1,721,062 research outputs found
Oxidation and reduction behavior of copper(II) complexes with open-chain analogs of tetraaza macrocycles
No full textElectrochem. 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
The competition between chemistry and biology in assembling iron-sulfur derivatives. Molecular structures and electrochemistry. Part IV. [Fe3S4](SγCys)3 proteins
No full textIron-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
Oxidation and reduction of copper(II) complexes with saturated polyaza macrocycles of varying size and denticity
No full textThe oxidn. and redn. of Cu(II) complexes with the tetra- and pentadentate amine macrocycles I (n-n2 = 0, 1) and II (n-n2 = 0; n = 1, n1 ≠ n2 = 1, 0) in CH3CN were studied by electrochem. methods. The redox changes Cu(III) → Cu(II) and Cu(II) → Cu(I) were detected through cyclic voltammetry at high potential scan rates. The half-wave potentials are discussed in terms of the properties and structural features of the macrocyclic ligands
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
No full textWithin 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])
X-ray structure and density functional theory studies of an unexpected product: trans-bis{2-[(2-cyanoethyl)iminomethyl]phenolato}copper(II)
No full textThe title compound, [Cu(C(10)H(9)N(2)O)(2)] or [Cu(II)(CYMB)(2)], (I), was obtained in an attempt to reduce trans-bis(2-{[3,5-bis-(trifluoromethyl) phenyl] iminomethyl} phenolato) copper(II), [Cu(TIMB)(2)], (II), with bis(pentamethylcyclopentadienyl)-cobalt(II) [decamethylcobaltocene, Cp*(2)Co, (III)]. The molecular structure of (I) has the Cu(II) centre located on an inversion centre of the C2/c space group. A density functional theory (DFT) analysis at the B3LYP/Lanl2dz(CuF); 6-31G**(CHNO) level performed in order to optimize the structures of the free ligands CYMB(-) and TIMB(-), and the metal complexes [Cu(I/II)(CYMB)(2)](-/0) and [Cu(I/II)(TIMB)(2)](-/0), reproduced well the X-ray diffraction structure and allowed us to infer the insertion of the cyanomethide anion on the 3,5-bis(trifluoromethyl) phenyl system from an evaluation of the Mulliken atomic charges and the electronic energies
Electrochemistry of the metallo-bisfullerene [Mo(eta(2)-C-60)(2)(CO)(2)(dbc-bipy)] (dbc-bipy=4,4 '-di(butylcarboxyl)-2,2 '-bipyridine)
No full textElectrochemical 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
Inorganic Electrochemistry. Theory, Practice and Application, 2nd Edition
No full textIn order to understand the basic aspects of an electrochemical investigation on inorganic molecules (in its widest meaning, of any molecule which contains at least one metal centre) it must be taken into account that in these molecules the metal-ligand bonds are of the prevailingly covalent type. Since electrochemical techniques allow you to add or remove electrons in a controlled manner, it is conceivable that the addition or removal of electrons inside these molecules can lead to the formation of new bonds or to the breakage of existing bonds. The main aim of this book is to study the effects of such electron addition and removal processes on the molecular frames.
The second edition of this classic book has been fully revised and updated and is a straightforward, logical introduction to electrochemical investigations for inorganic chemists. All chapters have been rewritten with new material including:
- the addition of reactivity with nitric oxide to the chapter on the reactivity of metal complexes with small molecules
- thiolate-protected gold nanoclusters has been added to the chapter on metal-sulfur and metal-carbonyl clusters
- a new chapter on the digital simulation of electrochemical responses
- a new chapter on the theoretical calculations to explain the nature of the electrochemical activity of metal complexes
- new chapters on spectroelectrochemistry and electrochemiluminescence.
The book covers every aspect of inorganic electrochemistry - the introduction is followed by chapters on the basic aspects of electrochemistry followed by practical and applicative aspects and ends with full appendices. It is probably the only publication with a simple approach to electrochemical aspects of the topics in inorganic chemistry.
Bridging the gap between undergraduate and research-level electrochemistry books, this publication will be a welcome addition to the literature of inorganic chemists. It will also be particularly useful to final year students in chemistry and as background reading for graduates and researchers without adequate electrochemical knowledge to become active in the discipline or who want to collaborate with electrochemists
Mononuclear Metallacarboranes of Groups 6-10 Metals. Analogues of Metallocenes: Electrochemical and X-Ray Structural Aspects
No full textMetallacarboranes containing carborane ligands possessing a pentagonal open face can coordinate metal atoms in a η5-manner quite similar to the cyclopentadienyl monoanion, thus affording metallocene analogues. By virtue of such an analogy, their electron transfer aptitude plays an important role in their physico-chemical characterisation. We review such an aspect, also providing evidence for the structural consequences of their electron transfer processes.
At variance with metallocenes, electrochemical investigations on the metallacarboranes have not yet become a routine tool to search for their potential application in fields which require electronic mobility
Magnetic and redox properties in hydroxo- and alkoxo-bridged Fe(III) binuclear complexes: A density functional study
No full textDFT calculations were carried out in order to deduce the dependence of magnetic coupling on the structure of doubly hydroxide/alkoxide-bridged diiron(III) dimers. The broken-symmetry formalism was employed to calculate the magnetic exchange parameter J. The potential surfaces of the ground state display a geometrical minimum at an Fe[BOND]O(H)[BOND]Fe angle of 105° and Fe Fe distance of 3.2 Å, in good agreement with experimental values. The calculated correlation between the magnetic coupling with the geometrical structure agrees well with the experimental literature data, although always overestimated. Electrochemical measurements show that a one-electron reduction is likely to cause dissociation into pseudooctahedral, monomeric subunits, and, consequently, no calculations were made for the reduced dimeric specie
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