Cyclic meso-ionic compounds. Part IX. Synthesis, spectroscopic properties, and chemistry of 1,3,4-thiadiazolium-2-olates and 1,3,4-oxadiazolium-2-thiolates

Abstract

The synthesis, spectroscopic properties, and reactions of 1,3,4-thiadiazolium-2-olates (III) and 1,3,4-oxadiazolium-2-thiolates (IV) are reported. The results establish the existence of corresponding pairs of isomeric meso-ionic compounds whose isomerisation [(IV)→(III)] involves exchange between endocyclic and exocyclic hetero-atoms.