On the preparation of binuclear S,S bridged molybdenum(V) complexes crystal and molecular structure of [Mo2S4(Et2dtc)2]

MoO₄^2? is reduced by diethyldithiocarbamate (Et₂dtc^?) on prolonged digestion in aqueous medium whereby the complex [Mo₂^VO₂S₂(Et₂dtc)₂] is formed. The central moiety Mo₂O₂S₂²⁺ has a high formation tendency. When [Mo₂^V(S₂)₆]^2? is refluxed with Et₂dtc^? in ethanol, [Mo₂^VS (Et₂dtc)₂] is formed, the X-ray crystal structure of which has been determined (space group P2₁2₁2₁, a = 10.550(2) Å, b = 13.820(5) Å, c = 14.723(12) Å, d_c = 1.90 g · cm^3?, Z = 4). The Mo? Mo distance of the diamagnetic compound is 2.817(2) Å and the average Mo=S_t distance 2.099(4) Å.     

Luminescence properties of mesoporous chromium(III) terephthalate and inclusion compounds of cluster complexes

The luminescence properties of mesoporous chromium(III) terephthalate [Cr₃O(C₈H₄O₄)₃F(H₂O)₂] (MIL-101) were discovered, and the luminescence spectra were detected at temperatures from 20 to 290 K. By the interaction of MIL-101 with solutions of anionic clusters [Mo₆Cl₁₄]^2- (Mo₆) and [Re₆S₈(CN)₆]^4- (Re₆) new hybrid materials Mo₆MIL-101 and Re₆MIL-101 were synthesized, the nanoporous framework of which contains _ca. 3.5 and 1.5 clusters per cage, respectively. The synthesized hybrid materials possess the luminescence properties different from those of the initial framework and cluster complexes.     

Dithiolylium‐Chlorooxomolybdate(V): Synthese und Kristallstruktur von (C3Cl3S2)[MoOCl4] und (C3Cl3S2)[Mo2O2Cl7]

Dithiolylium Chlorooxomolybdates(V): Synthesis and Crystal Structure of (C₃Cl₃S₂)[MoOCl₄] and (C₃Cl₃S₂)[Mo₂O₂Cl₇] The reaction of 3, 4, 5‐Trichlor‐1, 2‐dithiolylium chloride with MoOCl₃ in dichlormethane under solvothermal conditions at 65 °C simultaneously yields the green tetrachlorooxomolybdate(V) (C₃Cl₃S₂)[MoOCl₄] and the yellow‐brown heptachlorodioxodimolybdate(V) (C₃Cl₃S₂)[Mo₂O₂Cl₇]. The crystal structures of both compounds contain nearly planar (C₃Cl₃S₂)⁺ ions with a S—S bond length of 203 pm. The discrete [MoOCl₄]^— ion in the structure of (C₃Cl₃S₂)[MoOCl₄] has the shape of a square pyramid with the oxygen atom at the apex. The molybdenum atom is displaced by 58 pm from the basal plane towards the oxygen atom. The [Mo₂O₂Cl₇]^— ion in the structure of (C₃Cl₃S₂)[Mo₂O₂Cl₇] has the form of a face‐sharing double octahedron. It is formally composed of a [MoOCl₄]^— ion and a MoOCl₃ molecule connected by one symmetrical and two unsymmetrical chloro bridges. The molybdenum atoms placed in the centers of such connected octahedra are 357 pm apart, indicating no Mo—Mo bond.     

Polychalkogenoanionen der Übergangsmetalle. IV. Neuartige Redoxkondensationsreaktionen von MoO2S22− in H2O und zur Darstellung von Di-μ-sulfido-Komplexen von Mov

Polychalcogenoanions of the Transition Metals. IV. Novel Redox Condensation Reactions of MoO₂S₂^2? in H₂O and Preparation of Di-μ-sulfido Complexes of Mo^v Mo^VIO₂S₂^2? polymerizes after protonation in aqueous solution under physiological conditions forming polynuclear complexes with η-S₂^2? ligands (for example [Mo₂^vO₂S₂(S₂)₂]^2?). From the solution other di-μ-sulfido Mo^v complexes as for example [Mo₂O₂S₂(Et₂dtc)₂] can be easily obtained.     

