A short introduction on: Carbon nano tube and the reaction dynamics inside it-Part 2

Anant Babu Marahatta
Ph.D. student in Chemistry
Tohoku University,Japan

A carbon nanotube may be considered as a hollow cylinder formed by rolling up a graphite sheet. The chirality and diameter of a carbon nanotube is uniquely defined by a vector (n, m), na + mb; where a and b denote the unit vectors of the hexagonal lattice and n and m are integers.

Fig ; 2.  A unit cell of a system of twelve carbon nano tubes and 1540 water molecules.

Computational studies have suggested that CNTs can be designed as molecular channels to transport water. A single-walled CNT, with a diameter of 8.1 Å, has been studied by molecular dynamics (MD) simulations. The simulations revealed that the CNT was spontaneously filled with a single file of water molecules and that water diffused through the tube concertedly at a fast rate. The transportation of water molecules across nanometer water channels in membranes plays a key role in biological activities. It has been recognized that the existence of the charged residues in these water channels greatly reduces the permeation of protons across the channel but maintains quite stable water flows. Moreover, because charges are indispensable in both membrane proteins and physiological solutions inside and outside the cells, it is also important to understand how external charges influence the water permeation.

The electronic polarizability of carbon nanotubes has been the subject of numerous studies because of their potential use as novel photonic materials and molecular electronic elements. The axial polarizability of carbon nanotubes has been found to be much larger than the radial polarizability and is dependent on nanotube length. Dipolar species confined within or in the interstitial spaces between carbon nanotubes can interact with an induced image dipole becoming stabilized relative to the gas phase.

Experimentally, carbon nanotubes have been filled with a variety of materials. Carbon nanotubes have been filled with molten AgNO₃ and then created pure Ag particles inside the nanotubes by electron-beam-mediated reduction. Carbon nanotubes have also been filled with materials such as KI, Ag, Au, AuCl, ZrCl₄, and even C60 and higher fullerenes. Inorganic nanorods have been synthesized through carbon nanotube confined reactions. For example, Ga₂O vapor and NH₃ were reacted inside carbon nanotubes to create gallium nitrides (GaN) nanorods with diameters determined by the radius of the nanotubes. Similarly, silicon nitrides (Si₃N₄) nanorods have also been synthesized.

Due to their unique physical properties, carbon nanotubes are a novel nano scale environment to carry out chemical reactions in it. Reaction energetics, mechanism and dynamics could be significantly altered inside carbon nanotubes due to their large intrinsic polarizabilities and due to the severely decreased reaction volume. In an effort to examine the effect on reaction enthalpies and activation energies of confining reacting systems inside carbon nanotubes, calculations using hybrid density functional theory have been carried out for a model reaction.

In the studies of interaction of CNTs with organic compounds, especially amines, it has been found that the amine groups in the molecules are electron donating and responsible for charge transfer to the semi conducting nanotubes. Terminal carbon atom forms a covalent bond with the N atom of the amine.

In theoretical studies examining the effect of local environment present inside the carbon nano tube on chemical reactivity, the Menshutkin SN2 reaction has often been studied. It is the simplest system in which an amine is alkylated by an alkyl halide. Choosing ammonia as the nucleophile and methyl chloride as the methyl transfer reagent gives chloride as the anionic leaving group.

H₃N + H₃CCl           H₃NCH₃⁺  +   Cl^-

Menshutkin SN2 reactions, in which the reactants are neutral and the product species are formally charged, are quite sensitive to the polarity of the surrounding environment, becoming more favorable with increasing polarizability, which stabilizes the separation of charge throughout the reaction. Medium effects result in a reduction in reaction barrier.

 The effect of confinement of the simplest Menshutkin SN2 reaction inside carbon nanotubes on chemical reaction enthalpies and activation energies has also been investigated. It has been found that in comparison to the gas phase, the potential energy surface changes dramatically.

Fig; Menshutkin SN2 ion pair product structure inside the carbon nanotube as viewed down the symmetry axis of the nanotube (top) and from the side (bottom).

