Stabilisation of [Fe2(CO)9] and [Ru2(CO)9] bu substitution with bridging diphosphorus ligands

Reaction of [Fe₂(CO)₉] with a half molar amount of R₂PYPR₂ (Y = CH₂, R = Ph, Me, OMe or OPrⁱ; Y = N(Et), R = OPh, OMe or OCH₂; Y = N(Me), R = OPrⁱ or OEt) leads to the ready formation of a product which on irradiation with ultraviolet light rapidly decarbonylates to the heptacarbonyl derivative [Fe₂(μ-CO)(CO)₆{μ-R₂PYPR₂}]. Treatment of the latter with a slight excess of the appropriate ligand results, under photochemical conditions, in the formation of the dinuclear pentacarbonyl complex [Fe₂(μ-CO)(C))₄{μ-R₂PYPR₂}₂] but under thermal conditions in the formation of the mononuclear species [Fe(CO)₃{R₂PYPR₂}]. Reaction of [Ru₃(CO)₁₂] with an equimolar amount of (RO)₂PN(R′)P(OR)₂ (R′ = Me, R = Prⁱ or Et; R′ = Et, R = Ph or Me) under either thermal or photochemical conditions produces [Ru₃(CO)₁₀{μ-(RO)₂PN(OR)₂}] which reacts further with excess (RO)₂PN(R′)P(OR)₂ on irradiation with ultraviolet light to afford the dinuclear compound [Ru₂(μ-CO)(CO₄{μ-(RO)₂PN(R′)P(OR)₂}₂]. The molecular structure of [Ru₂(μ-CO)(CO)₄{μ-(MeO)₂PN(Et)P(OMe)₂}₂], which has been determined by X-ray crystallography, is described.     

Electrochemical behaviour of ditertiary phosphine and diphosphazane ligand-brdiged derivatives or di-iron and di-ruthenium nonacarbonyl

Cyclic voltammetric studies in acetone and benzonitrile show that the oxidation of [M₂(η-CO)(CO)₄(η-R₂PYPR₂)₂] (M  Fe, Y  CH₂, R  Ph or Me; M  Fe, Y  NEt, R  OMe, PRrⁱ or OEt; M  Ru, Y  NEt, R  OPrⁱ) generally proceeds via an EEC mechanism, whereas oxidation of [Ru₂(η-CO)(CO)₄ {η-(MeO)₂PN(Et)-P(OMe)₂}₂] proceeds via an ECE mechanism, for which removal of the second electron is easier than the first, giving rise to an overall 2e-transfer reaction. In both mechanisms the chemical step involves solvent attack.     

Contrasting halogenating action of halogenoalkanes and halogens towards diphosphazane-bridged derivatives of iron and ruthenium nonacarbonyl. Crystal structure of [Ru2Cl2(CO)4{μ-(MeO)2PN(Et)P(OMe)2}2]

Dissolution of [Fe₂(μ-CO)(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂] (R = Me, Prⁱ or Ph) and [Ru₂(μ-CO)(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂](R = Me or Prⁱ) in CCl₄ leads to the rapid formation of [Fe₂(μ-Cl)(CO)₄ {μ-(RO)₂PN(Et)P(OR)₂}₂]Cl and [Ru₂Cl₂(CO)₄ {μ-(RO)₂ PN(Et)P(OR)₂}₂], respectively, with the latter isomerising in dichloromethane or chloroform solution to [Ru₂(μ-Cl)(Cl(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂]Cl, which in turn decarbonylates to [Ru₂(μ-Cl)Cl(CO)₃{μ-(RO)₂PN(Et)P(OR)₂}₂]; the structure of [Ru₂Cl₂(CO)₄{μ-(MeO)₂PN(Et)P(OMe)₂}₂] has been established X-ray crystallographically.     

