Ueber Kobaltimolybdate

Friedheim, Carl; Keller, Fabian

doi:10.1002/cber.190603904133

Cited by 10 publications

(6 citation statements)

References 3 publications

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“…24 Crystal structures of 1 and 2 Single-crystal X-ray crystallographic analyses reveal that the heteropolymolybdate ĳCo 2 Mo 10 H 4 O 38 ] 6− in compounds 1-4 is a typical Evans-Showell type polyoxoanion. The polyoxoanion ĳCo 2 Mo 10 H 4 O 38 ] 6− was first prepared by Friedheim and Keller in 1906, 25 and was structurally determined as its ammonium salt by Evans and Showell in 1969. 15 The structure of ĳCo 2 Mo 10 H 4 O 38 ] 6− can be deduced from the planar Anderson ion ĳCoMo 6 H 6 O 24 ] 3− by removing one {MoO 5 } group from each of two ĳCoMo 6 H 6 O 24 ] 3− ions, turning one ~45°around the anionic equatorial plane and joining them so that the two CoO 6 octahedra share an edge.…”

Section: Synthesismentioning

confidence: 99%

Temperature-induced racemic compounds and chiral conglomerates based on polyoxometalates and lanthanides: syntheses, structures and catalytic properties

Wang

et al. 2015

CrystEngComm

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By controlling the reaction temperatures, four new architectures based on Evans-Showell type polyoxometalate, ĳLnĲH 2 O) 5 ]ĳLnĲH 2 O) 7 ]ĳCo 2 Mo 10 H 4 O 38 ] 6H 2 O (Ln = Sm 1; Eu 2), and (NH 4 ) 3 [Ln(H 2 O) 6 ] [Co 2 Mo 10 H 4 O 38 ] 6H 2 O (Ln = Sm 3; Eu 4) have been synthesized and characterized by elemental analysis,IR spectroscopy, TG analysis, solid diffuse reflective spectrum, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 are racemic compounds, obtained at the higher temperature (85°C). They show a 1D ladderlike structure constructed from left-handed chain and right-handed chain linked by lanthanide cations, which represent the first 1D self assembly based on Evans-Showell type polyoxometalate. When the reaction temperature was decreased to room temperature (25°C), two chiral species 3 and 4 were obtained, showing a mono-supporting structure composed of one [Co 2 Mo 10 H 4 O 38 ] 6− polyoxoanion and one [Ln(H 2 O) 6 ] 3+ unit. They crystallize in the chiral space group P2 1 , as conglomerates of two enantiomerically pure crystals. Their absolute configuration were determined by the Flack parameters and solid state circular dichroism spectroscopy. The structural differences between 1(2) and 3(4) reveal that the reaction temperature is the key factor controlling the products from racemic compounds to conglomerates. Four compounds 1-4 acted as Lewis acid-base catalysts through a heterogeneous manner to catalyse cyanosilylation with excellent efficiency.

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Section: Synthesismentioning

confidence: 99%

Temperature-induced racemic compounds and chiral conglomerates based on polyoxometalates and lanthanides: syntheses, structures and catalytic properties

Wang

et al. 2015

CrystEngComm

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“…Even if interest in compounds based on Anderson structure is maturing in the literature, only a few works deal with the dimeric HPA Co 2 Mo 10 O 38 H 4 6-, this anion being always associated with the ammonium countercations. Friedheim and Keller 10 first showed that a secondary product with the ratio Co/Mo ) 0.5 is formed during the synthesis of the ammonium salt of CoMo 6 O 24 H 6 4from a solution containing cobalt(II), AHM, and an oxidizing agent. Tsigdinos 11 12 However, these authors specify that from the initial solution two crystallographic forms of ammonium salts are obtained simultaneously, namely, form A and form B, and only the latter form was crystallographically investigated.…”

Section: Introductionmentioning

confidence: 99%

Evidence and Characterization of a New Decamolybdocobaltate Cobalt Salt: An Efficient Precursor for Hydrotreatment Catalyst Preparation

et al. 2005

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Heteropolyanions (HPAs) based on molybdenum and cobalt could be used as an alternative to the conventional ammonium heptamolybdate and cobalt nitrate precursors for the preparation of Co−Mo/Al2O3 hydrotreating catalysts. With this objective in mind, a cobalt salt of decamolybdocobaltate anion has been synthesized. This salt allows us to prepare catalyst with a Co/Mo atomic ratio of 0.5 corresponding to the optimum value encountered with classical catalyst preparation. The crystal structure refinement has been performed and reveals the formation of a new heteropolyoxomolybdate related to the well-known Anderson structure. Its structural, spectroscopic, and thermal properties have been investigated by physical techniques such as thermogravimetric analysis mass spectroscopy, X-ray diffraction, X-ray absorption spectroscopy, and vibrational spectroscopy. With the use of this new HPA precursor, initial catalytic results show a significant improvement of hydrodesulfurization catalytic performance.

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“…The support was preliminary loaded with various amounts of cobalt using the aqueous solution of Co(NO 3 ) 2 , in order to increase the ratio Co/Mo = 0.09 occurring in the initial salt (NH 4 ) 3 Co(OH) 6 [17]. Impregnation with the salt was also performed in a vacuum evaporator at 70°C then the impregnated support was dried 4 h at 105°C and calcined 2 h at 350°C.…”

Section: Catalyst Preparationmentioning

confidence: 99%

Effect of Co on HDS Activity of Alumina-supported Heteropolymolybdate

et al. 2010

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The hydrotreating CoMo/c-Al 2 O 3 catalysts (12 wt% Mo and 0.7-5.0 wt% Co) have been prepared by impregnation. The CoMo catalysts obtained from Anderson heteropolyoxomolybdate (NH 4 ) 3 [Co(OH) 6 Mo 6 O 18 ]Á 7H 2 O has been investigated by nitrogen physisorption, XRD, UV-Vis DRS, FT-IR, and TPR. The results are discussed in relation to the catalytic activity for the thiophene and 1-benzothiophene reactions. The influence of Co content on both the phase composition and catalytic activity in the HDS reactions has been shown. The effect of Co on the activity in the HDS reactions depends on its previously loaded amount. It is the most pronounced with the catalyst having Co/Mo ratio equal to 0.27.

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Ueber Kobaltimolybdate

Cited by 10 publications

References 3 publications

Temperature-induced racemic compounds and chiral conglomerates based on polyoxometalates and lanthanides: syntheses, structures and catalytic properties

Temperature-induced racemic compounds and chiral conglomerates based on polyoxometalates and lanthanides: syntheses, structures and catalytic properties

Evidence and Characterization of a New Decamolybdocobaltate Cobalt Salt: An Efficient Precursor for Hydrotreatment Catalyst Preparation

Effect of Co on HDS Activity of Alumina-supported Heteropolymolybdate

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