A selective proton transfer optical sensor for copper II based on chelation enhancement quenching effect (CHEQ)

Author(s)

Teixeira Alves Duarte, Luis Gustavo ^[1] ; Coelho, Felipe Lange ^[2] ; Germino, Jose Carlos ^[1] ; da Costa, Gabriela Gamino ^[2] ; Berbigier, Jonatas Faleiro ^[2] ; Rodembusch, Fabiano Severo ^[2] ; Zambon Atvars, Teresa Dib ^[1]

Affiliation

^[1] Univ Estadual Campinas, Chem Inst, Campinas, SP - Brazil

^[2] Univ Fed Rio Grande do Sul, Grp Pesquisa Fotoquim Organ Aplicada, Porto Alegre, RS - Brazil

• Document type: Journal article
• Source: DYES AND PIGMENTS; v. 181, OCT 2020.
• Web of Science Citations: 0

Abstract

A novel selective fluorescent sensor for Cu2+ in solution has been developed by means of chelation enhancement quenching effect (CHEQ). The compound N,N'-bis(salycilidene)-(2-(3',4'-diaminophenyl)benzothiazole (BTS) is reactive to intramolecular proton transfer on the electronic excited state (ESIPT) presenting fluorescence emission in the blue region with very large Stokes shift (8794 cm(-1)). Spectroscopic titration experiments indicate that not only the fluorescence quenching but also of the ESIPT reaction allowed naked eye detection as a paper strip-based sensor. This chemosensor showed to be selective to Cu2+ among 13 other cations. The sensor:Cu2+ ratio was determined by both Job and Benesi-Hildebrand plots as 1:2. In addition, the binding between sensor and metal was investigated by H-1 NMR, FTIR and HRMS in order to elucidate the formed complex and corroborate the results of BTS:Cu2+ ratio. The binding constant was also found as 3.0 x 10(10) mol(-)(2) L-2 at 25 degrees C. The detection and quantification limits were also obtained as 32 ppb and 108 ppb, respectively. (AU)

• FAPESP's process: 13/16245-2 - Photophysical properties of thin films of conjugated polymers
• Grantee: Teresa Dib Zambon Atvars
• Support Opportunities: Regular Research Grants