Halogenation behaviour of bidentate ligand-bridged derivatives of [Ru3(CO)12] and [Os3(CO)12]

Reaction of the ligand-bridged derivatives [M₃(CO)₁₀{μ-(RO)₂PN(Et)P(OR)₂}] and [M₃(CO)₈{μ-(RO)₂PN(Et)P(OR)₂}₂] (M = Ru or Os; R = Me or Prⁱ) with halogens leads to the formation of cationic products [M₃(μ-X)(CO)₁₀{μ- (RO)₂PN(Et)P(OR)₂}]⁺ and [M₃(μ-X)(CO)₈{μ-(RO)₂PN(Et)P(OR)₂}₂]⁺ (X = Cl, Br or I) in which the halogen bridges an opened edge of the metal atom framework; the crystal structure of [Ru₃(μ-I)(CO)₈{μ-(MeO)₂PN(Et)P(OMe)₂}₂]PF₆ is reported.     

Synthesis of [Ru4(μ3-η2-CO)(CO)9{μ-(RO)2PN(Et)P(OR)2}2] (R = Me or Pri): Butterfly clusters of ruthenium containing a triply bridging carbonyl ligand with an unusual mode of coordination. Crystal structure of [Ru4(μ3-η2-CO)(CO)9{μ-(MeO)2PN(Et)P(OMe)2}2]

Reaction of [Ru₃(CO)₁₂] with a two molar proportion of (RO)₂PN(Et)P(OR)₂ (R = Me or Prⁱ) in benzene under reflux affords a number of products including [Ru₃(CO)₁₀{μ-(RO)₂PN(Et)P(OR)₂}], [Ru₃(CO)₉{μ-(RO)₂PN(Et)P(OR)₂}{η¹-(RO)₂PN(Et)P(OR)₂}] and, as the major species, the tetranuclear derivative [Ru₄(μ₃-η²-CO)(CO)₉{μ-(RO)₂PN(Et)P(OR)₂}₂]. An X-ray diffraction study of [Ru₄(μ₃-η²-CO)(CO)₉{μ-(MeO)₂PN(Et)P(OMe)₂}₂] has revealed that the skeletal framework adopts a butterfly structure and that one of the carbonyl groups functions as a triply bridging four-electron donor ligand capping the two wing-tip and one of the hinge ruthenium atoms.     

The formal umpolung behaviour of protonic acids containing coordinating anions towards diphosphazane-bridged derivatives of nonacarbonyldiruthenium

Reaction of [Ru₂(μ-CO)(CO)₄{μ-(RO)₂PN(Et)(OR)₂}₂] (R = Me or Prⁱ) with the protonic acids HCl, HBr, HNO₃, H₂BO₂F, CF₃COOH, PhSH/HPF₆, and H₂CO₃/HPF₆ produces [Ru₂A(CO)₅ {μ-(RO)₂PN(Et)(OR)₂}₂]⁺ and/or [Ru₂(μ-A)(CO)₄{μ-(RO)₂PN(Et)(OR)₂}₂]⁺ (A = Cl, Br, ON(O)O, OB(F)OH, OC(CF₃)O, SPh, and OC(OH)O) via [Ru₂H(CO)₅{μ-(RO)₂PN(Et)(OR)₂}₂]⁺ as intermediate; the structure of [Ru₂{μ-OB(F)OH}(CO)₄{-(PrⁱO)₂PN(Et)P(OPrⁱ)₂}]⁺ has been established X-ray crystallographically.     

Synthesis of the solvento species [Ru2(CO)5(solvent){μ- (RO)2PN(Et)P(OR)2}2]2+ and its potential as a source for a wide range of dinuclear derivatives of ruthenium

