66172-60-9Relevant academic research and scientific papers
ELECTRON TRANSFER IN ORGANOMETALLIC CLUSTERS XI. REDOX CHEMISTRY OF M3(CO)12 (M = Ru, Os) AND PPh3 DERIVATIVES; MECHANISM OF CATALYSED NUCLEOPHILIC SUBSTITUTION
Downard, Alison J.,Robinson, Brian H.,Simpson, Jim,Bond, Alan M.
, p. 363 - 384 (1987)
The generality of a two-electron reduction process involving an mechanism has been established for M3(CO)12 and M3(CO)12-n(PPh3)n (M = Ru, Os) clusters in all solvents.Detailed coulometric and spectral studies in CH2Cl2 provide strong evidence for the formation of an 'opened' M3(CO)122- species the triangulo radical anions M3(CO)12 having a half-life of -6 s in CH2Cl2.However, the electrochemical response is sensitive to the presence of water and is concentration dependent.An electrochemical response for 'opened' M3(CO)122- is only detected at low concentrations -4 mol dm-3 and under drybox condition.The electroactive species found at higher concentrations and in the presence of water M3(CO)112- and M6(CO)182- were confirmed by a study of the electrochemistry of these anions in CH2Cl2; HM3(CO)11- is not a product.The couple -/2- is chemically reversible under certain conditions but oxidation of HM3(CO)11- is chemically irreversible.Different electrochemical behaviour for Ru3(CO)12 is found when (X = OAc-, Cl-) salts are supporting electrolytes.In these solutions formation of the ultimate electroactive species - at the electrode is stopped under CO or at low temperatures but Ru3(CO)12- is still trapped by reversible attack by X presumably as 1-C(O)XRu3(CO)11>-.It is shown that electrode-initiated electron catalysed substitution of M3(CO)12 only takes place on the electrochemical timescale when M = Ru, it is slow, inefficient and non-selective, whereas BPK-initiated nucleophilic substitution of Ru3(CO)12 is only specific and fast in ether solvents particularly THF.Metal-metal bond cleavage is the most important influence on the rate and specificity of catalytic substitution by electron or -initiation.The redox chemistry of M3(CO)12 clusters (M = Fe, Ru, Os) is a consequence of the relative rates of metal-metal bond dissociation, metal-metal bond strength and ligand dissociation and in many aspects resembles their photochemistry.
Nmr studies of Ru3(CO)10(PMe2Ph)2 and Ru3(CO)10(PPh3)2 and their H2 addition products: Detection of new isomers with complex dynamic behavior
Blazina,Duckett,Dyson,Johnson,Lohman,Sleigh
, p. 9760 - 9768 (2007/10/03)
The clusters Ru3(CO)10L2, where L = PMe2Ph or PPh3, are shown by NMR spectroscopy to exist in solution in at least three isomeric forms, one with both phosphines in the equatorial plane on the same ruthenium center and the others with phosphines in the equatorial plane on different ruthenium centers. Isomer interconversion for Ru3(CO)10(PMe2Ph)2 is highly solvent dependent, with ΔH? decreasing and ΔS? becoming more negative as the polarity of the solvent increases. The stabilities of the isomers and their rates of interconversion depend on the phosphine ligand. A mechanism that accounts for isomer interchange involving Ru - Ru bond heterolysis is suggested. The products of the reaction of Ru3(CO)10L2 with hydrogen have been monitored by NMR spectroscopy via normal and para hydrogen-enhanced methods. Two hydrogen addition products are observed with each containing one bridging and one terminal hydride ligand. EXSY spectroscopy reveals that both intra- and interisomer hydride exchange occurs on the NMR time scale. On the basis of the evidence available, mechanisms for hydride interchange involving Ru - Ru bond heterolysis and CO loss are proposed.
Synthesis and characterization of mixed ruthenium/platinum μ4-phosphinidene, phosphorus monoxide, and related clusters
Scoles,Yamamoto,Brissieux,Sterenberg,Udachin,Carty
, p. 6731 - 6736 (2008/10/08)
The mixed-metal cluster complexes [Ru4(CO)12Pt(CO)PPh3(μ4-PR)] [R = NiPr2(1), F(3)] were formed by capping the Ru3P face of the nido clusters [Ru4(CO)13(μs
Ruthenium carbonyl cluster complexes with nitrogen ligands. III. Reaction of Ru3(μ-AuPPh3)(μ-Cl)(CO)10 with pyridine; crystal structures of Ru3(μ-H)(μ-NC5H4)(CO)9(PPh3), Ru3(μ-Cl)2(CO)8(NC5H5)(PPh3) and Ru3(μ-Cl)2(CO)8(NC5H5)2
Cifuentes, Marie P.,Humphrey, Mark G.,Skelton, Brian W.,White, Allan H.
