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  2. Chirality - Wikipedia

    en.wikipedia.org/wiki/Chirality

    The term "chiral" in general is used to describe the object that is non-superposable on its mirror image. [18] In chemistry, chirality usually refers to molecules. Two mirror images of a chiral molecule are called enantiomers or optical isomers. Pairs of enantiomers are often designated as "right-", "left-handed" or, if they have no bias ...

  3. Chirality (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Chirality_(chemistry)

    Two enantiomers of a generic amino acid that are chiral (S)-Alanine (left) and (R)-alanine (right) in zwitterionic form at neutral pH. In chemistry, a molecule or ion is called chiral (/ ˈ k aɪ r əl /) if it cannot be superposed on its mirror image by any combination of rotations, translations, and some conformational changes.

  4. Enantiomer - Wikipedia

    en.wikipedia.org/wiki/Enantiomer

    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 ...

  5. Absolute configuration - Wikipedia

    en.wikipedia.org/wiki/Absolute_configuration

    Chiral molecules can differ in their chemical properties, but are identical in their physical properties, which can make distinguishing enantiomers challenging. Absolute configurations for a chiral molecule (in pure form) are most often obtained by X-ray crystallography , although with some important limitations.

  6. Racemic mixture - Wikipedia

    en.wikipedia.org/wiki/Racemic_mixture

    As examples, esomeprazole is a chiral switch of (±)-omeprazole and levocetirizine is a chiral switch of (±)-cetirizine. While often only one enantiomer of the drug may be active, there are cases in which the other enantiomer is harmful, like salbutamol [11] and thalidomide. The (R) enantiomer of thalidomide is effective against morning ...

  7. Optical rotation - Wikipedia

    en.wikipedia.org/wiki/Optical_rotation

    If two enantiomers are present in equal proportions, then their effects cancel out and no optical activity is observed; this is termed a racemic mixture. But when there is an enantiomeric excess, more of one enantiomer than the other, the cancellation is incomplete and optical activity is observed. Many naturally occurring molecules are present ...

  8. Chiral column chromatography - Wikipedia

    en.wikipedia.org/wiki/Chiral_column_chromatography

    The chiral stationary phase, CSP, can interact differently with two enantiomers, by a process known as chiral recognition. Chiral recognition depends on various interactions such as hydrogen bonding, π-π interaction, dipole stacking, inclusion complexation, steric, hydrophobic and electrostatic interaction, charge-transfer interactions, ionic interactions etc, between the analyte and the CSP ...

  9. Stereoisomerism - Wikipedia

    en.wikipedia.org/wiki/Stereoisomerism

    Pure enantiomers also exhibit the phenomenon of optical activity and can be separated only with the use of a chiral agent. In nature, only one enantiomer of most chiral biological compounds, such as amino acids (except glycine, which is achiral), is present. Enantiomers differ by the direction they rotate polarized light: the amount of a chiral ...