The crystal structure of (NH4)2[Mo2(S2)6].8/3H2

The black crystal of (NH₄)[Mo₂(S₂)₆]* 8/3 H₂O belongs to the orthorhombic system, space group D³₂-P22₁2₁, with a = 12.064(6), b = 12.534(4), c = 19.558(9)Å, V =2957(3)ų, Z = 4 and D_c = 2.23g.cm^?3. The intensity data were collected on a Syntex R3 four-circle diffractometer. The structure was solved by Patterson method and direct method, the light atoms (except H atoms) were obtained from ΔF syntheses. The structure was refined by least-squares with anisotropic thermal parameters. The values of R and R_w were 0.092 and 0.072 respectively. The crystal structure contains discrete dimeric cluster [Mo₂(S₂)₆]^2? ions, NH₄⁺ cations and H₂O molecules. There are two crystallographically independent [Mo₂S₂)₆]^2? ions in the crystal, one locates on general position [Figure 1(a)], the other locates on two-fold axis [Figure 1(b)]. It contains one and a half [Mo₂S₂)₆]^2? ions in an asymmetric unit. In [Mo₂S₂)₆]^2? each Mo is coordinated side on by four S₂^2? groups in a distorted dodecahedral arrangement, two of which are bridging and the other two are terminal. The Mo? S bond length is 2.441 Å (mean), and S? S is 2.049 Å (mean). The Mo? Mo distance is 2.784 Å (mean), which is to be regarded as a single bond length. The formal oxidation state of Mo is five, it is probably a mixed valence Mo^IV? Mo^VI, and so shows a remarkable deep colour.     

Studies of molybdenum thiolato-complexes. The crystal and molecular structures of two triply bridged Mo(V) dimers, [Bu 4 n N][Mo2O2Cl5(SPh)2] and [Mo2O3(SPh)2(S2CNMe2)2]

Summary The complex [Bu ₄ ⁿ N][Mo₂O₂Cl₅(SPh)₂] has been prepared by reaction of [Bu ₄ ⁿ N][MoO(SPh)₄] with stoichiometric amounts of HCl and characterised by single crystal X-ray structure analysis. The dimer is bridged by two oxo-groups and one chloride and each Mo has pseudo-octahedral co-ordination. The related compound [Mo₂O₃(SPh)₂(S₂CNMe₂)₂] was synthesised by reaction of [MoO₂(S₂CNMe₂)₂] with thiophenol in methanol and has also been characterised crystallographically. In this case the triple-bridge consists of two thiophenolate sulphurs and one oxo-group, each molybdenum having pseudo-octahedral geometry. These structures are compared with other triply-bridged species.     

Collision-Induced Decomposition (CID) of Triangular [Mo3S7-xSex]4+ Complexes (x = 0,3,7). A liquid SIMS and FTMS/MS study of [Mo3S7-xSex(Et2NCS2)3] +

