Synthesis and Reactivity of Organometallic Intermediates Relevant to Cobalt‐Catalyzed Hydroformylation

Intermediates relevant to cobalt‐catalyzed alkene hydroformylation have been isolated and evaluated in fundamental organometallic transformations relevant to aldehyde formation. The 18‐electron (R,R)‐(^iPrDuPhos)Co(CO)₂H has been structurally characterized, and it promotes exclusive hydrogenation of styrene in the presence of 50 bar of H₂/CO gas (1:1) at 100 °C. Deuterium‐labeling studies established reversible 2,1‐insertion of styrene into the Co?D bond of (R,R)‐(^iPrDuPhos)Co(CO)₂D. Whereas rapid β‐hydrogen elimination from cobalt alkyls occurred under an N₂ atmosphere, alkylation of (R,R)‐(^iPrDuPhos)Co(CO)₂Cl in the presence of CO enabled the interception of (R,R)‐(^iPrDuPhos)Co(CO)₂C(O)CH₂CH₂Ph, which upon hydrogenolysis under 4 atm H₂ produced the corresponding aldehyde and cobalt hydride, demonstrating the feasibility of elementary steps in hydroformylation. Both the hydride and chloride derivatives, (X=H^?, Cl^?), underwent exchange with free ¹³CO. Under reduced pressure, (R,R)‐(^iPrDuPhos)Co(CO)₂Cl underwent CO dissociation to form (R,R)‐(^iPrDuPhos)Co(CO)Cl.     

Syntheses and Catalytic Hydrogenation Performance of Cationic Bis(phosphine) Cobalt(I) Diene and Arene Compounds

Chloride abstraction from [(R,R)‐(^iPrDuPhos)Co(μ‐Cl)]₂ with NaBAr^F₄ (BAr^F₄=B[(3,5‐(CF₃)₂)C₆H₃]₄) in the presence of dienes, such as 1,5‐cyclooctadiene (COD) or norbornadiene (NBD), yielded long sought‐after cationic bis(phosphine) cobalt complexes, [(R,R)‐(^iPrDuPhos)Co(η²,η²‐diene)][BAr^F₄]. The COD complex proved substitutionally labile undergoing diene substitution with tetrahydrofuran, NBD, or arenes. The resulting 18‐electron, cationic cobalt(I) arene complexes, as well as the [(R,R)‐(^iPrDuPhos)Co(diene)][BAr^F₄] derivatives, proved to be highly active and enantioselective precatalysts for asymmetric alkene hydrogenation. A cobalt–substrate complex, [(R,R)‐(^iPrDuPhos)Co(MAA)][BAr^F₄] (MAA=methyl 2‐acetamidoacrylate) was crystallographically characterized as the opposite diastereomer to that expected for productive hydrogenation demonstrating a Curtin–Hammett kinetic regime similar to rhodium catalysis.     

Xantphite: A New Family of Ligands for Catalysis. Applications in the Hydroformylation of Alkenes

The novel bulky diphosphite (P∩P) ligands ( 3 and 4 ) based on the 2,7,9,9‐tetramethyl‐9H‐xanthene‐4,5‐diol ( 2 ) backbone were investigated in the Rh‐catalyzed hydroformylation of oct‐1‐ene, styrene, and (E)‐oct‐2‐ene. These diphosphites gave rise to very active and selective catalysts for the hydroformylation of oct‐1‐ene to nonanal with average rates>10000 (mol aldehyde)(mol Rh)⁻¹h⁻¹ (P(CO/H₂)=20 bar, T=80°, [Rh]=1 mM ) and maximum selectivities of 79% for the linear product. Relatively high selectivities towards the linear aldehyde (up to 70%, linear/branched up to 2.3) but very high activities (up to 39000 (mol aldehyde)(mol Rh)⁻¹h⁻¹) were observed for the hydroformylation of styrene in the presence of these bidentate ligands (P(CO/H₂)=2 – 10 bar, T=120°, [Rh]=0.2 mM ). Remarkable activities (up to 980 (mol aldehyde)(mol Rh)⁻¹h⁻¹) were achieved with these diphosphites for the hydroformylation of (E)‐oct‐2‐ene with selectivities for the linear product of 74% (l/b up to 2.8, P(CO/H₂)=2 bar, T=120°, [Rh]=1 mM ). A detailed study of the solution structure of the catalyst under catalytic conditions was performed by NMR and high‐pressure FT‐IR. The spectroscopic data revealed that under hydroformylation conditions, the bidentate ligands rapidly formed stable, well‐defined catalysts with the structure [RhH(CO)₂(P∩P)]. All the ligands showed a preference for an equatorial‐apical ( ea ) coordination mode in the trigonal bipyramidal Rh‐complexes, indicating that a bis‐equatorial ( ee ) coordination is not a prerequisite for highly selective catalysts.     