At first, the ion pair product is significantly stabilized, making the overall process more favorable. And in the second step, the transition state shifts towards the reactants and is stabilized, giving a lower reaction barrier. This result indicates that the effect of nanotube confinement on relative reaction energies closely resembles solvation and the chemical reactions in which there is a separation of charge along the reactio coordinate will be enhanced inside fullerene based materials due to their large electronic polarizabilities.

Thus the research on “reaction dynamics on carbon nanotubes” has been expected to contribute some roles in the field of nanotechnology. Modification of the surfaces of the nano tubes for studying several disciplines is not very common and convenient to every where. So the knowledge of the research is definetly applicable and will add some crucial points in the days to come.  

42-month PhD studentship on Nanoscience available in the University of Leicester

Duration: 42 months
Starting date: 1st October, 2011

Department of Chemistry, University of Leicester.

Applicants are invited for a 42-months postgraduate studentship fully funded by the UK EPSRC. This is to join in a world-leading research programme in Nanoscience. The scope of the project will include the synthesis of core-shell and core-multiple shell nanoparticles, and their characterization using state-of-the-art microscope and synchrotron measurement.

Applicants must be motivated and wish to commit to the research programme. You should also have an honored degree at 2.1 or 1st class in the field of Physics, Chemistry, Material Science or Nanoscience. The studentship will cover the annual stipend at standard rate and the tuition fee at the UK/EU rate.

You will be supervised by Dr Shengfu Yang (Chemistry) and Prof. Chris Binns (Physics). However, the research team will include other academic staff including Prof. Andy Ellis (Chemistry) and Dr. Klaus von Haeften (Physics). During the full period of the research project, you will be working with a postdoctoral research associate, Dr. Adrian Boatwright.

If you are interested, please contact Dr. S Yang (sfy1@le.ac.uk) directly to arrange an appointment.

The advertisement is also available at: http://www2.le.ac.uk/departments/chemistry/postgraduate-study/phd-s...

Postdoctoral Fellowships in the Division of Chemical Sciences & Engineering King Abdullah University of Science and Technology (KAUST)

Job Title
Postdoctoral Fellowships in the Division of Chemical Sciences & Engineering
Department of Chemical and Life Science and Engineering http://www.kaust.edu.sa
King Abdullah University of Science and Technology (KAUST)
Thuwal, Jeddah, Saudi Arabia

Application Deadline: Open until filled
Position Start Date: Available immediately

Apply By E-mail: sahraoui.chaieb@kaust.edu.sa

Job Categories: Post-Doc

Academic Fields: Chemistry - Biochemistry, Biology - Biochemistry, Physics - Atomic/Molecular/Optical/Plasma

Postdoctoral Fellowships in the Division of Chemical Sciences & Engineering

The Nanobiophysics Laboratory within the Division of Chemical and Life Science and Engineering invites applicants for several postdoctoral positions in the area of membrane biophysics applied to Cell Adhesion and vesicular trafficking in eukaryotes.

You could enjoy a truly unique Postdoctoral opportunity to contribute to Nanobiophysics research at a new university with exciting global ambitions. King Abdullah University of Science and Technology (KAUST) is one of the biggest, most significant developments in higher education of recent times.

We are interested in understanding the intimate relationship that exists between lipid molecules composing the cellular organelles and the proper function of the transmembrane proteins. In cell adhesion we are interested in the dynamics and statics of integrin clustering and its relationship to actin ordering. In the case of vesicular trafficking we are also interested in the behavior of coat proteins during vesicular transport. Our main interest will lie within the COPI/ArfGAP1 system and the vesicle generation. The methods applied will include in vivo and in vitro transport assays, protein chemistry, molecular biology, ultra structural analysis of cells and isolated organelles, as well as lipid biochemistry. We will use characterization tools such light scattering, Cryo-TEM, TIRF microscopy and optical tweezers. Our laboratory is equipped with the state of the art proteins purification such as FPLC and PCR. KAUST has also one of the best-equipped core labs in the world such as Genomics core labs, proteomics core labs, analytics and the Nanobiology laboratories.

