N-Amino-thieno[3,2-c]pyridin-4-ones: A new class of Aggregation Induced Emissive Pd 2+ chemosensor

Abstract

N-amino-thieno[3,2-c]pyridin-4-one derivatives 5a-c were synthesized in three steps using ketene dithioacetal as the primary precursor. Treatment of 3-amino-4-oxo-6-aryl-4Hthieno[3,2-c]pyran-2-carboxylate with hydrazine hydrate resulted in 3,5-diaminothieno[3,2c]pyridine-4-one derivatives (5). The photophysical properties of different functionalized Namino-thieno[3,2-c]pyridin-4-ones 5a-c were studied, and were explored for metal sensing, which resulted in selective recognition of Pd 2+ metal ion over the other metal ions with fluorescence turn-off properties. The fluorescence changes were observed through the ''naked eye'' under 365 nm UV lamp after the addition of Pd 2+ to the sample solution. Compounds 5b and 5c exhibit aggregation-induced emission (AIE).