Rhodium catalyzed deuteroformylation of styrene: (E)- and (Z)-β-deuterostyrene and β,β-dideuterostyrene formation via selective β-hydride elimination from the branched alkylrhodium intermediate

Deuteroformylation of styrene in the presence of Rh₄(CO)₁₂ as a catalytic precursor was carried out at 160 atm of CO and D₂ 1/1 at two temperatures (20 and 90°C) and for times yielding partial or complete conversion. Compounds recovered from the mixture produced by reaction and partial conversion at 90°C include unlabeled styrene, (E)- and (Z)-β-deuterostyrene, C₆H₅CHCHD, and β,β-dideuterostyrene, C₆H₅CHCD₂, whereas at room temperature the styrene does not take up deuterium. These results indicate that under hydroformylation conditions the branched alkylrhodium intermediate, which affords the branched aldehyde, in part dissociates into rhodium hydride and deuterated olefin. By contrast the linear alkyl intermediate does not dissociate under the same conditions, but instead yields almost completely the corresponding aldehyde.     

Reactions of conjugated dienes with cobalt carbonyls under hydroformylation conditions. a high pressure i.r. spectroscopic study

Summary The chemistry of cobalt carbonyls in the presence of dienes and high pressure of synthesis gas was studied by online i.r. spectroscopy. Dicobalt octacarbonyl reacts with butadiene under 95 bar CO/H₂ and 80°C to give [³-C₄H₇Co(CO)₃] (1) and [⁴-C₄H₆)₂Co₂(CO)₄] (2). Hydrogenation or hydroformylation are observed only with [HCo(CO)₄] as the starting catalyst, and only at the beginning of the reaction. The results are explained by formation of an alkenyl complex, [-C₄H₇Co(CO)₄], which either reacts with [HCo(CO)₄] to give butene and [Co₂(CO)₈], or loses CO to give (1), depending on the [HCo(CO)₄] concentration. The butene is hydroformylated. At temperatures >100°C (1) is transformed into a CO-free species, which catalyzes the oligomerisation of butadiene. Addition of tributylphosphine (L) leads to the formation of [³-C₄H₇Co(CO)₂L] (5) and [Co₂(CO)₆L₂] (6). In (5) the -allyl moiety is more labile than in (1) and a slow hydrogenation and hydroformylation of the butadiene is observed. In methanol solution the reaction of the cobalt carbonyls to give (1) is incomplete and the remaining H⁺ and [Co(CO)₄]^– catalyze the hydroformylation of butadiene. Isoprene is less reactive than butadiene but otherwise behaves similarly.     

Manganese‐σ‐Borane Complexes from Dihaloboranes

The hydride complex K[(η⁵‐C₅H₅)Mn(CO)₂H] reacted with a range of dihalo(organyl)boranes X₂BR (X = Cl, Br; R = tBu,Mes, Ferrocenyl) to give the corresponding borane complexes[(η⁵‐C₅H₅)Mn(CO)₂(HB(X)R)]., The presence of a hydride in bridging position between manganese and boron was deduced from ¹¹B decoupled ¹H NMR spectra. Additionally, the structure of the tert‐butyl borane complex was confirmed by single‐crystal X‐ray diffraction.     

Crystal and Molecular Structure of Carbonyl (1,1,4,4-Tetrafluoro-2-tert-Butyl-1,4-Disilabut-2-Ene) (η5-Cyclopentadienyl) Cobalt (II)

(C₃H₅)Co(CO)(Si₂F₄C₄H₁₀) was synthesized by the photochemical reaction between dicarbonyl (η⁵-cyclopentadienyl) cobalt and 1,1,2,2-tetrafluoro-1,2,-disilacyclobutene. Its structure was identified by IR, NMR and mass spectrometry. The single crystal structure was studied for confirmation. The compound crystalized in a monoclinic space group P2₁/n with unit cell a=7.120 (6), b=20.334. (3), c=10.682(1) Å, β=90.97(8)°, Z=4 final R=0.050 for 3667 observed reflections. The molecule has a mirror plane symmetry about the Co atom coordination sphere. The reaction between the cobalt carbonyl and the 1,2-disilacyclobutene produces only silicon-cobalt σ bonds.     

