[en] Binuclear molybdenum(0) carbonyl complexes were synthesized based on naphthophosphacyclophanes containing a 1,6-dihydroxynaphthalene fragment and diethylamide linkers. The physicochemical and spectral characteristics of the synthesized coordination systems were studied.

No abstract available

[en] Mo²O⁴Cl²(X-py)⁴.2H²O and (X-pyH)⁴[Mo²O⁴(NCS)⁶].H²O have been prepared. The infrared, electronic and reflectance spectra, molar conductances and magnetic susceptibility data of complexes are reported. Mo²O⁴Cl²(X-py)⁴.2H²O(X-py were 3- and 4-cyanopyridine, nicotinamide, 3,5-lutidine and 2-amino-4-picoline) were obtained by hydrolysis of the corresponding substituted pyridinium oxopentachloromolybdates (V). Addition of water and substituted pyridines to molybdenum(V0-thiocyanate ethylacetate extract yield brown compounds, (X-pyH)⁴[Mo²O⁴(NCS)⁶].H²O where X-py were pyridine, α-picoline, 3-bromopyridine 3,5-lutidine, 3-benzoyl-pyridine and 4-acetylpyridine. Binuclear, Mo²O⁴Cl²(X-py)⁴.2H²O prepared from hydrolysis of (X-pyH)²[MoOCl⁵].H²O were diamagnetic and nonelectrolytes. The anion of (X-pyH)⁴[Mo²O⁴(NCS)⁶].H²O was formulated as dimer and electrolyte. (Author)

[en] Equilibria of Mo(6) in acid aqueous solutions with excess of 2,3-dihydroxynaphthalene (DHN) c_DHN/c_Mo = 2,3 - 107(I = 0,6 mol l^-1(NaClO₄), 0,6% v/v ethanol) were studied spectrophotometrically. Formation constants of MoO₂R₂^2-(logK₀₁₂ = 5,89 ± 0,01) and presumed MoO₂(OH)(OH₂)R^-(logK₁₁₁ = 7,79 ± 0,01) chelates were evaluated using SQUAD-G program. (Authors)

[en] Green crystalline salts of substituted pyridinium oxopentachloromolybdates (V) were obtained from concentrated hydrochloric acid solution of molybdenum (V)-thiocyanate extract. MoOCl₃(X-py)₂(X-py were 4-and 3-cyanopyridine, 2-amino-4-picoline and 4-acetylpyridine) were obtained by reflux of the corresponding substituted pyridinium salts of oxopentachloromolybdates (V) in absolute ethanol. (X-pyH)₂[MoOCl₅].H₂O containing the NoOsup(3+) group are dissolved and hydrolysed in water but MoOCl₃ (X-py)₂ are insoluble in water, alcohol and acetone. The complexes are paramagnetic compounds. (Author)

[en] A method for the extractive separation of molybdenum has been developed based on the extraction of the Mosup(VI)-10-phenanthroline complex into isobutyl methyl ketone. Under appropriate conditions Wsup(VI), Crsup(III), Crsup(VI), Usup(VI), Vsup(V), Thsup(IV), Zrsup(IV), Sesup(IV), Bisup(III), Fesup(II), Fesup(III), Cosup(II), Cosup(II), Nisup(II), Mnsup(II), Mgsup(II), Cusup(II), Pbsup(II), Znsup(II) and Pdsup(II) do not interfere. The ratio of metal:ligand in the complex was found to be 1:4 by conductimetric titration. The method compares favourably with existing methods for the extractive separation of molybdenum. (author)

No abstract available

[en] The chemical behavior for Mo(0) and W(0) complexes, (M(CO)₂(PPH₃)₄) (M=Mo and W), has been investigated by UV-vis spectroscopic, magnetic, and electrochemical methods. Three absorption bands are observed in the UV-spectra. The crystal-field-splitting energy, spin-pairing energy, and bond strengths were deduced from the spectra. The metal d electrons in both complexes seemed to be delocalized in low-spin state. Metal ligand correlation appeared to strongly depend on bond strengths and diamagnetic properties. In electrochemical processes, both complexes exhibit an irreversible reduction wave

[en] Regularities of tungsten(6) extraction by the salts of amines and quaternary ammonium compounds from low-acid and alkaline solutions and regularities of molybdenum and tungsten separation, using different extractants, were considered

[en] Short communication. 3 refs