FULLERENE: A Crystalline Form of Carbon

Hi Dearies

Am going to dive into chemistry this time and talk about a rare form of carbon some might not have heard of, but I will need to clear what carbon is. Back then, when I was in school, I used to think carbon was that paper we use in creating some like the usual carbon paper…lol, well carbon is the fourth most abundant element in the universe. As I was taught back then in school and I saw on the periodic table, carbon is the 6th element on the periodic table and its chemical element just like oxygen, hydrogen or any other in the periodic table. They are the base of building blocks of humans, trees, soils, animals and plants. We should also know that carbon contains six protons and six neutrons in the nucleus, not forgetting the six electron orbiting around the outside. What determines the properties of carbon are the number of protons and electrons without which humans might not exist. They are very important amongst all life form on earth, so they pretty play a vital role in the living organism.

by Alpha six via wikimedia commons CC-BY-SA-2.0: These are Buckminster-Fullerenes (C60) in a Solution.

FORMS OF CARBON

Many people know that diamond and graphite are crystalline forms of carbon it’s just few people that know of the Buckminster fullerene also called the Buckyballs. Ok! A quick peak on diamond and graphite before heading to my main form of carbon, the one I will be emphasizing on which is the Fullerene.

• Graphite which are formed out of carbon atoms in layers are shiny, opaque (not transparent) and black. They are slippery material in nature. Mostly used in pencils, for many lubricants. Graphite have a high melting point, insoluble in water and a good conductor of electricity

by James St. John, flickr commons CC by 2.0

• Diamonds – yes! As the name implies, most people have this and most fight and die for this because of its worth, its sparkling nature, lustrous, colourless and clear (transparent). They are practically a giant molecule of carbon atoms, couple with the fact that it has a high melting point, it is hard. They are insoluble in water and doesn’t conduct electricity; so for those who pull off their jewelries when they want to fix or deal with an electrical issue, well you are safe…lol. But its better safe than sorry (you get the idea right..winks!). the reason carbons don’t conduct electricity is that they are bonded by four strong covalent bonds to their neighbours, thereby leaving no free electrons and no ions, that’s why they are hard and has high melting point.

FULLERENE

So am going to jump in fullerene now. What is fullerene you might ask, I didn’t even know about it as much until I decided to just do some little findings on it. Fullerene Is a form of carbon having a large shaped molecule consisting of a hollow cage of sixty to nine hundred atoms. It is simply a molecule entirely made up of carbon like a hollow cage. Buckminsterfullerene (C60) was the first known example discovered in 1985. In 2010, fullerenes (C60) was discovered in a cloud of cosmic dust around a distant star 6500 light years away Using NASA's Spitzer infrared telescope.

pixabay creative commons by PIRO4D

Types of Fullerene

There are various types of fullerene, which most people don’t know about. I will be listed them below

• Buckyballs Cluster: This is known as the smallest fullerene that occurs in nature. Even as small as it is, it still holds great importance in regards to natural occurrence. It is known for its tiniest member to be C20 and the most common is C60. They can be found in soot
• Nanotubes or Cylindrical Fullerenes: This are made of carbon which are usually wide and extend only a few nanometers up to many millimeters in length. They are mainly used in electronics industry, paper batteries and in space technology for producing of high-tensile carbon cables used for a space elevator. They are hollow in shape with small dimension
• Megatubes: As the name implies, you know would know it has to do with hugeness, mega or large. They have larger diameters than the nanotubes. The walls are built up with various thickness. They are used mainly for transport of variety of molecules having different sizes.
• Polymers: These are macromolecules, joined by covalent chemical bonds. 2-dimention and 3-dimension polymers are formed under high temperature and high pressure
• Nano-onion: This have spherical particles which are based upon multiple carbon layers and is a form of buckyball solid.
• Linked “ball-and-chain” dimers: A carbon chain that has two buckyballs linked
• Fullerene Rings

by Greyesro (own work) via wikimedia CC-BY-SA-3.0: Nucleophilic Addition to a p-Benzyne

Fullerene Reactions

1. Nucleophilic Addition: A nucleophilic addition reaction is an addition reaction where a chemical compound with an electron-deficient or electrophilic double or triple bond reacts with electron-rich reactant (nucleophile) with disappearance of the double bond and creation of two new single bonds. Examples of nucleophiles are Grignard reagents and organolithium reagents. Example of nucleophilic reaction is the reaction of C60 with methylmagnessium chloride and the Bingel reaction.

2. Pericyclic Reaction: This is the reaction of the (6,6) bonds of fullerenes which acts as dienes or dienophiles in cyclo additions.

