Synthesis of novel 5–arylidene rhodanine derivative molecules for the potentiometric detection of Nd3+ ions

In this study, the synthesis, characterization, and use of two new 5–arylidene rhodanine derivative molecules (1 and 2) as ionophores in potentiometric sensors were investigated. For this purpose, the newly synthesized rhodanine derivative molecules were characterized by various spectroscopic methods (1H–, 13C–NMR, FT–IR, and Q–TOF), and then all solid state PVC membrane potentiometric sensors were prepared using these novel molecules. Sensors having the synthesized new rhodanine derivative molecules as ionophores exhibited high selectivity towards Nd3+ ions. With the same sensor components and ratios, sensors prepared with (E)-4-((4-oxo-2-thioxothiazolidin-5-ylidene)methyl)phenyl 4-methoxybenzenesulfonate (1) exhibited better potentiometric behavior than sensors prepared with (E)-3-((4-oxo-2-thioxothiazolidin-5-ylidene) methyl)phenyl 4-bromobenzenesulfonate (2). The PVC membrane Nd3+–selective sensor prepared with molecule 1 had a linear working range of 1.0×10-1–1.0× 10-5 M (R2: 0.9992), Nernstian behavior (19.0±1.0 mV/decade), and a low detection limit (8.04× 10-6 M). Besides, the newly developed Nd3+–selective sensor had a fast response time (∼6 s) and a wide pH working range (4.0–10.0). The surface morphologies of the prepared sensors were also examined by scanning electron microscopy (SEM). The simple, economical, and easily prepared sensors were able to determine Nd3+ ions in various water samples with very high recoveries (>95.5%).

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