CHARACTERIZATION OF REFERENCE ELECTRODE AG/AGCL DRY TYPE BY CYCLIC VOLTAMMETRY

In the present work the characterisazion of reference electrode Ag/AgCl type dry by 0.01 M [Fe(CN) in 0.1 M KCl using the technique of cyclic voltammetry  at potential range of -0.2 to 0.8 V and scan rate variation..The anodic (Epa) and the cathodic (Epc) peak potentials. as well as the corresponding anodic (ipa) and cathodic(ipc) peak currents. were obtained at different scan rates (10. 20. 25. 50. 100. and 200)  mV/s . The half-wavepotentials (E1/2) of the [Fe(CN)6]4-/ [Fe(CN)6]3- couple in the investigated solvent media have been evaluated. Ipversus v1/2 have been calculated using the Randles-Sevcik equation..Keywords: cyclic voltammetry. half-wave potential. reference electrode Ag/AgCl6]3-/4

Characterization of Reference Electrode Ag/agcl Dry Type by Cyclic Voltammetry

In the present work the characterisazion of reference electrode Ag/AgCl type dry by 0.01 M [Fe(CN) in 0.1 M KCl using the technique of cyclic voltammetry at potential range of -0.2 to 0.8 V and scan rate variation..The anodic (Epa) and the cathodic (Epc) peak potentials. as well as the corresponding anodic (ipa) and cathodic(ipc) peak currents. were obtained at different scan rates (10. 20. 25. 50. 100. and 200) mV/s . The half-wavepotentials (E1/2) of the [Fe(CN)6]4-/ [Fe(CN)6]3- couple in the investigated solvent media have been evaluated. Ipversus v1/2 have been calculated using the Randles-Sevcik equation.

Tetrabenzoporphyrin and -mono-, - Cis -di- and tetrabenzotriazaporphyrin derivatives: Electrochemical and spectroscopic implications of meso CH Group replacement with nitrogen

Nonperipherally hexyl-substituted metal-free tetrabenzoporphyrin (2H-TBP, 1a) tetrabenzomonoazaporphyrin (2H-TBMAP, 2a), tetrabenzo-cis-diazaporphyrin (2H-TBDAP, 3a), tetrabenzotriazaporphyrin (2H-TBTAP, 4a), and phthalocyanine (2H-Pc, 5a), as well as their copper complexes (1b-5b), were synthesized. As the number of meso nitrogen atoms increases from zero to four, Îmax of the Q-band absorption peak becomes red-shifted by almost 100 nm, and extinction coefficients increased at least threefold. Simultaneously the blue-shifted Soret (UV) band substantially decreased in intensity. These changes were related to the relative electron-density of each macrocycle expressed as the group electronegativity sum of all meso N and CH atom groups, âχR. X-ray photoelectron spectroscopy differentiated between the three different types of macrocyclic nitrogen atoms (the Ninner, (NH)inner, and Nmeso) in the metal-free complexes. Binding energies of the Nmeso and Ninner,Cu atoms in copper chelates could not be resolved. Copper insertion lowered especially the cathodic redox potentials, while all four observed redox processes occurred at larger potentials as the number of meso nitrogens increased. Computational chemical methods using density functional theory confirmed 1b to exhibit a Cu(II) reduction prior to ring-based reductions, while for 2b, Cu(II) reduction is the first reductive step only if the nonperipheral substituents are hydrogen. When they are methyl groups, it is the second reduction process; when they are ethyl, propyl, or hexyl, it becomes the third reductive process. Spectro-electrochemical measurements showed redox processes were associated with a substantial change in intensity of at least two main absorbances (the Q and Soret bands) in the UV spectra of these compounds

Voltammetric Determination of Paracetamol with Carbon Paste Electrode Modified with Molecularly Imprinted Electropolymer

Paracetamol is a commom analgesic and antipyretic drug which used for reliefing fever and head ache. The determination of paracetamol dose in pharmaceuticals is very important, becauce an overdose can cause fulminating hepatic necrosis and other toxic effects. Therefore, it is necessary to measure the dose of paracetamol for the patient with precision to avoid harm. Many analytical methodologies have been proposed for determination of paracetamol dose. One of the methods was developed in the past two decades. Generally, electroanalytical approach especially voltammetry method is particularly design for determination of paracetamol dose especially in modifying electrode. This study aims to modified carbon paste electrode with molecularly imprinted polymer (MIP). Significant advantages of using MIP are the superior stability, low cost and ease of preparation. The poly (3-aminiophenol) film was prepared by cyclic voltammetry method and 3-aminophenol monomer in supporting electrolyte (HClO4) with and whitout presence of paracetamol molecule. The effect of paracetamol was seen at cyclic voltammogram was founded, where oxidation peak potential of poly (3-aminophenol) shifted to more cathodic potentials from 0.948 to 0.780 V, in presence of paracetamol. The Ipa showed a good linear relationship with concentration in the range 0.01–0.1 mM, and the detection limit was 4,63 μM

Unsupported boron–carbon σ-coordination to platinum as an isolable snapshot of σ-bond activation

σ-Complexes of transition metals—key intermediates in metal-mediated bond activation and homogeneous catalysis—have traditionally been isolable only when chelating or when one of the participating atoms is hydrogen. Here, by treating the Lewis-basic transition metal complex [Pt(PEt3)4] with an electron-poor borirene, we isolate a complex with an unsupported borirene ligand bound, not through the unsaturated C=C bond, but exclusively via a B–C single bond. Using NMR spectroscopy, X-ray crystallography and density functional theory calculations, we show, herein, that coordination of the borirene ligand is based on electron donation from the B–C σ bond to the metal, aided by a strong Pt-to-B dative interaction. The complex is the first isolable non-agostic σ-complex featuring two p-block elements and has broad implications as a model for the metal-mediated activation of strong p-block-p-block σ-bonds