, p. 211 - 220 (2007/10/02)
The reaction between Ru3(μ-AuPPh3)(μ-Cl)(CO)10 (1) and pyridine afforded a mixture of products from which the title complexes Ru3(μ-H)(μ-NC5H4)(CO)9(PPh3) (4), Ru3(μ-Cl)2(CO)8(NC5H5)(PPh3) (6) and Ru3(μ-Cl)2(CO)8(NC5H5)2 (7) have been obtained together with the previously reported pyridyl cluster Ru3(μ-H)(μ-NC5H4)(CO)10 (2) and the phosphine-substituted clusters Ru3(CO)10(PPh3)2 (3) and Ru3(μ-Cl)2(CO)8(PPh3)2 (5).Complex 4 has also been obtained with a high yield by phosphine substitution of 2 under mild conditions.The structural study of 4 reveals site-specific substitution at the N-ligated ruthenium.Products 5-7 are dichloro-bridged complexes related by successive replacement of PPh3 by NC5H5.Single-crystal X-ray diffraction studies of 6 and 7 indicate that these complexes contain triruthenium cores incorporating one and two ?-bound equatorially disposed pyridine ligands respectively, a new coordination mode for unsupported pyridine ligands on triruthenium clusters.Extremely long Ru-N distances in 6 and 7 are consistent with the lightly stabilizing nature of the pyridine ligand in trinuclear cluster chemistry.A comparison of the core geometries of 5-7 has revealed a contraction in the Ru-Ru distances on sequential replacement of the P-donor ligand by the N-donor ligand. Key words: Ruthenium; Carbonyl; Pyridine; Crystal structure
Oxygen atom transfer to metal carbonyls. Kinetics and mechanism of CO substitution reactions of M3(CO)11L (M = Fe, Ru, Os) in the presence of (CH3)3NO
Shen, Jian-Kun,Gao, Yi-Ci,Shi, Qi-Zhen,Basolo, Fred
, p. 4236 - 4239 (2008/10/08)
The rates and activation parameters are reported for CO-substitution reactions of M3(CO)11L (M = Fe, L = P(OEt)3, P(OMe)3; M = Ru, Os, L = P(OEt)3, P(OMe)3, P(n-Bu)3, PPh3, AsPh3, SbPh3) in the presence of (CH3)3NO. The rates of reaction are second order, first order in (CH3)3NO concentration, first order in M3(CO)11L concentration, and zero order in entering ligand concentration. For phosphite derivatives, the relative rates are M3(CO)11P(OMe)3 > M3(CO)11P(OEt)3. For other ligand-substituted complexes, the rates of reaction increase with increasing stretching frequency of the CO bands in the IR spectra. The mechanism involved appears to be similar to that proposed earlier of attack by the O atom of (CH3)3NO on a C atom of a CO coordinated to an unsubstituted metal atom. The unexpected slow rates for the reactions of M3(CO)11P(OR)3 are discussed in terms of shorter M-M bond distances in the cluster.
Wavelegth-, Medium-, and Temperature-Dependent Competition between Photosubstitution and Photofragmentation in Ru3(CO)12 and Fe3(CO)12: Detection and Characterization of Coordinatively Unsaturated M3(CO)11 Complexes
Bentsen, James G.,Wrighton, Mark S.
