Electron-deficient molybdenum/cobalt/sulfido clusters: Chemistry related to hydrodesulfurization (HDS) catalysis

The author's work on the reactions of Cp₂Mo₂Co₂S₃(CO)₄ (1) and Cp₂Mo₂ Co₂S₄(CO)₂ (2) with organosulfur compounds is reviewed. Reaction pathways that lead to C S bond scission are proposed, and the relexance of these results to HDS reactions mer commercial CoMoS catalysts is discussed.     

Binuclear cyclopentadienylcobalt sulfur and phosphinidene complexes Cp2Co2E2 (E = S, PX): Comparison with their Iron carbonyl analogues

Density functional theory studies on a series of Cp₂Co₂E₂ derivatives (E = S and PX; X = H, Cl, OH, OMe, NH₂, NMe₂) predict global minimum butterfly structures with one Co-Co bond for the “body” of the butterfly and four Co-E bonds at the edges of the “wings” of the butterfly. Tetrahedrane structures with both Co-Co and E-E bonds are higher in energy for Cp₂Co₂S₂ and Cp₂Co₂(PH)₂ and are not found in the other systems. This differs from the corresponding Fe₂(CO)₆S₂ and Fe₂(CO)₆(PX)₂ derivatives where tetrahedrane structures are predicted to be the lowest energy structures for all cases except X = NR₂ and OH and such a tetrahedrane structure is found experimentally for Fe₂(CO)₆S₂. The butterfly structures for the Cp₂Co₂E₂ derivatives are of two types. For Cp₂Co₂(PX)₂ (X = H, OH, OMe, NH₂, NMe₂) the lowest energy structures are unsymmetrical butterflies Cp₂Co₂(P)(PX₂) with two X groups on one phosphorus atom and a lone pair on the other (naked) phosphorus atom. Related low-energy unsymmetrical butterfly Fe₂(CO)₆(P)(PX₂) structures, not observed in previous theoretical studies, are now found for the corresponding Fe₂(CO)₆(PX)₂ derivatives. Symmetrical butterfly singlet diradical structures with one X group on each phosphorus atom in relative cis or trans positions are also found for the Cp₂Co₂(PX)₂ derivatives and are the global minima for Cp₂Co₂(PCl)₂ as well as Cp₂Co₂S₂. In all cases the cis structures are of lower energy than the corresponding trans structures. Rhombus structures having neither Co-Co nor E-E bonds are also found for all of the Cp₂Co₂(PX)₂ derivatives but always at higher energies than the butterfly structures, ranging from 17 to 29 kcal/mol above the global minima.     

Reduction of acetylene by zinc amalgam catalyzed by molybdenum cyclopentadienylcarbonyl complexes

Conclusions The products of the reduction of Cp₂Mo₂(CO)₆, Cp₂Mo₂(CO)₄, and Cp₂Mo₂(CO)₄(C₂H₂) are mononuclear CpMo(CO)_3-xL_x anions (x=0-2). These anions catalyze the reduction of acetylene by zinc amalgam with a quantitative yield of ethane and ethylene relative to amalgam consumedTranslated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 464–466, February, 1988.     

Reactions of dipropargyl manolate,terephthalate with Co2(CO)8, Mo2Cp2(CO)4 and RuCo2(CO)11 give the di or tetranuclear clusters. The crystal structure of [CH2(CO2CH2C2H-μ)2][Co2(CO)6]2 and [p-(HC2CH2OCO)C6H4(CO2CH2C2H-μ)][Co2(CO)6]

