Catalytic (ep)oxidation and corrosion inhibition potentials of CuII and CoII pyridinylimino phenolate complexes

The coordination chemical behavior of pyridinylimino phenolate sodium sulfonate (HPSS) was examined with Cu-II and Co-II ions to give two novel para-magnetic complexes, CuPSSACl and Co(PSS)(2), respectively. In CuPSSACl, Cu2+ ion reacts with HPSS in 1:1 and 1:2 of Co2+ ion to HPSS in Co(PSS)(2), respectively. Various physico-chemical spectroscopic tools were applied to characterize their molecular structures. The spectrophotometric measurements were used to determine the formation constants, K-f. CuPSSACl and Co(PSS)(2) exhibited performed catalytic potential towards the (ep)oxidation of 1,2-cyclooctene by an aqueous H2O2 under alternative conditions. The catalytic sufficiency of CuPSSACl and Co(PSS)(2) was influenced by other parameters (temperature, solvent and oxidant). CuPSSACl is more effective catalyst than Co(PSS)(2). The corrosion inhibition of HPSS and its chelates (CuPSSCl and Co(PSS)(2)) on carbon steel (CS) in HCl solution were studied using electrochemical (potentiodynamic polarization, PDP and electrochemical impedance spectroscopy, EIS) and surface (SEM and EDX) techniques. The inhibition efficiency incremented with the inhibiting agent concentrations following the sequence: CuPSSCl > Co(PSS)(2) > HPSS. Thermodynamically, those compounds act as mixed-type inhibiting agents and obeyed Langmuir adsorption isotherm via chemisorption. SEM and EDX investigations confirmed the protective efficiency of the titled inhibiting agents on CS in HCl. (C) 2018 Elsevier Ltd. All rights reserved.