Heterocumulenes

Heterocumulenes (top to bottom): diimides, isocyanates, ketenes and comparing the simplest accumulations propadiene (an Allen ). R is an organyl radical ( alkyl radical, aryl radical, alkylaryl radical, etc.).
The cumulative double bond system and the atoms involved are marked in blue .

Heterocumulenes are a group of substances in chemistry that are similar to cumulenes . The term “Heterokumulene” is a name derived from the ancient Greek ἕτερος heteros (“the other”) and the Latin word cumulare (for “to pile up”) for substances that contain at least one heteroatom and in which two or more double bonds are directly strung together; so they form a system of accumulated double bonds .

Whether the compounds derived from the allenes with two cumulated double bonds should be added to the group of substances of the heterocumulenes is controversially discussed in the specialist literature. The Römpp affirms this, while the Gold Book defines the heterocumulenes as compounds with a sequence of at least three cumulative double bonds and thus excludes substances such as isothiocyanates and isoselenocyanates from the heterocumulenes.

Some heterocumulenes with two cumulated double bonds ( carbodiimides , isocyanates , ketenes ) are widely used in laboratories and technology .

An example of a heterocumulene with four cumulated double bonds is carbon suboxide .

Individual evidence

1. ↑ ^{a b} Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 3: H-L. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1983, ISBN 3-440-04513-7 , p. 2268.
2. ^ Entry on Heterocumulenes . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.H02797 Version: 2.1.5.