LAUSR

Abstract N-Ethoxycarbonylpyrene- and perylene thioamides were used as building blocks in the synthesis of a variety of fluorescent dyes bearing thioimidate, 4-hydroxythiazolyl, 4-methoxythiazolyl and thiazole-4-one moieties, and an ester function. The synthesized compounds in DMSO solutions display fluorescence in the range of 412–672 nm with quantum yields 0.1–0.88. 2-(Pyrene-1-yl)-5-ethoxycarbonyl-4-hydroxythiazole and 2-(perylene-3-yl)-5-ethoxycarbonyl-4-hydroxythiazole show dual fluorescence resulting from the excitation of the neutral fluorophore and the corresponding enolate anion formed via excited state proton transfer (ESPT). As a result of ESPT the former fluorophore emits white light (CIE coordinates: 0.33, 0.36). The pyrenyl and perylenyl substituted 5-ethoxycarbonyl-5-methyl-(5H)-thiazole-4-ones displayed the highest emission efficiency (ΦF∼0.9) and emission maxima at 503 nm and 626 nm, respectively. The observed solvatochromism suggests that in this case emission originates from intramolecular charge transfer (ICT) excited states.