The Determination of Absolute Configuration of Planar and Axially Dissymmetric Molecules

Krow, Grant R.

doi:10.1002/9780470147146.ch2

Cited by 36 publications

(5 citation statements)

References 58 publications

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“…Moreover, now we have the bizarre situation that molecules analogous to A (i.e., asymmetric, Fig. 5) are designated by some authors147 as “axially asymmetric” and by others75, 141–144 as “axially dissymmetric,” surely an objectionable practice. The confusion is further deepened by usage such as “axially dissymmetric chiral [compound],”27 in which the meaning of dissymmetric is, indeed, entirely uninterpretable.…”

Section: The Language Of Chiral But Not Asymmetric: a Chaosmentioning

confidence: 99%

“…This state of affairs changed, however, with the launching50, 67 of the terms chiral and chirality in chemistry by Mislow in 1962, and chiral has now largely replaced dissymmetric as the term for “incongruous with its mirror image.” It has in fact been stated68, 69 that dissymmetric is an obsolete synonym of chiral. However, dissymmetric has not entirely disappeared from the literature in the meaning of chiral and appears with significant frequency in this definition 4, 70–75. For example, in their 2006 textbook Anslyn and Dougherty give the following definition: “ Dissymmetric .…”

Section: Dissymmetry Terminologymentioning

confidence: 99%

“…5) or other analogous structures, which are chiral and nonasymmetric by virtue of the presence of a proper rotation axis, are sometimes described, appropriately, as “axially symmetric”139 or as possessing “an axis of symmetry”140 or “axial symmetry.”1 Difficulties arise, however, when molecules such as A or B (or analogous structures) are described as “axially dissymmetric,” a designation in fact frequently seen in the literature. Thus, some authors use75, 141–144 “axially dissymmetric” in reference to type A (i.e., asymmetric, see Fig. 5) molecules.…”

Section: The Language Of Chiral But Not Asymmetric: a Chaosmentioning

confidence: 99%

“…“Axially dissymmetric” is also frequently applied to molecules such as B or analogous, chiral but not asymmetric, structures 27, 28, 75, 145–147. Here the meaning of dissymmetric is, in most cases, even more obscure.…”

Section: The Language Of Chiral But Not Asymmetric: a Chaosmentioning

confidence: 99%

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Stereochemical vocabulary for structures that are chiral but not asymmetric: History, analysis, and proposal for a rational terminology

Gál¹

2011

Chirality

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Asymmetric objects are necessarily chiral, but a structure may be chiral and not asymmetric if it possesses one or more proper rotation axes. Chiral but not asymmetric molecules are important in chemistry and its applications, but no suitable term exists for the designation of such structures, and their terminology in the literature is confused and chaotic. Dissymmetric has been redefined by some authors as "chiral but not asymmetric," in conflict both with Pasteur's definition of the term as "not superposable on its mirror image" (without other restrictions, i.e., chiral) and the understanding of the term in stereochemistry. Moreover, dissymmetric and asymmetric are frequently confused because of their similar forms. Furthermore, dissymmetric is widely used in many other definitions in chemistry, physics, and other disciplines. Thus, dissymmetric is unsuitable in the new definition of "chiral but not asymmetric," and a new term is needed. The adjective "symmanumorphous" is therefore proposed for "chiral but not asymmetric". "Sym" (from symmetry) indicates the presence of some symmetry in the structure, and "manu" (from "manus," Latin for hand, e.g., manual, manuscript) refers to its handedness. "Morphous," from the Greek "morphē," that is, form, is widely used, for example, anthropomorphous, enantiomorphous, etc. Symmanumorphous is convenient and euphonious and at 15 characters (same as enantiomorphous) is not unduly long. The nouns "a symmanumorph" (a structure that is chiral but not asymmetric) and "symmanumorphism" (the phenomenon of chirality without asymmetry) are also proposed. The new terminology is adaptable in other languages and would contribute to creating order out of linguistic chaos.

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Section: The Language Of Chiral But Not Asymmetric: a Chaosmentioning

confidence: 99%

Section: Dissymmetry Terminologymentioning

confidence: 99%

Section: The Language Of Chiral But Not Asymmetric: a Chaosmentioning

confidence: 99%

Section: The Language Of Chiral But Not Asymmetric: a Chaosmentioning

confidence: 99%

See 2 more Smart Citations

Stereochemical vocabulary for structures that are chiral but not asymmetric: History, analysis, and proposal for a rational terminology

Gál¹

2011

Chirality

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“…The latter, however, even though of tremendous importance for the establishment of configurational relationships since the days of Fischer, have not been incorporated. Their significance for the AC determination of compounds with axial and planar chirality 30 should be kept in mind, however.…”

Section: Some Final Commentsmentioning

confidence: 99%

Determination of absolute configuration—An overview related to this Special Issue

Allenmark¹,

Gawroński²

2008

Chirality

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Rapid progress in asymmetric synthesis stimulated a further development of methods and techniques for the determination of absolute configuration of chiral molecules. In recent years the direct methods, i.e. X-ray diffraction analysis, circular dichroism (vibrational and electronic), Raman optical activity, optical rotation measurements, as well as indirect methods for relative configuration assignment with the use of NMR spectroscopy or enzymatic transformations, are receiving increasing attention not only by specialists in the field but also by synthetic and structural chemists alike. This paper provides a short overview of the methods currently used, as well as references to contributions collected in this Thematic Issue of Chirality.

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Structure/Chiroptics Relationships of Planar Chiral and Helical Molecules

Grimme¹,

et al. 1998

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The Determination of Absolute Configuration of Planar and Axially Dissymmetric Molecules

Cited by 36 publications

References 58 publications

Stereochemical vocabulary for structures that are chiral but not asymmetric: History, analysis, and proposal for a rational terminology

Stereochemical vocabulary for structures that are chiral but not asymmetric: History, analysis, and proposal for a rational terminology

Determination of absolute configuration—An overview related to this Special Issue

Structure/Chiroptics Relationships of Planar Chiral and Helical Molecules

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