Dinuclear Molybdenum Complexes Research Articles

Novel oxo-bridged dinuclear molybdenum(II) complexes: reaction of [MO 2(O 32CCH 3) 2(CH 3CN) 6](BF 4) 2with aromatic isocyanides. X-Ray crystal structures of [Mo 2(μ-O)(RN 10](BF 4) 2 (R = 2,6-Me 2C 6H 3) and [Mo(= O)F(RNC) 4](BF 4) (R = 2,4,6-Me 3C 6H 2)

Treatment of the dinuclear molybdenum complex [Mo 2(O 2CCH 3) 2(CH 3CN) 6](BF 4) 2 with aromatic isocyanides (RNC) gave an oxo-bridged dinuclear molybdenum(II) complex, [Mo 2(μ-O)(RNC) 10](BF 4) 2 ( 1), and a mononuclear molybdenum(IV) complex, [Mo(= O)F(RNC) 4]BF 4( 2) (R = 2,6-dimethylphenyl (Xyl) or 2,4,6-trimethylphenyl (Mes)), which were characterized by IR, electronic, 1H and 19F NMR spectroscopy and X-ray crystallographic analyses. Complex 1a (R = Xyl) crystallizes in the triclinic form, space group P 1 , with a = 13.431(5) A ̊ , b = 15.548(7) A ̊ , c = 12.616(5) A ̊ , α = 111.74(3)°, β = 92.80(3)°, γ = 101.80(3)° and Z = 1 (R = 0.060 and R w = 0.054 for 2818 independent reflections with I >3 σ( I)) Complex 2b (R = Mes) crystallizes in the triclinic form, space group P 1 , with a = 14.317(4) A ̊ , b = 16.16(1) A ̊ , c = 8.968(8) A ̊ , α = 100.31(4)°, β = 97.54(2)°, γ = 91.69(4)° and Z = 2 (R = 0.059 and R w = 0.059 for 2225 independent reflections with I >3 σ( l)) Complex 1 consists of two molybdenum atoms bridged linearly by an oxygen atom. Each molybdenum atom is octahedrally coordinated by five isocyanides and an oxygen atom. Two equatorial planes, Mo(RNC) 4, mutually adopt an eclipsed form. The MoO bond length is 1.876(2) Å and the MoOMo angle is constrained to 180°. Complex 2 has a distorted octahedral geometry, in which molybdenum atom is occupied by four isocyanides, O and F atoms.

Reactions of Di- and Polynuclear Complexes. 14. Synthesis of Permethylated-Cyclopentadienyl Chalcogeno-Bridged Compounds: A Route to the Stable Thiolatosulfidocarbonyldimolybdenum(III) Complex [Cp*2Mo2(CO)2(.mu.-SMe)2(.mu.-S)]. Crystal Structure Determination of [Cp*2Mo2(CO)2(.mu.-SMe)2(.mu.-SH)][BF4

The new diamagnetic carbonyl-containing sulfido complex [Cp*2Mo2(CO)2 (μ-SMe)2(μ-S)] (8) has been obtained by the thermal reaction of the pentamethylcyclopentadienyl compound [Cp*2Mo2(CO)4] (1) with MeSSMe; the other predominant product of the reaction, [Cp*2Mo2(CO)4(μ-SMe)2] (3), results from the oxidative addition of dimethyl disulfide across the Mo2 center. Monitoring this thermal reaction by IR spectroscopy indicated that 8 arises from decarbonylative dimerization of [Cp*Mo(CO)3(SMe)] (2). Reactions with other dialkyl and diaryl chalcogenides, REER (ER = SPh, SeMe), and with thiol (HSBz) and selenol (HSePh) led only to the formation of tetracarbonyl chalcogenato-bridged derivatives [Cp*2Mo2(CO)4 (μ-ER)2] (ER = SPh (4), SBz (5), SeMe (6), SePh (7)). A thermolysis study showed the degradation of 3 to [Cp*2Mo2(μ-SMe)4] (12) via [Cp*2Mo2(CO)2(μ-SMe)2] (9); 8 was decarbonylated directly to 12. Investigation of the reaction between 8 and electrophilic reagents showed that dinuclear molybdenum(III) complexes [Cp2*Mo2(CO)2(μ-SMe)2(μ-SH)]X [X = BF4 (16), Cl (17), F(18)] were formed stereospecifically as the cis isomers. 16 has been structurally characterized by X-ray diffraction. Crystals of 16 are orthorhombic, space group Pcab, a = 15.655(5) A, b = 16.173(3) A, c = 23.662(5) A, and Z = 8. The complex cation has approximate C2v symmetry and the Mo-Mo bond length is 2.772(2) A. Complex 3 was readily oxidized by Ag[BF4] to yield the dicationic product [Cp*2Mo2(CO)4(μ-SMe)2][BF4]2 (21). All new thiolato-bridged complexes have been characterized by spectroscopic analyses. © 1995, American Chemical Society. All rights reserved.

