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This study presents a combination of dispersive liquid-liquid-solidified floating organic drop microextraction (DLLSFODM) and slotted quartz tube (SQT) with conventional flame atomic absorption spectrometry (FAAS) to improve the sensitivity for cadmium determination. A ligand namely 2-(4-methylphenyl)-1H-imidazo-[4,5-f]-[1,10]-phenanthroline which has not been used in trace analyte determination was used to form a cadmium complex. Stepwise optimization of parameters affecting complex formation (pH, ligand, and buffer solution) and extraction (extraction and dispersive solvents, salt effect and mixing) was done to maximize cadmium absorbance. The slotted quartz tube was fitted onto the flame burner and optimized to increase residence time of atoms in the flame. Instrumental parameters such as sample and fuel flow rate were also optimized to further enhance the absorbance signal for cadmium. Using optimal parameters and values, the limits of detection and quantification were determined to be 0.81 and 2.69 µg L-1, respectively. Low percent relative standard deviations (< 6.0%) indicated good precision for both extraction and instrumental measurements. Recovery tests were used to determine the accuracy of the method and the recovery results obtained were between 88 and 113%. [Figure not available: see fulltext.]. © 2018, Springer International Publishing AG, part of Springer Nature.

The title complex, [MnBr0.50Cl0.50(C19H15N4O)(CO)3]Br0.49Cl0.51·CH3OH, exhibits substitutional disorder of the halogen ligand in the asymmetric unit, with almost the same occupancies for Br and Cl. The MnI atom is coordinated in a distorted octahedral environment by three carbonyl C atoms, the disordered X − ligand (X = Br or Cl) and two N atoms from the 1,10-phenanthroline ligand bearing a nicotinamide pendant moiety. The cation displays a fac configuration of the carbonyl ligands. There is another disorder between the chloride ligand and its trans-situated carbonyl ligand, and between Cl− and Br− at the position of the counter-anion. In the crystal, intermolecular C—H...X, N—H...X, O—H...X (X = Br or Cl) and C—H...O hydrogen bonds lead to the formation of a three-dimensional network.

Two new water-soluble copper(II) complexes, [Cu(dmphen)(2)(NO3)]NO3 (1), [Cu(dmphen)(tyr)(H2O)] NO3 center dot H2O (2) and the diquartemary salt of dmphen (dmphen = 4,7-dimethyl-1,10-phenanthroline and tyr = L-tyrosine), have been synthesized and characterized by elemental analysis, H-1 NMR, C-13 NMR and IR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The CT-DNA binding properties of these compounds have been investigated by absorption, emission spectroscopy and thermal denaturation measurements. The supercoiled pBR322 plasmid DNA cleavage activity of these compounds has been explored by agarose gel electrophoresis. The cytotoxicity of these compounds against MCF-7, Caco-2, A549 cancer cells and BEAS-2B healthy cells was also studied by the XTT method. Complexes 1 and 2 exhibit significant cytotoxicity, with lower IC50 values than those of cisplatin.

New binary copper(II) complexes – [Cu(4-mphen)2(NO3)]NO3·H2O (1), [Cu(5-mphen)2 (NO3)]NO3·H2O (2), the known complex [Cu(dmphen)2(NO3)]NO3 (3) and [Cu(tmphen)2 (NO3)]NO3·H2O (4) - (4-mphen: 4-methyl-1,10-phenanthroline, 5-mphen: 5-methyl-1,10-phenanthroline, dmphen: 4,7-dimethyl-1,10-phenanthroline, tmphen: 3,4,7,8-tetramethyl-1,10-phenanthroline), have been synthesized and characterized by CHN analysis, ESI-MS, FTIR and single-crystal X-ray diffraction techniques. Interaction of these complexes with calf thymus DNA (CT-DNA) has been investigated by absorption spectral titration, ethidium bromide (EB) and Hoechst 33,258 displacement assay and thermal denaturation measurement. These complexes cleaved pUC19 plasmid DNA in the absence and presence of an external agent. Notably, in the presence of H2O2 as an activator, the cleavage abilities of these complexes are obviously enhanced at low concentration. Addition of hydroxyl radical scavengers like DMSO shows significant inhibition of the DNA cleavage activity of these complexes. BSA quenching mechanism was investigated with regard to the type of quenching, binding constant, number of binding locations and the thermodynamic parameters. The experimental results suggested that the probable quenching mechanism was an unusual static process and hydrophobic forces play a dominant role. The CT-DNA and BSA binding efficiencies of these complexes follow the order: 4 > 3 > 1 > 2. Furthermore, in vitro cytotoxicities of these complexes on tumor cells lines (Caco-2, MCF-7 and A549) and healthy cell line (BEAS-2B) showed that these complexes exhibited anticancer activity with low IC50 values. The effect of hydrophobicity of the methyl-substituted phenanthrolines on DNA and protein binding activities of these complexes is discussed.