The reactions of dipropargyl manolate and terephthalate, respectively, with Co₂(CO)₈ in THF at room temperature gave four new compounds [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ (R=CH₂, 1a; R=C₆H₄, 1b) and [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Co₂(CO)₆] (R=CH₂, 2a; R=C₆H₄-1,4-, 2b), and compounds 2a and b reacted with RuCo₂(CO)₁₁ to form two new linked clusters [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][RuCo₂(CO)₉] (R=CH₂, 3a; R=C₆H₄-1,4-, 3b). The treatment of two dipropargyl esters, respectively, with RuCo₂(CO)₁₁ afforded another two new clusters [R(CO₂CH₂C₂H-μ)₂][RuCo₂(CO)₉]₂ (R=CH₂, 4a; R=C₆H₄-1,4-, 4b). The reactions of dipropargyl manolate, terephalate with Mo₂Cp₂(CO)₄ gave rise to the formation of dinuclear complexes [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Mo₂Cp₂(CO)₄] (R=CH₂, 5a; R=C₆H₄-1,4-, 5b), compound 5a reacted with Co₂(CO)₈ to produce the cluster [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][Mo₂Cp₂(CO)₄] 6a. All the new clusters have been characterized by C/H elemental analysis, IR and ¹H NMR spectroscopies. The structure of [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ 1a and [p-(HC₂CH₂OCO)C₆H₄(CO₂CH₂C₂H-μ)][Co₂(CO)₆] 2b have been determined by single crystal X-ray diffraction methods.     

Reactivity of the unsaturated dimolybdenum anion [Mo2(η-C5H5)2(μ-PCy2)(μ-CO)2] towards electrophiles based on p- and d-block elements

The 30-electron binuclear anion [Mo₂Cp₂(μ-PCy₂)(μ-CO)₂]⁻ reacts with the chlorophosphite ClP(OEt)₂ or the organotin chlorides Cl₂SnPh₂ or ClSnPh₃ to give compounds of the formula trans-[Mo₂Cp₂(μ-E)(μ-PCy₂)(CO)₂], (E = P(OEt)₂, SnPh₃, SnPh₂Cl). In contrast, this anion reacts with the organosilicon chlorides ClSiR₃ (R = Ph, Me) to give unstable silyloxycarbyne-bridged complexes [Mo₂Cp₂(μ-PCy₂)(μ-COSiR₃)(μ-CO)], which rapidly hydrolyze to give the known hydride [Mo₂Cp₂(μ-H)(μ-PCy₂)(CO)₂]. Two main types of products were also observed in the reactions of the title anion with different chlorocomplexes of the transition and post-transition metals. Thus, the reactions with [MCl₂Cp₂] (M = Ti, Zr) give moisture-sensitive isocarbonyl-bridged complexes of the type [Mo₂Cp₂(μ-COMClCp₂)(μ-PCy₂)(μ-CO)]. In contrast, softer metallic electrophiles such as [AuCl(PR₃)] (R = ⁱPr, ptol) react with the anion at the dimolybdenum site to form new trimetallic clusters of the formula [AuMo₂Cp₂(μ-PCy₂)(CO)₂(PR₃)], also retaining a Mo−Mo triple bond. Subsequent reactions of the latter products with the solvate complexes [Au(PR₃)(THF)][PF₆] give the tetranuclear clusters [Au₂Mo₂Cp₂(μ-PCy₂)(CO)₂(PR₃)₂][PF₆] (Mo−Mo = 2.5674(3) Å and Au−Au = 2.7832(2) Å when R = ⁱPr). Finally, the reaction of the title anion with HgI₂ gives the pentanuclear cluster [Hg{Mo₂Cp₂(μ-PCy₂)(CO)₂}₂] or the trinuclear cluster [Mo₂Cp₂(μ-HgI)(μ-PCy₂)(CO)₂] depending on the stoichiometry being actually used for the reaction. The trinuclear species is only stable in tetrahydrofuran (THF), and decomposes to give a mixture of the dimeric species [Mo₂Cp₂(μ-HgI)(μ-PCy₂)(CO)₂]₂ along with variable amounts of the known iodide-bridged complex [Mo₂Cp₂(μ-I)(μ-PCy₂)(CO)₂].     

