What is Fullerences
With the advent of nanotechnology many new components and materials appeared to the world, one of such materials is fullerene.Fullerene is a molecule with total carbon compotsition and it is available in the form of tube, ellipsoid and hollow spheres.Cylinderical fullrenes are known as carbon nanotubes and spherical ones are called bucky balls.There structure is similar to the structure of graphite.
The very first fullerene was discovered from the family of carbon named buckminsterfullerene C60, and was prepared in 1985 by famous panel of researchers including Harold Kroto, James Heath, Sean O’Brien, Robert Curl and Richard Smalley at Rice University. It is still considered to be the most rare component which is seldomly found naturally. The discovery of fullerenes spreaded the number of known carbon allotropes, which are still limited to graphite, diamond, and amorphous carbon such as soot and charcoal. Researchers believe that Buckyballs and buckytubes still have the hidden properties in them which are required to be explored.
For the last decade, the characteristics of fullerenes both chemical and physical have been the subject in the field of research. Some restricted properties are still in use in the field of medical sciences for diagnosing cancer and bacteria in the living body.Some of the important charcteristics of the fullerenes are listed below.
Aromaticity is the reactivity of the certain material or molecule with other in the different temparature.Fullerene also has aromaticity in different situations.A spherical fullerene has pibonding electrons which are free to localize or delocalizein different chemical siuations.According to the Huckel’s rule the aromaticicty of fullerene is three dimentional.This property can be improved and managed according to the situation with the help of quantum chemical modelling which can empower the bonding. As a result, C60 in water tends to pick up two more electrons and become an anion.
According to the reseachers fullerenes are considered to be the stable molecules but not fully unreactive. In certain circumstances fullerene become reatcive. The reactive charatceristics of fullerene is electrophilic at double bonding, which reduces angle stress by changing hybridized carbons into sp3 hybridized ones. Due to the change in hybridized orbits, the bond angles tends to decrease from about 120° in orbitals of sp2 carbon atoms.This decrease in bond angles permits the bonds to bend lesser on closing the tube making fullerene molecule more stable.
Fullerenes are soluble in many kind of solvents. The most Common solvents for the fullerenes include, carbon disulfide. Solutions of pure fullerene have a deep purple or voilet color. Color solutions of C70 are a reddish brown. The higher fullerenes from C76 to C84 have diferent color according to the portion mixed with solvents.Fullerenes are the only present allotrope of carbon that have the property to get dissolved in common solvents at normal room temperature.But in some cases fullerene structures remain undissolved such as at their excite state these carbon allotropes are not soluble.
Applications and Examples
Fullerenes ae used in many applications because of their unique chemistry and, especially in materials science, electronics, and nanotechnology.Many examples are obvious which totally explains the popularity of fullerene.Some famous examples are buckyball clusters, nanotubes, megatubes, polymers ,nano onions and fullerene rings.All thses structures are used in fields of work to extract more imporved form of products from existing materials.
Safety and toxicity
When focusing the toxic affects of the fullerene ,it should be kept in mind that fullerene is not toxic in all forms. The physical bond of fullerene C60 is safe and non toxic but the derivatives of fullerenes could be harmful to the health. Other fullerenes with covalently bonded chemical groups such as fullerene complexes,host-guest complexes, such as cyclodextrin is highly toxic.Aggregation of nano particles of C60, and C60 crystallites in much larger form encourages the toxicity .