As a new approach to detect Cu2+, colorimetric detection of Cu2+ via organo radical formation of thiazolothiazole is reported. Upon the addition of Cu2+, thiazolothiazole derivatives 1 and 2 form relatively stable organo radicals, resulting in a distinct colorimetric change from greenish yellow to blue. Among the various metal ions, only Cu2+ showed a new peak appearance at 610 nm. In addition, a selective fluorescence quenching was also observed with Cu2+. To understand the origin of the Cu2+ selectivity of 1 and 2, series of electrochemical data are reported. Finally, EPR (electron paramagnetic resonance) data clearly support the formation of this unique organic radical formation.
Bibliographical noteFunding Information:
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (CRI No. 2012R1A3A2048814 for J.Y.; NRF-2013-020688 for C.L.). Mass spectral data were obtained from the Korea Basic Science Institute (Daegu) on a Jeol JMS 700 high resolution mass spectrometer.
- Colorimetric sensor
- Cu sensor
- Fluorescent sensor
- Organic radical