Dicyanovinyl-modified small-molecular monophenyl derivative for dual-channel fluorescence recognition of acid and aliphatic primary amine regulated by intramolecular charge transfer: Synthesis, stimuli-response and LED

The dicyanovinyl-modified monophenyl derivative TSH was synthesized via Vilsmeier and Knoevenagel reactions. TSH has photoluminescence in both solution and solid. It exhibits solvatochromic behavior, shifting from blue to orange due to the intramolecular charge transfer. TSH can undergo a reversible protonation/deprotonation reaction with trifluoroacetic acid/triethylamine, leading to acidochromism. Additionally, TSH reacts with aliphatic primary amines, causing fluorescence changes from yellow to blue for specific recognition of aliphatic primary amines. The fluorescence changes resulting from the recognition of acid and aliphatic primary amines are related to the change of intramolecular charge transfer. The two recognition phenomena are different, allowing for the design of various fluorescent anti-counterfeiting measures. Moreover, TSH can be utilized in fabricating yellow light-emitting diode device with high color purity (91 %).