In the title compound, [RuCl2(C12H6N2O2)(CO)2], the RuIIatom (site symmetry ..2) adopts a distorted octahedral coordination sphere defined by two carbonyl C atoms, two Cl−anions and two N atoms from the chelating 1,10-phenanthroline-5,6-dione (phendione) ligand. The carbonyl ligands arecisto each other, while the Cl atoms aretrans. In the phendione ligand, the C=O [1.239 (5) Å] and the C—C [1.537 (5) Å] bond lengths in the diketone moiety have typical values. In the crystal, C—H...Cl and C—H...O hydrogen bonds lead to the formation of a three-dimensional supramolecular network.

New copper(II) complexes-dimeric-[Cu(nphen)(gly)(H2O)](+) (1) and [Cu(dmphen)(gly)(NO3)(H2O)] (2) (nphen = 5-nitro-1,10-phenanthroline, dmphen = 4,7-dimethyl-1,10-phenanthroline, and gly = glycine)-have been synthesized and characterized by CHN analysis, single-crystal X-ray diffraction techniques, FTIR, EPR spectroscopy, and cyclic voltammetry. The CT-DNA-binding properties of these complexes have been investigated by thermal denaturation measurements and both absorption and emission spectroscopy. The DNA cleavage activity of these complexes has been studied on supercoiled pUC19 plasmid DNA by gel electrophoresis experiments in the absence and presence of H2O2. Furthermore, the interaction of these complexes with bovine serum albumin (BSA) has been investigated using absorption and emission spectroscopy. The thermodynamic parameters, free-energy change (Delta G), enthalpy change (Delta H), and entropy change (Delta S) for BSA + complexes 1 and 2 systems have been calculated by the van't Hoff equation at three different temperatures (293.2, 303.2, and 310.2 K). The distance between the BSA and these complexes has been determined using fluorescence resonance energy transfer (FRET). Conformational changes of BSA have been observed using the synchronous fluorescence technique. In addition, in vitro cytotoxicities of these complexes on tumor cell lines (Caco-2, A549, and MCF-7) and healthy cells (BEAS-2B) have been examined. The antimicrobial activity of the complexes has also been tested on certain bacteria cells. The effect of mono and dimeric in the above complexes is presented and discussed. New copper(II) complexes-dimeric-[Cu(nphen)(gly)(H2O)](+) (1) and [Cu(dmphen)(gly) (NO3)(H2O)] (2) (nphen = 5-nitro-1,10-phenanthroline, dmphen = 4,7-dimethyl-1,10-phenanthroline and gly = glycine)-have been synthesized and characterized by CHN analysis, single-crystal X-ray diffraction techniques, FTIR and EPR spectroscopy. They have been tested for their in vitro DNA/BSA interactions by the spectroscopic methods. These complexes exhibited higher cytotoxic and antimicrobial activities. Complex 1 shows better DNA / BSA interactions in comparison to complex 2.

Phenanthroline derivative, 2-(6-methylpyridin-2-yl)-1H-imidazo[4,5-f][1,10] phenanthroline (MIP) was synthesized and characterized by elemental analysis, FT-IR, 1 H NMR, 13 C NMR, and single crystal X-ray diffraction study. MIP was evaluated as corrosion inhibitor for mild steel in 0.5 M H 2 SO 4 solution using gravimetric and UV–Visible spectrophotometric methods at 303–333 K. Results obtained show that MIP acts as inhibitor for mild steel in H 2 SO 4 solution. The inhibition efficiency was found to increase with increase in MIP concentration but decreased with temperature. Activation parameters and Gibbs free energy for the adsorption process using statistical physics were calculated and discussed. The UV–Visible absorption spectra of the solution containing the inhibitor after the immersion of mild steel specimen indicate the formation of a MIP-Fe complex.