KAUST is located on the Red Sea in Thuwal (80km north of Jeddah). Newly opened in September 2009, KAUST is an independent and merit-based university and welcomes exceptional researchers, faculty and students from around the world. KAUST offers attractive base salaries and a wide range of benefits. Further information about KAUST can be found at http://www.kaust.edu.sa

Applicants need to have a PhD in biophysics, structural biology, biochemistry, bioengineering or a related field with some experience in instrumentation. To apply you please send your curriculum vitae, a list of publications and arrange for three letters of recommendations to be sent to Professor Sahraoui Chaieb at sahraoui.chaieb@kaust.edu.sa The review of applications will begin immediately and applicants are strongly encouraged to submit applications as soon as possible.

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EEO/AA Policy: EOE

Contact Information

Professor Sahraoui Chaieb

Chemical and Life Science and Engineering

King Abdullah University of Science and Technology (KAUST)

Thuwal, Jeddah Thuwal 23955-690

Saudi Arabia

Email: sahraoui.chaieb@kaust.edu.sa

Postdoctoral Positions -- Inorganic Chemical Synthesis of Thin Films and Nanomaterials King Abdullah University of Science and Technology

Job Title: Postdoctoral Positions -- Inorganic Chemical Synthesis of Thin Films and Nanomaterials

Physical Sciences and Engineering Division, King Abdullah University of Science and Technology
Thuwal, Jeddah, Saudi Arabia

Application Deadline: Open Until Filled
Position Start Date: Available Immediately

Apply By E-mail: husam.alshareef@kaust.edu.sa
Website For Job: http://www.kaust.edu.sa

Job Categories: Post-Doc
Academic Fields: Nanotechnology, Materials Sciences/Polymer Sciences, Environmental Sciences/Ecology/Forestry, Chemistry - Inorganic Chemistry - General Sciences - General

Postdoctoral Positions

Postdoctoral Fellows are sought, with experience in the Inorganic Chemical Synthesis of Thin Films and Nanomaterials. Experience in Chemical Synthesis of Oxides is preferred, but not required. The candidate is also expected to be familiar with key material characterization methods.

Detailed knowledge of any of the following areas is a plus.

• Thermoelectric Materials
• Semiconducting Oxides
• Multi-ferroic Oxides

A generous compensation package will be offered, that includes competitive, tax-free salary, health care medical and dental) and 30 days of annual vacation.

Appointments are for one year and may be renewed for up to three years, based on performance.

If interested, please send CV and names of two references, to Prof. Husam N. Alshareef, at: husam.alshareef@kaust.edu.sa

About Our Group:

We conduct multidisciplinary research focused on the applications of functional oxides in electronics, nanoelectronics and energy harvesting applications.

For more info., please visit: nanomaterials.kaust.edu.sa

About KAUST:
KAUST is located on the Red Sea, near Jeddah, Saudi Arabia. Opening in September 2009, KAUST welcomes exceptional researchers, faculty and students from around the world.
Further information can be found at: http://www.kaust.edu.sa/

Contact Information
Mr. Steve Bee
Physical Sciences and Engineering Division
King Abdullah University of Science and Technology
Thuwal, Jeddah 23955-690
Saudi Arabia

A short introduction on: Carbon nano tube and the reaction dynamics inside it-Part 1

Anant Babu Marahatta
Ph.D. Student in Chemistry
Tohoku University,Japan


This is the age of science and technology. In the world, many technological devices have been used and constructed which are the blessings of the science. In the field of science, nanotechnology plays crucial role for the innovation of several nano size devices from the nano materials either by modifying their properties or by using them directly.

Generally, nanotechnology is defined as the engineering of functional systems at the molecular scale. In recent years, properties and structures of nano size materials have attracted many people's attention. Their unique properties and small dimensionality give very promising future for various potential applications. Out of the several nano materials, the history of the newly discovered allotropic forms of carbon called “Fullerene” is the recent one. Significant progress has been made toward the understanding of the properties and structures of nano tubes.