[Mo₃S(S₂)₃(dtc)₃]I, [Mo₃S(SeS)₃(dtc)₃](dtc), and [Mo₃Se(Se₂)₃(dtc)₃](dtc) (dtc = N,N-diethyldithiocarbamate) were investigated by liquid SIMS-FTMS. The fragmentation pathways were essentially the same for the three compounds and can be explained by two types of fragmentation processes: stepwise abstraction of S/Se atoms as exemplified by the series [Mo₃X_z(dtc)₃]⁺ (4 ? z ? 7, X = S, Se), and ligand dissociation, as indicated by the generation of [Mo₃X_z(dtc)₂]⁺ (5 ? z ? 7, X = S, Se). The exclusive elimination of the Se-atoms from [Mo₃S(S_ax-Se_eq)₃(dtc)₃]⁺ confirmed the inequivalent reactivity of the bridging atoms in axial and equatorial position as observed in previous studies. Collision-induced decomposition (CID) of [Mo₃S₇(dtc)₃]⁺ ( 1 ), [Mo₃S₆(dtc)₃]⁺ ( 2 ), [Mo₃S(S_ax–Se_eq)₃(dtc)₃]⁺ ( 3 ), and [Mo₃Se₇(dtc)₃]⁺ ( 4 ) revealed distinctly different fragmentation reactions for the SIMS and CID mode. CID of 1, 3 , and 4 resulted in a two-step reaction with the exclusive elimination of diatomic molecules XY (X,Y = S/Se). In the case of 3 , the selective elimination of Se₂ indicated the abstraction of two Se-atoms located in equatorial positions of two different bridging groups. This result is discussed in terms of mechanisms, based on labile M? X_eq and inert M? X_ax bonds with an intramolecular formation of a X₄ fragment prior to the elimination of X₂.     

Two novel molybdenum complexes containing [Mo2O2S2]2+ fragment: synthesis,crystal structures and catalytic studies

Mo₂O₂S₂(HGly)(Gly)₂ 1 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 Mo? S? glycinate 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 Mo? S complex with two nitrilotriacetate ligands, each of which is coordinated to a molybdenum atom via its two β‐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 Mo? S? polycarboxylate complexes, a [Fe₄S₄] single cubane and a chainlike Mo? Fe? S compound were investigated and it was found that 1 exhibited relatively good catalytic activity. Copyright © 2007 John Wiley & Sons, Ltd.     

Solvothermal synthesis,crystal structure and properties of Mn2(tren)3[Mo2O2S6]2·1.3H2O exhibiting the new polymeric [Mn2(tren)3] n 4+ chain

The novel oxothiomolybdate Mn₂(tren)₃[Mo₂O₂S₆]₂·1.3H₂O [tren = tris(2-aminoethyl)amine], synthesized under solvothermal conditions, consists of one-dimensional novel [Mn₂(tren)₃] _n ⁴⁺ chains and discrete [Mo₂O₂S₆]^2– anions. There are two crystallographically independent chains and four [Mo₂O₂S₆]^2– anions in the asymmetric unit. Each Mn atom in the cationic chains is sixfold coordinated by N atoms of the chelating tren molecules. Two of the four crystallographically independent Mn atoms are tridentately coordinated by two tren molecules, whereas the other two are coordinated tetradentately by one tren molecule and monodentately by the remaining primary amino groups from the tren molecules that act as tridentate ligands. The tren ligand bonding modes lead to the formation of the polymeric [Mn₂(tren)₃] _n ⁴⁺ chain. One of the four Mn atoms is in the unusual trigonal prismatic coordination state with six surrounding N atoms.     

Binuclear cluster complexes of molybdenum containing 2,2′-bipyridine and 1,10-phenanthroline: Synthesis and structure

By the interaction between (Et₄N)₂[Mo₂O₂S₈] and I₂ in DMF with a subsequent addition of 2,2′-bipyridine or 1,10-phenanthroline, new binuclear complexes [Mo₂O₂S₂I₂(bipy)₂] (1) and [Mo₂O₂S₂I₂(phen)₂] (2) are obtained. The structure of [Mo₂O₂S₂I₂(bipy)₂] is determined using single crystal X-ray diffraction. The compounds are characterized by elemental analysis and IR spectra. The [MoO(S₂)₂(bipy)] complex as a product of oxidative destruction of 1 is isolated and characterized.     