A fluorescent and colorimetric molecular probe containing phenol groups has been designed and synthesized. The anion binding ability was evaluated for biolgically important anions (F−, Cl−, Br−, I−, AcO− and H2PO4−) by theoretical investigation, UV-Vis and fluorescence spectroscopy and 1H-NMR titration experiments. Results indicated the probe showed strong binding ability for H2PO4− without the interference of other anions tested and the interaction process was accompanied by color changes. Theoretical investigation analysis revealed that intramolecular hydrogen bonds existed in the structure of the probe and the roles of molecular frontier orbitals in molecular interplay were determined.

New 5,5-diethylbarbiturate (barb) complexes of Ni(II), Cu(II) and Zn(II) with 1,10-phenanthroline (phen) and 2,2'-dipyridylamine (dpya), namely [Ni(phen-kappa N,N')(3)]Cl(barb)center dot 7H(2)O (1), [Cu(barb-kappa N)(barb-kappa N-2,O)(phen-kappa N,N')]center dot H2O (2), [Cu(barb-kappa N)(2)(phen-kappa N,N')] (2a), [Zn(barb-kappa N)(2)(phen-kappa N,N')]center dot H2O (3), [Ni(barb-kappa N-2,O) (dpya-kappa N,N')(2)]Cl center dot 2H(2)O (4), [Cu(barb-kappa N-2,O)(2)(dpya-kappa N,N')]center dot 2H(2)O (5) and [Zn(barb-kappa N)(2)(dpya-kappa N,N')] (6), were synthesized and characterized by elemental analysis, UV-vis, FT-IR and ESI-MS. The structures of the complexes were determined by X-ray crystallography. Notably, 3 and 6 were fluorescent in MeOH : H2O at rt. The interaction of the complexes with fish sperm (FS) DNA and bovine serum albumin (BSA) was investigated in detail by various techniques. The complexes exhibited groove binding along with a partial intercalative interaction with DNA, while the hydrogen bonding and hydrophobic interactions played a major role in binding to BSA. It is noteworthy that 2 exhibited the highest affinity towards DNA and BSA. Enzyme inhibition assay showed that 1-4 show a preference for both A/T and G/C rich sequences in pUC19 DNA, while 5 and 6 display a binding specificity to the G/C and A/T rich regions, respectively. These findings were further supported by molecular docking. The cellular uptake studies suggested that 2 was deposited mostly in the membrane fraction of the cells. Among the present complexes, 2 exhibited a very strong cytotoxic effect on A549, MCF-7, HT-29 and DU-145 cancer cells, being more potent than cisplatin. Moreover, 2 induces cell death through the apoptotic mode obtained by flow cytometry.

The gamma-aminobutyric acid type A (GABA(A)) receptor channel opening involves translational and rotational motions of the five channel-lining, M2 transmembrane segments. The M2 segment's extracellular half is loosely packed and undergoes significant thermal motion. To characterize the extent of the M2 segment's motion, we used disulfide trapping experiments between pairs of engineered cysteines. In alpha1beta1 gamma2S receptors the single gamma subunit is flanked by an alpha and beta subunit. The gamma2 M2-14' position is located in the alpha-gamma subunit interface. Gamma2 13' faces the channel lumen. We expressed either the gamma2 14' or the gamma2 13' cysteine substitution mutants with alpha1 cysteine substitution mutants between 12' and 16' and wild-type beta1. Disulfide bonds formed spontaneously between gamma2 14'C and both alpha1 15'C and alpha1 16'C and also between gamma2 13'C and alpha1 13'C. Oxidation by copper phenanthroline induced disulfide bond formation between gamma2 14'C and alpha1 13'C. Disulfide bond formation rates with gamma2 14'C were similar in the presence and absence of GABA, although the rate with alpha1 13'C was slower than with the other two positions. In a homology model based on the acetylcholine receptor structure, alphaM2 would need to rotate in opposite directions by approximately 80 degrees to bring alpha1 13' and alpha1 15' into close proximity with gamma2 14'. Alternatively, translational motion of alphaM2 would reduce the extent of rotational motion necessary to bring these two alpha subunit residues into close proximity with the gamma2 14' position. These experiments demonstrate that in the closed state the M2 segments undergo continuous spontaneous motion in the region near the extracellular end of the channel gate. Opening the gate may involve similar but concerted motions of the M2 segments.