Treatment of [Ru₂(μ-CO)(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂] (R = Me or Prⁱ), electron-rich derivatives of [Ru₂(CO)₉], with a twice molar amount of a silver(I) salt in aprotic, weakly co-ordinating solvents such as acetone, acetonitrile or benzonitrile leads to the formation of the solvento species [Ru₂(CO)₅(solvent)- {μ-(RO)₂PN(Et)P(OR)₂}₂]²⁺. The structure of the benzonitrile derivative, [Ru₂(CO)₅(PhCN){μ-(PrⁱO)₂PN(Et)P(OPr_i)₂}₂](SbF₆)₂, has been established by X-ray crystallography. The acetone molecule in [Ru₂(CO)₅(acetone){μ- (RO)₂PN(Et)P(OR)₂}₂]²⁺ is readily replaced by various nucleophiles to afford products of the type [Ru₂(CO)₅L{μ-(RO)₂PN(Et)P(OR)₂}₂]²⁺, where L is a neutral ligand such as CO, Me₂C₆H₃NC, PhCN, C₅H₅N, H₂O, Me₂S or SC₄H₈, [Ru₂Y(CO)₅{μ-(RO)₂PN(Et)P(OR)₂}₂]²⁺, where Y⁻ is an anionic ligand such as Cl⁻, Br⁻, I⁻, CN⁻, SCN⁻, MeCO₂⁻, CF₃CO₂⁻ or [Ru₂(μ-Y)(CO)₄{μ-(RO)₂- PN(Et)P(OR)₂}₂]⁺ where Y⁻ is an anionic ligand such as Cl⁻, Br⁻, I⁻, SPh⁻, S₂CNEt₂⁻, MeCO₂⁻ or CF₃CO₂⁻.     

A convenient entry into diruthenium chemistry

In boiling toluene, diphenylacetylene is readily displaced from the dimetallocycle [Ru₂(CO)(μ-CO) {μ-C(O)C₂Ph₂} (η-C₅H₅)₂] by a variety of reagents (P(OMe)₃, SO₂, R₂CN₂, Ph₂PCH₂) to produce [Ru₂(CO){P(OMe)₃}(μ-CO)₂ - (η-C₅H₅)₂] or [Ru₂(CO)₂(μ-CO)(μ-L)(η-C₅H₅)₂] (L  SO₂, CR₂, CH₂) in high yield.     

Reactions involving alkynes and tungsten-tungsten triple bonds supported by alkoxide ligands

W₂(OR)₆L_n compounds [R = Bu^t n = 0; R = Prⁱ or Np (Np = neopentyl), L = py (py = pyridine) or HNMe₂, n = 2] react with alkynes (R′C-CR′) under mild conditions (hexane solutions, room temperature or below) to yield a variety of products depending upon the nature of the alkoxide, the alkyne and the mole ratio of the reactants. The products include alkylidyne complexes L_n(RO)₃W CR′ (n = 1 or 0) (Schrock et al., Organometallics 1985, 4, 74), alkyne adducts, W₂(OR)₆(py)_n(μ-C₂R′₂), alkylidyne-capped tritungsten complexes, W₃(μ₃-CR′)(OR)₉, and W₂(OR)₆(L)(μ-C₄R′₄) or W₂(OR)₆(μ-C₄R′₄) (μ²-C₂R′₂) compounds. Evidence for equilibria involving alkyne adducts and alkylidyne species is found for certain combinations of R and R′. (1) The alkylidyne complexes (Bu^tO)₃ WCMe and (py)₂(Pr_iO)₃ W CNMe₂ react with CO (1 atm 22°C, in hexane) to yield alkyne adducts W₂(OBu^t)₆(μ-C₂Me₂)(CO) and W₂[(OPrⁱ)₆(CO)₂(η²-C₂(NMe₂)₂], respectively. (2) The alkylidyne complexes [Pr_iO)₂(HNMe₂)(R′C)W(μ-OPr_i)]₂ react with alkynes R′CCR′ (> 2 equiv, hexane, 22°C) to give W₂(OPr_i)₆(μ-C₄R′₄)(η²-C₂R′₂) compound (R′ = Me or Et). (3) The alkyne adducts W₂(ONp)₆(py)_n(μ-C₂R′₂) (R′ = Et or Ph, n = 1; R′ = Me, n = 2) react with W₂(ONp)₆(py)₂ in a 1:2 mole ratio at 22°C in hexane to yield W₃(μ₃-CR′)(ONp)(₉ compounds. In related reactions involving 1,2-bishydrocarbyl-tetraalkoxides, W₂(CH₂R″)₂(OR)₄, and alkynes (R′CCR′) (2 equiv), alkyne adducts of formula W₂(CH₂R″)₂(η²-C₂R′₂)₂(OPrⁱ)₄ and W₂(CH₃)₂(μ-C₂R′₂)(OBu^t)₄(py), alkylidyne-bridged complexes HW₂(μ-CR″)(μ-C₄R′₄)(OPr_i)₄ and products of WW and CC metathesis have been isolated for various combinations of R, R′ and R″.     

