Coumarin based yellow emissive AIEE active probe: A colorimetric sensor for Cu2+ and fluorescent sensor for picric acid

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2019-12, Vol.223, p.117201, Article 117201
• Main Authors: Soufeena, P.P., Nibila, T.A., Aravindakshan, K.K.
• Format: Article
• Language: English
• Subjects: Aggregation Induced Emission Enhancement; Colourimetric and fluorescent sensor; Picric acid; Schiff base
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2019.117201

A hydrazine derived ESIPT active Schiff base, 1-(8-methanylylidene-7-hydroxy-4-methyl-2H-chromen-2-one)-2-(2, 4-dihydroxybenzylidene) hydrazine, L was synthesized and characterized by elemental analysis and by various spectroscopic techniques. L exhibited a colourimetric response towards Cu2+ ion by changing from colorless to yellow with relatively a little or no interference of other common metal ions. The probe also showed good response for the detection of Cu2+ in real water samples. The H-aggregated L displayed AIEE property in acetonitrile/water mixture. The restriction of molecular motions endued the luminogen with a yellow fluorescence through ESIPT emission at 562 nm having relatively large Stock's shift of 205 nm. The scanning electron microscopic study was carried out to investigate the morphology of the nanoaggregate. The aggregated luminogen displayed it yellow emission in the pH range of 4–7 without affecting the intensity. The applicability of the probe for the detection of picric acid was also checked. [Display omitted] •Synthesized and characterized a new Coumarine based Schiff base and its photohysical studies were carried out.•Observed a colourimetric response towards Cu2+ with relatively a little or no interference of other common metal ions.•The synthesized compound exhibits a yellow emission at 562 nm in the aggregated state with a Stock’s shift of 205 nm.•Discussed the effect of intramolecular motions and the interplay of ESIPT on Aggregation Induced Emission Enhancement.•The fluorescent emissive nanoaggregate exhibits a “turn-off” response with picric acid and was explored mechanistically.