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.
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.