Abstract
Two bis-sulfonamides, N,N'-(ethane-1,2-diyl)bis(2,5-dimethoxybenzenesulfonamide) (EBDMBS) and N,N'-(ethane-1,2-diyl)bis(2-methoxy-5-bromobenzenesulfonamide) (EBMBBS) were synthesized to study their applications as heavy metal sensors. These molecules were prepared via very environment friendly methodology using diaminoethane and respective sulfonyl chlorides as reactants. Aromatic rings were ornamented with electron donating and withdrawing groups for comparison studies and to choose a best ligand for sensor preparation. The synthesized molecules were well characterized using UV/VIS, IR and NMR (H-1 & C-13) spectroscopic techniques. Finally, single crystal X-Ray diffraction studies prove the structures of our designed molecules. For the selective and sensitive potential sensor application, EBDMBS and EBMBBS were fabricated onto glassy carbon electrode (GCE; surface area, 0.0316 cm(2)) with conducting nafion binders to develop a Co2+ ions sensor in phosphate buffer phase. The fabricated ionic-sensor with EBDMBS/GCE is exhibited higher sensitivity, large-dynamic concentration ranges, long-term stability, and improved electrochemical performances towards cobalt ions. The calibration plot is linear (r(2) = 0.9891) over the large Co2+ concentration ranges (0.35 nM-3.5 mM). The sensitivity and detection limit is similar to 1.87 mu A mu M(-1)cm(-2) and similar to 0.17 +/- 0.02 nM (signal-to-noise ratio, at a SNR of 3) respectively. This novel effort is initiated a well-organize way of efficient cationic sensor development for toxic pollutants in environmental and health-care fields in large scales. (C) 2016 Elsevier B. V. All rights reserved.