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 [μ_a = 1.763(1) D; μ_b = 0.661(1); μ_total = 1.883(1)] are discussed in terms of simple resonance structures.