Colorimetric chemosensor of symmetrical benzoylthiourea derivatives as for detection of Cu~(2+) in aqueous solution

摘要

A novel receptor, designed with a combination of oxygen (O), nitrogen (N) and sulfur (S) -binding sites for metal ions was synthesized. Ortho (A), meta (B) and para (C) bearing benzoyl thiourea were designed and synthesized with triamine group to apply as colorimetric chemosensors for detection of Cu~(2+). The structure was confirmed by characterized the compound using Elemental analysis, Fourier Infrared (FTIR) and proton Nuclear Magnetic Resonance (~1H NMR) spectroscopy. Functional groups of C=O, N-H, C=N and C=S were found at 1677 cm~(-1), 3240 cm~(-1), 1591 cm~(-1), 1024 cm~(-1) respectively while ~1H NMR shows peaks of alkane (CH2), benzene (Ar-H), CONH, CSNH at 3.68 - 4.14, 7.16 - 7.86, 8.74, and 9.2 respectively. Elemental analysis for A, B and C C2oH2iN502S2Br2 found was compatible with the expected theoretical calculation. For an application, all of these three sensors showed excellent colorimetric specific selectivity and high sensitivity for Cu~(2+) in acetonitrile/water binary solutions, so only A was selected for further studies towards sensitivity. When Cu~(2+) was added to the solution of A, a dramatic color change from yellow to green, while other cations Fe~(2+), Zn~(2+), Ni~(2+), Co~(2+), Cr~(3+) and Mn~(2+) did not interfere with the recognition process for Cu~(2+). The detection limit of the sensor C toward Cu~(2+) was 1.15 x 10~(-5) M, which is less sensitive that sensor A and B with a detection limit of 6.2 x 10~(-6) M and 1.5 x 10~(-6) M respectively. This indicated that the sensor A and B might be useful as an efficient chemical sensor.