Darstellung und reaktivität von zweikernigen pentamethylcyclopentadienyloxomolybdänsulfiden

Reaction of Cp^*₂Mo₂S₄ (Cp^*  η⁵C₅Me₅) with oxygen yields two isomers of Cp^*₂Mo₂OS₃ and Cp^*₂Mo₂O₂S₂, the constitution of which is determined by means of IR, ¹H and ⁹⁵Mo NMR spectroscopy as well as by X-ray diffraction analysis. The sulfur liberated in this reaction is oxidized and incorporated into an unusually coordinated μ,η¹-thiosulfate ligand of the compound [Cp^*₂Mo₂(μ,η²-S₂)(μ-S)(υ,η¹-S₂O₃)]. The reaction of all of these compounds with (CO)₅Cr(THF) and (CH₃CN)₃Cr(CO)₃, respectively, gives clusters either containing a trigonal-bipyramidal Mo₂CrS₂ or a cubane-like Mo₂Cr₂O_nS_4-n skeleton (n = 1,2) with five metal-metal bonds. This reaction enables the straightforward incorporation of oxygen atoms into 62-e heterocubane clusters and thus the investigation of ⁹⁵Mo chemical shifts of mixed oxo/thio-heterocubanes by means of NMR spectroscopy.     

Dithiolene transfer from nickel to a dimolybdenum centre: the first dithiolene alkyne complex

Transfer of dithiolene ligands from [Ni(S₂C₂Ph₂)₂] to the dimolybdenum complex [Mo₂(μ-C₂R₂)(CO)₄Cp₂] (R=CO₂Me, Cp=η-C₅H₅) affords the first example of a dithiolene alkyne complex, [Mo₂(μ-C₂R₂)(μ-S₂C₂Ph₂)₂Cp₂], together with [Mo₂(μ-SCRCR)(μ-SCPhCPh)Cp₂] in which sulfur transfer from dithiolene to alkyne has occurred.     

The structure and formation of niobocene carbonyl heteronuclear derivatives. The molecular structures of Cp2Nb(CO)(μ-CO)Mn(CO)4, Cp2Nb(CO)(μ-H)Ni(CO)3 and [Cp2Nb(CO)(μ-H)]2Mo(CO)4

The heteronuclear Cp₂Nb(CO)(μ-CO)Mn(CO)₄ (I), Cp₂Nb(CO)(μ-H)Ni(CO)₃ (II) and [Cp₂Nb(CO)(μ-H)]₂M(CO)₄ (III, M = Mo;IV, M = W) complexes were prepared by reaction of Cp₂NbBH₄/Et₃N with Mn₂(CO)₁₀ in refluxing toluene, direct reaction of Cp₂NbBH₄ with Ni(CO)₄ in ether, and reaction of Cp₂NbBH₄/Et₃N with M(CO)₅. THF complexes (M = Mo or W) in THF/benzene mixture. An X-ray investigation of compounds I–III was performed. It is established that in I the bonding between Mn(CO)₅ and Cp₂Nb(CO) (with the angle (α) between the ring planes being 44.2(5)°) fragments takes place via a direct NbMn bond (3.176(1) Å) and a highly asymmetric carbonyl bridge (MnC_co 1.837(5) Å, NbC_co 2.781(5) Å). On the other hand, in complex II the sandwich Cp₂Nb(CO)H molecule (angle α = 37.8°) is combined with the Ni(CO)₃ group generally via a hydride bridge (NbH 1.83 Å, NiH 1.68 Å, NbHNi angle 132.7°) whereas the large Nb?Ni distance, 3.218(1) Å, shows the weakening or even absence of the direct NbNi bond. Similarly, in complex III two Cp₂Nb(CO)H molecules (with α angles equal to 41.4 and 43.0°, respectively) are joined to the Mo(CO)₄ group via the hydride bridges (NbH 1.83 and 1.75 Å and MoH 2.04 and 2.06 Å) producing a cis-form. The direct NbMo bonds are probably absent, since the Nb?Mo distances are rather long (3.579 and 3.565 Å). The effect of electronic and steric factors on the structure of heteronuclear niobocene carbonyl derivatives is discussed.     

