Mo2O3Cl4(Pyridin)4 · CH2Cl2 Synthese, IR‐Spektrum und Kristallstruktur

El-Essawi, Mohyi M.; Weller, F.; Stahl, K.; Kersting, Meinolf; Dehnicke, Kurt

doi:10.1002/zaac.19865421123

Cited by 9 publications

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References 13 publications

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“…When adding the Mo−O−Mo multiple scattering path (Figure S-14, left, B), the “focusing-effect” within this pathway drastically enhances the multiple scattering contribution and introduces a complex oscillation pattern. Also, a distinct peak appears at ∼3.3−3.4 Å in the Fourier-transform, corresponding to the Mo−O−Mo distance ∼3.7 Å for a linear entity, as in the crystal structure of [Mo 2 O 3 Cl 4 (py) 4 ]·CH 2 Cl 2 . Such an FT peak is not observed for component I (see Figure S-10a).…”

Section: Resultsmentioning

confidence: 87%

Structural Characterization of Molybdenum(V) Species in Aqueous HCl Solutions

et al. 2007

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Mo(V) aqua-chloro complexes in hydrochloric acid solutions have been studied by means of Mo K- and L2,3-edge X-ray absorption and Raman spectroscopic methods. The solid compounds (HPPh3)2[MoOCl5] (1), 6[MoOCl4(H2O)]-.10(pyH)+.4Cl- (2), and (pyH)2[Mo2O4Cl4(trans-OH2)2] (3) were used for structural comparisons. The compound 2 crystallizes in the orthorhombic space group Pmma (no. 51) with a=21.398(3), b=8.057(4), c=13.330(4) A, and Z=4. In 0.2 M solutions of MoCl5 in 7.4-9.4 M HCl the mononuclear [MoOCl4(OH2)]- complex dominates with the bond distances Mo=O 1.66(2) A, Mo-Cl 2.38(2) A, and Mo-OH2 2.30(2) A. Its Raman band at 994 cm-1 for the Mo=O symmetric stretching vibration is closer to that of 2 (988 cm-1) than of 1 (969 cm-1). The Mo K-edge EXAFS spectrum for 0.2 M MoCl5 in 1.7 M HCl solution reveals a dinuclear [Mo2O4Cl6-n(OH2)n]n-4 (n=2, 3) complex with a double oxygen bridge and the average distances Mo=O 1.67(2) A, Mo-(mu-O) 1.93(2) A, Mo-Cl 2.47(3) A, Mo-Mo 2.56(2) A, and a short Mo-OH2 distance of 2.15(2) A, which implies that at least one of the aqua ligands is in equatorial position relative to the two axial Mo=O bonds. This position differs from the Mo-OH2 configuration exclusively trans to the M=O groups of the isomeric (with n=2) dinuclear complex in 3. The difference in the ligand field is also reflected in their L2,3-edge XANES spectra. For 0.2 M MoCl5 solutions in intermediate HCl concentrations (3.7-6.3 M) the Raman bands at 802 cm-1 (Mo-O-Mo) and 738 cm-1 (Mo-(mu-O)2-Mo) verify three coexisting classes of Mo(V) complexes: mononuclear complexes together with dinuclear mono-oxo (e.g., [Mo2O3Cl6(H2O)2]2-) and dioxo bridged species, even though principal component analysis (PCA) of the corresponding series of EXAFS spectra only could distinguish two major components. By fitting linear combinations of the appropriate EXAFS oscillation components, dioxo-bridged dinuclear complexes were found to dominate at HCl concentrations

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Section: Resultsmentioning

confidence: 87%

Structural Characterization of Molybdenum(V) Species in Aqueous HCl Solutions

et al. 2007

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ChemInform Abstract: Mo2O3Cl4(Pyridine)4·CH2Cl2. Synthesis, IR Spectrum, and Crystal Structure.

et al. 1987

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Pyrazine‐Assisted Dimerization of Molybdenum(V): Synthesis and Structural Characterization of Novel Dinuclear and Tetranuclear Complexes

2010

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12 pagesInternational audienceReactions of pyrazine (Pyz = C4H4N2) with [MoOCl4(H2O)]– or [MoOBr4]– afforded a series of complexes, dinuclear [(MoOX4)2(Pyz)]2– (X = Cl, Br), [{MoOCl3(Pyz)}2O]2– and tetranuclear [(Mo2O4Cl4)2(Pyz)2]4– anions, with N-donor ligands engaged either in monodentate or bidentate bridging coordination. A dinuclear [(MoOX4)2(Pyz)]2– ion, which may be viewed as a linkage of two mononuclear subunits with a bidentate pyrazine, crystallizes either as a PyH+ (pyridinium cation, C5H5NH+; compound 1), a {(C2H5)4N}+ (compound 2) or a {(C6H5)4P}+ salt (compounds 3 and 4). In (PyH)2- [{MoOCl3(Pyz)}2O] (5) with an anti-{Mo2O3}4+ core, pyrazine is bound to the metal through only one nitrogen atom. The tetranuclear [(Mo2O4Cl4)2(Pyz)2]4– ion, a linkage of two metal–metal bonded {Mo2O4}2+ cores with a pair of bidentate pyrazines, is found in two compounds, (MeNC5H5)2(PyzH2)- [(Mo2O4Cl4)2(Pyz)2] (6) [MeNC5H5 + = N-methylpyridinium cation, PyzH2 2+ = pyrazinium(2+) cation] and (PyH)4- [(Mo2O4Cl4)2(Pyz)2]·2CH3CN (7). In the presence of methanol, dinuclear {(C6H5)4P}2[(MoOBr4)2(Pyz)]·2CH3CN (4) was transformed directly into tetranuclear (PyH)4[(Mo2O4Br4)2- (Pyz)2]·2CH3CN (8). All compounds were fully characterized by X-ray crystallography and IR spectroscopy. The compounds containing the [(MoOX4)2(Pyz)]2– ions display an irreversible electrochemical reduction behaviour. Temperature- dependent magnetic measurements on {(C6H5)4P}2- [(MoOX4)2(Pyz)]·2CH3CN (X = Cl for 3, X = Br for 4) reveal a weak ferromagnetic coupling across the pyrazine bridge between a pair ofMoV S = 1/2 spins. The magnetic properties of {(C2H5)4N}2[(MoOCl4)2(Pyz)] (2), another compound with dinuclear complex anions, are dominated by antiferromagnetic intermolecular interactions

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Mo₂O₃Cl₄(Pyridin)₄ · CH₂Cl₂ Synthese, IR‐Spektrum und Kristallstruktur

Cited by 9 publications

References 13 publications

Structural Characterization of Molybdenum(V) Species in Aqueous HCl Solutions

Structural Characterization of Molybdenum(V) Species in Aqueous HCl Solutions

ChemInform Abstract: Mo2O3Cl4(Pyridine)4·CH2Cl2. Synthesis, IR Spectrum, and Crystal Structure.

Pyrazine‐Assisted Dimerization of Molybdenum(V): Synthesis and Structural Characterization of Novel Dinuclear and Tetranuclear Complexes

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