FIG.1 [a] A hexagonal graphite sheet to create a zig-zag or armchair nanotube by rolling up along or y axis; [b] A graphite sheet with active –COOH groups; [c] An armchair SWNT with a diameter of 8.15 Å; [d] A hydrophilic SWNT with –COOH groups having an inner diameter of 8.40 Å.

Carbon nanotubes (CNTs) are carbon allotropes. Their name has been derived from their size, since the diameter of a nanotube is in the order of a few nanometers (approximately 50,000 times smaller than the width of a human hair), while they can be up to several millimeters in length. They are mainly of two types: single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs). A single-walled carbon nanotube is a one-atom thick sheet of graphite (called graphene) rolled up into a seamless cylinder with diameter on the order of a nanometer. This results in a nanostructure where the length-to-diameter ratio exceeds 10,000. SWNTs are a very important variety of CNT because they exhibit important electric properties that are not shared by MWNTs. The remarkable properties of SWNTs stem from the symmetry and unusual electronic structure of graphene.

The nature of the bonding of a nanotube is described by applied quantum chemistry, specifically, orbital hybridization. The chemical bonding of nanotubes are composed entirely of sp² bonds, similar to those of graphite. This bonding structure provides the molecules with their extraordinary and unique strength and possibility of studying reactions dynamics into it. Such cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science. They exhibit electrical properties, and are efficient conductors of heat. Due to strong sp2 bonding, carbon nanotubes are much less susceptible to electromigration (EM) problems that plague copper interconnects and can carry very high current density.

Computational Chemistry: visual mode

DEATH BY COMMON SALT [NaCl]

Anant Babu Marahatta
Ph.D.student in Chemistry
Quantum Chemistry group, Department of chemistry, Tohoku University, Sendai,Japan

There is no doubt that common salt or sodium chloride (NaCl) is indeed essential to all life. It is the basic milieu of mammals. It occurs as colorless cubic crystals or as white crystalline powder. It is available at everyone’s home as well as in laboratory. No one suspect that it is a poison. One who studied biochemistry must have learnt that salt is a poison and can be used to kill infants. It is indeed a rather safe poison because one doesn’t need to buy anything when salt is administered in larger quantities than required, it can cause death too.

One teaspoonful of salt weighs about 5gms. Normal uptake by adults is about 5 to 15gm daily or about 1-3 teaspoonfuls. Children consume less salt is even necessary for normal growth. The sodium needed for growth is 0.5 mEq/kg from birth to 3 months of age, which decreases to 0.1mEq/kg at 6 months. The average content of sodium in human milk is 7mEq/L and that in cow milk is 21mEq/L.

Since, chemists and biochemists find it easier to talk in terms of equivalent weights. Equivalent weights are actually measures of the characteristic proportions in which the given elements combine .As we all know that 1mEq.sodium equals 23 mg and that of NaCl equals 58.5mg, and 1mEq would be equal to 1/1000 Equivalent weight. Thus, when one says that sodium needed for growth is 0.5 mEq/kg from birth to three months of age; he simply means that for every kg of baby’s weight, 0.5mEq of sodium is needed. Thus if the infant weighs, say, 4kg he would need 4 x 0.5 or about 2mEq of sodium. Since 1mEq of sodium is 23 mg, it would mean that the infant would need about 46mg of sodium daily. This much sodium would be available from about 117 mg of salt. Similarly we can convert other values given above.

Most people will not believe that common salt is a deadly poison. The only difference between this and other commonly known poisons is that one has to administer rather large quantities. One or two tea spoonfuls of salt would not kill an adult but can easily kill a 6 month old baby. About 40 teaspoons of common salt would kill an adult human being too. The toxic oral dose of salt is 0.5 to 1.0 gm/kg. For a 70 kg man this amount is about 35-70 gm. That means if an adult consumes about 70 gm of salt [or about 14 teaspoons], he would be severely poisoned. The estimated fatal amount, i.e. amount sufficient to kill, is about 1 to 3 gm /kg [remember that weight of one teaspoon common salt is about 5 gm.]. This amounts to about 70 to 210 gm. [about 40 teaspoonfuls] of salt for a 70 kg man.

