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Molybdenum Complexes (molybdenum + complex)
Selected AbstractsBis(dithiolene) Molybdenum Complex that Promotes Combined Coupled Electron,Proton Transfer and Oxygen Atom Transfer Reactions: A Water-Active Model of the Arsenite Oxidase Molybdenum CenterEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2006Hideki Sugimoto Abstract Combined CEPT (coupled electron,proton transfer)/OAT (oxygen atom transfer) reactions were accomplished in (Bu4N)2[MoIVO(bdtCl2)2] (1) and (Bu4N)2[MoVIO2(bdtCl2)2] (2) complexes in aqueous media. The reaction mechanism of the CEPT reaction was analyzed electrochemically and the conversion of 1 to 2 was revealed to proceed by a two-proton two-electron oxidative process. The structural and reaction profiles provide a new model for the arsenite oxidase catalytic center. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Electrochemical Synthesis, Crystal Structure, and Photomagnetic Properties of a Three-Dimensional Cyano-Bridged Copper,Molybdenum Complex.CHEMINFORM, Issue 23 2005Toshiya Hozumi Abstract For Abstract see ChemInform Abstract in Full Text. [source] Nanoparticle Supported, Magnetically Recoverable Oxodiperoxo Molybdenum Complexes: Efficient Catalysts for Selective Epoxidation ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Sankaranarayanapillai Shylesh Abstract Organic-inorganic hybrid heterogeneous nanocatalyst systems were synthesized by covalent anchoring of oxodiperoxomolybdenum complexes [(LL)MoO(O2)2] on silica coated magnetic nanoparticles as an active, magnetically separable epoxidation catalyst. [source] Dehydrogenative Dimerization of Di- tert -butyltin Dihydride Photochemically and Thermally Catalyzed by Iron and Molybdenum Complexes,ANGEWANDTE CHEMIE, Issue 34 2009Hemant Zinn-Zinn-Bindungen entstehen in der Titelreaktion, die in hoher Ausbeute tBu2HSnSnHtBu2 liefert , entweder photochemisch, katalysiert durch den Eisenkomplex [(,5 -C5H5)Fe(CO)2Me] oder dessen Molybdän-Analogon [(,5 -C5H5)Mo(CO)3Me], oder thermisch in Gegenwart von [(,5 -C5H5)Fe(CO)(PPh3)Me] oder [(,5 -C5H5)Mo(CO)2(PPh3)Me]. [source] Molybdenum Carbonyl Complexes Bearing PN Ligands Based on 2-Aminopyridine,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2009Christina Maria Standfest-Hauser Abstract Molybdenum complexes of the general formula Mo(PN)(CO)4 containing both achiral and chiral phosphorus-nitrogen donor bidentate ligands based on 2-aminopyridine were prepared and characterized by their NMR and IR spectra. The oxidative addition of allyl bromide to Mo(PN)(CO)4 was studied with PN = N -(diisopropylphosphanyl)-2-aminopyridine (PN- iPr). X-ray structures of representative compounds were determined. The mechanism of the oxidative addition of allyl bromide to Mo(PN- iPr)(CO)4 was analyzed by DFT/B3LYP calculations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Synthesis of the First Chiral Bidendate Bis(trifluoromethyl)phosphane Ligand through Stabilization of the Bis(trifluoromethyl)phosphanide Anion in the Presence of AcetoneCHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2006Berthold Hoge Priv.-Doz. Abstract Lewis acid/Lewis base adduct formation of the P(CF3)2, ion and acetone leads to a reduced negative hyperconjugation and, therefore, limits the CF bond activation. The resulting increased thermal stability of the P(CF3)2, ion in the presence of acetone allows selective substitutions and enables the synthesis of the first example of a chiral, bidentate bis(trifluoromethyl)phosphane ligand: a DIOP derivative, [(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis(diphenylphosphane), in which the phenyl groups at the phosphorus atoms are replaced by strong electron-withdrawing trifluoromethyl groups. The resulting high electron-acceptor strength of the synthesized bidentate (CF3)2P ligand is demonstrated by a structural and vibrational study of the