Molybdenum alkyl- and aryl-thiolates

The reaction between [(η⁵-C₅H₅)MoH(CO)₃] and disulphides gives dimeric or trimeric complexes depending upon the conditions. The syntheses of the novel trinuclear molybdenum carbonyl complex [{Mo(η⁵-C₅H₅)(SR)(μ-CO)(CO)}₃] (R = Me), and dinuclear compounds [Mo₂(η⁵-C₅H₅)(μ-SR)₃(CO)₄] (R = Me) and [Mo₂(η⁵-C₅H₅)₂(SR)₂(CO)₂(μ-SR)(μ-Br)] (R = Me or Ph) are reported.     

Formation of mixed-metal alkoxides mediated by the reactivity of coordinated pinacol: Synthesis and molecular structures of Ce2Ti2(μ3-O)2(μ,η2-OCMe2CMe2O)4(OPri)4(PriOH)2 and of Ce2Nb2(μ3-O)2(μ,η2-OCMe2CMe2O)4(OPri)6

The addition of pinacol to mixtures of titanium and cerium isopropoxides as well as the use of insoluble titanium and cerium pinacolate synthons was investigated as a route to M-Ce (M=Ti, Nb) species. Pinacol was able to promote the formation of mixed-metal species and the first Ce-Ti and Ce-Nb species namely Ce_2Ti(pin)₂(OPrⁱ)₈ and [M₂Ce₂(μ₃-O)₂(μ,η²pin)₄(OPrⁱ)₆H_x] [M=Ti, x=2; M=Nb, x=0; pin=OCMe₂-COMe₂] were isolated and characterized by FT-IR and ¹H NMR. The latter were also characterized by X-Ray diffraction. Their structures are based on a rhombus compressed along the M⋯M direction with 6-coordinated metals. The pinacolate moieties act as bridging-chelating ligands. The metal–oxygen bond lengths vary according to M–O(pin)<M-μ₃–O<Mμ–O(pin)<Ce–OPrⁱ<Ce–μ₃O.     

Synthesis and structural properties of a series of pentacoordinate rhodium nitrosyl complexes: Crystal and molecular structures of cis-dibromonitrosylbis(methoxydiphenylphosphine)rhodium and trans-dibromonitrosylbis(iso-propoxydiphenylphosphine)rhodium

The pentacoordinate rhodium nitrosyl complexes [RhBr₂(NO)L₂ [L = P(OPh)₂Ph, P(OMe)Ph₂ or P(OPrⁱ)Ph₂] have been synthesized and the structures of [RhBr₂(NO){P(OMe)Ph₂}₂] and [RhBr₂(NO){P(OPrⁱ)Ph₂}₂] have been determined X-ray crystallographically. Both of these latter compounds are tetragonal pyramidal with the nitrosyl group apical. The methoxydiphenylphosphine ligands in [RhBr₂(NO){P(OMe)Ph₂}₂] are cis-disposed whereas the larger cis-propoxydiphenylphosphine ligands in [RhBr₂(NO){P(OPrⁱ)Ph₂}₂] are mutually trans. The nitrosyl group in trans-[RhBr₂(NO){P(OPrⁱ)Ph₂}₂] eclipses an Rh-P axis but in cis-[RhBr₂(NO){P(OMe)Ph₂}₂] it is staggered with respect to the P-Rh-P linkage. The isomeric behaviour of nitrosyl complexes of type [RhX₂(NO)L₂] (X = halogen, L = phosphorus donor ligand) is rationalized in terms of the size of the ligand L.     

