Z,Z Isomers of Sterically Hindered 1,3-Bis(aryl)-1,3-diaza-2-thiaallenes, (ArN=)2S, in the Crystal and in Solution

It has been shown by X-ray structure analysis, ¹H NMR spectroscopy (including NOE) and PM3 calculations that symmetric isomers of the title compounds in the crystal and in solution have a Z,Z configuration stabilized by n_N,π interaction, but not the E,E configuration suggested earlier.