The reaction of diphenylcyclopropenethione with carbonyl-stabilized triphenylphosphonium methylides (2) to yield 2H-pyran-2-thiones was studied. It was clarified that electron-releasing substituents increased the reactivity of 2.
Novel fluorophores, 1-aryl-3,4-diphenylpyrido[1,2-a]benzimidazoles were synthesized. They emit intense blue to green fluorescence in solution (Φ: ca. 0.7) and show weak negative solvatofluorochromism by about 10 nm which was caused by the combination of π–π* and n–π* transitions. In the powdered form, they emit intense fluorescence whose intensity is at least two times stronger than that of Alq3.