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Stereo chemistry Importance  Stereochemistry is an important aspect of carbon compounds. It is prevalent in the whole universe. The human body is structurally chiral with the heart lying to the left and the liver to the right in the body. Many plants show chirality which help them to wind around supporting structures. Most of the molecules found in animals and plants are chiral and usually only one form of chiral molecules occur in a species. All the naturally occurring amino acids have L configuration. The synthesized D-proteins made from D aminoacids are some what resistant to break down by protein digesting enzymes.All naturally occurring sugars are of D-configuration. The enzyme, yeast can specifically ferment D-glucose and not its L-form. Stereo chemistry also plays an important role in deciding the physiological properties of compounds. (-) Nicotine is much more toxic than (+) Nicotine. (+) Adrenaline is very active in constriction of blood vessels than (-) Adrenali...

Separation of Dextro and Laevo components The synthesis of optically active compounds in the laboratory usually results in racemic mixture. The d and l forms can be separated from the racemic mixture. The separation of a racemic mixture in to dextro and laevo components is termed resolution . Due to identical physical properties of optical isomers their separation cannot be effected by simple physical methods. Usual methods which have been used for resolving racemic compounds are Mechanical Separation, Biochemical separation and by means of salt formation. Methods of separation of a racemic mixture in to dextro and laevo components 1. Mechanical Separation When the two varieties of isomers form well defined crystals they can be separated by hand picking. The crystals of Sodium ammonium racemate can be separated by this method. 2. Biochemical Separation In this method certain micro organism such as mould, bacteria or fungi when allowed grow in a solution of racemic mixt...

Optical Isomers Definition Optical isomerism arises due to chirality or asymmetry of the molecule. Optical isomers resemble one another in chemical properties and most of their physical properties but differ in their behavior towards polarized light. The isomer, which rotate the plane of polarized light clockwise is called dextro rotatory isomer (d - isomer) and the one which rotate the plane of polarized light anticlockwise is called laevo rotatory isomer (l - Isomer). The necessary condition for a molecule to be optically active is asymmetry or chirality of the molecule. Chirality is not just the presence of the asymmetric carbon atom but asymmetry of the molecule as a whole. Most of the chiral molecule contains at least one asymmetric carbon atom (Chiral Carbon atom). Still, there are some organic molecules which exhibit optical isomerism with out having chiral carbon (example: Substituted biphenyls). Some of the organic molecules are optically inactive even though they cont...

Optical Isomers of Tartaric acid (HOOC-CHOH-CHOH-COOH) Two chiral carbon atoms are present in tartaric acid . The difference in spatial arrangements of various groups in tartaric acid results in d-tartaric acid , l-tartaric acid and an active form known as meso form . In addition to these, racemic modification, another inactive form also exist. Dextro tartaric acid rotates the plane of polarization of light to right. The rotation due to upper half is strengthened by the rotation of lower half. Laevo tartaric acid is a mirror image of d-form, which rotate the palne of polarization to left. Racemic tartaric acid is an equimolar mixture of d and l -isomers. It is optically inactive due to external compensation, it can be resolved into d and l forms. Meso tartaric acid is an inactive variety and the rotation of upper half is compensated by the rotation due to lower half. It cannot be resolved into active constituents. It is therefore inactive due to internal compensation. Mes...

Compounds with the same molecular formula but with different structures and so different properties are called isomers and the phenomenon is called isomerism. Different types of isomerism 1) Structural isomerism If the difference in properties result from the difference in the arrangement of atoms within the molecule, it is called structural isomerism. The various types are: a) Ionization Isomerism :- This type of isomerism arises when the compound gives different ions in solution. Eg : [CoBr(NH3)5]SO4 and [CoSO4(NH3)5]Br are ionization isomers. The former gives [CoSO4(NH3)5]2+ and (SO4)2- as ions and latter gives [CoSO4(NH3)5]+ and Br- as ions. b) Co-ordination Isomerism :- Here the cation part and the anion part of the compound are complexed. But the ligands co-ordinated to the metal are different. Eg: [Cu(NH3)4][PtCl4] and [Pt(NH3)4][CuCl4] c) Linkage Isomerism :- If the ligand has two or more different atoms which can act as donor atoms, it can be linked to the metal differently...