アキラルな、光学不活性の

関: optically inactive

WordNet

canna grown especially for its edible rootstock from which arrowroot starch is obtained (同)indian shot, arrowroot, Canna indica, Canna edulis

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/02/01 23:03:19」(JST)

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For other uses, see Chirality (disambiguation).

Two enantiomers of a generic amino acid

Chirality /kaɪˈrælɪtiː/ is a property of asymmetry important in several branches of science. The word chirality is derived from the Greek, χειρ (kheir), "hand", a familiar chiral object.

An object or a system is chiral if it is not identical to its mirror image, that is, it cannot be superposed onto it. A chiral object and its mirror image are called enantiomorphs (Greek opposite forms) or, when referring to molecules, enantiomers. A non-chiral object is called achiral (sometimes also amphichiral) and can be superposed on its mirror image.

The term was first used by Lord Kelvin in 1893 in the second Robert Boyle Lecture at the Oxford University Junior Scientific Club which was published in 1894.^[1]

I call any geometrical figure, or group of points, 'chiral', and say that it has chirality if its image in a plane mirror, ideally realized, cannot be brought to coincide with itself.

Human hands are perhaps the most universally recognized example of chirality: The left hand is a non-superimposable mirror image of the right hand; no matter how the two hands are oriented, it is impossible for all the major features of both hands to coincide.^[2] This difference in symmetry becomes obvious if someone attempts to shake the right hand of a person using his left hand, or if a left-handed glove is placed on a right hand. In mathematics chirality is the property of a figure that is not identical to its mirror image.

Mathematics[edit]

Achiral 3D object without central symmetry or a plane of symmetry

A table of all prime knots with seven crossings or fewer (not including mirror images).

Main article: Chirality (mathematics)

In mathematics, a figure is chiral (and said to have chirality) if it cannot be mapped to its mirror image by rotations and translations alone. For example, a right shoe is different from a left shoe, and clockwise is different from anti-clockwise.

A chiral object and its mirror image are said to be enantiomorphs. The word enantiomorph stems from the Greek ἐναντίος (enantios) 'opposite' + μορφή (morphe) 'form'. A non-chiral figure is called achiral or amphichiral.

The helix (and by extension a spun string, a screw, a propeller, etc.) and Möbius strip are chiral two-dimensional objects in three-dimensional ambient space. The J, L, S and Z-shaped tetrominoes of the popular video game Tetris also exhibit chirality, but only in a two-dimensional space.

Many other familiar objects exhibit the same chiral symmetry of the human body, such as gloves, glasses (where two lenses differ in prescription), and shoes. A similar notion of chirality is considered in knot theory, as explained below.

Some chiral three-dimensional objects, such as the helix, can be assigned a right or left handedness, according to the right-hand rule.

Geometry[edit]

In geometry a figure is achiral if and only if its symmetry group contains at least one orientation-reversing isometry. In two dimensions, every figure that possesses an axis of symmetry is achiral, and it can be shown that every bounded achiral figure must have an axis of symmetry. In three dimensions, every figure that possesses a plane of symmetry or a center of symmetry is achiral. There are, however, achiral figures lacking both plane and center of symmetry.

Knot theory[edit]

A knot is called achiral if it can be continuously deformed into its mirror image, otherwise it is called chiral. For example the unknot and the figure-eight knot are achiral, whereas the trefoil knot is chiral.

Physics[edit]

Animation of right-handed (clockwise), circularly polarized, light as viewed in the direction of the source, in agreement with physics and astronomy conventions.

Main article: Chirality (physics)

In physics, chirality may be found in the spin of a particle, which may be used to define a handedness (aka chirality) for that particle. A symmetry transformation between the two is called parity. Invariance under parity by a Dirac fermion is called chiral symmetry.

Electro-magnetism[edit]

Electromagnetic wave propagation as handedness is wave polarization and described in terms of helicity (occurs as a helix). Polarization of an electromagnetic wave, is the property that describes the orientation, i.e., the time-varying, direction (vector), and amplitude of the electric field vector. For a depiction, see the image to the right.

Chemistry[edit]

(S)-Alanine (left) and (R)-alanine (right) in zwitterionic form at neutral pH

Main article: Chirality (chemistry)

A chiral molecule is a type of molecule that has a non-superposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom.^[3]^[4]

The term chiral in general is used to describe an object that is non-superposable on its mirror image.^[5]

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-" and "left-handed."