Activation and properties of Mo=O bonds in Mo/SiO2 catalysts

The existence of the charge transfer excited triplet state [Mo⁵⁺-O^-] produced by UV-irradiation of Mo/SiO₂ catalysts, and its reactivity are evidenced by experiments of photoluminescence, photoinduced metathesis, and photoreduction of CO. Mo⁵⁺ ions can be produced separately by thermal activation and O^- ions by further adsorption of N₂O on those Mo⁵⁺ ions. The latter of which are adsorbed on Mo⁶⁺ ions are found to be more reactive than O^2- of [Mo⁶⁺ =O^2-] bond. They are able either to add a molecule such as CO or C₂H₄, or to abstract hydrogen from H₂, CH₄ or trans-dicyanoethylene, or a CN group form tetracyanoethylene (TCNE). The Mo⁵⁺ ions are able to coordinate gas phase ligands when their coordination sphere possesses vacant sites. This is the case for tetracoordinated Mo⁵⁺ _4c ions arising from reduction of tetrahedral Mo⁶⁺ ions (Eq. (7)). These Mo⁵⁺ _4c ions are similar to those produced by UV-irradiaiion (Eq. (2)). In addition, if the adsorbed molecule has a sufficiently large electron affinity, such as TCNE or O₂, an electron transfer can occur (Eq. (9) and (17)). The [Mo⁵⁺-O^-] bond obtained by thermal activation is more difficult to evidence than that obtained with UV-activation because it is not detectable by EPR. However, the EPR results obtained at low temperature show that the O^- ions adsorbed on Mo/SiO₂ catalysts as well as the [Mo⁵⁺-O^-] excited triplet state obtained by UV-irradiation of 1Mo⁶⁺=O²] interact with methanol (Eq. (16)). They are consistent with the mechanism of methanol oxidation occurring at high temperature (Eq. (4)).     

The Electron Transfer Series [MoIII(bpy)3]n (n=3+, 2+, 1+, 0, 1−), and the Dinuclear Species [{MoIIICl(Mebpy)2}2(μ2‐O)]Cl2 and [{MoIV(tpy.)2}2(μ2‐MoO4)](PF6)2⋅4 MeCN

The electronic structures of the five members of the electron transfer series [Mo(bpy)₃]ⁿ (n=3+, 2+, 1+, 0, 1?) are determined through a combination of techniques: electro‐ and magnetochemistry, UV/Vis and EPR spectroscopies, and X‐ray crystallography. The mono‐ and dication are prepared and isolated as PF₆ salts for the first time. It is shown that all species contain a central Mo^III ion (4d³). The successive one‐electron reductions/oxidations within the series are all ligand‐based, involving neutral (bpy⁰), the π‐radical anion (bpy^.)^1?, and the diamagnetic dianion (bpy^2?)^2?: [Mo^III(bpy⁰)₃]³⁺ (S=3/2), [Mo^III(bpy^.)(bpy⁰)₂]²⁺ (S=1), [Mo^III(bpy^.)₂(bpy⁰)]¹⁺ (S=1/2), [Mo^III(bpy^.)₃] (S=0), and [Mo^III(bpy^.)₂(bpy^2?)]^1? (S=1/2). The previously described diamagnetic dication “[Mo^II(bpy⁰)₃](BF₄)₂” is proposed to be a diamagnetic dinuclear species [{Mo(bpy)₃}₂(μ₂‐O)](BF₄)₄. Two new polynuclear complexes are prepared and structurally characterized: [{Mo^IIICl(^Mebpy⁰)₂}₂(μ₂‐O)]Cl₂ and [{Mo^IV(tpy^.)₂}₂(μ₂‐Mo^VIO₄)](PF₆)₂?4 MeCN.     

Solvothermal Synthesis, Crystal Structure, and Properties of the New Oxothiomolybdate Ni(dien)2[Mo2O2S6]

Summary.  The reaction of NiCl₂ · 6H₂O, Na₂MoO₄ ċ 2H₂O, and sulfur in a mixture of diethylenetriamine and 0.2 M ammonia solution (1:4) under solvothermal conditions leads to the formation of orange-red crystals of the oxothiomolybdate Ni(dien)₂[Mo₂O₂S₆] (dien = diethylenetriamine) in nearly 100% yield. The structure consists of [Ni(dien)₂]²⁺ cations and discrete dimeric [Mo₂O₂S₆]²⁻ anions. The compound crystallizes in the monoclinic space group P2₁/c (a = 8.726(2), b = 18.111(4), c = 14.419(3) ?, β = 101.686(3)°). Upon heating the compound decomposes in a single step starting at about 250°C. The final decomposition product was identified by X-ray powder diffractometry as MoS₂ and Ni₃S₂. Spectroscopic data as well as detailed synthetic procedures for Ni(dien)₂[Mo₂O₂S₆] are reported. Received November 6, 2000. Accepted November 17, 2000     