Interestingly, the Chinese used saturated salt solution for suicide. Salt intoxication and death have occurred when it is used to induce vomiting as well. When some body has consumed a poison, it is imperative to remove as much poison from his stomach as possible. One of the best ways to do this is to make the person vomit. It has been known from the ancient times that a strong solution of common salt induces vomiting and that is why for centuries, it was a favorite method of doctors to induce vomiting for poisoned patients. But now it is known that saturated solution of salt itself can cause salt poisoning, so it is rarely used these days. Thus accidental poisoning and death takes place due to the common salt if the person consuming less harmful poison is induced vomiting by injecting saturated salt solution orally. This is the most common accident frequently observed in the society.

THUS, THIS IS OUR WORK TO MAKE THE SOCIETY AWARE ABOUT THE SALT POISONING. SALT SOLUTION INFACT INDUCES VOMITTING BUT ITS HIGH CONCENTRATION ACTS AS FATAL.


DOCTORAL EVIDENCES OF COMMON SALT POISONING

The stomach contents and the blood analysis of the person poisoned by common salt tell the doctor that salt has been administered to the patient. While examining the brain tissue under the microscope, it has been found the capillaries of the brain are damaged and they are full of blood. There are innumerable bleeding points- technically known as hemorrhages in the brain. Many venous channels of the brain called dural sinuses are blocked. All these findings are strongly in favor of salt poisoning.

PhD Positions in Materials Research (Energy and Nanoelectronics) King Abdullah University of Science and Technology

Job Title: Ph.D. Student Positions -- Materials Research (Energy and Nanoelectronics)
Physical Sciences and Engineering Division, King Abdullah University of Science and Technology
Thuwal, Jeddah, Saudi Arabia

Application Deadline: Open Until Filled
Position Start Date: Available Immediately

Apply By E-mail: husam.alshareef@kaust.edu.sa
Website For Job: http://www.kaust.edu.sa

Apply Online Here
http://www.kaust.edu.sa/academics/faculty/alshareef....

Job Categories: Graduate Student
Academic Fields: Physics - General, Nanotechnology Materials Sciences/Polymer Sciences
Environmental Sciences/Ecology/Forestry, Chemistry - General Sciences - General

Ph.D. Students are sought for exciting Materials Research opportunities (in Energy and Nanoelectronics), at King Abdullah University of Science & Technology (KAUST). Successful candidates must have Bachelor's or M.S. Degrees in Physics, Chemistry or Materials Science. Only students with excellent grades and demonstrated English language proficiency need apply.

Ideal candidates must have minimum B+ averages and must have passed the TOEFL Examination.
A generous compensation package will be offered, that includes:
1) Competitive salary; 2) Free, furnished housing and utilities; and, 3) Free health care.

If interested, please send CV, two recommendation letters and dates of availability, to Professor Husam N. Alshareef, at: husam.alshareef@kaust.edu.sa

About KAUST: KAUST is a new university, located on the shores of the Red Sea in Saudi Arabia. The community has many things to offer, including housing, healthcare, shopping, dining and many parks and sports facilities (including a golf course, sailing facilities, gyms with swimming pools, running tracks, etc.).

There is a very good campus transport system.

The University's research facilities include extensive world-class nanofabrication and characterization facilities, including a fully-equipped class 100 clean room, central imaging and characterization facilities and several focused research centers.

