Mo Sn Research Articles

Tetranuclear heterodimetallic metallamacrocyles with M–Sn(IV) (M=Mo or W) bonds. Crystal structures of { p-[(CO) 3MoC 5H 4C(O)] 2C 6H 4}{(Ph 2Sn) 2S} and { p-[(CO) 3MoC 5H 4C(O)] 2C 6H 4}{(Ph 2Sn) 2CH 2}

The dianions {[ p-(CO) 3MC 5H 4C(O)] 2C 6H 4} 2− reacted with Ph 2SnBr 2 in a 1:2 or 1:1 ratio to give tetranuclear heterodimetallic complexes p-[(Ph 2BrSn)(CO) 3MC 5H 4C(O)] 2C 6H 4 (M=Mo ( 1) or W ( 2), respectively), and with CH 2(SnPhBr 2) 2 to yield tetranuclear heterodimetallic metallamacrocycles { p-[(CO) 3MC 5H 4C(O)] 2C 6H 4}{(Ph 2− n Br n Sn) 2CH 2} ( n=1, M=Mo ( 5) and W ( 6); n=0, M=Mo ( 7) and W ( 8), respectively). Only one bromide on the tin atom was replaced by the metallic anions owing to the electron-withdrawing groups on the cyclopentadienyl rings greatly decreasing the nucleophilicity of the metallic anions. Treatment of complexes 1 and 2 with Na 2S·9H 2O yielded the novel metallamacrocyclic complexes { p-[(CO) 3MC 5H 4C(O)] 2C 6H 4}{(Ph 2Sn) 2S} (M=Mo ( 3) and W ( 4), respectively). All compounds have been characterized by elemental analyses, IR and 1H-NMR spectra. The crystal structures of complexes 3 and 7 determined by X-ray crystallography indicate a novel 14-membered organometallic metallamacrocyclic ring system in which two Mo–Sn units are linked by the bridging cyclopentadienyl ligand and the sulfur or carbon atom. In addition, the carbonyl group π-system is coplanar with the adjacent cyclopentadienyl ring system, but markedly deviates from the bridging phenyl plane.

Synthesis and Reactivity of Group 6 Metal Carbonyl Complexes Containing bis(Pyrazol‐1‐yl)methane with Bulky Substituents on the 3‐ and 5‐Positions of Pyrazole Rings

Two new bis(pyrazol‐1‐yl)methane ligands, bis(3,5‐diisopropylpyrazo‐1‐yl)‐methane and bis(3,5‐diisobutylpyrazol‐1‐yl)methane, were synthesized by the reaction of 3,5‐diisopropylpyrazole or 3,5‐diisobutylpyrazole with CH2Br2 under phase transfer catalysis. These ligands can react with M(CO)6 (M=Cr, Mo or W) under UV irradiation at room temperature to yield bis(pyrazo‐1‐yl)methane tetracarbonylchromium, molybdenum or tungsten complexes. Treatment of the molybdenum or tungsten complexes with SnCl4 gives Mo–Sn or W–Sn heterobimetallic complexes, one of which has been characterized by X‐ray analysis. All new compounds have also been characterized by elemental analyses and spectroscopic (1H NMR and IR) studies.

Relative timing of deformational, metamorphic and mineralisation events at the Mt. Todd (Yimuyn Manjerr) Mine, Pine Creek Inlier, Northern Territory, Australia