Synthesis and characterization of linked alkyne-bridging Co2C2 tetrahedral clusters and expansion reactions of (Co2(CO)6(μ-HCCCH2OOC))2R with Fe3(CO)12

Two new linked alkyne-bridging tetrahedral carbonyl clusters containing Co₂C₂ Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₃COOCH₂CCH-μ)Co₂(CO)₆, 1, and Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₈COOCH₂CCH-μ)Co₂(CO)₆, 2, have been prepared by reactions of two dipropargyl esters (HC≡CCH₂OOC)₂R (R = (CH₂)₃, (CH₂)₈) with Co₂(CO)₈. Expansion reactions of 1 and Co₂(CO)₆(μ-HCCCH₂OOCCOOCH₂CCH-μ)Co₂(CO)₆, 3, with Fe₃(CO)₁₂ give two new mixed-metal linked clusters Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₃COOCH₂CCH-μ,η⁴)Co₂Fe₂(CO)₁₂, 4, and Co₂(CO)₆(μ-HCCCH₂OOCCOOCH₂CCH-μ,η⁴)Co₂Fe₂(CO)₁₂, 5. The new clusters were characterized by elemental analysis, IR, ¹H-NMR and ESI-MS analysis.     

Investigation of the formation of new bimetallic clusters of the type (η-C5Me5)2M2M′2(μ3-S)4(CO)2 (M  Cr,Mo; M′  Co), containing the M2M′2S4 core

The reaction of the sulfur rich pentamethylcyclopentadiene complexes (C₅Me₅)₂Cr₂S₅ and (C₅Me₅)₂Mo₂S₄ with Co₂(CO)₈ results in the formation of new bimetallic clusters of composition (C₅Me₅)₂M₂Co₂(μ₃-S)₄(CO)₂ (M  Cr, Mo), containing the M₂Co₂S₄ core.     

Organometallic chemistry and homogeneous catalysis of Rh and Rh-Co mixed metal carbonyl clusters

The reactions of hydrosilane and/or alkyne as well as isonitriles with rhodium and rhodium cobalt mixed metal carbonyl clusters, e.g., Rh₄(CO)₁₂ and Co₂Rh₂(CO)₁₂, are studied. Novel mixed metal complexes, e.g., CoRh(CO)₅ (HCCBu ⁿ ), (R₃Si)₂Rh(CO) _n Co(CO)₄, Rh(R–NC)₄Co(CO)₄, Co₂Rh₂(CO)₁₀(HCCR), and Co₂Rh₂(CO)₉(HCCBu ⁿ ), are synthesized and identified. The catalytic activities of these rhodium and rhodium-cobalt mixed metal complexes are examined in hydrosilyation, silylformylation, and novel silylcarbocyclization reactions. Possible mechanisms for these reactions are proposed and discussed.     

Crystal and molecular structure of (μ-η2,η3-propargyl)- bis(cyclopentadienyl)tetracarbonyldimolybdenum tetrafluoroborate and (μ-η2,η3-1,1-dimethylpropargyl)- bis(cyclopentadienyl)tetracarbonyldimolybdenum tetrafluoroborate

An X-ray study of [(μ-η²,η³-HCCCH₂)Cp₂Mo₂(CO)₄]⁺(BF₄⁻) (1) and [(μ-η²,η³-HCCCMe₂)Cp₂Mo₂(CO)₄]⁺(BF₄⁻) (2) reveals their structures to be similar to the structure of neutral compounds of the series (μ-η²,η²-RCCR)Cp₂Mo₂(CO)₄, the difference between 1 and 2 being mainly due to the markedly different MoC⁺ bond lengths, which accounts for different stability and fluxional behavior of these compounds in solution.     