, p. 4530 - 4544 (2007/10/02)
Irradiation of 0.1 mM Ru3(CO)12 (λ = 313 nm) or 0.02 mM Fe3(CO)12 (λ = 366 nm) in a methylcyclohexane or 2-methyltetrahydrofuran (2-MeTHF) glass at 90 K yields loss of one CO as the only IR detectable photoreaction to yield products formulated as M3(CO)11 or M3(CO)11(2-MeTHF), respectively.An initially observed axially vacant form of Ru3(CO)11 (II) having no bridging CO's rearranges at 90 K to an axially vacant form (III), having at least one bridging CO, also adopted by Fe3(CO)11 in an alkane glass.An initially observrd, equatorially substituted form of Ru3(CO)11(2-MeTHF) (I') rearranges at 90 K to III or a 2-MeTHF adduct of III.I' is extremely photosensitive with respect to further substitution by 2-MeTHF for up to three CO ligands.Ru3(CO)11 (III) reacts with N2 or 13CO to yield Ru3(CO)11(N2) or axial-13CO-Ru3(CO)11(13CO) complexes, respectively.Ru3(CO)11 and Fe3(CO)11 react with C2H4 to yield M3(CO)11(C2H4) complexes.M3(CO)11 (III) reacts with PPh3 to yield Ru3(CO)11(Ph3) at 298 K and Fe3(CO)11(PPh3) at 195 K.Long wavelegth excitation of Ru3(CO)12 (λ = 366 nm) or Fe3(CO)12 (λ = 436 nm) yields negligible photochemistry in alkane or 2-MeTHF glasses but yields associative photosubstitution of C2H4, C5H10, and 13CO but not N2 or 2-MeTHF for CO at 90 K.Long wavelegth (λ > 540 nm) excitation of Fe3(CO)12 yields no photochemistry at 90 K but gives assymetric fragmentation in C2H4-containing alkane solutions at 298 K to yield 1 equiv each of Fe(CO)5, Fe(CO)4(C2H4), and Fe(CO)3(C2H4)2; competitive photosubstitution occurs in the presence of PPh3 to yield Fe3(CO)11(PPh3).At 195 K, the Fe3(CO)11L/Fe(CO)5-n(L)n (L = C2H4, PPh3; n = 0-2) product ratios increase with decreasing irradiation wavelegth.Long wavelegth (λ > 420 nm) irradiation of o.2 mM Ru3(CO)12 in 195 K alkane solutions containing excess L = CO or C2H4 initially yields 1 equiv each of Ru(CO)4L and Ru2(CO)8L; Ru2(CO)8(C2H4) fragments at 195 K to yield 2 more equiv of Ru(CO)4(C2H4).Long wavelength irradiation of Ru3(CO)12 in PPh3-containing solutions at 195 K yields conversion to a CO-bridged product which reacts thermally at 195 K to form Ru(CO)11(PPh3), in competition with Ru3(CO)12 regeneration; Ru(CO)4(PPh3) and Ru(CO)3(PPh3)2 are only observed as secondary photoproducts at 195 K.The low temperature photochemistry of Ru3(CO)12 is discussed in terms of a wavelength-dependent competition between dissociative loss of equatorial CO from higher energy excitation and generation of a nonradical, reactive isomer of Ru(CO)12 from long wavelength excitation.Implications of the new results for the photocatalyzed isomerization of 1-pentene to cis- and trans-2-pentene by M3(CO)12 (M = Ru, Fe) precursors are discussed.
THE PREPARATION, CHARACTERIZATION AND SOME REACTIONS OF AND
Foulds, G. A.,Johnson, B. F. G.,Lewis, J.
, p. 147 - 154 (2007/10/02)
The clusters and have been prepared from the reaction of with NMe3O in the presence of CH3CN.Thus, these new clusters have been shown to be convenient precursors in the preparation of other Ru3 cluster spec
Cyclopentadienyl-Ruthenium and -Osmium Chemistry. XXII. Synthesis, X-Ray Structure and Some Reactions of RuCl(PPh3)(η1-Ph2PCH2PPh2)(η-C5H5), Containing a Monodentate CH2(PPh2)2 Ligand
Bruce, Michael I.,Humphrey, Mark G.,Patrick, Jennifer M.,White, Allan H.
, p. 2065 - 2072 (2007/10/02)
Stoichiometric amounts of RuCl(PPh3)2(η-C5H5) and dppm react in refluxing C6H6 to give RuCl(PPh3)(η1-dppm)(η-C5H5), which has been fully characterized by an X-ray study (triclinic, space group P, a 22.377(6), b 9.913(2), c 9.826(3) Angstroem, α 70.46(2), β 78.72(2), γ 80.40(2) deg, Z 2) in which 3299 data were refined to R 0.046, R' 0.052.Structural parameters are similar to those of other RuX(PR3)2(η-C5H5) complexes.The chloro complex was converted was converted into 2-dppm)(η-C5H5)>+ salts; the other PPh3 ligand can be replaced by a second dppm ligand to give +, which contains both mono- and bidentate dppm ligands.Alkylation of the uncoordinated phosphorus with Mel is accompanied by halogen exchange to give I, while reactions with a variety of transition metal complexes result in abstraction of PPh3 and formation of RuCl(dppm)(η-C5H5).
CLUSTER CHEMISTRY. XVII. RADICAL ION-INITIATED SYNTHESES OF RUTHENIUM CLUSTER CARBONYLS CONTAINING TERTIARY PHOSPHINES, PHOSPHITES, ARSINES, SbPh3 OR ISOCYANIDES
Bruce, Michael I.,Matisons, Janis G.,Nicholson, Brian K.
, p. 321 - 344 (2007/10/02)
The syntheses of over sixty known and new derivatives of Ru3(CO)12 and H4Ru4(CO)12 by substitution reactions initiated by sodium diphenylketyl are described.The range of ligands studied includes isocyanides, tertiary phosphines and phosphites, tertiary ar