Gallium alkoxides: Synthesis and properties

Compounds Ga(OR)₃ (R = Me, Et, Prⁱ, Buⁿ, C₂H₄OMe) were synthesized by exchange reactions between gallium chloride and alkali metal alkoxides, the reetherefication of Ga(OPrⁱ)₃ and Ga(OC₂H₄OMe)₃ by other ROH (R = Me, Et), and anodic dissolution of metallic gallium in the presence of a electroconductive additive (LiCl, Bu₄NBr). When solid GaCl₃ is introduced into an alcoholic solution of NaOEt, stable soluble gallium oxoalkoxyhalides are formed. The same reaction with a GaCl₃ solution in toluene or electrochemical synthesis produces nonvolatile Ga(OEt)₃ samples, which have the polymer zigzag configuration [Ga(OR)_4/2(OR)]_∞. Mass spectrometry shows that only Ga(OPrⁱ)₃ and freshly prepared X-ray amorphous Ga(OEt)₃ samples (produced by reetherefication) are transferred to the gas phase. The spectra of the latter contain ions generated by penta-and hexanuclear oxoalkoxide molecules, along with fragments of orthospecies [Ga(OEt)₃]_2?4. IR spectra are described for all compounds synthesized.     

Synthesis and characterization of heterobimetallic mixed-ligand complexes containing Zr(μ-OPri)2Al bridging units

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPrⁱ) _n }₂ (L)] (where M = Al, n = 4, L = OC₆H₄CH = NCH₂CH₂O (1); M = Nb, n = 6, L = OC₆H₄CH = NCH₂CH₂O (2); M = Al, n = 4, L = OC₁₀H₆CH = NCH₂CH₂O (3); M = Nb, n = 6, L = OC₁₀H₆CH = NCH₂CH₂O (4)), [Zr{Al(OPrⁱ)₄}₂Cl(OAr)] (where Ar = C₆H₃Me₂-2,5 (5); Ar = C₆H₂Me-4-Bu₂-2,6 (6), [Zr{Al(OPrⁱ)₄}₂(OAr)₂] (where Ar = C₆H₃Me₂-2,5 (7); Ar = C₆H₂Me-4-Bu₂-2,6 (8), [Zr{Al(OPrⁱ)₄}₃(OAr)] (where Ar = C₆H₃Me₂-2,5 (9); Ar = C₆H₃Me₂-2,6 (10), [ZrAl(OPrⁱ)_7-n (ON=CMe₂) _n ] (where n = 4 (11); n = 7 (12), [ZrAl₂(OPrⁱ)_10-n (ON=CMe₂) _n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPrⁱ)₄}₂{ON=CMe(R)} _n Cl_2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., ¹H-, and ²⁷Al- n.m.r.) studies.     

Some recent developments in the chemistry of multiply bonded dimetal complexes that contain the intramolecular bridging phosphine ligands R2P(CH2)nPR2

Recent synthetic and structural studies on multiply bonded complexes of stoichiometry M₂X₄[μ-R₂P(CH₂)_nPR₂]₂ (M = Mo, W or Re; X = Cl, Br or I; R = Me, Et or Ph; n = 1 or 2), the ditungsten(III) hydride W₂(μ-H)(μ-Cl)Cl₄(μ-dppm)₂ (dppm = Ph₂PCH₂PPh₂), Re₂Cl₄(μ-dmpm)₃ (dmpm = Me₂PCH₂PMe₂), and M₂(μ-Cl)₂ Cl₄(μ-R₂PCH₂PR₂)₂ (R = Me or Ph) are surveyed. The first examples of multiply bonded complexes that contain the Ph₂PCH  CHPPh₂ ligand (abbreviated dppee) are described, viz. the α- and β-isomers of M₂X₄(dppee)₂ (M = Mo or Re, X = Cl or Br). The reactions of Re₂X₄(dppm)₂ (X = Cl or Br) with RNC, RCN and CO ligands that yield complexes in which a metal-metal multiple bond is preserved are reviewed.     

Synthesis of novel termetallic isopropoxides

Novel termetallic isopropoxides are reported which may be represented by the general formulae: [(PrⁱO)₃M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂], [(PrⁱO)₂M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂]₂ [where M = Ti(IV), Zr(IV) and Hf(IV)] and [(PrⁱO)₄M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂] [where M = Nb(V) and Ta(V)]. Attempts to synthesize derivatives with the general formula, [(PrⁱO)₇M₂(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂] [where M = Ti(IV), Zr(IV) or Hf(IV)], were unsuccessful and in all such cases a mixture of M(OPrⁱ)₄ and [(PrⁱO)₃M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂] was obtained. All these derivatives are soluble in common organic solvents and with the exception of titanium(IV) derivatives, they can be volatilised without noticeable disproportionation. These products have been characterized by elemental analyses, molecular weights, IR, ¹H NMR and (in representative cases) mass spectral studies also.     