Stabilization of tautomeric forms P(OH)3 and HP(OH)2 and their derivatives by coordination to palladium and nickel atoms in heterometallic clusters with the Mo3MQ44+ core (M = Ni, Pd; Q = S, Se)

The cluster aqua complexes [Mo₃(MCl)Q₄(H₂O)₉]³⁺ (M = Pd or Ni) in hydrochloric acid solutions induce isomerization of the hydrophosphoryl compounds (HO)₂P(O)H, (HO)P(O)H₂, PhP(O)(OH)H, and Ph₂P(O)H into the hydroxo tautomers P(OH)₃, HP(OH)₂, PhP(OH)₂, and Ph₂P(OH), which are stabilized by coordination of the phosphorus atom to the Pd or Ni atoms. The reactions were studied by ³¹P NMR and UV-Vis spectroscopy. The kinetics of the reactions of phosphorous acid with [Mo₃(PdCl)Q₄(H₂O)₉]³⁺ was investigated by spectrophotometry. The [Mo₃(Pd(PhP(OH)₂))S₄(H₂O)₂Cl₇]³⁻ complex was isolated as a supramolecular adduct with cucurbit [8]uril, and the [Mo₃(Ni(P(OH)₃))S₄(H₂O)₈Cl]³⁺ complex was isolated as an adduct with cucurbit [6]uril. The structures of both compounds were established by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 606–613, March, 2005.     

The Potential of Molybdenum Complexes Bearing Unsubstituted Heterodiatomic Group 15 Elements as Linkers in Supramolecular Chemistry

The reactions of tetrahedral molybdenum complexes bearing unsubstituted heterodiatomic Group 15 elements, [Cp₂Mo₂(CO)₄(μ,η²:η²‐PE)] (Cp=C₅H₅; E=As ( 1 ), Sb ( 2 )), with Cu^I halides afforded seven unprecedented neutral supramolecular assemblies. Depending on the Mo₂PE units and the Cu^I halide, the oligomers [?{Cp₂Mo₂(CO)₄}{μ₄,η²:η²:η²:η¹‐PE}?₄?{CuX}{Cu(μ‐X)}?₂] (E=As (X=Cl ( 3 ), Br ( 4 )); E=Sb (X=Cl ( 6 ), Br ( 7 ))) or the 1D coordination polymers [{Cp₂Mo₂(CO)₄}{μ₄,η²:η²:η¹:η¹‐PAs}{Cu(μ‐I)}]_n ( 5 ) and [{Cp₂Mo₂(CO)₄}{μ₄,η²:η²:η²:η¹‐PSb}₂{Cu(μ‐X)}₃]_n (X=I ( 8 ), Br ( 9 )) are accessible. These solid‐state aggregates are the first and only examples featuring the organometallic heterodiatomic Mo₂PE complexes 1 and 2 as linking moieties. DFT calculations demonstrate that complexes 1 and 2 present a unique class of mixed‐donor ligands coordinating to Cu^I centers via the P lone pair and the P?E σ‐bond, revealing an unprecedented coordination mode.     

Synthesis of heterometallic cluster compounds from Fe3(μ3-Te)2(CO)9 and comparisons with analogous sulfide clusters