Bis(η5-indenyl)tetrakis(μ-iodo)dimolybdenum(Mo—Mo)

The title compound, [Mo 2 (I) 4 (C 9 H 7 ) 2 ], is synthesized by the reaction of MoI 3 (thf) 3 (thf = tetrahydrofuran) and sodium indenyl, followed by the further reaction of an intermediate product with tetraphenylphosphonium iodide to form tetraphenylphosphonium indenyltriiodomolybdate. The title compound forms from the latter compound by loss of tetraphenylphosphonium iodide. The product is a tetra-μ-iodo-bridged dinuclear molybdenum complex with two terminal indenyl ligands. The indenyl groups are η 5 -bonded to the Mo atoms. The molecule sits on a crystallographic inversion center and has non-crystallographic symmetry C 2h .The metal-metal distance is 2.720 (4) A

Voltammetric Behavior of Doubly-Bridged Dioxobis(dithiocarbamato)dimolybdenum(V) Complexes in Dichloromethane

Abstract The electrochemical behavior of the di-μ-oxo, μ-oxo-μ-sulfido and di-μ-sulfido dinuclear molybdenum(V) complexes ligating a series of dithiocarbamates, [Mo2O4−nSn(R2dtc)2] (n = 0—2; R2dtc− = dithiocarbamate), was investigated in dichloromethane. Each complex undergoes a one-electron quasi-reversible reduction, followed by a homogeneous chemical reaction, except for the di-μ-sulfido complex [Mo2O2S2(Ph2dtc)2] which shows a complicated electrochemical process. The chemical stability of the one-electron reduction products of [Mo2O4−nSn(R2dtc)2] increases with increase in the number of bridging sulfides and in the electron-donating ability of the substituents on the dithiocarbamate ligands.

The Synthesis and Crystal Structure of the First Trinuclear Molybdenum Complex Containing PyS Ligands [Mo_3(CO)_6(μ-PyS)_2(μ_3-PyS)_2

The deprotonated derivative pyridine-2-thiolato (PyS~-) of pyridine-2-thione (PySH)is a potentially amibidentate or multi-functional donor which coordinates toward transitionmetals with either the exocyclic S or heterocyclic N atom or both atoms to form differentcoordination modes. We have recently reported the synthesis and crystal structure ofthe first dinuclear molybdenum complex with doubly-bridging PyS ligands [Mo_2(CO)_4(μ-PyS)_2(PPh_3)_2]which was obtained from the reaction of [Mo(CO)_3(CH_3CN)_3] with

Synthesis of water soluble sulfur-bridged molybdenum dimers with substituted cyclopentadienyl ligands

