MOUNTAIN TOP UNIVERSITY CHM 102 Organic Chemistry FULLERENES, NANOCHEMISTRY & NANOSTRUCTURE Dr. (Mrs.) NDUKWE, Nelly Acha           FULLERENES, NANOCHEMISTRY & NANOSTRUCTURE by Dr. (Mrs.) Ndukwe, Nelly Acha is licensed under a Creative Commons Attribution-Non Commercial 4.0 International License

Carbon structures Graphite: Diamond: Buckminster fullerene: black, opaque, lusterous, slippery, conducts electricity Diamond: colourless, clear, lusterous, high m.p., does not conduct electricity Buckminster fullerene: Black solid, deep red solution in petrol

Fullerenes Chemistry They are spheres of only carbon atoms and are also allotropes of carbon One example is the Buckminsterfullerene (Buckyball) It has a formula C60 It is a black solid Dissolves in petrol to make a red solution Free moving electrons so conducts electricity

What are fullerenes? Fullerenes are closed hollow cages consisting of carbon atoms interconnected in pentagonal and hexagonal rings. Each carbon atom on the cage surface is bonded to three carbon neighbors therefore is sp2 hybridized. The most famous fullerene is C60, known also by “ buckyball ". Other relatively common clusters are C70, C72, C74, C76, C80, C82 and C84 (plenty of others, higher or lower than C60, exist too but less abundant in the experimentally produced mixture fullerene soot).

C60: An unusual form of carbon Dissolves in common solvents like benzene, toluene, hexane Readily vaporizes in vacuum around 400°C Low thermal conductivity Pure C60 is an electrical insulator C60 doped with alkali metals shows a range of electrical conductivity: Insulator (K6 C60) to superconductor (K3 C60) < 30 K!

Review: Carbon Chemistry What is carbon’s electron orbital diagram? How many bonds does carbon always form? Four These can be: four single bonds two single bonds and one double bond two double bonds one single bond and one triple bond

Bonding pattern in carbon Four single bonds Tetrahedral with bond angles of approximately 109º. C Two single bonds and one double bond Planar with 120º bond angles. =C= Two double bonds Linear with 180º bond angles. C One single bond and one triple bond Linear with 180º bond angles.

Diamond How are the carbon atoms arranged in diamond? Each interior carbon is covalently bonded to four others in a tetrahedron.

Graphite How are carbon atoms arranged in graphite? arranged in planar layers (sheets) each interior carbon atom is covalently bonded to three others in a hexagonal pattern very weak forces exist between the layers (gray lines in the figure above) the individual layers extend indefinitely in two dimensions

Graphite Knowing that: carbon always forms four bonds; each carbon atom in graphite is covalently bonded to three other carbon atoms; and the graphite layers are flat. What is the bonding pattern around a given carbon atom in graphite? C Two single bonds and one double bond

Fullerenes: Uses They can cage other molecules In the future this may be used to deliver drugs in small amounts for slow release. E.g. Cancer treatment

Nanotubes – How big are they? Nanotubes are being developed for use in computer technology. These tubes are: 1-2nm diameter 100mm long

Nanotubes & Fullerene derivatives

Nanotubes Uses Biological: drug delivery, trap dangerous substances, immobilization of enzymes, DNA transfection Paints: improving strength & conductivity Actuators: changing electrical energy into mechanical energy e.g. robotics Electronics: semiconductors, diodes. Chemical industry: catalysts e.g. zeolites in hydrocarbon cracking Excellent website: http://nanotechinkorea.free.fr/english/nanoco.php

Application o Nanotubes A range of applications intended to improve life quality and to provide novel approaches to diagnostic and therapy, based on suitably designed nanostructures, nanoparticles or smart molecular systems. Currently, a number of research groups is studying such topics, as witnessed also by specifically devoted scientific journals.

Types of nanotubes Semiconductor: It is a chiral nanotube - “twists” along its length. Conductor (metallic): Straight nanotubes [Only conducts electricity under specific conditions]

Application of nanochemistry This discipline involves both new materials and new principles, as powerful tools for an extremely effective action against a range of diseases. For example a physicochemical phenomenon called Surface Plasmon Resonance is used to develope a technology for drug discovery, antibody screening, ligand fishing and therapeutics.

Application of nanochemistry Futuristic kinds of nanorobots have been even imagined, able not only to take care of our health from inside our body, but also to replicate themselves or to modify themselves according to the specific problem to be solved. Increasing funding initiatives are supporting this fascinating and promising research field.

Nanomedicine Nanotechnology provides a wide range of new technologies for developing customized solutions that optimize the delivery of pharmaceutical products. Today, harmful side effects of treatments such as chemotherapy are commonly a result of drug delivery methods that don't pinpoint their intended target cells accurately.  Researchers at Harvard and MIT, however, have been able to attach special RNA strands, measuring nearly 10 nm in diameter, to nano-particles, filling them with a chemotherapy drug. These RNA strands are attracted to cancer cells. When the nanoparticle encounters a cancer cell, it adheres to it, and releases the drug into the cancer cell. This directed method of drug delivery has great potential for treating cancer patients while avoiding negative effects (commonly associated with improper drug delivery)

Nanorobotics Nanorobotics is the emerging technology field creating machines or robots whose components are at or close to the scale of a nanometer (10−9 meters).   More specifically, nanorobotics refers to the nanotechnology engineering discipline of designing and building nanorobots, with devices ranging in size from 0.1–10 micrometers and constructed of nanoscale or molecular components.[  The names nanobots, nanoids, nanites, nanomachines or nanomites have also been used to describe these devices currently under research and development.

The nanotube is used here to connect two Diode: The nanotube is used here to connect two electrodes (yellow) on a silicon dioxide base (green) [Diodes allow a current to travel in one direction only] Superconductors or Insulators:

NANOTUBES Nanotubes are made by joining fullerenes together Properties Hexagons curled into a tube shape Very strong Conducts electricity Small with a large surface area Can be separated from liquid products for re- use Uses Reinforce Graphite in tennis racquets Semi conductors in electric circuits in modern computers and electric circuits Industrial catalysts

Drug Delivery – ‘Buckydrugs’ ‘Cages’ made of Buckminster fullerene structures can be used to carry drugs

Bacteria can be used to carry drugs, DNA or sensors attached to nanoparticles into cells for treatment, gene therapy or diagnosis.

Replacing Antibiotics

FULLERENES, NANOCHEMISTRY & NANOSTRUCTURE by Dr. (Mrs           FULLERENES, NANOCHEMISTRY & NANOSTRUCTURE by Dr. (Mrs.) Ndukwe, Nelly Acha is licensed under a Creative Commons Attribution-Non Commercial 4.0 International License