Fe₃Te₂(CO)₉ is shown to be a useful precursor to a variety of heterometallic carbonyl clusters in reactions which appear to proceed via the intermediacy of Fe₂(Te₂)(CO)₆. Fe₃Te₂(CO)₉ decomposed in polar solvents to give Fe₂(Te₂)(CO)₆ which could be dimerized to Fe₄Te₄(CO)₁₂. Fe₃Te₂(CO)₉ reacted with C₅H₅Co(CO)₂ and Pt(C₂H₄)(PPh₃)₂ to give good yields of (C₅H₅CO)Fe₂Te₂(CO)₇ and Fe₂PtTe₂(CO)₆(PPh₃)₂, respectively. (C₅H₅Co)Fe₂Te₂(CO)₇ underwent reversible decarbonylation to give a mixture of two isomers of (C₅H₅Co)Fe₂Te₂(CO)₆ as established by ¹²⁵Te NMR spectroscopy. Upon reaction with Co₂(CO)₈, Fe₃Te₂(CO)₉ gave Co₂FeTe(CO)₉ or Co₄Te₂(CO)₁₁ depending on the reaction conditions. Co₄Te₂(CO)₁₁, like Fe₃Te₂(CO)₁₀ and (C₅H₅Co)Fe₂Te₂(CO)₇, can be reversibly decarbonylated. The assembly of Co₂FeTe(CO)₉ may be mechanistically related to the conversion of Fe₂(S₂)(CO)₆ to FeCo₂S(CO)₉ which was found to proceed via Co₂Fe₂S₂(CO)₁₁. Alternatively, Co₂Fe₂S₂(CO)₁₁ reacted photochemically with [C₅H₅Mo(CO)₃]₂ to give the known, chiral cluster (C₅H₅Mo)CoFeS(CO)₈. While Fe₂(Te₂)(CO)₆ thermally dimerized to Fe₄Te₄(CO)₁₂, Fe₂(S₂)(CO)₆ gave the analogous dimer only upon photolysis. In contrast to the stability of (C₅H₅CO)Fe₂Te₂(CO)₇, the reaction of C₅H₅Co(CO)₂ with Fe₂(S₂)(CO)₆ gave only (C₅H₅CO)Fe₂S₂(CO)₆ which is proposed to be structurally related to Fe₃S₂(CO)₉ and not (C₅H₅Co)₃S₂ or Fe₂PtS₂(CO)₆(PPh₃)₂.     

Influence of d-p π-conjugate interaction upon electronic spectra in some cluster compounds

The UV-vis electronic absorption spectra of the clusters Mo₂S₄(dtp)₂ and Mo₃S₄(dtp)₄·Py have been observed, and the electronic excitation energies have been calculated using the INDO/S-CI method. Comparing the calculated values with the observed results, the absorption bands have been assigned. The influence of d-p π-conjugate interaction strength upon the electronic absorption spectrum is discussed in the clusters Mo₂S₄(dtp)₂ (1), Mo₃S₄(dtp)₄·Py (2), Mo₃O₄(H₂O)₉⁴⁺ (3) and Mo₃S₄(H₂O)₉⁴⁺ (4) [dtp = S₂P(OC₂H₅), Py = pyridine]. It has been found that the absorption bands of clusters 2 and 4, with larger d-p π-conjugate interaction over rings, causes a red-shift compared with those of clusters 1 and 3, with a smaller d-p π-conjugate interaction.     

Synthese und kristallstrukturuntersuchung von bis[dicarbonyl(μ-trifluormethylisocyanid)-(η-pentamethylcyclopentadienyl)molybdän)], [Mo(CO)2(μ-CNCF3)(η-Cp)]2 und dessen isomerisierung zu Cp(CO)2Mo(μ-F3CNCCNCF3)Mo(CO)2Cp

Trifluoromethyl isocyanide adds to the metal—metal triple bond of bis[dicarbonyl(η-pentamethylcyclopentadienyl)molybdenum] forming Mo₂Cp₂(CO)₄(η²-μ-CNCF₃) as the first isolated product. Further addition of trifluoromethyl isocyanide at 0°C leads to the formation of [Mo(CO)₂(μ-CNCF₃)(η-Cp)]₂, which according to crystal structure analysis contains two bridging CF₃NC ligands. During the isomerization of this compound in dichloromethane solution at room temperature or in the solid state above 110°C molybdenum—molybdenum bond cleavage and carbon—carbon bond formation occurs, leading to Cp(CO)₂Mo(μ-F₃CNCCNCF₃)Mo(CO)₂Cp, which contains 1,1,1,6,6,6-hexafluoro-2,5-diaza-2,3,4-hexatriene as bridging ligand.     

