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Rabindranath Mukherjee - One of the best experts on this subject based on the ideXlab platform.
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Five-coordinate [(L2)2CuII(X)]z+ (X = H2O, z = 2; X = N3−, SCN−, NO2−, MeCO2−, Cl−, Br−, z = 1; L2 = 1-benzyl-[3-(2-pyridyl)]pyrazole) complexes: Structural index, EPR and redox Potential correlations
Inorganica Chimica Acta, 2020Co-Authors: Jhumpa Mukherjee, Arunava Sengupta, Rabindranath MukherjeeAbstract:Abstract Mononuclear five-coordinate complexes [(L2)2CuII(X)]z+(ClO4)n (X = H2O, 1, n = z = 2; X = N3– 2, SCN– 3, NO2– 4, MeCO2– 5, Cl– 6, Br– 7 n = z = 1; L2 = 1-benzyl-[3-(2-pyridyl)]pyrazole) have been synthesized and structurally characterized with crystal composition 1, 2, 3•2MeCN, 4•Et2O, 5•3H2O, 6•MeCN and 7•MeCN. The didentate ligand L2 provides a pyridyl and a pyrazole for coordination. Structural index parameter (τ; it assumes a value of 0 and 1 for ideal square pyramidal and trigonal bipyramidal geometry, respectively) for 1–7 are 0.60, 0.01, 0.33, 0.41, 0.26, 0.62, 0.57, respectively. Absorption and EPR spectroscopic, and redox properties of 1–7 have been investigated. Cathodic Peak Potential (Epc, V vs. saturated calomel electrode, SCE) values in MeCN of 1–7 are 0.08, –0.05, 0.07, 0.05, 0.05, 0.23 and 0.14, respectively. For anion-bound complexes 2, 3, 5–7 useful correlations have been established: (i) Epc (Cathodic Peak Potential of CuII–CuI redox process) vs. structural index parameter τ, (ii) g‖ vs. τ and (iii) Epc vs. g‖ and (iv) A‖ vs. τ. The observed trends have been rationalized.
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cobalt iii complexes using in plane tetradentate pyridinecarboxamide ligands and two monodentate axial ligands spectroelectrochemical correlation
Polyhedron, 1992Co-Authors: Rabindranath MukherjeeAbstract:Abstract A series of diamagnetic cobalt(III) complexes of bpb and bpc ligands [H 2 bpb = 1,2-bis(2-pyridinecarboxamido)benzene; H 2 bpc = 4,5-dichloro-1,2-bis(2-pyridinecarboxamido) benzene] with axial ligands (Cl − , N 3 − , SCN − , NO 2 − or MeCO 2 − ) has been synthesized. The trans geometry has been shown by 1 H NMR spectroscopy. The brown or green crystalline complexes display dominant ligand-to-metal charge-transfer transitions at ca 400 nm, while in the low-energy region ligand field transitions are observed. From an analysis of the d-d transition(s) ligand field parameters of the in-plane and axial ligands have been determined. In acetonitrile solution the complexes exhibit an irreversible Co III -Co II couple [ E pc −0.42 to −1.18 V vs saturated calomel electrode (S.C.E.)] and a quasi-reversible Co II -Co I couple ( E f −1.12 to − 1.27 V vs S.C.E.). When X = SCN − this couple is irreversible ( E pc = −1.40 V vs S.C.E.). These complexes display an additional quasi-reversible oxidative response (0.69-0.92 V vs S.C.E.) of primarily ligand oxidation origin. When X = NO 2 − and SCN − this couple is irreversible [ E pa = 0.88 V (NO 2 − ); E pa = 1.00 V (SCN − )]. A linear spectroelectrochemical correlation has been obtained between the ligand field strength of the axial ligands and the Cathodic Peak Potential for the Co III -Co II couple.
Shuchang Lin - One of the best experts on this subject based on the ideXlab platform.
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Indirect measurement of brucine by adsorptive stripping voltammetry at mercury electrode.
Talanta, 1995Co-Authors: Shuchang LinAbstract:After reaction with nitric acid, brucine can be transformed into cacotheline, and then measured indirectly by adsorptive stripping voltammetry. This method is based on the adsorptive accumulation of cacotheline at a hanging mercury drop electrode, followed by Cathodic linear sweep voltammetry. The Cathodic Peak Potential is about −0.35 V (vs. saturated AgAgCl). The detection limit of 2.0 × 10−9 M is obtained under optimized conditions. The electrochemical behaviour of cacotheline and the mechanism of the electrode reactions are discussed.
