The i.r., Raman and microwave spectra of 1-butene-3-yne (vinylacetylene) and 1-butene-3-yne-4d

Article abstract of DOI:10.1016/0584-8539(80)80177-2

The i.r. spectra of 1-butene-3-yne and 1-butene-3-yne-4d in the vapour phase and as crystalline solids at 90 K were recorded in the region 5000-100 cm^-1.Raman spectra, including semiquantitative polarization data, of the neat liquid and of the solid were obtained at 90 K.Microwave spectra of the compounds were recorded in the region 8-40 GHz at ambient temperature.Rotational transitions of the vibrational ground state and of the two lowest vibrational excited states ν₁₃(a') and ν₁₈(a'') were measured.The fundamental frequencies of both compounds were assigned in excellent agreement with the results of normal coordinate calculations.Rotational fine structure was observed for several bands and interpreted as the Q-sub-branches of the perpendicular bands (in the symmetrical top approximation).For six bands the Q-sub-branches were assigned to the proper K-values.The Coriolis coupling constant ξ^a_13,18 was derived from the i.r. and from the microwave spectra.