STEREOCHEMISTRY OF (R)-2-METHYLAZIRIDINE COMPLEXES OF COBALT(III) AND DIMERIZATION OF THE LIGAND

Abstract

A cobalt(III) complex containing (R)-2-methylaziridine (R-meaz), [Co(R-meaz)(NH₃)₅]³⁺, was prepared and the two diastereomers arising from the presence of the chiral nitrogen atom (N(R) and N(S)) were separated by column chromatography. Molecular mechanics calculations estimated the N(R)-isomer to be more stable. This result was supported by the x-ray structure determination of the more abundant (ca. 94%) isomer, N(R)-[Co(R-meaz)(NH₃)₅]Br₃H₂O. Crystal data: monoclinic, P2₁, a = 7.357(1), b = 9.780(1), c = 10.426(1) Å, μ = 93.58(1)°, V= 748.7(3) ų, Z= 2. Kinetic studies of isomerization (epimerization) between the two isomers revealed that inversion at the nitrogen center was very slow (5 × 10^?2 M^?1 S^?1at 25 °C). The small rate constant seems to be related to the strained three-membered structure of the meaz ligand. The reaction of Na₃[Co(N0₂)6] and R-meaz yielded a complex containing two dimerized R-meaz chelates, trans-[Co(NO₂)2(di-R-meaz)₂] (di-R-meaz =RR)-α,2-dimethyl-l-aziridineethanamine). The crystal strucrure of trans-[Co(NO₂)₂ (di-R-meaz)₂]C1O₄H₂O was established by x-ray crystallography. Crystal data: orthorhombic, P2₁2₁2₁, a = 11.784(6), b = 21.023(9), c = 8.608(7) Å, V = 2133(2) ų, Z = 4.     

Syntheses and Structures of Two Selenite Chloride Hydrates: Co(HSeO3)Cl · 3 H2O and Cu(HSeO3)Cl · 2 H2O

The first selenite chloride hydrates, Co(HSeO₃)Cl · 3 H₂O and Cu(HSeO₃)Cl · 2 H₂O, have been prepared from solution and characterised by single‐crystal X‐ray diffraction. The cobalt phase adopts an unusual “one‐dimensional” structure built up from vertex‐sharing pyramidal [HSeO₃]^2–, and octahedral [CoO₂(H₂O)₄]^2– and [CoO₂(H₂O)₂Cl₂]^4– units. Inter‐chain bonding is by way of hydrogen bonds or van der Waals' interactions. The atomic arrangement of the copper phase involves [HSeO₃]^2– pyramids and Jahn‐Teller distorted [CuCl₂(H₂O)₄] and [CuO₄Cl₂]^8– octahedra, sharing vertices by way of Cu–O–Se and Cu–Cl–Cu bonds. Crystal data: Co(HSeO₃)Cl · 3 H₂O, M_r = 276.40, triclinic, space group P 1 (No. 2), a = 7.1657(5) Å, b = 7.3714(5) Å, c = 7.7064(5) Å, α = 64.934(1)°, β = 68.894(1)°, γ = 71.795(1)°, V = 337.78(7) ų, Z = 2, R(F) = 0.036, wR(F) = 0.049. Cu(HSeO₃)Cl · 2 H₂O, M_r = 263.00, orthorhombic, space group Pnma (No. 62), a = 9.1488(3) Å, b = 17.8351(7) Å, c = 7.2293(3) Å, V = 1179.6(2) ų, Z = 8, R(F) = 0.021, wR(F) = 0.024.     

