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Optical activity is reciprocal, i.e. it is the same for opposite directions of wave propagation through an optically active medium, for example, clockwise polarization rotation from the point of view of an observer. In case of optically active isotropic media, the rotation is the same for any direction of wave propagation.
Recording optical rotation with a polarimeter: The plane of polarisation of plane polarised light (4) rotates (6) as it passes through an optically active sample (5). This angle is determined with a rotatable polarizing filter (7). In chemistry, specific rotation ([α]) is a property of a chiral chemical compound.
In chemistry, racemization is a conversion, by heat or by chemical reaction, of an optically active compound into a racemic (optically inactive) form. This creates a 1:1 molar ratio of enantiomers and is referred to as a racemic mixture (i.e. contain equal amount of (+) and (−) forms).
There are three common naming conventions for specifying one of the two enantiomers (the absolute configuration) of a given chiral molecule: the R/S system is based on the geometry of the molecule; the (+)- and (−)- system (also written using the obsolete equivalents d- and l-) is based on its optical rotation properties; and the D/L system is based on the molecule's relationship to ...
For example, tartaric acid can exist as any of three stereoisomers depicted below in a Fischer projection. Of the four colored pictures at the top of the diagram , the first two represent the meso compound (the 2 R ,3 S and 2 S ,3 R isomers are equivalent), followed by the optically active pair of levotartaric acid (L-( R,R )-(+)-tartaric acid ...
Chiral purity is a measure of the purity of a chiral drug. Other synonyms employed include enantiomeric excess, enantiomer purity, enantiomeric purity, and optical purity. Optical purity is an obsolete term since today most of the chiral purity measurements are done using chromatographic techniques (not based on optical principles).
A polarimeter [1] is a scientific instrument used to measure optical rotation: the angle of rotation caused by passing linearly polarized light through an optically active substance. [ 2 ] Some chemical substances are optically active, and linearly polarized (uni-directional) light will rotate either to the left (counter-clockwise) or right ...
It is an important tool in the production of optically active compounds, including drugs. [3] Another term with the same meaning is optical resolution. The use of chiral resolution to obtain enantiomerically pure compounds has the disadvantage of necessarily discarding at least half of the starting racemic mixture.