Contact Information
Mr. Steve Bee
Physical Sciences and Engineering Division
King Abdullah University of Science and Technology
Thuwal, Jeddah 23955-690
Saudi Arabia

Postdoctoral Fellow -- Chemistry, University of Pittsburgh

Postdoctoral Fellow -- Chemistry, University of Pittsburgh

Date Posted: Aug. 24, 2010

Job Title: Postdoctoral Fellow -- Chemistry
Department Department of Chemistry
Department Website
http://www.chem.pitt.edu/
University of Pittsburgh, Pittsburgh, PA

Application Deadline: Open Until Filled
Position Start Date: Available Immediately

Apply By E-mail: asher@pitt.edu
Website For Job: http://www.pitt.edu/~asher/homepage/index.html

Job Categories: Post-Doc
Academic Fields: Chemistry - Physical, Chemistry - Analytical, Chemistry - General, Sciences - General

Postdoctoral Fellow wanted for a research program, studying interparticle interactions and photonic crystal materials, formed by self-assembled crystalline colloidal arrays.

Useful areas of expertise include Colloidal Chemistry, Physical Chemistry and Analytical Chemistry.

The ideal outstanding scientist would be interdisciplinary and have high aspirations.

Please respond with a CV and three letters of reference, to:

Professor S. Asher
University of Pittsburgh
Department of Chemistry
Pittsburgh, PA 15260
asher@pitt.edu

EEO/AA Policy
The University of Pittsburgh is an Affirmative Action, Equal Opportunity Employer.

Contact Information
Professor Sanford Asher
Department of Chemistry
University of Pittsburgh
Chevron Science Center
219 Parkman Avenue, Rm. 701
Pittsburgh, PA 15260

Phone Number
412-624-8570
Fax Number:
412-624-0588
Email:
asher@pitt.edu

Tribhuvan University BSc Chemistry Syllabus

Scanned copy of Tribhuvan University BSc Chemistry Syllabus has been uploaded to the web. This is the latest syllabus of TU. I hope it will be useful for many of us.

Thank You Dr. Ajaya Bhattarai for sending me these scanned copies.
Basant

Tribhuvan University BSc Chemistry Syllabus 2008

TU M Sc Chemistry Syllabus Available Online

Chemistry syllabus of Master of Science in Chemistry of Tribhuvan University, 1999 has been scanned from printed copy and  uploaded here. You can download and print.


I hope it will be useful to many of us.


Thanks
BasantTU Chemistry Syllabus

Congratulations to Dr. Krishna Panthi for Completing his PhD

Defence Seminar

Dr. Panthi with his Professors

Krishna Panthi has successfully defended his PhD degree on December 7, 2010 from Bowling Green State University. His research focused on the synthesis of compounds which are useful in organic solar cells, organic nanoparticles, organic sensors, organic light emitting diodes and related fiends. 

He has accepted a post doctoral research associate position in University of Texas at Austin.

Congratulations Dr. Panthi and we wish you a very bright future.


Some of his recent publications can be viewed here.

1. Panthi et al., J. Phys. Chem. A. 2010 A
2. Panthi et al., J. Phys. Chem. A. 2010 B
3. Panthi et al., J. Photochem. Photobiol. A: Chem., 2010
4. Panthi et al., Tetrahedron. 2010

Dr. Rabindra Dhakal Receives The Academy of Sciences for the Developing World(TWAS) Award

Dr. Rabindra Dhakal has received "The Academy of Sciences for the Developing World (TWAS)" award for his contribution to the study of modified cellulose biopolymers for recovering precious metal ions from the wastes.

TWAS, the academy of sciences for the developing world, is an autonomous international organization, founded in 1983 in Trieste, Italy, by a distinguished group of scientists from the South under the leadership of the late Nobel laureate Abdus Salam of Pakistan. It was officially launched by the secretary-general of the United Nations in 1985.

This Award is recently given annually to 4 scientists who have made remarkable contribution in the selected disciplines of Biology, Chemistry, Mathematics, and Physics by NAST (National Academy of Science and Technology) in Nepal. 

This years receipients are Dr. Prasamsa Singh from Physics, Dr. Manoj Thapa from Biology, Dr. Rabindra Prasad, Dhakal from Chemistry, and Dr. Mahendra Maharjan from Biology.

NepaChem team would like to Congratulate all the award receipients.