141 research outputs found
Electron transfer and CO addition to polynitrido cobalt carbonyl clusters: Parallel pathways for conversion of the [Co10N2(CO)(19)](4-) anion to the novel [Co11N2(CO)(21)](3-) anion
The redox aptitude of the dinitrido anion [Co10N2(CO)19]4- has been tested from both chemical and electrochemical points of view, together with its reactivity toward CO that induces disproportionation. In any case, through a remarkable overlapping of intermediate steps, the new anion [Co11N2(CO)21]3- (4) is eventually obtained. A detailed study of the pathways to 4 allowed the identification of three labile intermediates by their characteristic IR spectra as well as their electrochemical and paramagnetic properties. The unprecedented structure of trianion 4 has been studied in details in two different crystalline salts
The Competition Between Chemistry and Biology in Assembling Iron–Sulfur Derivatives: Molecular Structures and Electrochemistry. Part VI. {[Fe 4 S 4 ](S γ Cys ) 3 (nonthiolate ligand)} Proteins
2noWithin a couple of years we have planned to systematically update structure/electrochemistry of the different classes of metalloproteins harboring iron–sulfur clusters. In this picture we have so far dealt with {Fe(Cys)4}, {[Fe2S2](Cys)4}, {[Fe2S2](Cys)3(X)} (X = Asp, Arg, His), {[Fe2S2](Cys)2(His)2}, {[Fe3S4](Cys)3}, and {[Fe4S4](Cys)4} cores. Since a significant number of structurally characterized [4Fe–4S] proteins harbor {[Fe4S4](SγCys)3(nonthiolate ligand)} iron–sulfur centers, the aim of the present review paper is to complement our paper review on {[Fe4S4](Cys)4} cores with structure and electrochemistry of {[Fe4S4](SγCys)3(nonthiolate ligand)} proteins in order to gain a panoramic overview of the state-of-the-art of structure/electrochemistry of all the [4Fe–4S] proteins (excluding obviously those proteins which harbor mixed iron–sulfur clusters such as [4Fe–4S] + [2Fe–2S], [4Fe–4S] + [3Fe–4S], [4Fe–4S] + [3Fe–4S] + [2Fe–2S], and [4Fe–4S] + [3Fe–4S] + [4Fe–3S]).nonemixedZanello, Piero; Corsini, MaddalenaZanello, Piero; Corsini, Maddalen
Solvent effects on the redox potential of the uranium(VI)?uranium(V) couple
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
Endohedral Metallofullerenes Today: More and More Versatile Ships in Multiform Bottles-Electrochemistry of X-Ray Characterized MonometallofullerenesAdvances in Organometallic Chemistry and Catalysis
Endohedral Metallofullerenes Today: More and More Versatile Ships in Multiform Bottles—Electrochemistry of X-Ray Characterized Monometallofullerene
The competition between chemistry and biology in assembling iron-sulfur derivatives. Molecular structures and electrochemistry. Part IV. [Fe3S4](SγCys)3 proteins
Iron-sulfur clusters are ubiquitous and evolutionary ancient prosthetic groups which participate in electron transfer processes of crucial biological interest. In view of such a significant aspect we aimed to update their structure and electrochemistry. In this picture, after having reviewed Fe(SγCys)4 rubredoxins (Coord. Chem. Rev., 257 (2013) 1777–1805), [Fe2S2](SγCys)4 ferredoxins (Coord. Chem. Rev., 280 (2016) 50–83) and Rieske [Fe2S2](SγCys)2(His)2 ferredoxins (Coord. Chem. Rev., 306 (2016) 420–442), we will now deal with [3Fe-4S] proteins. As usual, we will also deal with the synthetic analogues of the related iron-sulfur clusters
Conoscere la Chimica. Fondamenti di Chimica Generale e Inorganica con elementi di Organica
Oxidation and reduction behavior of copper(II) complexes with open-chain analogs of tetraaza macrocycles
Electrochem. methods were used to study the redox behavior of the Cu(II) complexes of H2N(CH2)nNH(CH2)mNH(CH2)nNH2 (n, m = 2, 3) in MeCN. Cu(III) complexes persisted in soln. only on the time-scale of the cyclic voltammetry expt., whereas fairly stable Cu(I) complexes were obtained with both the shortest- and longest-chain ligands studied. Electrode potentials for both the Cu(III) → Cu(II) and Cu(II) → Cu(I) redox reactions were compared with those reported for the corresponding complexes with macrocyclic tetraamines
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