The microwave spectrum of propynethial, HC≡C-CHS

Abstract

We have demonstrated that the flash pyrolysis of dipropargyl sulfide yields propynethial, HC≡CCHS, among the products. The microwave spectrum of the major isotopic species of propynethial and of HCCCH34S have been analysed. The derived rotational constants for these species enable us to eliminate any alternative structures for the pyrolysis product. The measured dipole moment components [μa = 1.763(1) D; μb = 0.661(1); μtotal = 1.883(1)] are discussed in terms of simple resonance structures.