corresponding tetracarbonyl,molybdenum complex. The stabilization of the P(CF3)2, ion in the presence of acetone is based on the formation of a dynamic Lewis acid/Lewis base couple, (CF3)2PC(CH3)2O,. Although there is no spectroscopic evidence for the formation of the formulated alcoholate ion, the intermediate formation of (CF3)2PC(CH3)2O, could be proved through the reaction with (CF3)2PP(CF3)2, which yields the novel phosphane,phosphinite ligand (CF3)2PC(CH3)2OP(CF3)2. This ligand readily forms square-planar Pt(II) complexes upon treatment with solid PtCl2. [source] Stereoselective Synthesis of the First Chatt-Type Bis(dinitrogen)-Molybdenum(0) Complex with a Tetraphosphane LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2008René Römer Abstract The first Chatt-type Mo0 dinitrogen complex with a tetraphosphane ligand has been prepared and characterized by NMR as well as infrared and Raman spectroscopy. Importantly, the employed reaction route allows the stereospecific synthesis of this complex as trans -[Mo(N2)2(meso -prP4)] (prP4 = a tetraphos ligand with a central propylene bridge). The stereoselectivity in the reaction course is induced by the oxido-iodido-molybdenum(IV) precursor [Mo(O)I(prP4)]+ which directs both phenyl groups of the bridging P atoms of prP4 into a meso configuration. The paper establishes a general strategy to synthesize mononuclear Mo0 dinitrogen and related molybdenum complexes with multidentate phosphane ligands which has not been possible to date. Moreover, the obtained molybdenum tetraphos N2 complex should exhibit a higher thermodynamic stability in the reactions of the Chatt cycle of synthetic nitrogen fixation than the conventional bis(diphos) complexes, due to the linkage of the two diphosphane units by an alkyl bridge. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Reactions of Aminobis(phenolate)-Supported Dioxidotungsten(VI) and Dioxidomolybdenum(VI) ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2006Ari Lehtonen Abstract The dioxidotungsten(VI) and -molybdenum(VI) complexes [WO2(O2NOMe)] (1), [MoO2(O2NOMe)] (2) and [{MoO2(O2NMe)}2] (3) [O2NOMe methoxyethylamino- N,N -bis(2-methylene-4,6-dimethylphenolate) dianion, O2NMe = methylamino- N,N -bis(2-methylene-4,6-dimethylphenolate) dianion] can react with chloride sources (Me3SiCl, SOCl2) to form resultant monooxido dichloro compounds [WOCl2(O2NOMe)] (4), [MoOCl2(O2NOMe)] (5) and [MoOCl2(O2NMe)] (6), respectively. The reaction of tungsten complex yields of the mixture of cis - 4 and trans - 4, which can be separated and characterized. The reactions of analogous molybdenum complexes with Me3SiCl yield trans isomers of 5 and 6 as individual products. Reaction of dioxidotungsten complex 1 with isopropyl isocyanate was found to produce a tungsten(VI) complex [W(O2NOMe)(N- iPr)(L)] (7) (L = N,N,-diisopropylureate) with a terminal imido group and a bidentate ureate ligand. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] A Single-Source-Precursor Approach to Late Transition Metal Molybdate Materials: The Structural Role of Chelating Ligands in the Formation of Heterometallic Heteroleptic Alkoxide ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2006Pia Werndrup Abstract The synthesis and structural determination of three new heterometallic molybdenum complexes, one with cobalt and two with nickel and two of these with ,-diketonate ligands and one with amino alcohol ligands, are presented. The reaction of cobalt acetylacetonate with [MoO(OMe)4] provides [Co2Mo2O2(acac)2(OMe)10] (1) and [MoO(acac)(OMe)3] (4),and the reaction of nickel acetylacetonate with [MoO(OMe)4]provides [Ni2Mo2O2(acac)2(OMe)10] (2) and 4. The reaction of [Ni(ORN)2] (RN = CHMeCH2NMe2) with [MoO(OMe)4] yields [Ni2Mo2O2(ORN)2(OMe)10] (3). The two new oxomolybdenum complexes undergo ether elimination upon storage to give the corresponding dioxo complexes [MoO2(acac)(OMe)]2 (5) and [MoO2(ORN)(OMe)]2 (6). Compounds 3 and 4 could also be obtained from the reaction of stoichiometric amounts of Hacac with [MoO(OMe)4] and [MoO2(OMe)2], respectively. The local structure around the nickel atom in compound 2 in solution and compound 3 in the solid state and in toluene/hexane solution has been determined by means of EXAFS spectroscopy. The complexes are intended to be used as single-source precursors, which are attractive in coatings and for the preparation of mesoporous materials; its application for the synthesis of nickel molybdate by sol,gel processing is therefore reported. The oxide material obtained from 3 displays a uniform grain size and a large surface area. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Two novel molybdenum complexes containing [Mo2O2S2]2+ fragment: synthesis, crystal structures and catalytic studiesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 12 2007Jun-Feng Wu Abstract Mo2O2S2(HGly)(Gly)21 and K6[Mo2O2S2(nta)2][Mo2O2S2(ntaH)2]·4H2O 2 were synthesized by the reactions of (NH4)2MoS4 and amino acids L (L = glycine, nitrilotriacetic acid) in ethanol,water medium at ambient temperature. The two complexes were characterized by elemental analysis, infrared spectra, UV,visible spectra, TG,DTA and XPS. X-ray crystallographic structural analyses revealed that compound 1 is a binuclear MoSglycinate complex, a glycinate ligand is coordinated to each molybdenum atom through its amine nitrogen and carboxylato oxygen, respectively, and the third glycinate acts as a bridge through its two carboxylato oxygens linking the two molybdenum atoms. Compound 2 is also a binuclear MoS complex with two nitrilotriacetate ligands, each of which is coordinated to a molybdenum atom via its two ,-carboxylato oxygens and a nitrogen atom. Simultaneously, each molybdenum atom in 1 and 2 is chelated to a terminal oxygen and two bridging sulfurs to complete the octahedral configuration. Their catalytic activities in the reduction from C2H2 to C2H4 as well as other binuclear MoSpolycarboxylate complexes, a [Fe4S4] single cubane and a chainlike MoFeS compound were investigated and it was found that 1 exhibited relatively good catalytic activity. Copyright © 2007 John Wiley & Sons, Ltd. [source] Preparation of Imidazolin-2-iminato Molybdenum and Tungsten Benzylidyne Complexes: A New Pathway to Highly Active Alkyne Metathesis CatalystsCHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2010Birte Haberlag Dipl.-Chem. Abstract The reaction of [PhCMBr3(dme)] (dme=1,2-dimethoxyethane) with the hexafluoro- tert- butoxides LiX or KX [X=OC(CF3)2Me] afforded the benzylidyne complexes [PhCMX3(dme)] (2,a: M=W, 2,b: M=Mo), which further reacted with the lithium reagent Li(ImtBuN), generated with MeLi from 1,3-di- tert -butylimidazolin-2-imine (ImtBuNH), to form the imidazolin-2-iminato complexes [PhCMX2(ImtBuN)] (3,a: M=W, 3,b: M=Mo). The propylidyne complex [EtCMoX2(NImtBu)] (4) was obtained by treatment of 3,b with an excess of 3-hexyne. Complexes 3,a and 3,b are able to efficiently catalyse alkyne cross metathesis of various 3-pentynyl benzyl ethers 5 and benzoic esters 7 at room temperature, to afford 2-butyne and the corresponding diethers 6 and diesters 8. The tungsten complex 3,a proved to be a superior catalyst for ring-closing alkyne metathesis, and the [10]cyclophanes 10 and 12 were synthesised in high yield from 1,3-bis(3-pentynyloxymethyl)benzene (9) and bis(3-pentynyl) phthalate (11), respectively. The molecular structures of compounds 2,a, 2,b, 3,a, 3,b, 4, and 12 were determined by single-crystal X-ray diffraction. DFT calculations have been carried out for catalyst systems based on the imidazolin-2-iminato tungsten and molybdenum complexes 3,a and 3,b by choosing the alkyne metathesis of 2-butyne as the model reaction; the studies revealed a lower activation barrier for the tungsten system. [source] | ||||||||||||||||||||||