Reaktionen von Cyclostibanen (RSb)n [R = (Me3Si)2CH,n = 3; Me3CCH2, n = 4, 5] mit den Übergangsmetallcarbonyl‐Komplexen [W(CO)5(thf)], [CpxMn(CO)2(thf)], [CpxCr(CO)3]2 und [Co2(CO)8]; Cpx = MeC5H4

Reactions of Cyclostibanes, (RSb)_n [R = (Me₃Si)₂CH, n = 3; Me₃CCH₂, n = 4, 5] with the Transition Metal Carbonyl Complexes [W(CO)₅(thf)], [Cp^xMn(CO)₂(thf)], [Cp^xCr(CO)₃]₂, and [Co₂(CO)₈]; Cp^x = MeC₅H₄ (RSb)₃ [R = (Me₃Si)₂CH] reacts with [W(CO)₅(thf)], [Cp^xMn(CO)₂(thf)], or [Co₂(CO)₈] to give [(RSb)₃W(CO)₅] ( 1 ), [RSb{Mn(CO)₂Cp^x}₂] ( 2 ) or [RSbCo(CO)₃]₂ ( 3 ). The reaction of (R′Sb)_n (n = 4, 5; R′ = Me₃CCH₂) with [Cp^xCr(CO)₃]₂ leads to [(R′Sb)₄{Cr(CO)₂Cp^x}₂] ( 4 ); Cp^x = MeC₅H₄, thf = Tetrahydrofuran.     

Reactions of tungsten and molybdenum propargyl complexes with Co2(CO)8, Co4(CO)12, and Cp2Mo2(CO)4. A crossover study of formation of (CO)3 Cp(CO)2

The nature of the protonation reaction of (

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o(CO)₃ (M = Mo, W; R = Me, Ph, p-MeC₆H₄) (2) (obtained from (CO)₃CpMCH₂CCR (1) and Co₂(CO)₈) to give (CO)₃ Cp(CO)₂ (3) was further investigated by a crossover experiment. Thus, reaction of an equimolar mixture of 2b (M = W, Cp = η⁵-C₅H₅, R = Ph) and 2e (M = W, Cp = η⁵-C₅H₄Me; R = p-MeC₆H₄) with CF₃COOH affords only 3b (same M, Cp, and R as 2b) and 3e (same M, Cp, and R as 2e) to show an intramolecular nature of this transformation. Reaction of (CO)₃CpWCH₂CCPh (1b) with Co₄(CO)₁₂ was also examined and found to yield 2b exclusively. Treatment of 1 with Cp₂Mo₂(CO)₄ at 0–5°C provides thermally sensitive compounds, possibly (CO)₂Cp

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oCp(CO)₂ (5), which decompose at room temperature to give Cp₂Mo₂(CO)₆ as the only isolated product.     

Coordination of Phenylsulfinate PhSO2— to Mo3MS44+ Clusters (M = Ni,Pd)

Reaction of heterometal cuboidal clusters [Mo₃(MCl)S₄(H₂O)₉]³⁺ (M = Ni, Pd) with PhSO₂Na in aqueous HCl leads to the substitution at Ni or Pd to give the [Mo₃(M(PhSO₂))(H₂O)_9—xCl_x]^(3—x)+species, isolated as supramolecular adducts with cucurbituril (Cuc) [Mo₃(Ni(PhSO₂))S₄Cl_1.17(H₂O)_7.83][Mo₃(Ni(PhSO₂))S₄Cl_2.22(H₂O)_6.78]Cl_2.61 · Cuc · 15H₂O ( 1 ) and [Mo₃(Pd(PhSO₂))S₄Cl_1.12(H₂O)_7.88][Mo₃(Pd(PhSO₂))S₄Cl_2.29(H₂O)_6.71]Cl_2.59 · Cuc · 11H₂O ( 2 ), respectively. Crystal structure of 1 and 2 was determined, revealing that the PhSO₂ is coordinated via its sulfur atom (Ni — S 2.182 Å, Pd — S 2.305 Å). The structure of these isostructural compounds is built from triple aggregates {(cluster)(Cuc)(cluster)} united into zigzag chains via hydrogen bonds between coordinated PhSO₂ and H₂O ligands.