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Chiral molecules will usually have a stereogenic element from which chirality arises. The most common type of stereogenic element is a stereogenic center, or stereocenter. In the case of organic compounds, stereocenters most frequently take the form of a carbon atom with four distinct (different) groups attached to it in a tetrahedral geometry.
A meso compound or meso isomer is an optically inactive isomer in a set of stereoisomers, at least two of which are optically active. [1][2] This means that despite containing two or more stereocenters, the molecule is not chiral. A meso compound is superposable on its mirror image (not to be confused with superimposable, as any two objects can ...
A meso compound is superposable on its mirror image, therefore it reduces the number of stereoisomers predicted by the 2 n rule. This occurs because the molecule obtains a plane of symmetry that causes the molecule to rotate around the central carbon–carbon bond. [12] One example is meso-tartaric acid, in which (R,S) is the same as the (S,R) form
Homotopic groups in a chemical compound are equivalent groups. Two groups A and B are homotopic if the molecule remains achiral when the groups are interchanged with some other atom (such as bromine) while the remaining parts of the molecule stay fixed. Homotopic atoms are always identical, in any environment.
Chirality(/kaɪˈrælɪti/) is a property of asymmetryimportant in several branches of science. The word chiralityis derived from the Greekχείρ(kheir), "hand", a familiar chiral object. An object or a system is chiralif it is distinguishable from its mirror image; that is, it cannot be superposed(not to be confused with superimposed) onto it.
Roughly 10% of racemic chiral compounds crystallize as conglomerates. [7] Racemic compound (sometimes true racemate) If molecules have a greater affinity for the opposite enantiomer than for the same enantiomer, the substance forms a single crystalline phase in which the two enantiomers are present in an ordered 1:1 ratio in the elementary cell ...
Chiral auxiliary. In stereochemistry, a chiral auxiliary is a stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. [1][2] The chirality present in the auxiliary can bias the stereoselectivity of one or more subsequent reactions.
However, compounds that contain an even number of asymmetric atoms sometimes lack chirality because they are arranged in mirror-symmetric pairs, and are known as meso compounds. For instance, meso tartaric acid (shown on the right) has two asymmetric carbon atoms, but it does not exhibit enantiomerism because there is a mirror symmetry plane.