The Mt. Todd Mine (also known as the Yimuyn Manjerr Mine), located approximately 40 km northwest of the township of Katherine, in the Northern Territory, Australia, is host to several discrete ore bodies that strike NNE within a broad NE-trending corridor of gold mineralisation. The mine lies in the southern region of the Central Domain of the Pine Creek Inlier (PCI) and is hosted by a Palaeoproterozoic sequence of rocks termed the Burrell Creek Formation, which is dominated by greywacke, siltstone, sandstone and shale that exhibit sedimentary features akin to those of a river-dominant delta front to prodelta environment. The formation is conformably overlain by volcanoclastic and volcanolithic sedimentary rocks of the Tollis Formation (∼1890 Ma). Three deformation events are recognised in the Mt. Todd region, D1, D2 and D3. The earliest deformation, D1, is characterised by close to tight, NE to N to NW-trending asymmetric folds (F1), and a continuous axial–planar cleavage (S1). The deformation is associated with the development of conjugate buck–quartz veins and was preceded by the emplacement of the Yenberrie Leucogranite, which produced contact metamorphism of the sedimentary rocks of the Burrell Creek Formation to hornblende–hornfels facies (H1), with the development of cordierite porphyroblasts (type C1). D1 was coincident with peak regional metamorphism to greenschist facies. D2 is associated with westerly trending open folds (F2), and a spaced disjunctive to fracture cleavage (S2) in transection to the folds. It was preceded by the emplacement of the Tennysons Leucogranite of the Cullen Batholith (1835–1820 Ma), which produced contact metamorphism of the Yenberrie Leucogranite and the sedimentary rocks of the Burrell Creek and Tollis formations to hornblende–hornfels facies (H2), with the development of cordierite porphyroblasts (type C2). D3 is characterised by the reactivation of strike-slip faults (mostly sinistral), a steeply dipping Type S3-C type foliation, and mesoscopic en échelon folds (F3) that trend oblique to the faults in a left stepping (sinistral) array. The age of emplacement of the Tennysons Leucogranite, and the timing of D1 and D2 are broadly constrained by the age of emplacement of the Cullen Batholith at 1835–1800 Ma. D1 and D2 are correlated with deformation during the Maud Creek Event (∼1850 Ma), while D3 is correlated with deformation during the Shoobridge Event (∼1780 Ma). The age of the Yenberrie Leucogranite is constrained to the age of emplacement of granite batholiths at 1870–1860 Ma. A temporal and broad structural relationship exists between D2 structures, the Tennysons Leucogranite, and the several gold-bearing quartz–sulphide veins and lode systems of the Mt. Todd Mine. The systems appear to have formed after peak thermal metamorphism associated with the emplacement of the pluton at about 1825 Ma, and early in D2, prior to the development of the regional S2 fabric. W–Mo–Sn–Bi–Cu greisen-type mineralisation in the carapace of the Yenberrie Leucogranite of the Yenberrie Wolfram Field constitutes a discrete mineralising event that preceded the emplacement of the Tennysons Leucogranite.

Characterization of Mo–Sn–O system by means of Raman spectroscopy and electrical conductivity measurements

Mo–Sn–O systems were characterized by Raman spectroscopy and electrical conductivity measurements. The catalysts were obtained from precipitation of SnCl 4 by ammonia in the presence of (NH 4) 2Mo 7O 24 using four different levels of Mo concentration. The electrical conductivity measurements showed that particles are formed by agglomeration of SnO 2 crystals aggregated by polymolybdate. Raman spectroscopy suggested that four-coordinated species are dispersed at the external surface while six-coordinated species are inside the particles. For high Mo concentration (Mo >10%), octahedral coordinated species are also on the surface. Bulk MoO 3 oxide was not observed. These results confirm the model previously proposed.

Investigation of thin films of mixed oxides for gas‐sensing applications

AbstractRecently, the thin films of some mixed metal oxides (Mo, Ti, Sn, W, etc.) have been indicated as very promising materials for gas‐sensing applications. Nevertheless, there is still a significant lack of experimental information on these compounds, where the surface properties can be defined not only by their chemical composition but also by the nanosized morphology of the films.In this study we report the results of XPS investigations of Mo–Ti, Mo–Sn and Mo–W oxides. The films of mixed oxides with different composition ratios were prepared by sol–gel and magnetron sputtering techniques. The gas sensitivity of the films at different temperatures was studied by measuring the electrical response to typical gases.Selected‐area XPS depth profiling of the samples was carried out by using cyclic Ar+ sputtering. The separation of different chemical species of the same element and quantitative analysis of experimental depth profiles enabled us to reveal completely the chemical composition of the films investigated. In such a way, the samples of mixed oxides, prepared by two different techniques and annealed at different temperatures (450–700°C), were characterized and compared. Copyright © 2002 John Wiley & Sons, Ltd.

