Topological isomerism

Principle of the topological isomerism of catenanes.

Topological isomerism is a term used in stereochemistry . It can occur with groups of substances such as catenanes or rotaxanes , in which chemically independent molecules are held together by mechanical links. Topological isomerism can also occur with knotanes .

Instead of topological chemistry - a term that goes back to Edel Wasserman (1961) - and topological bonding , one also speaks of mechanically interlocked molecules and mechanical bonding . They provide a direct application of mathematical topology in chemistry, in which topological ideas also found their way into graph theory (see topological descriptor ), for example in the counting theory of trees and molecules by George Pólya .

The synthesis of topological isomers was achieved through the production of linked macromolecules in 1964. In nature, deoxyribonucleic acids intertwined in a catenane fashion have been detected.

The conversion of topological isomers into one another requires breaking a bond and re-establishing a bond. The separation of topological isomers is achieved, for example, by means of chiral high-performance liquid chromatography .

It is to be distinguished from topomerization , in which no bonds are broken.

See also

• Topoisomerase
• Supercoiled DNA

literature

• Oleg Lukin, Fritz Vögtle : Knotting and threading molecules: chemistry and chirality of molecular knots and their ensembles. In: Angewandte Chemie . 117, 2005, pp. 1480-1501, doi : 10.1002 / anie.200460312 .

Individual evidence

1. ↑ Wolfgang Bähr, Hans Theobald: Organic stereochemistry. Springer Verlag, 1973, ISBN 3-540-06339-0 , p. 116.
2. ↑ Fritz Vögtle u. a .: New molecular knots with amide structure: complete enantiomeric separation, chiroptical properties, absolute configuration. In: Angewandte Chemie . 113, 2001, pp. 2534-2537, doi : 10.1002 / 1521-3757 (20010702) 113: 13 <2534 :: AID-ANGE2534> 3.0.CO; 2-A .
3. ↑ G. Schill, A. Lüttringhaus: Targeted synthesis of catena compounds [1]. In: Angewandte Chemie. 76, 1964, pp. 567-568, doi : 10.1002 / anie.19640761304 .
4. ↑ Bruce Hudson, Jerome Vinograd: Catenated circular DNA molecules in HeLa cell mitochondria. In: Nature . 216, 1967, pp. 647-652.