British chemist Harold Kroto had a great interested in molecules found in interstellar space and he “wanted to show that molecules containing long chains of carbon atoms”. New apparatus were being developed which allowed the conditions of space to be reproduced. With graphite as a source of carbon, experimentation began with a high powered laser.
These experiments were successful, these long chain molecules were found to be formed in the apparatus. Looking at the results the scientists noticed unusual patterns. A molecule with a mass spectrum, showing it consisted of exactly 60 carbon atom was formed “and appeared to be surprisingly stable”.Under the right conditions C60 dominated the mass spectrum.
Deciding to deviate from the original program, the scientists concentrated on why the number 60 was so special. These experiments resulted in the accidental discovery of a “completely new form of carbon”. Although the information gathered pointed to this new form of carbon, the scientists struggled to find an explanation for C60’s stability. The explanation must lie in its structure. The chemist, Harold Kroto, recalled his memories of the geodesic dome at the Montreal expo, but also remember building a “star dome” consisting of pentagons and hexagons, “could C60 be a geodesic sphere? “Richard Smallery built a paper model of 12 pentagons and 20 hexagons. “The scientist named the carbon 60 “buckminsterfullerene” after the architect. For several years this theory of the structure of the Bucky ball was technically unproved but few disputed it. To prove any theory, the scientists had to make larger amounts to allow analytical studies to be carried out.
One physicist decided to look back over data collected six year previous, with a German colleague. This data was the results of “experiments on soot produced by electrically heating graphite rods”.The odd bumps in the graph, which were thought originally to be contamination could be the characteristics of buckminsterfullerene. Two years after this initial discovery, Huffman and Kratschmer announced that physicists had being making the new substance all along and in abundant amounts. By refining their technique, they had produced soot containing 10% C60, contaminated with a small amount of C70. In 1990 it was discovered that, the soot, if dissolved in benzene, a red solution would be obtained.
The red colouring was unbelievable to the scientists, C60 was the only explanation.It’s 13C nuclear magnetic resonance spectrum was almost incontrovertible proof of the structure, the ultimate “one-line” proof. “In the highly symmetrical structure of buckminsterfullerene, all the carbon atoms have exactly the same environment there is only one type of carbon atom. ” This “one-line” evidence was obtained in September 1990 and “dramatic further evidence for the whole family of closed caged molecules – the Fullerenes – was obtained from chemists work on C70. Finally a scientist in San Francisco had obtained a picture of C60 with gold atoms using the technique of scanning tunneling microscopy.Buckminsterfullerene consisted of exactly 60 carbon atoms and has the structure of a modern football.
The ultra violet absorption of C60 is unusual, on a graph it is a hump in a negative correlation, It is soluble in certain solvents forming coloured solution. It has a very low density (1. 65g cm-3) compared with a diamond (3. 51g cm-3). It is a good electrical insulator (unlike graphite, which conducts). C60 has “specially useful to exploit” properties, which “are their photophyical and electrochemical properties”. C60 seems to be more reactive like alkenes but unlike the similar benzene.It is easy to hydrogenate.
Its photophysical properties of “C60 molecule can absorb the energy from the light to produce a higher energy form. ” This molecule gives up energy readily and turns back to normal C60. *C60 can give of heat energy and can re-emit light. C60 is an optical limiter. “The electrochemical properties of C60 are especially remarkable. Not only is it easy to add one electron to C60, but up to six can be added in a stepwise manner to form C606-. C60, being an optical limiter means that if you increase the intensity of light passing thought it, the concentration of excited C60 is increased.
Thus, the intensity of the transmitted light is limited to a maximum value. ” Responding instantaneously to intense flashes of light like lasers, they can be used to protect sensitive equipment (eyes) from accidental exposure. Due to the way *C60 reacts with O2 to create excited O2 can be used to treat some forms of cancer.
This *O2 is toxic to living tissue when light is present of a certain wavelength. So in photodynamic therapy cancerous cells are illuminated specifically and a drug is given converting normal O2 into *O2, which is distributed thought out the body, only killing cancerous cells.This treatment has led to the development of C60 based drugs, which use its ability to generate *O2.
C60 superconductor properties would allow the use with in electronics, which would be good as with a superconductor no heat is produced so no cooling needed. Meaning smaller and more compact items can be produced. Buckminsterfullerene’s discovery relied on just the curiosity of a scientist, yet its discovery was a blessing as so much can be done with it. The possibilities for its use seem endless, so within the scientific world it discovery is of great significance and excitement.
Its use in the medical world t fight cancer, must be almost revolutionary. C60 discovery was a long and drawn out journey but all the work and years that the physicists and chemist put into it seem to be paying off. The discovery of buckminsterfullerene virtually revolutionised the ways in which scientist thought about carbon. First discovered in 1985 by British and American scientists, C60 and other fullerenes have bought versatility and potential of carbon forward.
C60 properties are now being exploited and used in new treatment of cancer, and electronics.