The influence of the Ce–Mo–Sn preparation methods on ethanol oxidation

Ce–Mo–Sn systems were studied for the catalytic oxidation of ethanol. The catalysts were obtained from precipitation of SnO 2· xH 2O in the presence of (NH 4) 2Mo 7O 24, with and without control of pH. Ce(NO 3) 3 and (NH 4) 2Ce(NO 3) 6 were used as Ce precursors, which were added to the system either by Mo–Sn impregnation or during coprecipitation. Mo and Ce concentrations were fixed at 9.2 and 1 wt.%, respectively, for every preparation. The solids were characterized by TPR and CO 2 adsorption. The results indicate that cerium in Mo–Sn systems may be a poison or a promoter for ethanol oxidation, depending on the preparation method. Also, the results suggest that the formation of Ce species that behavior as promoters needs OH groups on the Mo–Sn surface.

Shape changes of N=66 isotones Mo–Ce in DPPQ model

The dynamic pairing plus quadrupole model is used to study the changes in nuclear structure of N=66 isotones of Mo–Sn–Ce. Two different single-particle configurations have been used for Z<50 and Z⩾50 regions and their suitability for respective regions is illustrated. The variations with Z of the quadrupole deformation β, deformation energy E d, and the 2 1 + state energy, B(E2;0 +→2 +) and quadrupole moment Q(2 +) are reproduced. The role of the spin–orbit partner (SOP) orbitals in n–p interaction for inducing the deformation in each region is studied.

Synthesis, structure and characterization of MSn (M=Mo, W) bonded heterobimetallic complexes containing bis(pyrazol-1-yl)methane ligands

The reaction of bis(pyrazol-1-yl)methane tetracarbonylmolybdenum(0) or tungsten(0) complexes with RSnCl 3 (R=Ph, Cl) at room temperature yielded heterobimetallic complexes CH 2(Pz) 2M(CO) 3(Cl)(SnCl 2R) (Pz represents substituted pyrazole; M=Mo or W; R=Ph or Cl) in good yields, which have been characterized by elemental analysis, 1H NMR and IR spectroscopy. The reaction of bis(3,5-dimethyl-4-halopyrazol-1-yl)methane tetracarbonyl tungsten with PhSnCl 3 did not take place even in refluxing CH 2Cl 2. The electronic and steric characteristics of substituents on the pyrazole ring remarkably influence the structures of the products. The structures of CH 2(3,5-Me 2-4-BrPz) 2W(CO) 3(Cl)(SnCl 3) ( 8) and CH 2(4-BrPz) 2Mo(CO) 3(μ-Cl)(SnCl 2Ph) ( 17) (Pz: pyrazole) determined by X-ray crystallography show that no chlorine-bridged WSn bond is observed in complex 8, while one chlorine-bridged MoSn bond exists in complex 17. The SnM bond length is 2.7438(5) Å in complex 8 (WSn) and 2.7559(4) Å in complex 17 (MoSn).

The role of cerium in the oxidation of ethanol over SnO 2-supported molybdenum oxides

The role of Ce in the system Ce–Mo–Sn–O was studied by means of catalytic oxidation of ethanol. The catalysts were obtained from precipitation of SnCl 4 by addition of ammonia in the presence of (NH 4) 2Mo 7O 24 and Ce(NO 3) 3. Mo concentration was fixed at 8 wt.%, and Ce at 0, 1, 2.7 wt.%. These catalysts were characterized by XRD, DRS-UV, TPR, CO 2 adsorption and Mo superficial measurement. It was verified that the presence of Ce changes not only the texture and the Mo species, but also the basic properties of the Sn–Mo system. The results have also shown that cerium increases both activity and selectivity to acetic acid and acetaldehyde.

