Schiff bases electrodes

The paper presents the experimental and theoretical data regarding the realization and characterization of three liquid-membrane electrodes, which have not been mentioned in the specialized literature so far. The active substances whose solutions in nitrobenzene have constituted the membranes on a graphite rod, are simple complex combinations of the Cu(II) and Ni(II) ions with Schiff base N-[2-thienylmethylidene]-2-aminothiophenol (TNATPh). 

In this section, we present material dealing with the direct oxidation and reduction of a variety of organocobalt species, including complexes with more than one cobalt center, electrodes functionalized with cobalt complexes, cobalt-containing SchifF-base complexes, cobalt porphyrins and corroles, and macrocyclic tetraamines. 

The PVC membrane electrode based on new Schiff base complexes of 2,2-[(l,3,dimethyl-l,3-propanediylidene)dini-trilojbis-benzenethiolato with Cd(II) [381] and cadmium-salen N, Ai -bis-salicyli-dene-l,2-ethylenediamine) complex [382] were used as the selective electrodes for tiocyanate ions. 

In situ photoacoustic spectroscopy has been used to study the redox process on the surface of an electrode using copper metal in alkaline solution.1029 The E° values of copper(II) Schiff base complexes1030 absorbed on optically transparent thin-layer electrodes (OTTLE) have been... 

Thin-layer CV is frequently used in conjunction with an optically transparent thin-layer electrode to obtain spectra, E°, and n for redox couples by the spectropotentiostatic technique and thin-layer coulometry, as described earlier in this chapter. CV is used initially to locate the redox couple and give an estimate of E°. Once the CV is obtained, appropriate potentials can be selected for the spectropotentiostatic experiment and potential-step coulometry. A typical thin-layer cyclic voltammogram for the Schiff base complex Co(sal2en) in nonaqueous solvent is shown in Figure 3.34. 

In this way, alkoxides, glycolates, catecholates, carboxylates, or Schiff base complexes have been obtained.37,38 Other metal chelates have been synthesized by electro-oxidation of the bare metal electrode phosphido, azolates, phthalocyanines, semicarbazides, Schiff bases, etc.37 In addition to the syntheses of monometallic complexes, electrochemistry has been proven to yield polynuclear complexes by using assembling or multidentate ligands.37... 

Liu KZ, Wu QG, Liu HI. 1990. Application of a Nafion - Schiff-base modified electrode in anodic-stripping voltammetry for the determination of trace amounts of mercury. Analyst 115(6) 835-837. 

The ion-selective electrodes based on different types of zinc-Schiffs bases were used for the determination of 504 [468] and thiocyanate ions concentration [469]. 

Figure 14-1 Functionalization and activation of electrode materials, a) silanization of supports bearing hydroxylic groups b) reaction with cyanuric chloride c) activation with cyanogen bromide d) binding via amide bonds after activation with 1,1-carbonyldiimidazole e) activation with good leaving groups such as tresyl chloride f) formation of Schiff bases between aldehyde groups on the support and amino groups at the biomolecule g) activation of carboxylic groups with carbodiimides or h) via the acid chlorides.

In most of the work on oligo-deoxynucleotides (ODNs) to date, very similar chemistry has been used for covalent binding of organometallics to the ODNs (Schiff base, activated acids, metal-catalyzed couplings). Anne< /tf/. reported an interesting enzymatic reaction to extend the 3 terminus of an ODN. They use a ferrocenylated di-deoxynu-cleotide uridine triphosphate (Fc-ddUTP) as the substrate, which is accepted as an enzyme substrate and terminates the oligomer. Other Fc-dUTP derivatives were also tested as substrates for common DNA polymerases. This approach was later extended to ferrocene-labeled RNA, and electrochemical RNA detection on Au-DNA electrodes could be achieved. ... 

Electropolymerization techniques have also been popular for the preparation of electrodes modified by thin films of Schiff-base metallopolymers for prospective electrocatalytic, chemical sensing, and electrochromic applications [79-85]. In... 

Electropolymerization techniques, which have been successfully used to prepare electrode films of metallopolymers, based on polypyridyl and Schiff-base ligation (see Sections 7.2 and 7.3), have also been shown to provide a versatile route to a variety of other interesting materials. An early example reported in 1994 is provided by Re polymers 7.48, formed by anodic oxidation of a bis(thiazole) bearing thiophene substituents followed by complexation through treatment with Re(CO)5Cl and then Ag) ] (Scheme 7.8). The observed conductivities of 7.48 were, however, substantially lower than those of the uncomplexed material [90]. 

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