The ester substituted cyclopentadienyl ligand C[sub 5]H[sub 6]CO[sub 2]CH[sub 3][sup [minus]] was used in the synthesis of dinuclear molybdenum complexes with bridging sulfur ligands. New derivatives include [MeO[sub 2]C-CpMoSC[sub 2]H[sub 4]S][sub 2], 3, [MeO[sub 2]C-CpMoSCHCPhS][sub 2], 4, and [MeO[sub 2]C-CpMo)[sub 2](S[sub 2]CH[sub 2])(SC[sub 2]H[sub 4]S)], 7. Analogous dinuclear complexes with one ester substituted and one unsubstituted Cp ligand have also been isolated and characterized. The base hydrolysis reaction of 7 leads to the formation of the water soluble derivative (NaO[sub 2]C-CpMo([mu]-S))[sub 2]S[sub 2]CH[sub 2], 9. A second water soluble derivative containing three carboxylate substituents, (NaO[sub 2]C-CpMo([mu]-S))[sub 2]S[sub 2]C(H)CO[sub 2]Na, 11, was also synthesized and characterized. The formyl substituted cyclopentadienyl ligand was used in the preparation of new dinuclear molybdenum derivatives, including (OHC-CpMoSC[sub 2]H[sub 4]S[sub 2], 13, and [OHC-CpMoSC[sub 2]H[sub 2]S][sub 2], 14. Spectroscopic data for the new complexes are presented. The reactivity of the new series of complexes has been surveyed and found to be qualitatively similar to that of the unsubstituted cyclopentadienyl derivatives. The new products will permit a more detailed study of solvent and substituent effects on sulfur ligand reactivity. 16 refs., 2 tabs.

Oxalic acid mediated coupled electron-proton transfer to sulfur-rich [formula omitted]-dioxomolybdenum(VI) center. Generation of oxalatomolybdenum (VI), -(IV) and bridged oxalato dinuclear molybdenum(V) complexes: Synthesis, spectra and electrochemical studies

Oxalic acid mediated coupled electron-proton transfer to sulfur-rich [formula omitted]-dioxomolybdenum(VI) center. Generation of oxalatomolybdenum (VI), -(IV) and bridged oxalato dinuclear molybdenum(V) complexes: Synthesis, spectra and electrochemical studies

Preparation, X-ray crystal structure and theoretical study of the bonding in [Mo 2O 4I 2L 3] (L = OPPh 3), an example of an unsymmetrical dinuclear molybdenum complex

The reaction between the oxomolybdenum(V) complex Et 4N[MoOI 4(H 2O)] and triphenylphosphine oxide (L = OPPh 3) produces the mononuclear complex [MoOI 3L 2] and the dinuclear complex 1 [Mo 2O 4I 2L 3], the crystal structure of which has been studied by X-ray. Each metal centre is bound to a terminal and two bridging oxygen atoms; the Mo 2O 2 central fragment appears slightly disymmetric with a short MoMo distance [2.557(1) Å], in agreement with a single metalmetal bond. The whole structure is strongly asymmetric, with the three phosphorus ligands bound to a first molybdenum atom with a distorted octahedral MoO 6 coordination and the two iodo ligands bound to a second molybdenum atom which has a cis-MoOO 2I 2 square-pyramidal coordination. Extended Hückel calculations on the model [Mo 2O 4I 2L 3] (L = OPH 3), the structure of which was derived from the averaged structure of 1, have been performed to understand the structure and bonding in this unsymmetrical dimer. They show a HOMO-LUMO gap of 1.06 eV and indicate that 1 can be considered unambiguously as an Mo VMo V [and not an Mo IVMo VI] dinuclear complex. An orbital explanation is provided to rationalize why the cis conformation is generally preferred for Mo VMo V dinuclear species: such a conformation allows a stronger MoMo bond. Some predictions are made, concerning the reactivity of the MoMo bond with respect to nucleophilic and electrophilic attacks.

When does a nitrogen attached to a λ3-phosphorus assume a pyramidal geometry? Crystal structures of Group 6 metal carbonyl complexes of isomeric forms of λ3-cyclotriphosphazanes

The reaction of [Mo(CO)4(nbd)](nbd = norbornadiene) with trans-[EtNP(OC6H3Me2-2,6)]3(L1) or cis-[EtNP(OCH2CF3)]3(L2) yields the mono- and di-nuclear molybdenum(0) complexes [Mo(CO)4(L1)]1 and [{Mo(CO)4(µ-L2)}2]2, respectively. They represent the first organometallic transition-metal derivatives of λ3-cyclotriphosphazanes and have been characterised by elemental analysis and IR and NMR spectroscopy and their structures confirmed by X-ray crystallography. The different co-ordination behaviour of the cis and trans isomeric forms of this type of ligand is revealed. A pyramidal geometry observed around one of the nitrogen atoms of the P3N3 ring in complex 1 is unprecedented among λ3-phosphazanes.