Molecular chirality is of interest because of its application to stereochemistry in inorganic chemistry, organic chemistry, physical chemistry, biochemistry, and supramolecular chemistry.

Biology[edit]

Shells of two different species of sea snail: on the left is the normally sinistral (left-handed) shell of Neptunea angulata, on the right is the normally dextral (right-handed) shell of Neptunea despecta

In anatomy, chirality is found in the imperfect mirror-image symmetry of many kinds of animal bodies. Organisms such as gastropods exhibit chirality in their coiled shells, resulting in an asymmetrical appearance. Over 90% of gastropod species ^[6] have dextral (right-handed) shells in their coiling, but a small minority of species and genera are virtually always sinistral (left-handed). A very few species (for example Amphidromus perversus^[7]) show an equal mixture of dextral and sinistral individuals.

In humans, chirality (also referred to as handedness or laterality) is an attribute of humans defined by their unequal distribution of fine motor skill between the left and right hands. An individual who is more dexterous with the right hand is called right-handed, and one who is more skilled with the left is said to be left-handed. Chirality is also seen in the study of facial asymmetry.

In flatfish, the Summer flounder or fluke are left-eyed, while halibut are right-eyed.

References[edit]

^ Sir William Thomson Lord Kelvin (1894). The Molecular Tactics of a Crystal. Clarendon Press.
^ Georges Henry Wagnière, On Chirality and the Universal Asymmetry: Reflections on Image and Mirror Image (2007).
^ Organic Chemistry (4th Edition) Paula Y. Bruice.
^ Organic Chemistry (3rd Edition) Marye Anne Fox ,James K. Whitesell.
^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "chirality".
^ Schilthuizen M. & Davison A. (2005). "The convoluted evolution of snail chirality". Naturwissenschaften 92(11): 504–515. doi:10.1007/s00114-005-0045-2.
^ Amphidromus perversus (Linnaeus, 1758)

External links[edit]

Look up chirality in Wiktionary, the free dictionary.

English Journal

Adding the right (or left) twist to tris-chelate complexes - coordination chemistry of chiral oxazolylphenolates with M(3+) ions (M = Al or lanthanide).

Aspinall HC, Bacsa J, Beckingham OD, Eden EG, Greeves N, Hobbs MD, Potjewyd F, Schmidtmann M, Thomas CD.Author information Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK. hca@liv.ac.uk.AbstractA series of homoleptic tris-chelate complexes ML3 (M = Al or rare earth; L = chiral or achiral oxazolyl phenolate or -naphtholate) is reported. In all cases, complexes crystallize as mer-isomers and complete diastereoselectivity is observed on crystallization of the complexes: ML3 crystallize with Λ-helicity at the metal where L = (S)-oxazolylphenolate. Complexes have been characterized in solution by NMR spectroscopy, demonstrating rapid ligand exchange at ambient temperature for rare earth complexes, and slow exchange on the NMR timescale for complexes of Al; in all cases the mer-isomer is observed exclusively. Crystal structures are reported for [YL3]2 (L = (S)-2-(4-isopropyl-4,5-dihydrooxazol-2-yl)-phenolate), mer-[YbL3] (L = (S)-2-(4-isopropyl-4,5-dihydrooxazol-2-yl)-6-methylphenolate) and mer-[AlL3] (L = (S)-2-(4-isopropyl-4,5-dihydrooxazol-2-yl)-6-methylphenolate, L = (S)-2-(4-isopropyl-4,5-dihydrooxazol-2-yl)-6-cyanophenolate), L = (S)-1-(4-isopropyl-4,5-dihydrooxazol-2-yl)naphthalen-2-olate, L = 1-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)naphthalen-2-olate).
Dalton transactions (Cambridge, England : 2003).Dalton Trans.2014 Jan 21;43(3):1434-42. doi: 10.1039/c3dt52366g. Epub 2013 Nov 8.
A series of homoleptic tris-chelate complexes ML3 (M = Al or rare earth; L = chiral or achiral oxazolyl phenolate or -naphtholate) is reported. In all cases, complexes crystallize as mer-isomers and complete diastereoselectivity is observed on crystallization of the complexes: ML3 crystallize with �
PMID 24201227

Foldamer-mediated remote stereocontrol: >1,60 asymmetric induction.

