Elements of symmetry, chiral and achiral molecules
DL system of nomenclature of optical isomers, sequence rules
RS system of
nomenclature of optical isomers
Reactions of chiral molecules
Racemic modification and resolution of racemic mixture.
Asymmetric synthesis : partial and absolute
1. Optical Isomers
Optical isomerism could be a case where the isomers display identical characteristics in terms of mass still as chemical and physical properties. However, they differ in their effect on the rotation of polarized light.
Optical isomerism occurs mainly in substances that have the identical molecular and molecular formula, but they can not be superimposed on one another. In simple words, we will say that they're mirror images of every other. Alternatively, it may also be found in substances that have an asymmetric atom.
2. Elements of symmetry
In chemistry and crystallography, a symmetry element may be a point, line, or plane about which symmetry operations can happen. specifically, a symmetry element may be a mirror plane, an axis of rotation (either proper and improper), or a middle of inversion. For an object like a molecule or a crystal, a symmetry element corresponds to a collection of symmetry operations, which are the rigid transformations employing the symmetry element that leave the article unchanged. The set containing these operations form one amongst the symmetry groups of the item. the weather of this symmetry group shouldn't to be confused with the "symmetry element" itself. Loosely, a symmetry element is that the geometric set of fixed points of a symmetry operation. for instance, for rotation about an axis, the points on the axis don't move and in a very reflection the points that remain unchanged conjure a plane of symmetry.
3. Asymmetric synthesis
Asymmetric synthesis could be a subclass of stereoselective reactions, where a replacement chiral stereogenic unit is formed during a reaction. The new stereogenic unit is a chiral centre, a chiral axis or a chiral plane. The reaction must proceed with unequal formation of possible stereoisomers. The chiral unit may be produced from substrates bearing pro-chiral units like pro-chiral centre, a pro-chiral plane or a pro-chiral axis. The pro-chiral unit is enantiotopic or diastereotopic.
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