Synthesis and catalysis of a silica-supported cobalt carbonyl cluster

The supported metal cluster, Co₄(CO)₈(μ₂-CO)₂(μ₄-PC₆H₄)/(SiO₂) (2), which decomposed at 290°C, was synthesized. The cobalt and phosphorus contents were 10.51 and 2.64%, respectively. The IR spectrum of 2 exhibits absorptions at 2010 and 1840 cm⁻¹ assigned to the terminal carbonyl and bridged carbonyl, respectively. The effects of the reaction conditions and the structure of olefins on the hydroformylation using 2 have been investigated. Nearly 100% conversion and selectivity could be reached by hydroformylation of 1-hexene under conditions of 130°C, 40 kg/cm², H₂/CO = 1, for 6 h. The rate order of hydroformylation of olefins was as follows: 1-hexene > cyclohexene > diisobutene > styrene. The catalytic activity was kept almost constant after ten-time repeated use (240 h).     

Ruthenium Tris(pyrazolyl)borate Complexes. Part 20 [1]. Synthesis,Characterization, and Reactivity of Neutral Trispyrazolylborate Ruthenium Vinylidene Complexes

Summary. The reaction of RuTp(COD)Cl (1) with PPh₂Prⁱ and terminal alkynes HCCR (R=C₆H₅, C₄H₃S, C₆H₄OMe, Fc, C₆H₄–Fc, C₆H₉) affords the neutral vinylidene complexes RuTp(PPh₂Prⁱ) (Cl)(=C=CHR) (2a–2f) in high yields. These complexes do not react with MeOH to give methoxy carbene complexes of the type RuTp(PPh₂Prⁱ)(Cl)(=C(OMe)CH₂R), but react with oxygen to yield the CO complex RuTp(PPh₂R)(Cl)(CO) (3). The structures of 2b, 2f, and 3 have been determined by X-ray crystallography.     

Stereoselectivity in Reactions of Metal Complexes. Part XV. Structure and stability of chiral cobalt(III) complexes with pentadentate ligands

The syntheses and characterization of four new linear pentadentate ligands and their Co^III complexes are described: N,N′-[(pyridine-2,6-diy)bis(methylene)]bis[sarcosine] (sarmp), N,N′-[(pyridine-2,6-diyl)bis(methylene)]bis[(R)- or (S)-proline] ((R,R)- or (S,S)-promp), N,N′-[(pyridine-2,6-diyl)bis(methylene)]bis[N-(methyl)-(R)- or (S)-alanine] ((R,R)- or (S,S)-malmp); 2,2′-[pyridine-2,6-diyl]bis[(S)- or rac-N-(acetic acid)pyrrolidine] ((S,S)- or rac-bapap). The complexes were characterized and, with but one exception, complex formation is stereospecific: Δ-exo-(R,R) (or Λ-exo-(S,S)) for promp and Λ-(R,R) (or Δ-(S,S)) for bapap. The exception is [Co((R,R)- or (S,S)-malmp)H₂O]ClO₄ for which two forms are obtained, to which Λ-endo-(R,R) (or Δ-endo-(S,S)) and, tentatively, Δ-unsymmetric-(R,R)- (or Λ-unsymmetric-(S,S)-) configurations are assigned. X-Ray crystal structures are presented for the complexes [Co(sarmp)H₂O]ClO₄, [Co((S,S)-promp)H₂O]ClO₄, [Co(rac-bapap)H₂O]ClO₄ and endo-[Co(rac-malmp)H₂O]ClO₄. Ligand acid dissociation and Co^II and Fe^II complex-formation constants are reported.     

Bis(2,4,7‐tri­methyl­indenyl)­cobalt(II) and rac‐2,2′,4,4′,7,7′‐hexamethyl‐1,1′‐biindene

The crystal and molecular structures of bis(η⁵‐2,4,7‐tri­methyl­indenyl)­cobalt(II), [Co(C₁₂H₁₃)₂], (I), and rac‐2,2′,4,4′,7,7′‐hexamethyl‐1,1′‐biindene, C₂₄H₂₆, (II), are reported. In the crystal structure of (I), the Co atom lies on an inversion centre and the structure represents the first example of a bis(indenyl)cobalt complex exhibiting an eclipsed indenyl conformation. The (1R,1′R) and (1S,1′S) enantiomers of the three possible stereoisomers of (II), which form as by‐products in the synthesis of (I), cocrystallize in the monoclinic space group P2₁/c. In the unit cell of (II), alternating (1R,1′R) and (1S,1′S) enantiomers pack in non‐bonded rows along the a axis, with the planes of the indenyl groups parallel to each other and separated by 3.62 and 3.69 Å.     