Reaction of [V(VI)OCl(2)(thf)(2)] with a bidentate nitrogen-donor ligand (L: phen=1,10-phenanthroline, 5-mephen=5-methyl-1,10-phenanthroline, bipy=2,2'-bipyridine, 5,5'-me(2)bipy=5,5'-dimethyl-2,2'-bipy) in methyl alcohol, in the presence of triethylamine, leads to the formation of hexameric [V(2) (IV)V(4) (V)] oxo-alkoxo-vanadates of the general formula [V(6)O(12)(mu(2)-OCH(3))(4)(L)(4)].x H(2)O [L=phen (1.4 H(2)O), 5-mephen (2.6 H(2)O), bipy (3.4 H(2)O), 5,5'-me(2)bipy (4.H(2)O)]. X-ray structure analysis of 1.2 H(2)O and 4.8 CH(3)OH revealed a pair of V(3)O(13)N(4) trimeric units sharing two corners, with a centrosymmetric planar V(6)-core. In addition, a fully oxidized V(V) species [V(V) (4)O(8)(OCH(3))(2)(mu(3)-OCH(3))(2)(5,5'-me(2)bipy)(2)].3 CH(3)OH (5.3 CH(3)OH) was isolated from the reaction mixture used for the synthesis of 4.H(2)O. The crystal structure of 5.3 CH(3)OH revealed a dicubane-like framework with two missing vertices. Electron paramagnetic resonance (EPR) and variable temperature magnetic susceptibility studies for the hexamers 1.4 H(2)O and 3.4 H(2)O showed the complete localization of the single 3d electrons on the V(IV) ions and unusual ferromagnetic interaction between the two paramagnetic vanadium(IV) ions separated by a distance of about 5.1 A. Furthermore, intermolecular antiferromagnetic interactions through pi-contacts of phenyl rings were observed for these species below 8 K. The ferromagnetic exchange coupling observed in the hexanuclear compounds 1.4 H(2)O and 3.4 H(2)O is also discussed using ab initio UHF calculations on a model compound. The value of the exchange coupling constant (3.7 cm(-1)) for this model compound, calculated using the broken symmetry approach, is in good agreement, both in sign and magnitude, with the experimental J values (6.00 cm(-1) for 1.4 H(2)O and 8.54 cm(-1) for 3.4 H(2)O).

Binary and ternary water soluble copper(II) complexes - [Cu(nphen)(2)(H2O)](NO3)(2)center dot H2O (1), [Cu(phen)(2)(H2O)](NO3)(2) (2), [Cu(nphen)(L-tyr)(H2O)]NO3 center dot 2H(2)O (3), [Cu(Phen)(tyr)(H2O)] NO3 center dot 2H(2)O (4) - and diquarternary salts of nphen and phen (nphen = 5-nitro-1,10-phenanthroline, phen = 1,10-phenanthroline and tyr = L-tyrosine) have been synthesized and characterized by CHN analysis, H-1 NMR, C-13 NMR and IR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The CT-DNA binding properties of these compounds have been investigated by thermal denaturation measurements, absorption and emission spectroscopy. The supercoiled pUC19 plasmid DNA cleavage activity of these compounds has been explored by agarose gel electrophoresis. The cytotoxicity of these compounds against MCF-7, Caco-2, A549 cancer cells and BEAS-2B healthy cells was also studied by using XTT method. The complexes 1-4 exhibit significant high cytotoxicity with low IC50 values in compared with cisplatin. The effect of the substituents of phen and coordinated amino acid in the above complexes are presented and discussed.