Synthesis and substitution reactions of dinuclear molybdenum complexes containing Mo-Mo quadruple bonds and labile solvent ligands

The kinetically labile acetonitrile ligands of [Mo 2 (O 2 C-t-Bu),(MeCN) 2 ]+(BF 4 - ) (1) have been selectively replaced by the anions derived from deprotonation of 6-hydroxy-2-methylpyridine (mhp) and 2,6-dimethylpyridine (dmp) to yield the triscarboxylate complexes Mo 2 (O 2 C-t-Bu) 3 (mhp) (3) and Mo 2 (O 2 C-t-Bu) 3 (dmp) (4), respectively

Syntheses and structures of dinuclear molybdenum complexes containing reactive .mu.-thiolate-thioether ligands

Certain thiolate-bridged cationic complexes of the formula [(CpMo) 2 (S 2 CH 2 )(μ-S)(μ-SR)]SO 3 CF 3 react reversibly with olefins: The resulting adduct contains a thiolate-thioether bridging ligand. The stability of the olefin adduct varies significantly as the R substituent on the thiolate ligand and the substituents on the olefin and varied. The reaction of allene with [(CpMo) 2 (S 2 CH 2 )(μ-S)(μ-SR)]SO 3 CF 3 , where R=2-propenyl, led to the formation of an isolable thiolate-thioether complex, [(CpMo) 2 (S 2 CH 2 )(SC(=CH 2 )CH 2 SC(CH 3 )(=CH 2 ))]SO 3 CF 3 (3). The reaction of [(CpMo) 2 (S 2 CH 2 )(μ-S)(μ-SR)]SO 3 CF 3 (2; R=tert-butyl) with acetylene led to the isolation of a product of the formula [(CpMo)(SCH=CHSCMe 3 )(S 2 CH 2 )-MoCp]SO 3 CF 3 (4). X-ray structures of 4 and 3

Interconversion of mononuclear and quadruply bonded dinuclear dibenzotetraaza[14]annulene complexes of molybdenum

Several aspects of the chemistry of the previously reported dinuclear molybdenum(II) complexes ([{Mo(R 2 C 22 H 20 N 4 )} 2 ]), in which the substituted dibenzotetraaza[14] annulene ligand adopts its usual tetradentate coordination mode, have been developed

ChemInform Abstract: Photochemistry of Some Dinuclear Molybdenum and Tungsten Cyclopentadienyl Carbonyl Complexes in Frozen Gas Matrices at ca. 12 K: IR Spectroscopic Evidence for Carbon Monoxide Ejection as a Primary Photoprocess.

AbstractThe non‐methylene‐bridged and methylene‐bridged dimers (I) and (III) undergo photochemically induced CO ejection processes in frozen argon, methane, CO and N2 matrices at ca. 12 K. The products are different in each case, as are the rates of reactions.

Reactions of a sulfido-bridged dinuclear molybdenum complex with nitriles and isonitriles under hydrogen: facile C.tplbond.N bond cleavage

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of a sulfido-bridged dinuclear molybdenum complex with nitriles and isonitriles under hydrogen: facile C.tplbond.N bond cleavagePaul Bernatis, J. C. V. Laurie, and M. Rakowski DuBoisCite this: Organometallics 1990, 9, 5, 1607–1617Publication Date (Print):May 1, 1990Publication History Published online1 May 2002Published inissue 1 May 1990https://doi.org/10.1021/om00119a037RIGHTS & PERMISSIONSArticle Views180Altmetric-Citations33LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Photochemistry of some dinuclear molybdenum and tungsten cyclopentadienyl carbonyl complexes in frozen gas matrices at ca. 12 K: infrared spectroscopic evidence for carbon monoxide ejection as a primary photoprocess