Ruthenium Tris(pyrazolyl)borate Complexes. Part 20 [1]. Synthesis, Characterization, and Reactivity of Neutral Trispyrazolylborate Ruthenium Vinylidene Complexes

The reaction of RuTp(COD)Cl (1) with PPh₂Prⁱ and terminal alkynes HCCR (R=C₆H₅, C₄H₃S, C₆H₄OMe, Fc, C₆H₄–Fc, C₆H₉) affords the neutral vinylidene complexes RuTp(PPh₂Prⁱ) (Cl)(=C=CHR) (2a–2f) in high yields. These complexes do not react with MeOH to give methoxy carbene complexes of the type RuTp(PPh₂Prⁱ)(Cl)(=C(OMe)CH₂R), but react with oxygen to yield the CO complex RuTp(PPh₂R)(Cl)(CO) (3). The structures of 2b, 2f, and 3 have been determined by X-ray crystallography.     

A novel heterobidentate chiral phosphine and its coordination chemistry in transition metal clusters

The optically active ligand R,R-PHAZAN (1,3-bis[(1R)-1-Phenylethyl]-2-(2-thienyl)-1,3,2-diazaphospholane) has been prepared and the products resulting from the reactions with Rh₆(CO)₁₅NCMe, H₃RhOs₃(CO)₁₂, and H₄Ru₄(CO)₁₂ have been investigated by X-ray crystallography and a variety of multinuclear NMR methods. X-ray studies show that PHAZAN can behave as a bidentate ligand in Rh₆(CO)₁₄(μ₂,κ²-R,R-PHAZAN) (with coordination through P and S) or a monodentate ligand (through P coordination) in H₄Ru₄(CO)₁₁(κ¹-R,R-PHAZAN) and NMR studies show that these structures are retained in solution. In Rh₆(CO)₁₄(μ₂,κ²-R,R-PHAZAN), edge-bridging coordination of PHAZAN results in the formation of an additional two novel chiral centres and these are observed in solution. Reaction of PHAZAN with H₃RhOs₃(CO)₁₂ results in cleavage of the thienyl group and formation of the phosphido cluster, H₂RhOs₃(CO)₁₁(μ₂-PNN), (PNN = 1,3-bis-(1-phenylethyl)-[1,3,2]diazaphospholidine-2-yl). A variety of NMR measurements show that the hydride site-occupancies in the solid state are retained in solution and there is evidence for interaction of an ortho-phenyl hydrogen and a hydride through “dihydrogen” bonding.     

Bis(cyclopentadienyl)methan-verbrückte Zweikernkomplexe,V. Heteronukleare Co/Rh-, Co/Ir-, Rh/Ir- und Ti/Ir-Komplexe mit dem Bis(cyclopentadienyl)methan-Dianion als Brückenliganden

Bis(cyclopentadienyl)methane-bridged Dinuclear Complexes, V^[1]. – Heteronuclear Co/Rh-, Co/Ir-, Rh/Ir-, and Ti/Ir Complexes with the Bis(cyclopentadienyl)methane Dianion as Bridging Ligand^* The lithium and sodium salts of the [C₅H₅CH₂C₅H₄]^- anion, 1 and 2 , react with [Co(CO)₄I], [Rh(CO)₂Cl]₂, and [Ir(CO)₃Cl]n to give predominantly the mononuclear complexes [(C₅H₅-CH₂C₅H₄)M(CO)₂] ( 3, 5, 7 ) together with small amounts of the dinuclear compounds [CH₂(C₅H₄)₂][M(CO)₂]₂ ( 4, 6, 8 ). The ¹H- and ¹³C-NMR spectra of 3, 5 , and 7 prove that the CH₂C₅H₅ substituent is linked to the π-bonded ring in two isomeric forms. Metalation of 5 and 7 with nBuLi affords the lithiated derivatives 9 and 10 from which on reaction with [Co(CO)₄I], [Rh(CO)₂Cl]₂, and [C₅H₅TiCl₃] the heteronuclear complexes [CH₂(C₅H₄)₂][M(CO)₂][M′(CO)₂] ( 11–13 ) and [CH₂(C₅H₄)₂]-[Ir(CO)₂][C₅H₅TiCl₂] ( 17 ) are obtained. Photolysis of 11 and 12 leads almost quantitatively to the formation of the CO-bridged compounds [CH₂(C₅H₄)₂][M(CO)(μ-CO)M′(CO)] ( 14, 15 ). According to an X-ray crystal structure analysis the Co/Rh complex 14 is isostructural to [CH₂(C₅H₄)₂][Rh₂(CO)₂(μ-CO)] ( 16 ).     