The reaction of VCl(3) with 1,10-phenanthroline and a series of dipeptides (H(2)dip), having aliphatic as well as aromatic side chains, in methyl alcohol and in the presence of triethylamine affords vanadium(III) compounds of the general formula [V(III)(dip)(MeOH)(phen)]Cl. Aerial oxidation/hydrolysis of the vanadium(III) species gives their oxovanadium(IV) analogues of the general formula [V(IV)O(dip)(phen)]. X-ray crystallographic characterization of the [V(IV)O(dip)(phen)] compounds (where dip(2-)=Gly- L-Ala, Gly- L-Val and Gly- L-Phe) revealed that the vanadium atom possesses a severely distorted octahedral coordination and is ligated to a tridentate dip(2-) ligand at the N(amine) atom, the deprotonated N(peptide) atom and one of the O(carboxylate) atoms, as well as an oxo group and two phenanthroline nitrogen atoms. Circular dichroism characterization of the V(III)/V(IV)O(2+)-dipeptide compounds revealed a strong signal for the V(IV)O(2+) species in the visible range of the spectrum, with a characteristic pattern which may be exploited to identify the N(am), N(pep) and O(car) ligation of a peptide or a protein to V(IV)O(2+) center, and a weak Cotton effect of opposite sign to their vanadium(III) analogues. The visible spectra of the V(III)-dipeptide compounds revealed two d-d bands with high intensity, thus indicating that the covalency of the metal-donor atoms is significant, i.e. the vanadium d orbitals are significantly mixed with the ligand orbitals, and this is confirmed by the low values of their Racah B parameters. The high-intensity band of the V(IV)O(2+)-dipeptide compounds at approximately 460 nm implies also a strong covalency of the metal with the equatorial donor atoms and this was supported by the EPR spectra of these compounds. Moreover, the V(III)/V(IV)O(2+)-dipeptide complexes were characterized by EPR and IR spectroscopies as well as conductivity and magnetic susceptibility measurements.

Ni(II) and Co(II) coordination by the macrocyclic ligand 2,5,8,11-tetraaza[12]-13,26-phenanthrolinophane (L), which contains a tetraamine chain linking the 2,9 positions of phenanthroline, has been studied in anaerobic conditions by means of potentiometric and UV–vis spectrophotometric measurements in aqueous solution. These complexes are far less stable than those with the aliphatic hexaazamacrocycle [18]aneN6. This experimental observation suggests that in the [ML]2+ complexes some amine groups are weakly involved or not involved in metal coordination. This hypothesis is supported by the crystal structure of [NiL(H2O)]2+, which shows the metal hexacoordinated by five nitrogens of the macrocyclic ring and an oxygen of a water molecule, with a distorted octahedral coordination geometry. One of the benzylic amine groups is not bound to the metal. A similar coordination environment is also proposed for the Co(II) complex. The kinetic study of Ni(II) complexation with L, carried out by means of spectrophotometric UV measurements, points out that the rate-determining step for Ni(II) coordination is the formation of the first bond. This involves the metal ion and one of the two nitrogen atoms of the phenanthroline moiety.

Inhibition of protein kinases in the fight against disease remains a constant challenge for medicinal chemists, who have screened multitudes of predominantly planar organic scaffolds, natural and synthetic, to identify potent-albeit not always selective-kinase inhibitors. Herein, in an effort to investigate the potential biological utility of metal-based compounds as inhibitors against the cancer-relevant targets mitogen-activated protein kinase and cyclin-dependent kinase 2, we explore various parameters in planar platinum(II) complexes with substituted phenanthroline ligands and aliphatic diamine chelate co-ligands, to identify combinations that yield promising inhibitory activity. The individual ligands' steric requirements as well as their pattern of hydrogen bond donors/acceptors appear to alter inhibitory potency when modulated.The online version of this article (doi:10.1007/s12154-011-0059-5) contains supplementary material, which is available to authorized users.

