Friday 27 November 2009

Chemistry Dealing With the Study of Chemical Compounds Containing Bond Between Carbon and Metal

The branch of chemistry that deals with the study of chemical compounds containing bonds between carbon and a metal is called as Organometallic chemistry. It combines the aspects of inorganic chemistry with organic chemistry, so such compounds are also known as organo-inorganic compounds. 


Including all the traditional metals; lanthanides, actinides and semi-metals are considered to form organometallic compounds. There are many complexes also that feature the coordination bonds between a metal and an organic ligands, as organic ligands would always bind a metal through a heteroatom such as nitrogen or oxygen, and such compounds are then considered as coordination compounds. But, if any of the ligands would form a direct metal-carbon bond, then it would usually be considered as organometallic compound. In case of lipophilic and metal alkoxides it would be termed as metalorganics.


There are many organic coordination compounds that occur naturally in nature like hemoglobin which simply contain an iron centre that is coordinated to nitrogen atoms. When speaking of chlorophyll, magnesium acts as centre of a chlorine ring. The study of such inorganic compounds is termed as bioinorganic chemistry. The status of such compounds may vary with the nature of anionic moiety, and they may not usually be considered as organometallic.
Depending on the nature of the organic compound, the nature of the bond may also vary from ionic or covalent type. So the organic compounds that are bonded to sodium are ionic while those bonded to lead or tin are usually covalent whereas the ones bonded to lithium may have bonds with intermediate properties.

Such compounds also find their practical uses as stoichiometric and catalytic active compounds, like the use of ferrocene instead of tetraethyl lead as an anti knock agent. Organometallic compounds of reactive metals are extremely basic and are used as reductants. The act as superbases in organic synthesis, but their flammability reduces their industrial uses severely. The Monsanto process utilizes rhodium-carbonyl complex to manufacture acetic acid industrially. Also the Wacker process is used in the oxidation of olefins. Another titanium based organometallic compound called Ziegler-Natta catalyst is used in the production of polyethylene and other polymers.

The key to understand the chemical bonding in such compounds the isobal principle is used. NMR and infrared spectroscopy techniques are commonly used to determine the structure and bonding. Organometallics play an important role in other branches of chemistry such as biological and analytical. So, chemists sometimes refer to a particular molecule as organometallic making it more convenient to understand that molecules has reaction chemistry that derives from an organometallic molecule.
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Author: lalit sharma

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