A series of π-extended thiadiazoles fused with electron-donating heteroaromatic moieties: synthesis, properties, and polymorphic crystals.

摘要: π-Extended thiadiazoles 4-8 fused with various electron-donating heteroaromatic moieties have been designed and synthesized. Just like 1-3 synthesized previously, exhibit intramolecular charge-transfer (CT) interactions, moderate-to-good fluorescence quantum yields of up to 0.78, electrochemical amphoterism. In comparison 1-3, the benzannulation in 4-7 moderately extends π conjugation significantly increases stability cationic species formed upon oxidation. The increase remarkably from 3 6 7 due efficient suppression nonradiative intersystem crossing resulting benzannulation. properties strongly reflect different annulated pyrrole rings, namely benzothiophene, naphthalene, benzofuran. Eleven crystals, including poly- pseudopolymorphic crystals 1 (1-Crys.(Y) 1-Crys.(G)), 2 (2-Crys.(O) 2-Crys.(G)), 4 (4-Crys.(O) 4-Crys.(G)), (6-Crys.(O) 6-Crys.(G)), were obtained characterized by X-ray crystallography. colors efficiencies are distinct for each pseudopolymorph 1, 2, 4, 6. It has suggested that both extent electronic interactions π-stacked dimers presence excitonic originating 1D face-to-face slipped columns affect wavelengths pseudopolymorphs.