ChemInform Abstract: A Sandwich Cubane-Type Mo-Sn Cluster: Synthesis and Crystal Structure of [(H2O) 9Mo3OS3SnS3OMo3 (H2O)9] (CH3C6H4SO3) 8×18H2O.

A novel sandwich cubane-type mixed-metal Mo–Sn cluster compound [Mo6SnO2S6(H2O)18](pts)8·18H2O (A) was synthesized by the reaction of [Mo3(µ3-S)(µ-O)(µ-S)2(H2O)9]4+ (B) with tin metal in p-toluensulphonic acid (Hpts) solution. The compound A was characterized by the X-ray structure determination and UV–vis spectrum.

A Sandwich Cubane-Type Mo–Sn Cluster: Synthesis and Crystal Structure of [(H2O)9Mo3OS3SnS3Omo3(H2O)9](CH3C6H4SO3)8·18H2O

Abstract A novel sandwich cubane-type mixed-metal Mo–Sn cluster compound [Mo6SnO2S6(H2O)18](pts)8·18H2O (A) was synthesized by the reaction of [Mo3(µ3-S)(µ-O)(µ-S)2(H2O)9]4+ (B) with tin metal in p-toluensulphonic acid (Hpts) solution. The compound A was characterized by the X-ray structure determination and UV–vis spectrum.

A novel Mo–Sn chlorocarbonyl compound. X-ray crystal structure of [(CO) 4Mo(μ-Cl) 3Mo(SnCl 3)(CO) 3] and [MoCl(SnCl 3)(CO) 3(NCEt) 2

The new heterobimetallic complex [(CO) 4Mo(μ-Cl) 3Mo(SnCl 3)(CO) 3] ( 1) has been prepared by photochemical reaction of Mo(CO) 6 with SnCl 4. The structure of complex 1 was established by X-ray crystallography. The basic structural units of 1 are two seven-coordinate molybdenum atoms, which are linked by three chlorine atoms occupying a bridging position between the molybdenum atoms. The mononuclear seven-coordinate complex [MoCl(SnCl 3)(CO) 3(NCMe) 2] ( 2) is formed by reaction of [(CO) 4Mo(μ-Cl) 3Mo(SnCl 3)(CO) 3] with acetonitrile. Treatment of compound 2 with propionitrile affords [MoCl(SnCl 3)(CO) 3(NCEt) 2] ( 3). A single-crystal X-ray diffraction study of the complex [MoCl(SnCl 3)(CO) 3(NCEt) 2] ( 3) showed that the environment of the molybdenum atom is a distorted capped octahedron with the SnCl 3 anionic ligand occupying the unique capping position above an octahedral face defined by the bridging chlorine and two carbonyl groups.

Synthesis and reactivity of Mo–Sn compounds: X-ray crystal structure of a novel [Mo(SnCl 3) 2(CO) 2(NCEt) 3

[Mo(CO) 4(NCMe) 2] reacts with SnCl 4 in CH 2Cl 2 to produce a mixture of compounds which can be regarded as the results of oxidative addition with the elimination of CO and the formation of a Mo–Sn bond. The compound [MoCl(SnCl 3)(CO) 3(NCMe) 2] 1 is the main product but others containing Mo–Sn bond compounds can be formed also in variable amounts, as was shown by IR and NMR investigation of the reaction mixture. The structure of a novel [Mo(SnCl 3) 2(CO) 2(NCEt) 3] 4 was established by X-ray crystallography. This is the first structurally characterized molybdenum(II) carbonyl complex containing two anionic SnCl 3 ligands and the very rare example of the 4:3 piano stool seven-coordinate geometry. In the reaction of 1 with alkynes, complexes were isolated in which CO and/or acetonitrile ligands were replaced by alkyne ligands. The alkyne molybdenum(II) complexes formed were characterized structurally by IR and NMR spectroscopy. However, the reaction of 1 with phenylacetylene leads to the catalytic coupling of alkyne molecules and the formation of cycloligomers and polymers. The possible mechanisms for the formation of molybdenum(II) complexes and their role in the catalytic process are discussed.