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Indirect Determination of Strychnine by Adsorptive Stripping Voltammetry
Analytical Letters, 1995Co-Authors: Shuchang LinAbstract:Abstract After reacted with nitric acid, strychnine can be transformed into dinitrostrychnine, and then measured by adsorptive stripping voltammetry. This method is based on the adsorptive accumulation of dinitrostrychnine at the hanging mercury drop electrode, followed by Cathodic linear sweep voltammetric determination. The Cathodic Peak Potential is about -0.28 V (vs. Saturated Ag/AgCl). The detection limit of 4.0×10−9 M is obtained under optimized condition. The electrochemical behaviour of dinitrostrychnine and the mechanism of electrode reaction were discussed.
R. Rajavel - One of the best experts on this subject based on the ideXlab platform.
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Redox Behavior and DNA Cleavage Studies of Copper (II) Schiff Base Complex Derived From 2-Aminobenzaldehyde
Asian Journal of Research in Chemistry, 2010Co-Authors: P. Jayaseelan, S. Prasad, R. RajavelAbstract:The tetradentate Schiff base ligand was prepared by condensation of 2-aminobenzaldehyde with o-phenylenediamine. The synthesized complex has been studied by using cyclic voltammetry and DNA cleavage studies. The resulting voltammogram consists of a single quasi-reversible one electron transfer attribute to couple [Cu(II)L]/[Cu(I)L]. Trends in Cathodic Peak Potential (Epc) values are observed which can be correlated with electron effects of Schiff base ligand, changes with basis of liquid groups are determinant for electrochemical trends. The interaction of Cu(II) complex with Calf Thymus DNA has been studied by using absorption, viscosity and cyclic voltammetry. Cyclic voltammetry studies reveal that the complex prefer to bind to DNA in Cu(II) rather than(I) oxidation state.
Toyohiko Nishiumi - One of the best experts on this subject based on the ideXlab platform.
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Voltammetric Potentials of polyaniline varying with electric percolation
Electrochimica Acta, 2010Co-Authors: Han Chen, Fumihiko Kawaguchi, Koichi Aoki, Jingyuan Chen, Toyohiko NishiumiAbstract:The reduction of the emeraldine form of polyaniline film into leucoemeraldine, which corresponds to the conversion of an electric conductor into an insulator, shifted in the positive direction with increasing scan rate and film thickness. Similar dependence was found in the diffusion-controlled voltammograms of dispersed polyaniline latex particles with eight diameters ranging from 0.2 to 7.5 μm. The particles were synthesized by coating dispersed polystyrene latex with polyaniline. These variations were explained in terms of electric percolation of the conducting species to the electrode. The theoretical expression for the Nernst equation was derived on the assumption that the percolated and the un-percolated conducting species took inner Potentials of the electrode and the solution phase, respectively. The conducting species does not participate in the determination of the equilibrium Potential, though it participates in the Faradaic current. The Cathodic Peak Potential shifted in the negative direction with an increase in particle size, solution viscosity, and film thickness, as predicted from the derived Nernst equation.
Antonio Decinti - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical studies of copper(II) complexes with Schiff-base ligands
Polyhedron, 2002Co-Authors: Santiago Zolezzi, Evgenia Spodine, Antonio DecintiAbstract:Abstract The electrochemical reduction of copper(II) complexes with salen Schiff-base ligands derived from ethylenediamine or (R,R) or (S,S)-1,2-diphenylethylenediamine and 5-methoxy, 5-bromo and 5-nitrosalicylaldehyde have been studied by cyclic voltammetry in the Potential range +1 to −2.3 V in dimethyl sulfoxide (DMSO) as a solvent. The resulting voltammograms consist of a single quasi-reversible one-electron transfer attributable to the couple [Cu(II)L]/[Cu(I)L]−. Trends in Cathodic Peak Potential (Epc) values are observed which can be correlated with the electronic effects of the 5-substituents of the Schiff-base ligands. Changes in the basicity of the ligand groups are determinant for such electrochemical trends.