Molybdenum complexes electrochemistry

Electrochemical methods have been extensively used to characterize model oxo-molybdenum compounds (Sections IV and V). Electrochemistry provides a convenient method for generating reactive molybdenum complexes in situ (see Sections V.B and C) and for investigating the reaction rates and possible reaction mechanisms of transient molybdenum complexes. 

A1 Obaidi, N., Beer, P.D., Bright, J.P., Charsley, S.M., Jones, C.J., McCleverty, J.A., and Salam S.S. (1986) "Ilie synthesis and electrochemistry of novel redox-responsive molybdenum complexes containing cyclic polyether cation binding sites, J.Chem.Soc.Chem.Comm., 239-41 Beer, P.D., Jones, C.J., McCleverty, J.A. and Salam, S.S. (1987) Redox-responsive metal complexes containing cation binding sites, JJncl.Phenom., 5, 521-4. 

N-Donor Ligands. The full account of the crystal structure of [Mo02(8-hydroxyquinolate)2] has been published. The dimensions of the M0O2 unit are O—Klo—O = 104.C and Mo—O = 171(2) pm. The electrochemistries of this and the related molybdenum(v) complex. [ MoO(8-hydroxyquino-late)2 2 0], have been investigated as simple models of molybdenum-fluoro-protein enzymes (p. 146). Reduction of the molybdenum(vi) complex occurs in two one-electron steps with solvent attack of the reduced intermediates and displacement of the 8-hydroxyquinolato-groups. ... 

The electrosynthesis of hydride complexes directly from molecular hydrogen at atmospheric pressure by reduction of Mo(II) and W(II) tertiary phosphine precursors in moderate yield has been described as also the electrosynthesis of trihydride complexes of these metals by reduction of M(IV) dihydride precursors [101,102]. Hydrogen evolution at the active site of molybdenum nitrogenases [103] is intimately linked with biological nitrogen fixation and the electrochemistry of certain well-defined mononuclear molybdenum and tungsten hydrido species has been discussed in this context [104,105]. 

Cyclic voltammetry and controlled-potential electrolysis are the techniques that have been used to investigate the electrochemistry of oxo-chromium and oxo-molybdenum corrolates. The data have been related to those obtained for similar porphyrin complexes. Redox potentials are reported in Table 17. 

Data on the redox potentials of germylenes, stannylenes, plumbylenes and their complexes are scarce. In fact, only the electrochemistry of dihalogermylenes, dihalostan-nylenes and their complexes with Lewis bases338 as well as with chromium, molybdenum and tungsten pentacarbonyles339 has been studied. 

Because of their properties they are widely used in electrochemistry, in electrophotography, as well as in photocatalysis and photochemical water cleavage. Thus Hennig and Rehorek in 1986 reported the sensitization of photochemical reactions by Prussian blue analogues of molybdenum octacyanide, and Kaneko and his group in 1984 found that water can be photolyzed with visible light in presence of Pmssian blue and tris (2, 2 -bipyridine) ruthenium (II) complex. 

CHEMISTRY AND ELECTROCHEMISTRY OF ALKYNE- AND ISOCYANIDE-DERIVED CARBYNE COMPLEXES OF RHENIUM, MOLYBDENUM OR TUNGSTEN... 

The reduction of various substrates (N2 RCN, RNC, CN% N03 ) by metalloenzymes with molybdenum-sulfur sites (nitnogenase, nitrate reductase) has prompted active studies of the chemistry and electrochemistry of complexes with Mo-S assemblies which could mediate or catalyse the reduction of these substrates. 

Dinitrogen binding and electrochemistry in complexes of molybdenum and tungsten... 

Key words Molybdenum, nitrosyl, pyrazolylborate, electrochemistry, cyclic polyether, complexation, sodium, potassium. 

Thus, on the basis of the spectral data alone we cannot draw a conclusion concerning the preferable dissolution order of the above mentioned elements. However, the absence of absorption peaks of MoClg , NiCl4 , TiCls " complex ions indicates that these elements do not transfer to the electrolyte during the anodic dissolution of steel. This was also confirmed by the results of the chemical analysis of melt samples. From the electrochemistry point of view, the fact that electropositive nickel [30] and molybdenum [31] remain in the anode material points to the electrochemical nature of the corrosion process. The results of the spectroscopy measurements and chemical analysis were confirmed by X-ray microanalysis - the electrode surface after 2 h of anodic dissolution was slightly depleted in iron and chromium and was enriched in nickel. 

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