Infrared spectroscopic evidence, including the use of 13CO-labelling, is presented to show that CO ejection is a primary process when the non-methylene-bridged and methylene-bridged dimers, [{M(η5-C5H5)(CO)3}2] and [M2(µ-η5:η5′-C5H4CH2C5H4)(CO)6](M = Mo or W), respectively, are photolysed in frozen argon, methane, carbon monoxide, and nitrogen matrices at ca. 12 K. The [M2(η5-C5H5)2(CO)5](M = Mo or W) photoproduct fragments for the non-methylene bridged species are proposed to have two terminal, two bridging (2-electron) and one bridging (4-electron) CO ligands whereas in the case of the photolysis of the parent methylene bridged species, which are constrained in a cis geometry and which undergo slower photolysis, the [M2(µ-η5:η5′-C5H4CH2C5H4)(CO)5] photoproduct fragments are proposed to contain three terminal and two bridging (2-electron) CO ligands. Surprisingly, no secondary reactions were observed in carbon monoxide and nitrogen matrices and no 13CO-exchange was observed for 13CO-doped methane matrices. The low-temperature results are discussed in relation to solution and flash photolysis studies at ambient temperatures.

Cleavage of saturated oxygen heterocycles by a dinuclear molybdenum complex containing sulfido and hydrosulfido ligands

Cleavage of saturated oxygen heterocycles by a dinuclear molybdenum complex containing sulfido and hydrosulfido ligands

Electrochemical Properties of Electrodes Modified with Polymers Containing a Sulfur Bridged Dinuclear Molybdenum Complex

We report here on the redox and chemical properties of a new polymer prepared by attachment of the dinuclear molybdenum complex to a chloromethylated polystyrene backbone. The resulting polymer is then dip or spin coated onto electrode surfaces and examined in acetonitrile solvent in which the polymer is insoluble. The electrochemical behavior of the film is dependent on the extent of loading and the solution electrolyte cation. Reactions analogous to those observed in solution occur with the polymer bound complex; these reactions include the catalytic multielectron reduction of azobenzene.

Synthesis and X-ray structures of molybdenum(VI)complexes with benzamide oximes. A rare linear tetramolybdenum compound [Mo4O11{p-TolC(NH2)NHO}2{p-TolC(NH)NHO}{p-TolC(NH)NO}

An asymmetrical dinuclear molybdenum complex [Mo2O5(Hbao)2] with benzamide oxime (H2bao) and a rare linear tetranuclear molybdenum complex [Mo4O11(H2mbao)2(Hmbao)(mbao)]- with p-methylbenzamide oxime (H2mbao) have been prepared and characterized by X-ray diffraction.

ChemInform Abstract: Synthesis and Reactivity of Dienyl‐Metal Compounds. Part 30. Alkylation of Thiolato Bridges: A Route to Stable Dialkyl Sulfide Bridged Dinuclear Molybdenum Complexes. Crystal Structure Determination of ((η‐C5H5)(CO)Mo(μ‐SMe2)2Mo(PMe3)(η‐C5H5)) (BF4)2.

AbstractThe stepwise methylation of the binuclear MeS‐bridged Mo complex (I) with one equiv. (Me3O)BF4 (II) in each case leads to the stable cationic dimethylsulfide‐bridged products (III) and (Va).

Electrochemical studies of dinuclear molybdenum(V) complexes with EDTA in aprotic solvents

The electrochemical behaviour of the dinuclear complexes [Mo 2O 4- n S n (edta)] 2− ( n = 0–2) was investigated in various aprotic solvents, acetonitrile (CH 3CN), dimethyl sulphoxide (DMSO), N,N-di-methylformamide (DMF) and N,N-dimethylacetamide (DMA). These complexes undergo quasi-reversible one-electron reduction and quasi-reversible one-electron oxidation in CH 3CN. This behaviour is quite different from that in aqueous media. The formal potentials for the reduction of these complexes, as well as the formal potentials for the oxidation of these complexes, shift in the positive direction with an increase in the number of bridging sulphides. The electrochemical behaviour of these complexes in DMF and DMA is similar to that in CH 3CN. The only exception is the oxidation processes of [Mo 2O 4edta)] 2−. in which an irreversible and nearly two-electron transfer occurs in DMF or DMA. The complexes of [Mo 2O 4− n S n edta)] 2− ( n = 0–2) also undergo quasi-reversible one-electron reduction in DMSO. However, anomalies were observed for the oxidation process in this solvent.