Synthesis and properties of bis(1,3-benzodithiolium) salts containing a 1,3-di(2-thienyl)azulene unit

Abstract

Bis(1,3-dithiolium) salt 1 containing a 1,3-di(2-thienyl)azulene unit has been designed as a novel dye. The compound 1 was synthesized by hydride abstraction of the corresponding precursor which was prepared by acid-catalyzed condensation of 1,3-bis(5-formyl-2-thienyl)azulene and 1,2-benzenedithiol. The dication 1 shows bluish green color in the acetonitrile solution and has an intense absorption at 689 nm.