A D-π-A-π-D organic conjugated molecule with multiple chelating points: Spectral property and its reversible visual sensing Cu2+

A novel water-soluble D-n-A-n-D conjugated organic molecule, 3,5-di-2',4',6'-trihydrolxyl phenyl azo-triazole, was identified and developed, combining conjugated azo as colorimetric chromophore and multidentate hydroxyl and triazolyl groups as multiple receptors to chelate Cu2+. After its UV-vis spectral property was investigated and optimized, it was noted to find that PTAT exhibited high sensitivity and selectivity for real-time, reversibly and visually sensing Cu2+ in aqueous, accompanying with a large partitioned linear range among 4.0-320 x 10(-7) mol/L and obvious color change from brown-yellow to brown-red. Importantly, the present sensor was efficiently applied for sensing trace Cu2+ in environmental water samples and fruit juices samples in practice, with a detection limit as low as 3.7 x 10(-9) mol/L, a recovery among 95.6%-106.7% and an analytical precision less than 4.3%. The action mechanism to Cu2+ was confirmed to form some stable 5-membered condensed rings between Cu2+ and O or N atoms.