3. Hydrogenation: This is the chemical reaction of hydrogen with another substance, especially with an unsaturated organic compound (e.g. fullerene), and usually under the influence of temperature, pressure and catalyst. Fullerenes are easily hydrogenated by several methods. Examples of hydrofullerenes are C60H18 and C60H36. However, completely hydrogenated C60H60 is only hypothetical because of large strain. Highly hydrogenated fullerenes are not stable, as prolonged hydrogenation of fullerenes by direct reaction with hydrogen gas at high temperature conditions results in cage fragmentation. At the final reaction stage this causes collapse of cage structure with formation of polycyclic aromatic hydrocarbons

4. Oxidation: Oxidation is simply the addition of oxygen. It is also a reaction in which the atoms of an element lose electrons and the valence of the element increases. Oxidation of fullerene is possible for instance with oxygen and osmium tetra oxide

5. Hydroxylation: This is the process of introducing a hydroxyl (-OH) group into a compound. Fullerenes can be hydroxylated to fullerenols or fullerols. Water solubility depends on the total number of hydroxyl groups that can be attached. The maximum number of hydroxyl groups that can be attached (hydrogen peroxide method) stands at 36 - 40

6. Electrophilic Addition: This is an addition reaction where in a chemical compound, a pi-bond is broken and two new omega bonds are formed. Fullerenes reacts in electrophilic additions e.g reaction with bromine adding up to 24 bromine atoms to the sphere.

7. Retro Addition: This is used in removing substituents after they have served their purpose. e.g. are the retro - Bingel reaction and retro - prato reaction

8. Carbene Additions: A Carbene is a molecule containing a neutral carbon atom with a valance of two and two unshared valence electrons. Methylene (H2C:) is the simplest form. Carbene addition is the introducing of Carbene to another compound. Fullerene react with Carbene to form methanofullerene.

9. Radical Addition: A radical is a group of atoms joined by covalent bonds that take part in reactions as a single unit. Fullerene can be considered as radical scavengers (a chemical substance added to a mixture in order to remove or de-activate impurities and unwanted reaction products).

No machine-readable author provided. Su-no-G assumed: Mechanism for electrophilic addition of Bromine to alkenes via wikimedia commons

Fullerene Purification

This is the process of obtaining a fullerene compound free of contamination. The first available purification method for C60 fullerene was by HPLC (High performance liquid chromatography) from which small amounts could be generated at large expense.

Properties of Fullerene

(1) Fullerene is stable but not totally unreactive
(2) Fullerene can trap other atoms inside them to form inclusion compounds known as endohedral fullerenes e.g. the egg-shaped fullerene Tb3NaC84.
(3) Fullerene is sparingly soluble in many solvents e.g. toluene
(4) Some fullerenes are inherently chiral
(5) They tend to react as electrophiles
(6) Fullerene can be found in soot, interstellar dust and geological formations on the earth.

by CMSherwood (own work) via wikimedia CC-BY-SA-3.0: ruthenium fullerene complex

Uses of Fullerene

Fullerenes are widely used, but I will just be listing but a few of the uses below
(1) Fullerene binds specific antibiotics to the structure to target resistant bacteria and even target certain cancer cells such as melanoma.
(2) Fullerene can be used as light activated antimicrobial agents
(3) It is used as an insulator
(4) It is used as a catalyst
(5) It is used as a semiconductor in computers and flat screen TV's
(6) Some fullerenes are used as super conductors

APPLICATIONS

Researchers has really gone wide and far about the biomedical application of this particular molecule, ever since it was discovered. Below are several application of fullerene

1. As Antiviral Agents: fullerene has always got the potential as an antiviral agent because of their application to suppress the replication of the Human Immunodeficiency Virus (HIV), and with this, it delays the setting of Acquired Immuedeficiency Syndrome (AIDS). The bivalent metal derivation of amino acid derivatives of fullerene are also viewed to be active like the C60-1-Ala against HIV and human cyclomegalovirus replication.

No machine-readable author provided. Ragesoss assumed via wikimedia CC: 400 mg tablets of the antiviral drug acyclovir (aciclovir)

1. In the Research of Tumour: With the help of fullerene for tumour research, breakthroughs will soon be reached in getting the cure to cancer. With researches, it is observed that fullerene can be made to be absorbed by Hela cells. immediately treatment is finished, the free radicals are reabsorbed to stop damage to other tissues.

2. Hydrogen Gas Storage: With the help of fullerene structure, hydrogenate and dehydrogenate are enabled. Fullerene has a conjugated carbon ring with c=c double bonds. Hydrogen content tends to increase as the colour of hydrogenated fullerenes change from black to brown – red – orange and finally yellow. The molecule will be efficient, better and safer storage device as one fullerene molecule can retain up to 36 hydrogen atoms.

3. Antioxidants and Biopharmaceuticals: Fullerenes has lots to offer in health and personal care applications. They are powerful anti-oxidants always available to react with free radicals at a high rate which most time are the cause of death or cell damage. It can be used for Ocular tissue screening test for toxicity indicating no adverse effect. They are strong as they can neutralize 20 or more free radicals per fullerene molecule.

4. Polymer Additives: Because they are chemically reactive, they can be added to polymer structures to bring about a different copolymer with specific physical and mechanical properties.

5. Hardening Agents: Due to the sp2 hybridization of the carbon, it can be the future of developing comparatively lightweight metals with high tensile strength without revealing the ductility of the metal.

In other words, the use of fullerene is very essential as it can be used for lots of things as mentioned in the content even as organic photovoltaics (OPV). Studies and researches are still being carried out to know the potential use of fullerenes in developing molecular conductors and even cost-effective method for synthesizing molecules. I really hope you were educated with fullerene as a form of carbon. Please you can read more about it following the reference links provided. Until we meet next post, Au revoir says the French man…lol. I remain sparklez!

Reference

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