial. 8.0 mg of
AlCl3 were then added. 3.0 mL of toluene were pipetted into the
vial, which was sealed and mixed with a magnetic stirrer. The solution was
initially a gray-pink color, but by the time stirring began, it had darkened to
a reddish-brown tone. After 2 minutes of stirring, the mixture had again
changed color, this time to a brown-purple, which deepened gradually during the
stirring procedure. At the end of the 2-hour mixing process, the solution
(which was now practically black) was quenched with approximately 1.5 mL
distilled water. The mixture was stirred for one minute to diffuse the water
and was transferred to a separatory funnel. It was then left undisturbed for
five minutes to allow separation to occur. The water layer, which was on the
bottom, was drained from the funnel. The remaining contents were transferred
to a clean 4 mL conical vial and left to settle for about 68 hours (one
weekend). After this time, the solution had turned a deep orange-red color,
with a small amount of a white solid on the bottom. The white solid was
deduced to be AlCl3 and water which had not initially separated from
the toluene solution. The toluene/fullerene mixture was drawn off the top
using a Pasteur pipette and transferred into a round-bottomed microflask. The
flask was placed into a micro-distillation apparatus with vacuum and was
heated. At a water bath temperature of 50oC and a pressure of 27.5
mm Hg, the mixture began to boil. Within 25 minutes, the distillation was
complete, with a final bath temperature of 62oC and a constant 27.5
mm Hg pressure. The final product was a dark red solid.
The toluene reaction was repeated on a larger scale. 3.0 mL of toluene were
added to 25.0 mg of C60 in a conical vial. This solution was
allowed to mix for two and one half hours to dissolve the C60. The
solution turned from a clear to a vibrant violet color which deepened as the
two and one half hours passed; at the end it was practically black with a
purple tint. When the C60 was completely dissolved, 25.7 mg of
AlCl3 was added to catalyze the reaction. The solution was stirred
for twenty hours, during which time the solution took on a red/purple/black
color. The solution was quenched with 20 drops of distilled water (about 1
mL), stirred for ten minutes, and was transferred to a separatory funnel. The
solution quickly separated into a reddish-black top layer of toluene and
fullerenes and a cloudy bottom layer of water and AlCl3. This
bottom layer was then funneled off. The remaining toluene solution was
transferred to a conical vial and allowed to sit for three days. After this
time, the solution was nearly black, and a small layer of water had developed
at the bottom. The toluene solution was transferred to a round-bottomed
microflask with a Pasteur pipette and was distilled using a micro-distillation
apparatus. The distillation was run at 41 mm Hg, and the toluene began to boil
off at 60o C. After 45 minutes of boiling between 60oC
and 63oC, the toluene had completely distilled, leaving behind a
dark red-black solid.
The fourth reaction was with ferrocene. This procedure varied slightly from the others because ferrocene is a solid while the other aromatics are liquids. First, 25.1 mg C60 and 25.0 mg ferrocene were placed in a 4.0 mL conical vial. They were then dissolved in 4.5 mL CS2 and allowed to mix for 20 minutes, at which time the solution was a dark brown color. Next, 24.6 mg AlCl3 was added, and the solution was mixed for an additional four and one half hours. The mixture was then transferred to a separatory funnel. Approximately 10 mL of distilled water were added. The solution was the thoroughly mixed and allowed to sit to separate the water from the ferrocene mixture. The layers instantly and clearly separated into a dark red-black C60 /CS2/ferrocene layer on the bottom and a totally clear water layer on top. From the funnel we then filtered out the dark ferrocene layer in to a clean round-bottomed microflask. Because the CS2 evaporated so quickly, we decided not to distill, but simply to attach the vial to the distillation apparatus under no heat, and run the vacuum. The excess came off at 35 mm Hg. This came off very quickly, and the product was dried in 20 min. To be sure as to remove all moisture, we let the product sit out in the hood for an addition al 30 minutes. The product remaining was a black solid that was very crumbly and thin. This product was then used for spectral analysis.
The third fullerenation reaction to be attempted was with bromobenzene. Once again, 25.0 mg of C60 and 3.0 mL bromobenzene were placed into a 4.0 mL conical vial to mix. However, even after thirty minutes of stirring there was no indication that the fullerene was dissolving in the bromobenzene; the black C60 continued to stay in the bottom of the vial while the bromobenzene remained clear. Although the C60 had not dissolved, 25.4 mg AlCl3 was added to the mixture to catalyze the reaction. Within ten minutes, there appeared to be some mixing occurring, because the bottom fourth of the vial took an a slight brown greenish color. The mixture was allowed to stir for 22 hours. By this time, a black substance had formed on the magnetic stir bar and halted its motion. The substance had also stuck to the bottom of the vial, but the bromobenzene continued to be clear. The mixture was quenched with about 1 mL distilled water, but it was impossible to determine where the water was in the clear bromobenzene solution. After separate samples of pure bromobenzene and water were mixed in a test tube, it was determined that the two were most likely miscible in each other. Because of this complication, the separation/distillation technique was ruled out as an isolation procedure. It was decided to use vacuum filtration instead. The mixture was transferred to a Buchner funnel, and rinsed with distilled water, in which the product proved to be insoluble. After all of the product was transferred, rinsed, and dried, it was a gray powder which had collected on the filter paper. As this powder dried, the color deepened to black resembling that of straight buckyball. The filtrate, figured to be a solution of water, bromobenzene, and AlCl3, was clear, with no sign of the gray powder in it. The product was allowed to dry for two days before it was analyzed.
A similar procedure was used to react aniline with the C60. First, 26.5 mg of the fullerene and 3 mL aniline were mixed in a 4 mL conical vial. The solution was a dark brown color with an orange tint. When the C60 was completely dissolved (after about twenty minutes), 24.6 mg AlCl3 was added, and the solution was allowed to mix for 22 hours. After this time, the solution, which was still dark brown, was quenched with about 1.5 mL distilled water. The water was mixed through the solution for ten minutes and allowed to stand for ten more. The mixture was transferred into a separatory funnel, and separation was attempted. This proved to be difficult; although the water and aniline were clearly separated from each other, they refused to separate into top and bottom layers. The solution was swirled and tilted in order to collect the water at the bottom of the separatory funnel. Most of the water was funneled off at this point; the rest remained mixed with the brown aniline solution, making further separation difficult. The mixture was transferred to a conical vial and allowed to stand for 72 hours to attempt further separation of the remaining water and the aniline. However, after this time, only a small amount of water had collected at the bottom. The remainder was suspended in the aniline in the form of clear water `bubbles'. A Pasteur pipette was used to carefully remove the aniline and transfer it to a round-bottomed microflask. Some of the aniline contained too many of the water `bubbles' to be transferred, but nonetheless about 2.5 of the original 3.0 mL of aniline was successfully transferred. Distillation was then attempted on the solution, but this once again proved to be difficult. The aniline, at a pressure of 35 mm Hg, only began to distill at 98o C; the water bath also began to boil at 98o C. This meant that the distillation process had to be constantly halted while the water bath was refilled. After two days, only a fraction of the aniline had distilled off, so the decision was made to use a sand bath instead of a water bath. The solution of C60 and aniline was then placed in the sand bath, with a temperature of 120o C. When the solution reached a temperature of 35o C, the aniline began to evaporate, leaving behind our product. The vacuum pressure was kept at a steady 3.0 cm Hg. The product that was left behind, was a dark brown-black solid that had a very crumbly texture to it. Spectral analysis of the substance was then performed.