Toward molecular wire: Synthesis, crystal, molecular, and ?-electronic structure of 1,7-bis(aryl)-1,3,5,7-tetraaza-2,4,6-trithia-1,2,5,6-heptatetraenes

The title compounds were obtained by the reaction of 1-aryl-3-trimethylsilyl-1,3-diaza-2-thiaallenes with dichloromonosulfane or 1-aryl-4-(1-phtalimidyl)-1,3-diaza-2,4-dithia-1,2-butadienes in the presence of CsF. The latter route also afforded nonsymmetric derivatives. In contrast, the reaction of N,N,N′,N′-tetrakis(trimethylsilyl)diaminosulfane with S,S-dichloro-N-aryliminosulfuranes (1:2) led to 1,3-bis(aryl)-1,3-diaza-2-thiaallenes and cyclotetra(azathiene). As shown by the X-ray structure analysis, the molecule of the title compound with Ar = Ph is planar, with configuration of the azathiene chain being similar to that of poly(azathiene) (SN)x. The MNDO calculations indicate that most of the π-MOs of this compound, including the frontier ones, are delocalized throughout the whole molecule. The data obtained confirm the possibility of creating molecular wire for molecular electronic devices on the basis of extended acyclic azathienes. An attempt to synthesize more extended compounds than the title ones resulted in spontaneous shortening of their azathiene chains.