An unusual emissive and colorimetric copper (II) detection by a selective probe based on a pseudo-crown cysteine dye: Solution and gas phase studies

An off-on-off emissive and colorimetric probe L, based on a Pseudo-Crown cysteine dye was designed for Copper (II). Compound L was studied in solution and in gas-phase (MALDI-MS) over alkaline, alkaline, earth-alkaline and transition metal ions (Li+, Na+, K+, Ca2+, Mg2+, Zn2+, Cu2+, Co2+, Ni2+, Pb2+, and Hg2+) in organic media. The recognition of Cu2+ by L lead to red/dark red colored complexes, one emissive L2Cu and another LCu, less emissive. In regards to fluorescent quantum yield in both cases an increase respective to L was visualized (2 fold for LCu and 7 fold for L2Cu). The paramagnetic nature of both complexes was proved by the synthesis of both complex species, as well as, through H-1 NMR and FTIR. Compound L demonstrate to be able to detect and quantify the minimal amounts of 1.3 mu M/3.3 mu M of Cu2+. (C) 2017 Elsevier B.V. All rights reserved.