Symmetry, Vol. 15, Pages 752: Electrochemistry of Rhodanine Derivatives as Model for New Colorimetric and Electrochemical Azulene Sensors for the Detection of Heavy Metal Ions

Symmetry, Vol. 15, Pages 752: Electrochemistry of Rhodanine Derivatives as Model for New Colorimetric and Electrochemical Azulene Sensors for the Detection of Heavy Metal Ions

Symmetry doi: 10.3390/sym15030752

Authors: Ovidiu-Teodor Matica Cornelia Musina (Borsaru) Alina Giorgiana Brotea Eleonora-Mihaela Ungureanu Mihaela Cristea Raluca Isopescu George-Octavian Buica Alexandru C. Razus

Rhodanine (R) is a heterocycle having complexing properties for heavy metal (HM) ions. Considering the similar electron-donating character of diethylaminobenzene and azulene, electrochemical characterization of (Z)-5-(azulen-1-ylmethylene)-2-thioxo-thiazolidin-4-one (R1) and 5-(4 diethylamino-benzylidene)-2-thioxo-thiazolidin-4-one (R2) was performed to establish their common features. Chemically modified electrodes based on R1 and R2 were compared for HM recognition. Evidence for the formation of films was provided by scanning and controlled potential electrolysis, and HM recognition experiments were performed using their films. Parallel studies for analysis of HMs by complexation in solution were performed by UV-Vis. The analogy between R1 and R2 created the premise for easier selection of compounds for certain applications. The performance of the chemically modified electrodes was evaluated as detection limits for HMs. The azulene monomer (R1) proved to be the best candidate for Pb(II) detection, being about eight times more sensitive than R2. However, in solution, R2 proved to be a good choice for optical measurements, having a higher absorption coefficient. These results support the two ligands having different behaviors in homogeneous and heterogeneous systems.