Novel Ni(II) Mixed Ligand Complex Modified Electrode: Catalytic Effect on Anodic Oxidation of Phenol

Abstract

Cyclic voltammetry, using graphite paste electrode (GPE) and chemically modified GPE with Ni(II) mixed ligand complex (MGPE), is described for sensing and detoxification of phenol. A novel mixed ligand complex of nickel with 1,4,8,11-tetraaza cyclotetradecane (cyclam) and thiocyanate in the molar ratio of 1 : 2 : 5 is synthesized and characterized by spectroscopic and electrochemical studies. The Ni(II)-cyclam-thiocyanate complex behaves as a fast electron-transfer mediator, as nickel ions exist in higher oxidation state of Ni(III) on applying a potential of 1.25 V (vs. Ag/AgCl), which catalyses the oxidation of the target species. The mixed ligand complex, when incorporated in the graphite paste electrode, is sensitive to detect phenol as low as 10 mg/L in solution. The catalytic effect of the Ni(II)-cyclam-thiocyanate complex enhanced many folds the oxidation of phenol compared to GPE. The technique has potential for sensing/monitoring and detoxification of phenol released in the ecosystem from polluting industries.

Ceftriaxone: a novel corrosion inhibitor for mild steel in hydrochloric acid

“…The electrochemical studies were made using a threeelectrode cell assembly at room temperature [21,22]. The working electrode was a mild steel of above composition of 1 cm 2 area and the rest being covered by using commercially available lacquer.…”

Sensor for fisetin based on gold nanoparticles in ionic liquid and binuclear nickel complex immobilized in silica

“…The sensitivity of this sensor is greater than that of other sensors constructed with nickel complexes, for the determination of phenolic compounds, described in the literature. 15,16,18 The satisfactory analytical performance of the proposed sensor can be attributed to the chemical stability and catalytic properties of the complex immobilized on silica, the high conductivity of the ionic liquid and the fact that the metal nanoparticles facilitate the electron transfer. This intrinsic catalytic contribution of each one of these materials contributes to significantly to improving the sensitivity.…”

“…Various sensors for the determination of phenolic compounds have been constructed employing electroactive mono-and polymetallic complexes. [15][16][17][18] The redox behavior of complexes which present catalytic activity toward important species is of great interest and has been attracting the attention of researchers for some time, due to the possibility of their application in sensor development. For example, de Oliveira et al 17 presented a dinuclear iron complex, [Fe III Fe II (BPBPMP)(OAc) 2 ]ClO 4 , containing the unsymmetrical ligand 2-bis[{(2-pyridylmethyl)-amino-methyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)}-aminomethyl]-4-methylphenol (H 2 BPBPMP), which has been described as being the first synthetic analogue for the redox properties of uteroferrin.…”

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