Olefin-aminocarbyne coupling in diiron complexes: Synthesis of new bridging aminoallylidene complexes

The bridging aminocarbyne complexes [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (R = Me, 1a; Xyl, 1b; 4-C₆H₄OMe, 1c; Xyl = 2,6-Me₂C₆ H₃) react with acrylonitrile or methyl acrylate, in the presence of Me₃NO and NaH, to give the corresponding μ-allylidene complexes [Fe₂{μ-η¹:η³- C_α(N(Me)(R))C_β(H)C_γ(H)(R′)}(μ-CO)(CO)(Cp)₂] (R = Me, R′ = CN, 3a; R = Xyl, R′ = CN, 3b; R = 4-C₆H₄OMe, R′ = CN, 3c; R = Me, R′ = CO₂Me, 3d; R = 4-C₆H₄OMe, R′ = CO₂Me, 3e). Likewise, 1a reacts with styrene or diethyl maleate, under the same reaction conditions, affording the complexes [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(R′)C_γ(H)(R″)}(μ-CO)(CO)(Cp)₂] (R′ = H, R″ = C₆H₅, 3f; R′ = R″ = CO₂Et, 3g). The corresponding reactions of [Ru₂{μ-CN(Me)(CH₂Ph)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (1d) with acrylonitrile or methyl acrylate afford the complexes [Ru₂{μ-η¹:η³-C_α(N(Me)(CH₂Ph))C_β(H)C_γ(H)(R′)}(μ-CO)(CO)(Cp)₂] (R′ = CN, 3h; CO₂Me, 3i), respectively.The coupling reaction of olefin with the carbyne carbon is regio- and stereospecific, leading to the formation of only one isomer. C-C bond formation occurs selectively between the less substituted alkene carbon and the aminocarbyne, and the C_β-H, C_γ-H hydrogen atoms are mutually trans.The reactions with acrylonitrile, leading to 3a-c and 3h involve, as intermediate species, the nitrile complexes [M₂{μ-CN(Me)(R)}(μ-CO)(CO)(NC-CHCH₂)(Cp)₂][SO₃CF₃] (M = Fe, R = Me, 4a; M = Fe, R = Xyl, 4b; M = Fe, R = 4-C₆H₄OMe, 4c; M = Ru, R = CH₂C₆H₅, 4d).Compounds 3a, 3d and 3f undergo methylation (by CH₃SO₃CF₃) and protonation (by HSO₃CF₃) at the nitrogen atom, leading to the formation of the cationic complexes [Fe₂{μ-η¹:η³-C_α(N(Me)₃)C_β(H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CN, 5a; R = CO₂Me, 5b; R = C₆H₅, 5c) and [Fe₂{μ-η¹:η³-C_α(N(H)(Me)₂)C_β(H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CN, 6a; R = CO₂Me, 6b; R = C₆H₅, 6c), respectively.Complex 3a, adds the fragment [Fe(CO)₂(THF)(Cp)]⁺, through the nitrile functionality of the bridging ligand, leading to the formation of the complex [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(H)C_γ(H)(CNFe(CO)₂Cp)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (9).In an analogous reaction, 3a and [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃], in the presence of Me₃NO, are assembled to give the tetrameric species [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(H)C_γ(H)(CN[Fe₂{μ- CN(Me)(R)}(μ-CO)(CO)(Cp)₂])}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = Me, 10a; R = Xyl, 10b; R = 4-C₆H₄OMe, 10c).The molecular structures of 3a and 3b have been determined by X-ray diffraction studies.     