O-atom transfer biomimetic oxidation of benzoin in the presence of monooxomolybdenum(IV) thiolate complexes

Novel catalytically active monooxomolybdenum(IV) species containing four thiolate ligands obtainable in solution by NaBH₄ reduction of [Mo^vO(SC₆H₅)₄]⁻, [Mo^vO(Z-cys-Val-OMe)₄]⁻, (Z=benzyloxycarbonyl), or [Mo^vO(S₂C₆H₄)₂]⁻ perform the pyridine-N-oxide oxidation of benzoin in N,N-dimethylformamide at 30 °C. The order of catalytic activity is [Mo^vO(Z-cys-Val-OMe)₄]⁻ > [Mo^vO(S₂C₆H₄)₂]⁻ > [Mo^vO(SC₆H₅)₄]⁻ ([benzoin]/[oxidant]/[catalyst]= 20/20/1), while the oxidation by air under the same catalytic conditions gives a different order, [Mo^vO(Z-cys-Val-OMe)₄]⁻> [Mo^vO(SC₆H₅)₄]⁻ >[Mo^vO(S₂C₆H₄)₂]⁻. During the catalytic cycle in the amine-N-oxide oxidation, two intermediate species, [Mo^IVOL₄]²⁻ and [Mo^VIO₂L₄]²⁻, were detected by ¹H NMR, while in the air oxidation an unidentified Mo(VT) species is involved.     

Mechanochemical Synthesis of Tri-μ2-Disulfido-μ3-Thio-Tris(Diethyldithiocarbamato)-S,S"-triangular- Trimolybdenum Diethyldithiocarbamate {Mo3(μ3-S)(μ2-S2)3[(C2H5)2NCS2]3}+[(C2H5)2NCS2]–

The mechanoactivated solid-state reaction of [Et₄N]₂[Mo₃S₇Br₆] with Na(Et₂NCS₂) in a vacuum vibration ball mill yields the [Mo₃S₇(Et₂NCS₂)₃]⁺[Et₂NCS₂]^–complex. The product was studied by IR and Raman spectroscopy and differential thermal analysis.     

Zweikern-Komplexe des Wolframs und Molybdäns mit zentraler {XMS2 MX}2+-Einheit (X=O,S) und S 2 2− -bzw. S 4 2− -Liganden

The synthesis and crystal structures of the compounds [PPh ₄]₂[W₂S₁₂]·0.5DMF, [PPh ₄]₂[W₂O₂S₁₀]·0.5DMF, [PPh ₄]₂[W₂S₁₀]··0.5DMF, [PPh ₄][NEt ₄][Mo₂OS₇]·CH₃CN, and [PPh ₄]₂[Mo₂O₂S₁₀] are reported.

     

A dinuclear molybdenum cluster containing i-mnt ligand: synthesis and crystal structure of [Mo_2S_4(i-mnt)_2] (Et_4N)_2

A dinuclear molybdenum(V) cluster compound (Et4N)2[Mo2S4(i-mnt)2] (i-mnt=l,l-dicyanoethylene-2,2-dithiol, (S2C=C(CN)2]2-) has been prepared by the ligand substitution reaction of Mo2S4(iso-pr2dtp)2 (iso-pr2dtp=S2P(OC3H7)2-) with K2(i-mnt) in the presence of Bt4NI. This cluster was characterized by inrrared spectrum, UV-Vis spectrum and single crystal structure analy-sis. The cluster anion [Mo2S4(i-mnt)2]2- possesses C, symmetry with a crystallographic mirror plane through two bridging S atoms. By the S....S supramolecular interactions between two adjacent cluster anions the [Mo2S4(i-mnt)2]2- anions are linked to form infinite chains along the b axis. Crystal data: monoclinic, space group C2/m, a=1.8748(6), b=1.5360(4), c=1.4322(5) nm, ,β=112.02(2)°, V=3.823(4) nm3, Z=4, Dc=1.50 g/cm3. The final R=0.038 and .RW=0.053 for 3015 observed unique reflections.     

