Methylene bridge

A methylene bridge is a functional group in organic chemistry. It has the structure −CH2−: a carbon atom with two chemical bonds to hydrogen atoms, and two more bonds to other parts of a molecule.

In formal chemical nomenclature, the methylene bridge is not normally named like other functional groups. Instead, the methylene bridges are named as part of chains of carbon atoms: C6H14 is "hexane", not "dimethyl tetramethylene". Still, many chemicals have non-IUPAC names that mention methylene bridges: one notable example is hexamethylenediamine (systematic name hexane-1,6-diamine), an ingredient in nylon.

Most methylene bridges do not react with other chemicals. Alkanes, which are made of chains of methylene bridges, are also called "paraffins" (meaning "without affinity") because they are so unreactive. Methylene bridges can become "activated" if they are near electron-withdrawing groups. An activated methylene bridge can lose one of its hydrogen atoms to become a carbanion. Malonic acid and acetylacetone are examples of chemicals with activated methylene bridges.


This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.