The Generation, Microwave Spectrum, and Structure of Propadienethione, H2C=C=C=S

Article abstract of DOI:10.1021/ja00211a018

The third member of the cumulene-thione series H2CnS, propadienethione, has been produced by pyrolysis of cyclopenteno-1,2,3-thiadiazole and detected by microwave spectroscopy.The rotational constants from a number of isotopomers have been used to derive a molecular geometry, which shows that propadienethione is a planar molecule of C_2v symmetry, unlike propadienone which is kinked.A fully optimized geometry from a set of ab initio calculations done at the MP3/6-31G level is in agreement with the experimental results.The dipole moment has been calculated from the Stark effect to be 2.064 Debye.