August 2018

Cyanopropyne

In 1984, Broten and coworkers reported the detection of cyanoproyne (CH3C3N) toward Taurus Molecular Cloud 1 (TMC-1) on the basis of four consecutive rotational transitions. The observations were made with the 37m telescope at Haystack Rado Observatory and with the NRAO 43m telescope at Green Bank, which served for over 50 years and has recently returned to service after a brief retirement. The detection was confirmed in a 2004 publication by Kaifu et al., who reported two additional rotational lines of cyanopropyne from a survey they made of TMC-1.

Researcher Links
Broten et al 1984
Kaifu et al 2004

Cyanopropyne is known by several other names. It was called methylcyanoacetylene by Broten et al. in the detection paper cited above. Its preferred IUPAC name is 2-butynenitrile. The 2- indicates that the triple bond starts on the second C atom away from the N atom, as seen in the image above or CH3–C≡C–C≡N. There is another isomer called 3-butynenitrile where the triple bond connects the third and fourth C atoms. Its structure is HC≡C–CH2–C≡N. While 2-butynenitrile has a linear backbone, 3-butynenitrile does not and thus has a more complex rotational spectrum.

Methylisocyanoacetylene, CH3C2NC, was sought for but not detected by Scappini et al. in 1996.


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