Magnetic chemistry
Encyclopedia
Magnetic chemistry are chemical reactions in which either reactant, reagent
or product
have magnetic properties. Even though this definition in theory includes even single magnetic atoms, in practice the smallest magnetic units are magnetic nanoparticles
. Magnetic chemistry and its applications are an interdisciplinary field between chemistry
, biology
, material sciences and chemical engineering
.
are used in connection with magnetic chemistry only in scientific research such as a biocatalyst, catalyst, catalyst support
and solid phase synthesis support, as well in biotechnology
and medicine
. An industrial use has yet to be established. The potential and versatility of magnetic chemistry arises from the fast and easy separation of the magnetic nanoparticles, eliminating tedious and costly separation processes usually applied in chemistry. Furthermore the magnetic nanoparticles can be guided via a magnetic field to the desired location which could, for example, enable pin-point precision in fighting cancer.
attached to magnetic nanoparticles was shown by T.-J Yoon et al.
An other example of a catalyst immobilized onto magnetic nanoparticles is shown by Schätz et al.. The catalyst in this case is the stable radical
TEMPO
, which was attached to the graphene
coated Cobalt nanoparticles in several steps starting with a diazonium reaction, known well from carbon nanotubes, and successive click chemistry
. The resulting catalyst was then successfully used for the chemoselective oxidation of primary and secondary alcohols.
Thanks to the magnetic properties of the nanoparticles, the catalytic reaction can take place in a continuous flow reactor instead of a batch reactor
with no remains of the catalyst in the end product. Graphene coated cobalt nanoparticles have been used for that experiment since they exhibit a higher magnetization than Ferrite
nanoparticles, which is essential for a fast and clean separation via external magnetic field.
Reagent
A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
or product
Product
- Business :*Product , an item that ideally satisfies a market's want or need**Product , a deliverable or set of deliverables that contribute to a business solution**Nanoproduct, a product that has been enhanced with nanotechnology...
have magnetic properties. Even though this definition in theory includes even single magnetic atoms, in practice the smallest magnetic units are magnetic nanoparticles
Magnetic nanoparticles
Magnetic nanoparticles are a class of nanoparticle which can be manipulated using magnetic field. Such particles commonly consist of magnetic elements such as iron, nickel and cobalt and their chemical compounds. While nanoparticles are smaller than 1 micrometer in diameter , the larger microbeads...
. Magnetic chemistry and its applications are an interdisciplinary field between chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
, material sciences and chemical engineering
Chemical engineering
Chemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...
.
Field of use
Since magnetic nanoparticles are time and cost intensive to produce, their use only makes sense in reactions where they can be either reused, used only in catalytic amounts, or the resulting product is even more precious. So far, magnetic nanoparticlesMagnetic nanoparticles
Magnetic nanoparticles are a class of nanoparticle which can be manipulated using magnetic field. Such particles commonly consist of magnetic elements such as iron, nickel and cobalt and their chemical compounds. While nanoparticles are smaller than 1 micrometer in diameter , the larger microbeads...
are used in connection with magnetic chemistry only in scientific research such as a biocatalyst, catalyst, catalyst support
Catalyst support
In chemistry, a catalyst support is the material, usually a solid with a high surface area, to which a catalyst is affixed. The reactivity of heterogeneous catalysts occurs at the surface atoms. Consequently great effort is made to maximize the surface area of a catalyst by distributing it over...
and solid phase synthesis support, as well in biotechnology
Biotechnology
Biotechnology is a field of applied biology that involves the use of living organisms and bioprocesses in engineering, technology, medicine and other fields requiring bioproducts. Biotechnology also utilizes these products for manufacturing purpose...
and medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
. An industrial use has yet to be established. The potential and versatility of magnetic chemistry arises from the fast and easy separation of the magnetic nanoparticles, eliminating tedious and costly separation processes usually applied in chemistry. Furthermore the magnetic nanoparticles can be guided via a magnetic field to the desired location which could, for example, enable pin-point precision in fighting cancer.
Biotechnology and medical applications
Enzymes, proteins and other biologically and chemically active substances have been immobilized on magnetic nanoparticles. Allowing for reactions even within the human body itself such as cellular labelling/cell separation, detoxification of biological fluids, tissue repair, drug delivery, magnetic resonance imaging, hyperthermia and magnetofection.Direct catalysis
Uncoated metallic magnetic nanoparticles are very prone to oxidation which makes them unsuitable for direct applications in catalysis.Catalyst support
Conventional solid support catalysis often suffers from reduced reactivity and selectivity due to the fact that the catalytic active center is embedded in a solid support. Immobilizing the catalytic center on top of nanoparticles with a large surface to volume ratio counters this problem. In the case of magnetic nanoparticles it adds the property of facile a separation. An early example of a catalysis with RhodiumRhodium
Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...
attached to magnetic nanoparticles was shown by T.-J Yoon et al.
An other example of a catalyst immobilized onto magnetic nanoparticles is shown by Schätz et al.. The catalyst in this case is the stable radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
TEMPO
TEMPO
oxyl, or oxidanyl or TEMPO is a chemical compound with the formula 32NO . This heterocycle is a red-orange, sublimable solid. As a stable radical, it has applications throughout chemistry and biochemistry. TEMPO was discovered by Lebedev and Kazarnowskii in 1960...
, which was attached to the graphene
Graphene
Graphene is an allotrope of carbon, whose structure is one-atom-thick planar sheets of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The term graphene was coined as a combination of graphite and the suffix -ene by Hanns-Peter Boehm, who described single-layer...
coated Cobalt nanoparticles in several steps starting with a diazonium reaction, known well from carbon nanotubes, and successive click chemistry
Click chemistry
Click chemistry is a chemical philosophy introduced by K. Barry Sharpless of The Scripps Research Institute, in 2001 and describes chemistry tailored to generate substances quickly and reliably by joining small units together...
. The resulting catalyst was then successfully used for the chemoselective oxidation of primary and secondary alcohols.
Thanks to the magnetic properties of the nanoparticles, the catalytic reaction can take place in a continuous flow reactor instead of a batch reactor
Batch reactor
The Batch reactor is the generic term for a type of vessel widely used in the process industries. Its name is something of a misnomer since vessels of this type are used for a variety of process operations such as solids dissolution, product mixing, chemical reactions, batch distillation,...
with no remains of the catalyst in the end product. Graphene coated cobalt nanoparticles have been used for that experiment since they exhibit a higher magnetization than Ferrite
Ferrite
Ferrite may refer to:* Ferrite , iron or iron alloys with a body centred cubic crystal structure.* Ferrite , ferrimagnetic ceramic materials used in magnetic applications....
nanoparticles, which is essential for a fast and clean separation via external magnetic field.