Ion-exchange voltammetry of tris(2,2′-bipyridine) nickel(II), cobalt(II), and Co(salen) at polyestersulfonated ionomer coated electrodes in acetonitrile: Reactivity of the electrogenerated low-valent complexes

Abstract

The electrochemical behaviour of [Ni(bpy) 3 (BF 4 ) 2 ], [Co(bpy) 3 (BF 4 ) 2 ], and Co(salen) (where bpy = 2,2 -bipyridine, and salen = N,Nbis(salicylidene)ethylenediamine) is studied at a glassy carbon electrode modified with the poly(estersulfonate) ionomer Eastman AQ 55 in acetonitrile (MeCN). It is shown that the nickel complex is strongly incorporated into the polymer. The reduction of the divalent nickel compound features a two-electron process leading to a nickel(0) species which is released from the coating because of the lack of electrostatic attraction with the ionomer. Yet, the neutral zerovalent nickel-bipyridine complex is reactive towards ethyl 4-iodobenzoate and di-bromocyclohexane despite the presence of the polymer. The activation of the aryl halide occurs through an oxidative addition, whereas, an electron transfer is involved in the presence of the alkyl halide making the catalyst regeneration much faster in the latter case. The electrochemical study of [Co(bpy) 3 (BF 4 ) 2 ] shows that incorporation of the cobalt complex into the polymer is efficient, provided excess bpy is used. This excess bpy does not interfere with the electrocatalytic activity of the cobalt complex incorporated in the AQ coating and efficient electrocatalysis is observed towards di-bromocyclohexane and benzyl-bromide as substrates. Finally, replacement of the bpy ligand with the macrocycle N,N -bis(salicylidene)ethylenediamine, salen, leads to the incorporation of the non-charged Co II (salen) complex into the AQ 55 polymer showing the relevancy of hydrophobic interactions. The reaction between the electrogenerated [Co I (salen)] − with 1,2-dibromocyclohexane exhibits a fast inner sphere electron transfer.

Ion exchange voltammetry at permselective copolymer modified electrode and its application for the determination of catecholamines

“…Subsequently, the sensitivity increases because of the increased current due to the oxidation or reduction of the analyte of interest. A wide range of polyanionic and polycationic organic polymers are used as ion exchange materials [1][2][3][4]. In addition, charged conducting polymers [5], clays [6], zeolites [7,8], Nafion Ò [9], protonated poly(vinyl pyridine) [10], other polymeric resins and silica-based organic-inorganic hybrids [11][12][13][14] are also used for the same purpose.…”

“…The basis of this technique lies on the charge selective film usually an ion selective material coated on the electrode surface [1][2][3][4]. Preconcentration of analytes by charge selective films can enhance the concentration of electroactive ionic species at the electrode surface.…”

MCNTs@MnO2 Nanocomposite Cathode Integrated with Soluble O2-Carrier Co-salen in Electrolyte for High-Performance Li–Air Batteries

“…It is known that N,N'-bis(salicylidene)ethylenediaminocobalt(II) (Co II -salen), one model compound of Schiff base complexes of Co II , can reversibly coordinate and release oxygen in human body, [28][29][30][31] suggesting its potential electrochemical application in LABs. 32 Such versatile Co II -salen has not ever been studied in LOBs or LABs, and it has a potential to provide a new reaction route to avoid the formation of superoxide intermediate. Therefore, combining precisely coated nanocomposite of MCNTs@MnO2 and powerful oxygen carrier of Co-salen is of importance to comprehensively enhance the electrochemical performance of LABs in dry air with 21% O2.…”

Effect of the Concentration of Supporting Electrolyte on Spectroelectrochemical Detection of [Ru(bpy)3]2+

“…[Ru(bpy) 3 ] 2 + , a cation with well-known electrochemical and optical properties [4,[11][12][13][14][15][16] 2 + preconcentrates in both Nafion and SSEBS films [4,17]. Nafion is a well-studied ion exchange material and the partitioning, diffusion and electrochemical behaviors of [Ru(bpy) 3 ] 2 + /3 + in Nafion have also been previously studied [18].…”