Einfache Darstellungsmethoden des einzigen bekannten Perthiometallats [(S2)2 Mo(S2)2Mo(S2)2]2−. Zur Kenntnis der Einheit {Mo2(S2)2}6+

Simple Preparation Methods of the Only Known Perthiometallate [(S₂)₂(Mo)S₂)₂ Mo(S₂)₂]^2? · On the Moiety {Mo₂(S₂)₂}⁶⁺ Different aspects of the preparation of the only known perthiometallate [(S₂)₂Mo(S₂)₂Mo(S₂)₂]^2? (a compound with the unusual coordination number (9) have been discussed. Simple preparation methods could be developed. A discussion of the properties of the stabilising central moiety {Mo(S₂)₂}⁶⁺ containing a metal-metal bond follows.     

Synthesis,characterization and X-ray structure of one-dimensional polymeric complexes with triangular molybdenum clusters as building blocks: Na2Ga2[Mo3O4(O2CEt)8]2 and Na2AlGa[Mo3O4(O2CEt)8]2

The heterometallic polymeric cluster complexes Na₂Ga₂[Mo₃O₄(O₂CEt)₈]₂ (1) and Na₂AlGa[Mo₃O₄(O₂CEt)₈]₂ (2) have been prepared by reaction of Mo(CO)₆, NaMoO₄·2H₂O with GaCl₃ and a mixture of AlCl₃ and GaCl₃ (1:1 molar ratio), respectively, in heated propionic anhydride and characterized by X-ray crystallography. The structures are isostructural and each consists of two triangular propionate cluster units [Mo₃O₄(O₂CEt)₈]⁴⁻, which act as polydentate ligands to link trivalent heterometal and sodium ions forming one-dimensional chain structures. Both clusters decompose in 2 M HCl at room temperature to produce discrete [Mo₃O₄]⁴⁺ cluster units. Thermal analysis of 1 reveals that the complex is air stable up to 250°C. IR spectra show the characteristic bands of [Mo₃O₄]⁴⁺ cores at 745–812 cm⁻¹.     

Coordination Chemistry of [Nb2(S2)2]4+ Clusters: Preparation and Crystal Structures of K4[Nb2(S2)2(C2O4)4] · 6 H2O and (NH4)6[Nb2(S2)2(C2O4)4](C2O4)

Bis(disulfido)bridged Nb^IV cluster oxalate complexes [Nb₂(S₂)₂(C₂O₄)₄]^4– were prepared by ligand substitution reaction from the aqua ion [Nb₂(μ‐S₂)₂(H₂O)₈]⁴⁺ and isolated as K₄[Nb₂(S₂)₂(C₂O₄)₄] · 6 H₂O ( 1 ), (NH₄)₆[Nb₂(S₂)₂(C₂O₄)₄](C₂O₄) ( 2 ) and Cs₄[Nb₂(S₂)₂(C₂O₄)₄] · 4 H₂O ( 3 ). The crystal structures of 1 and 2 were determined. The crystals of 1 belong to the space group P1, a = 720.94(7) pm, b = 983.64(10) pm, c = 1071.45(10) pm, α = 109.812(1)°, β = 91.586(2)°, γ = 105.257(2)°. The crystals of 2 are monoclinic, space group C2/c, a = 1567.9(2) pm, b = 1906.6(3) pm, c = 3000.9(4) pm, β = 95.502(2)°. The packing in 2 shows alternating layers of cluster anions and of ammonium/uncoordinated oxalates perpendicular to the [1 0 1] direction. Vibration spectra, electrochemistry and thermogravimetric properties of the complexes are also discussed.