Synthesis and Spectroscopic [Electronic,IR, NMR (1H, 13C, 89Y)] Characterization of Hexaisopropoxoniobates and ‐Tantalates of Yttrium(III) and Lanthanides(III)

Hexaisopropoxoniobates/tantalates of lathanides of the type [Ln{(μ‐OPrⁱ)₂M(OPrⁱ)₄}₃] (M = Nb, Ln = Y( 1 ), La( 2 ), Nd( 3 ), Er( 4 ), Lu( 5 ); M = Ta, Ln = Y( 6 ), Gd( 7 )) have been prepared by the reactions of LnCl₃.3PrⁱOH with three equivalents of KM(OPrⁱ)₆ in benzene. Reactions in 1:2 molar ratio of LnCl₃.3PrⁱOH with KTa(OPrⁱ)₆ yielded derivatives of the type [{(PrⁱO)₃Ta(μ‐OPrⁱ)₃}Ln{(μ‐OPrⁱ)₂Ta(OPrⁱ)₄}(Cl)] (Ln = Y( 8 ), Gd( 9 )), which on interactions with one equivalent of KOPrⁱ afforded [{(PrⁱO)₃Ta(μ‐OPrⁱ)₃}Ln {(μ‐OPrⁱ)₂Ta(OPrⁱ)₄}(OPrⁱ)] (Ln = Y( 10 ), Gd( 11 )). All these derivatives have been characterized by elemental analyses and molecular weight measurements as well as by their spectroscopic [IR, ¹H and ¹³C NMR (Y, La, Lu), electronic (Nd, Er)] studies. ⁸⁹Y NMR studies have also been carried out on derivatives ( 6 ), ( 8 ), and ( 10 ).     

Fixation of Metallo Nitrile Ylides and Metallo Nitrile Imines as Ligands in Transition Metal Complexes [1]

1,3‐Dipoles of the type metallo nitrile ylide and metallo nitrile imine were prepared by mono‐α‐deprotonation of CH‐acidic {[W(CO)₅CHCH₂PPh₃]PF₆, M(CO)₅CNCH₂CO₂R (M = Cr, W; R = Me, Et), [Pt(Cl)(CNCH₂CO₂Et)(PPh₃)₂]BF₄} and NH‐acidic isocyanide complexes (Cr(CO)₅CNNH₂) and were stabilized by coordination to a second transition metal complex fragment {Cr(CO)₅, [M(CO)₅]⁺ (M = Mn, Re), [FeCp(CO)₂]⁺, [Pt(Cl)(PR₃)₂]⁺ (R = Et, Ph)}. All dinuclear products 1 – 7 , 10 , and 11 are neutral species except [(Ph₃P)₂(Cl)Pt{μ₂‐CNCH(CO₂Et)}Pt(Cl)(PPh₃)₂]BF₄ ( 8 ). Complex (OC)₅W{μ₂‐CNCH(CO₂Et)}Pt(Cl)(PEt₃)₂ ( 5b ) was characterized by X‐ray diffraction. Twofold deprotonation/platination to give (OC)₅Cr{μ₃‐CNC(Ph)}[Pt(Cl)(PPh₃)₂]₂ ( 9 ) was achieved in the case of Cr(CO)₅CNCH₂Ph.     

Synthesis and reactions of phosphido-bridged μ3-alkylidyne clusters; X-ray crystal structures of the complexes [Co2W(μ-PEt2)3(CO)5(η-C5H5)], [Co2W{μ3-C(R)C(Et)C(Et)C(O)}(μ-CO)(CO)4(PPh2{C(Et)CHEt})(η-C5H5)], and [CoW{μ-C(R)C(Et)C(Et)C(OH)}(CO)4(η-C5H5)] (R = C6H4Me-4)

Reactions of the phosphido-bridged complexes [Co₂W(μ-H)(μ₃-CC₆H₄Me-4)(μ-PR₂)(CO)₆(η-C₅H₅)] (R = Ph or Et) with PR₂H (R = Ph or Et) or RCCR (R = Me or Et) are dominated by processes involving facile PC, CC and CH bond formation. The X-ray structures of the complexes [Co₂W(μ-PEt₂)₃(CO)₅(η-C₅H₅)], [Co₂W{μ₃-C(R)C(Et)C(Et)C(O)}(μ-CO)(CO)₄(PPh₂{C(Et)CHEt})(η-C₅H₅)], and [CoW{μ-C(R)C(Et)C(Et)C(OH)}(CO)₄(η-C₅H₅)] (R = C₆H₄Me-4) have been determined.