The synthesis of novel bridging cyclopentadienyl WSn(IV) bonded bimetallic complexes. Crystal structure of Cl 3SnMo(CO) 3C 5H 4(CH 3) CNNHC 6H 3(NO 2) 2 and μ-[C 5H 4(CH 3) CNN(CO)Ph]W(CO) 3SnCl 2 · (EtOH) 2

The reaction of CH 3COC 5H 4(CO) 3MoSnCl 3 with 2,4-dinitrophenyl-hydrazine yielded the corresponding hydrazone, Cl 3SnMo(CO) 3C 5H 4(CH 3)CNNHC 6H 3(NO 2) 2 ( 1). Crystals of 1 are monoclinic: a = 8.6724(9), b = 21.549(2), c = 12.378(1) A ̊ , β = 102.099(8)° , space group, P2 1 n , Z = 4 , MoSn distance 2.7040(7) Å. The reaction of CH 3COC 5H 4(CO) 3WSnCl 3 with benzoyl-hydrazine in refluxing ethanol gave μ[C 5H 4(CH 3)CNNC(O)PH]WSnCl 2(C 2H 5OH) 2 ( 2). Crystals of 2 are monoclinic. a = 16.897(2), b = 13.780(1), c = 12.429(2) A ̊ , β = 116.80(1)° , space group Cc, Z = 4, WSn distance 2.7767(9) Å.

Seven-coordinate MoSn complexes containing bidentate PP-donor ligands

Two different routes have been studied to produce heterobimetallic MoSn compounds containing bidentate PP-donor ligands. The first, involving the reaction of [Mo(SnRCl 2(Cl)(CO) 3(CH 3CN) 2] (R  Me, Ph) with PP-donor ligands [PP = 1,2-bis(diphenylphosphine)ethane, dppe; 1,3-bis(diphenylphosphine)propane, dppp] always gave rise to neutral seven-coordinate complexes of the type [Mo(SnRCl 2)(Cl)(CO) 3( η 2-PP)] ( I). On the other band, three types of compounds were isolated from reactions of [Mo(CO) 3( η 2-LL)(L′)] [LL  PP- or NN-donor ligand, PP = bis(diphenylphosphine)methane (dppm), NN = 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (dmp); L′ = CO or η 1-dppm] with SnCl 4 used as second synthetic route. So, the cationic six-coordinate complex [Mo(SnCl 3)(CO) 3( η 2-dppm)] + II and neutral or cationic seven-coordinate complexes [Mo(SnCl 3)(Cl)(CO) 3( η 2-NN)] ( III) and [Mo(SnCl 3)(CO) 3( η 2-NN)( η 2-dppm)] + ( IV) are obtained depending on the solvent and the nature of the ligands.

Heterobimetallic MoSn complexes. Reactions of [Mo(CO) 3(CH 3CN) 2(Cl)(SnRCl 2)] (R = Me, Ph) with 4(4-XC 6H 4) 3 (X = Cl, F, H, Me, MeO)

Three families of heterobimetallic compounds were obtained by reaction of [Mo(CO) 3(CH 3CN) 2(Cl)(SnRCl 2)] (R = Ph, Me) with P(4-XC 6H 4) 3 (X = Cl, F, H, Me, MeO). The type of compound obtained dependent on the solvent and concentration of the starting compound. So, [Mo(CO) 2(CH 3COCH 3) 2(PPh 3)(Cl)(SnRCl 2)]· nCH 3COCH 3 (R = Ph, n = 0.5; R = Me, n = 1) (type I) and [Mo(CO) 3{P(4-XC 6H 4) 3}(μ-Cl)(SnRCl 2)] 2 (R = Ph, X = Cl, F, H, Me, MeO; R = Me, X = Cl, F) (type II) were isolated from acetone solution in ca 0.05 M and 0.1 M concentrations, respectively. However, [Mo(CO) 3(CH 3CN) {P(4-XC 6H 4) 3}(Cl)(SnRCl 2)] (R = Ph, X = H; R = Me, X = Cl, F, H) (type III) were obtained from dichloromethane solution independently of the concentration used. All new complexes showed a seven-coordinate environment at molybdenum, containing MoCl and MoSn bonds. Mössbauer spectra indicated a four-coordination at tin for type III complexes.

