Linear thiophene-containing π-conjugated aldehydes with aggregation-induced emission for building solid red luminophors

Two linear thiophene-containing it-conjugated aldehydes 4-(thiophen-2-yl)benzaldehyde and 2,5-bis[4-(formyl)phenyl]thiophene exhibiting aggregation-induced emission (AIE) were demonstrated. The photophysical properties of the two aldehydes in solution and THF/H2O mixtures were studied, and aggregates formed with different water fractions were studied by scanning electron microscopy. Results indicated that amorphous nanoscale aggregates exhibit distinct AIE behavior when assembled in solutions with appropriate water contents. Condensation of 1,3-indandione with 4-(thiophen-2-yl)benzaldehyde generated a new luminophor 2[4-(thiophen-2-yl)benzylidene]-2H-indene-1,3-dione; this product presents as a solid powder that emits intensely red photoluminescence at 620 nm with a quantum yield of 12.8%. (C) 2014 Elsevier Ltd. All rights reserved.