Helicity of Molecules Different Definitions and Application to Circular Dichroism
Any object which is not superposable onto its mirror image was called “chiral” at the end of last century by Lord Kelvin , who derived the term from the Greek word χειϱ for hand. In particular, molecules are called chiral if they have this mentioned property, and it has been well known since the middle of last century  that in the non-ordered state (gases, liquids, amorphous solids) optical activity can be measured only if the molecules are chiral. Chirality is thus a molecular property, whereas optical activity is a bulk property of a substance, i.e. in all practical cases can be measured only for a large ensemble of molecules. It is thus wrong to speak of a “chiral substance”, as it is incorrect to speak of “optically active molecules”!
KeywordsCircular Dichroism Torsional Angle Absolute Configuration Full Turn Magnetic Transition Moment
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- 1.Lord Kelvin (1904) The Baltimore lectures on molecular dynamics and the wave theory of light, p 436. Clay & Sons LondonGoogle Scholar
- 2.Pasteur L (1922) OEuvres T 1, p 327. Mason ParisGoogle Scholar
- 4.Saenger W (1984) Principles of Nucleic Acid Structure. Springer New York Berlin Heidelberg TokyoGoogle Scholar
- 5.Martin RH (1982) Angew Chem 94: 614Google Scholar
- 7.Snatzke F Snatzke G (1980) In: Kienitz H Bock R Fresenius W Huber W Tölg G (eds) Analytiker-Taschenbuch Bd 1, p 217. Springer Berlin Heidelberg New York. When a rule is described there then rather that reference will be cited than the original literatureGoogle Scholar
- 10.cf. Block BP Powell WH Fernelius WC (1990) Inorganic Chemical Nomenclature, ACS Professional Reference Book, p 148/9. ACS Washington DCGoogle Scholar
- 12.Harada N Nakanishi K (1983) Circular Dichroic Spectroscopy — Exciton Coupling in Organic Stereochemistry. University Science Books Mill ValleyGoogle Scholar
- 13.Snatzke G (1978) In: Mason SF Optical Activity and Chiral Discrimination, pp 25 if and 43 ff. D Reidel Publ Coy DordrechtGoogle Scholar
- 16.Snatzke G Schaffner K (1968) Tetrahedron 51: 986Google Scholar
- 17.Snatzke G (1969) Riechst., Aromen, Körperpfl. 19: 98Google Scholar
- 19.Frelek J Perkowska A Snatzke G Tima M Wagner U Wolff HP (1983) Spectroscopy Interntl J 2: 274Google Scholar