Complexes of magnesium(II) and other divalent metal ions with adenosine 5′-triphosphate and 2,2′-dipyridylamine in aqueous solution

Binary and ternary systems involving adenosine 5′-triphosphate (ATP), 2,2′-dipyridylamine (DPA) and magnesium, calcium, strontium, manganese, cobalt, copper, and zinc(II) metal ions have been investigated in aqueous media by potentiometric titrations. The analysis of the titration curves shows the existence of M(ATP)2−, M(ATP)(H)−, and M(ATP)2(H)24− species for alkaline-earth metal ions, while no ternary complex can be detected. For transition metal ions both binary and ternary species are found. Binary M(ATP)2(H)24− complexes are present in solutions containing manganese and cobalt(II) metal ions but these species cannot be revealed in the case of copper and zinc(II). Ternary complexes as M(ATP)(DPA)2− and M(ATP)(DPA)(H)− are common to all transition metals. Binuclear and hydroxo complexes as M2(ATP)(OH)− and M(ATP)(OH)3− are found only for copper and zinc(II). A hypothesis on the possible role of the species M-ATP in 1:2 ratio in the dephosphorylation mechanism is advanced on the basis of a comparison between the equilibrium data in the solution phase and the solid state structures of the magnesium, calcium, and manganese(II)- ATP-DPA systems

Electrochemical investigations on pentagonal bipyramidal complexes of manganese(II), iron(II), and cobalt(II) with a heptadentate Schiff-base ligand in non-aqueous solvents

The voltammetric properties of the complexes formed by manganese(II), iron(II), and cobalt(II) ions with a heptadentate Schiff-base ligand have been investigated by cyclic voltammetry and controlled-potential coulometry at mercury and platinum electrodes in acetonitrile and dimethyl sulfoxide solvents.All the species undergo a single one-electron oxidation process leading to the corresponding stable metal(III) complexes which have been isolated and characterized.The cathodic behaviour of manganese(II) and iron(II) derivatives is very similar, in that the less cathodic process occurs at nearly equal potential values, indicating that the ligand moiety is reduced rather than the metal centre. The one-electron reduction process of the cobalt(II) complex leads to the corresponding cobalt(I) derivative, stable in the electrolysis solution

Electrochemical synthesis of the N,N\u2032-ethylenebis-(monothioacetylacetominiminato)cobalt(II), copper(II), nickel(II) and zinc(II) complexes

Cobalt(II), copper(II), nickel(II) and zinc(II) complexes are synthesised via electrochemistry, by anodic polarisation of the corresponsding metal in a solution containing the ligand. The resulting complexed are then purified and characterised

Electrochemical behaviour ofcis-dichloro(arylisocyanide)(tertiaryphosphine) platinum (II) and palladium(II) complexes in an aprotic solvent

The electrochemical behaviour of neutral platinum(II) and palladium(II) isocyanide complexes has been investigated in an aprotic medium at platinum and mercury electrodes. Platinum(II) derivatives are reduced to platinum(0) species, Palladium(II) compounds give rise to palladium(0) species at room temperature, while at 0\ub0 it is possible to obtain palladium(I) compounds

Voltammetric investigations on mercury(II) and silver(I) polyamine complexes in dimethyl sulphoxide solution

he formation of mercury(II) and silver(I) complexes with polyamines in dimethyl sulphoxide solvent has been studied by anodic dissolution of mercury and silver electrodes in the presence of ethylenediamine, sym-dimethyl-ethylenediamine, NNN\u2032N\u2032-tetramethylethylenediamine, propane-1,3-diamine, and triethylenetetramine. D.c. polarography at a dropping mercury electrode, d.c. voltammetry at a solid electrode with periodical renewal of the diffusion layer, cyclic voltammetry, and controlled-potential coulometry has allowed a determination of electrode reaction orders, the complexation steps, and the stability constants of the complex species arising at the electrode surface. Short-lived species have been detected by cyclic voltammetry and the species formed in the bulk of the solution have been identified by coulometry

Electrochemistry of the metallo-bisfullerene [Mo(eta(2)-C-60)(2)(CO)(2)(dbc-bipy)] (dbc-bipy=4,4 '-di(butylcarboxyl)-2,2 '-bipyridine)

Electrochemical investigations on the dumb-bell like [Mo(η2-C60 )2 (CO)2 (dbc-bipy)] show that the two fullerene subunits undergo a sequence of slightly separated stepwise reductions. The mutual electronic interaction of the two cages, which is responsible for the separation of the sequential electron additions, is comparable with that of C120 , C121 , C120 O, C122 H4 and C120 SiPh2 , which actually are the only symmetric bis-fullerenes able to display intramolecular electronic interactions. Changing the solvent (from CH2 Cl2 to THF) causes a slight increase in the stepwise reductions exhibited by [Mo(η2-C60 )2 (CO)2 (dbc-bipy)], thus supporting a Mo-mediated through-space communication between the two fullerene moieties

Electrochemical behavior of complexes of copper(II) with 14-membered saturated tetraaza macrocycles

The electrochem. behavior of the complexes of Cu(II) with the macrocycles I (n ≠ m = 1,2) and II was studied. Both anodic and cathodic electrode processes involve complicated mechanisms; the E1/2 values for the couples [CuL]3+-[CuL]2+ and [CuL]2+-[CuL]+ (L = macrocycle) were detd. by cyclic voltammetry at high potential scan rates. Redn. and oxidn. mechanisms were studied, and the half-life of the anodically electrogenerated species [CuL]3+ was detd