Cyanopolyyne

Cyanopolyynes are a group of chemicals with the chemical formula HC
nN (n=3,5,7, ...). Structurally, they are polyynes with a cyano group covalently bonded to one of the terminal acetylene units. A rarely seen group of molecules both due to the difficulty in production and the unstable nature of the paired groups, the cyanopolyynes have been observed as a major organic component in interstellar clouds. This is believed to be due to the hydrogen scarcity of some of these clouds. Interference with hydrogen is one of the reason for the molecule's instability due to the energetically favorable dissociation back into hydrogen cyanide and acetylene. Cyanopolyynes were first discovered in interstellar molecular clouds in 1971 using millimeter wave and microwave telescopes. Since then many higher weight cyanopolyynes such as HC
7N and HC
11N have been discovered, although some of these identifications have been disputed. Other derivatives such as methycyanoacetylene CH
3C
3N and ethylcyanoacetylene CH
3CH
2C
3N have been observed as well. The simplest example is cyanoacetylene, H−C≡C−C≡N. Cyanoacetylene is more common on earth and it is believed to be the initial reagent for most of the photo-catalyzed formation of the interstellar cyanopolyynes. Cyanoacetylene is one of the molecules that was produced in the Miller–Urey experiment and is expected to be found in carbon-rich environments.