A new bis-phenanthroline dicopper(II) complex has been synthesized and characterized by elemental analysis and spectroscopic methods. The molecular structure of the dinuclear Cu(II) complex [Cu2(?-CH 3COO)(?-H2O)(?-OH)(phen)2]2+ (phen = 1,10-phenanthroline) (1) was determined by single crystal X-ray diffraction technique. The coordination environment around each Cu(II) ion in complex 1 can be described as slightly distorted square pyramidal geometry. The distance between the Cu?Cu centers in the complex is found to be 2.987 �. The electronic, redox, phosphate hydrolysis, DNA binding and DNA cleavage have been studied. The antiproliferative effect of complex 1 was confirmed by the lactate dehydrogenase (LDH) enzyme level in MCF-7 cancer cell lysate and content media. The dicopper(II) complex inhibited the LDH enzyme as well as the growth of the human breast cancer MCF7 cell line at an IC 50 value of 0.011 ?g ml-1. The results strongly suggest that complex 1 is a good cancer therapeutic agent. Electrochemical studies of complex 1 showed an irreversible, followed by a quasi-reversible, one electron reduction processes between -0.20 to -0.8 V. Michaelis-Menten kinetic parameters for the hydrolysis of 4-nitrophenyl phosphate by complex 1 are kcat = 3.56 � 10-2 s-1 and KM = 4.3 � 10-2 M. Complex 1 shows good binding propensity to calf thymus DNA, with a binding constant value of 1.3 (�0.13) � 105 M-1 (s = 2.1). The size of the binding site and viscosity data suggest a DNA intercalative binding nature of the complex. Complex 1 shows efficient hydrolytic cleavage of supercoiled pBR322-DNA in the dark and in the absence of any external reagents, as demonstrated by the T4 ligase experiment. The pseudo-Michaelis-Menten kinetic parameters for DNA hydrolysis by complex 1 are kcat = 1.27 � 0.4 h-1 and KM = 7.7 � 10-2 M. � 2011 The Royal Society of Chemistry.

A new fullerene-substituted phenanthroline ligand has been obtained by reaction of a phenanthroline derivative bearing a 1,3-phenylenebis(methylene)-tethered bis-malonate with C(60) in a double Bingel cyclopropanation. The relative position of the two cyclopropane rings in the resulting bis-methanofullerene derivatives has been determined on the basis of the molecular symmetry (C(s)()) deduced from the (1)H and (13)C NMR spectra. The corresponding Cu(I) complex F-Cu-F has been prepared in good yields by treatment of the ligand with Cu(CH(3)CN)(4)BF(4). In the resulting multicomponent system, both C(60) moieties are in a tangential orientation relative to their bridging phenyl ring, and the central bis(phenanthroline)Cu(I) core is sandwiched between the two carbon spheres. The electrochemical properties of F-Cu-F suggest the existence of ground-state electronic interactions in this multicomponent array based on the mutual effects exerted by the fullerene units to the bis(2,9-diphenyl-1,10-phenanthroline)Cu(I) complex and vice versa. Close vicinity and electronic interactions between the inorganic core and the peripheral fullerene units are also suggested by increased electronic absorption around 430 nm. The distance between the two moieties is estimated to be 4.3 A by molecular modeling studies. The excited-state properties of F-Cu-F have also been investigated. Photoinduced electron transfer from the central chromophore to the external fullerene units occurs but, surprisingly, only following population of the excited states of the central inorganic unit and not of the external carbon spheres. This is mainly attributed to kinetic factors related to the different nature of the two types of excited states involved, namely charge transfer (excitation on the metal-complexed moiety) vs a localized state (excitation on the fullerene units).

cited By 1; International audience; Surface electrode reactions involving lateral uniform interactions between adsorbed species is studied by means of square-wave voltammetry (SWV). Interactions are represented by the interaction product aθ, were a is the Frumkin interaction parameter (a is positive for attraction and negative for repulsion forces) and θ is the surface coverage. The properties of the SW voltammetric response enable detection of interactions and recognition of the type of interaction forces by a simple procedure. The influence of the interactions on the apparent electrochemical reversibility of the surface electrode reaction is studied in detail. Utilizing "quasireversible maximum" the simple methodology for estimation of the standard redox rate constant without knowing the exact value of the interaction product aθ is developed. Theoretical predictions are illustrated and confirmed by experiments with Mo(VI) in the presence of phenantroline and an excess of fulvic acids.

cited By 5; International audience; The reduction process of molybdenum in the presence of fulvic acids and phenanthroline was investigated by square-wave voltammetry (SWV), The mixed-ligand complex of molybdenum exhibits a pronounced tendency to adsorb onto the mercury electrode surface. The electrode reaction proceeds as a surface process in which both components of the redox couple are firmly confined to the electrode surface. The kinetics of the electrode reaction is studied utilizing the properties of "split SW peaks" and "quasireversible maximum". The kinetic parameters obtained with two different square-wave voltammetric methods are in good agreement. In 0.5 mol/L NaCl solution with pH 2.5 the kinetic parameters are: standard rate constant ks = 8 ± 2 s-1, cathodic electron transfer coefficient α = 0.41 ± 0.05, and number of exchanged electrons n =2. The SW kinetic measurements are confirmed by cyclic voltammetric method.