Heterobimetallic MoSn complexes of the type [Mo(CO) 2(phen){P(4-XC 6H 4) 3}(Cl)(SnRCl 2)

New heterobimetallic complexes [Mo(CO) 2(phen){P(4-XC 6H 4) 3}(Cl)(SnRCl 2)] (X = Cl, F, me, MeO; R = Cl, Me, Ph) were prepared by reaction between [Mo(CO) 3(phen){P(4-XC 6H 4) 3}] and SnRCl 3. The reactions involve retention of the phosphine ligand and elimination of CO. A seven-coordination at the molybdenum is produced by two cis-CO, NN-bidentate and phosphine ligands, the other two positions being occupied by the chlorine and SnRCl 2 groups, as deduced by IR and NMR ( 1H and 31P) spectroscopy. Mössbauer spectral data agree with a five-coordination at tin(IV) due to the presence of a chlorine group bridging the MoSn bond.

Übergangsmetall-stannyl-komplexe: VIII. Unterschiedlicher verlauf der umsetzung von Cp 2Mo(H)ER 3 (ER 3  SiMePh 2 und SnPh 3) mit butyllithium. Substitutions-reaktionen des anionischen stannyl-komplexes [Cp 2Mo-SnPh 3] − und bildung von Cp 2Mo(SnPh 3)(CH 2) 4OSiMe 3 mit Me 3SiCl und Tetrahydrofuran

Reaction of Cp 2Mo(H)SiMePh 2 with butyllithium followed by protonation with methanol gives (π-C 5H 5)(π-C 5H 4SiMePh 2 )MoH 2 due to silyl migration. Contrary to that, the anionic stannyl complex Li[Cp 2Mo-SnPh 3] ( 4) is obtained upon reaction of Cp 2 Mo(H)SnPh 3 with butyllithium. Complex 4 reacts with Me 3SnCl or MeI to give the bis(stannyl) complex Cp 2Mo(SnPh 3)SnMe 3 and the alkyl stannyl complex Cp 2Mo(SnPh 3)Me. The reaction of 4 with Me 3SiCl or CF 3SO 3SiMe 3 in THF results in the formation of Cp 2Mo(SnPh 3)(CH 2) 4OSiMe 3 instead of the silyl stannyl complex. The complexes Cp 2Mo(SnPh 3)Me (MoSn 275.42(9), MoC 230(1) pm, SnMoC 79.6(3)°) and Cp 2Mo(SnPh 3)(CH 2) 4OSiMe 3 (MoSn 276.9(1), MoC 228(1) pm, SnMoC 79.7(3)°) were characterized by X-ray structure analyses.

Heterobimetallic MoSn complexes with seven-coordinate molybdenum and five-coordinate tin

New heterobimetallic complexes [Mo(SnRCl 2)(CH 3CN) 2(CO 3)(Cl)] [( 1)R  C 6H 5, ( 2) R  CH 3] have been obt

Reactivity of the MoSn bond. Reactions of [MoSnPh 3(CO) 3(n-C 5H 5)] with HgX 2 (X = Cl, OCOCF 3)

The cleavage of the MoSn bond has been studied in the reactions of [MoSnPh 3(CO) 3(n-C 5H 5)] with HgX 2 (X = Cl, OCOCF 3). Two new compounds were isolated, their formation depending on the reaction conditions.