Byrne L, Solà J, Boddaert T, Marcelli T, Adams RW, Morris GA, Clayden J.Author information School of Chemistry, University of Manchester, Oxford Rd., Manchester M13 9PL (UK).AbstractAn N-terminal L-α-methylvaline dimer induces complete conformational control over the screw sense of an otherwise achiral helical peptide foldamer formed from the achiral quaternary amino acids Aib and Ac6 c. The persistent right-handed screw-sense preference of the helix enables remote reactive sites to fall under the influence of the terminal chiral residues, and permits diastereoselective reactions such as alkene hydrogenation or iminium ion addition to take place with 1,16-, 1,31-, 1,46- and even 1,61-asymmetric induction. Stereochemical information may be communicated in this way over distances of up to 4 nm.
Angewandte Chemie (International ed. in English).Angew Chem Int Ed Engl.2014 Jan 3;53(1):151-5. doi: 10.1002/anie.201308264. Epub 2013 Nov 8.
An N-terminal L-α-methylvaline dimer induces complete conformational control over the screw sense of an otherwise achiral helical peptide foldamer formed from the achiral quaternary amino acids Aib and Ac6 c. The persistent right-handed screw-sense preference of the helix enables remote reactive si
PMID 24375739

Two-dimensional liquid chromatography for direct chiral separations: a review.

León-González ME, Rosales-Conrado N, Pérez-Arribas LV, Guillén-Casla V.Author information Analytical Chemistry Department, Faculty of Chemistry, Complutense University of Madrid, E-28040, Madrid, Spain.AbstractSeparation of enantiomers remains a challenge owing to their identical physical and chemical properties in an achiral environment, and research on specialized separation techniques such as multidimensional achiral-chiral liquid chromatography continues to resolve individual enantiomers in complex samples. Recent advances in application of multidimensional liquid chromatography applied to chiral analysis are reviewed. For this reason, benefits of achiral-chiral coupling are shown, with emphasis in applications on biological and pharmaceutical fields as well as pesticide analysis. A description of standard instrumental setup in both heart-cut and comprehensive multidimensional liquid chromatography is shown. The most broadly used chiral stationary phases for multidimensional liquid chromatography are summarized. An extensive overview of different interface designs applied to complex samples is presented. Copyright © 2013 John Wiley & Sons, Ltd.
Biomedical chromatography : BMC.Biomed Chromatogr.2014 Jan;28(1):59-83. doi: 10.1002/bmc.3007. Epub 2013 Aug 24.
Separation of enantiomers remains a challenge owing to their identical physical and chemical properties in an achiral environment, and research on specialized separation techniques such as multidimensional achiral-chiral liquid chromatography continues to resolve individual enantiomers in complex sa
PMID 23982862

Japanese Journal

Synthesis and characterization of a novel donor–acceptor–donor chiral inducer and its application in electrochemical polymerization

Dong Jiuchao,Kawabata Kohsuke,Goto Hiromasa
Journal of materials chemistry. C 3(9), 2024-2032, 2015-03
… Electrochemical polymerization of an achiral monomer was performed in a cholesteric liquid crystal induced by the inducer. …
NAID 120005604026

Intramolecular charge transfer (ICT) of a chiroptically active conjugated polymer showing green colour

Kawashima Hirotsugu,Kawabata Kohsuke,Goto Hiromasa
Journal of materials chemistry. C 3(5), 1126-1133, 2015-02
… A donor–acceptor type achiral monomer 4,7-bis(2,3-dihydrothieno[3,4-b]-1,4-dioxin-5-yl)-2,1,3-benzothiadiazole was synthesised and electrochemically polymerised in a cholesteric liquid crystalline (CLC) medium. … The preparation of chiral polymer films even from achiral monomers is demonstrated. …
NAID 120005572753

Precision synthesis, structure and function of helical polymers

OKAMOTO Yoshio
Proceedings of the Japan Academy, Series B 91(6), 246-261, 2015
… In 1979, we succeeded in the synthesis of a one-handed helical polymer from an optically inactive achiral monomer, triphenylmethyl methacrylate (TrMA). …
NAID 130005075692