Synthesis and structures of five-coordinate bis-o-iminobenzosemiquinone complexes M(ISQ-R)2X (X = Cl, Br, I, or SCN; M = CoIII, FeIII, or MnIII)

New five-coordinate complexes Co(ISQ-Prⁱ)₂Cl, Co(ISQ-Me)₂Cl, Co(ISQ-Me)₂I, Co(ISQ-Me)₂(SCN), Mn(ISQ-Prⁱ)₂Cl, and Fe(ISQ-Me)₂Br (ISQ-Prⁱ and ISQ-Me are the 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-and 4,6-di-tert-butyl-N-(2,6-dimethylphenyl)-o-iminobenzosemiquinone radical anions, respectively) were synthesized. The complexes were characterized by UV-Vis and IR spectroscopy and magnetochemistry. The molecular structures of the Fe(ISQ-Me)₂Br and Mn(ISQ-Prⁱ)₂Cl complexes were established by X-ray diffraction. The singlet ground state (S = 0) of the cobalt complexes is caused by antiferromagnetic coupling between the unpaired electrons of the radical ligands (S = 1/2) through the fully occupied atomic orbitals of low-spin cobalt(III) (d⁶, S = 0). The effective magnetic moments of the complexes at 10 K are 0.18 μ_B for Co(ISQ-Prⁱ)₂Cl and 0.16 μ_B for Co(ISQ-Me)₂I. The ground state of the manganese complex is triplet (S = 1). Two unpaired electrons of the o-iminobenzosemiquinone ligands are strongly antiferromagnetically coupled with two of four unpaired electrons of high-spin manganese(III) (d⁴, S = 2). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 43–51, January, 2006.     

Hydrido cyclopentadienyliron dicarbonyl and its role in olefin hydroformylation

The compound hydrido cyclopentadienyliron dicarbonyl has been shown by infrared and proton NMR to be present in substantial quantities during hydroformylation of propene and 1-pentene in the presence of [(η⁵-C₅H₅)Fe(CO)₂]₂. This and related observations strongly suggest that the hydride is an important link in the catalytic cycle as is HCo(CO)₄ in Co₂(CO)₈-catalyzed olefin hydroformylation.     

Komplexchemie polyfunktioneller liganden : XXXVII. Darstellungsmethoden für hydrido-kobalt(I)-komplexe des 1,1,1-tris(diphenylphosphinomethyl)äthans

[Co(CO)₂(R₂PCH₂)₃CCH₃][Co(CO)₄] (R  C₆H₅) reacts with NaBH₄, depending on the reaction conditions, to give CoH(CO)₂(R₂PCH₂)₂C(CH₃)CH₂PR₂ · BH₃ and CoH(CO)(R₂PCH₂)₃CCH₃. The hydride CoH(CO)(R₂PCH₂)₃CCH₃ is also formed by the reaction of [Co(CO)₂(R₂PCH₂)₃CCH₃][Co(CO)₄] with LiOH, NaOH and NaNH₂. The reaction with LiOH primarily gives (acetone)₃-LiCo(CO)(R₂PCH₂)₃CCH₃, which is also formed by reduction of [Co(CO)₂(R₂PCH₂)₂C(CH₃)CH₂PR₂]₂ with lithium in THF/acetone solution. In liquid ammonia [Co(CO)₂(R₂PCH₂)₃CCH₃][Co(CO)₄] at 20°C yields Co(CONH₂)(CO)(R₂PCH₂)₃CCH₃. This compound reacts in the same solvent at 60°C to yield the hydride CoH(CO)(R₂PCH₂)₃CCH₃. CH₃I and HClO₄ react with CoH(CO)(R₂PCH₂)₃CCH₃ yielding CoI(R₂PCH₂)₃CCH₃ and the unstable [Co(H)₂(CO)(R₂PCH₂)₃CCH₃]ClO₄, respectively. The deutero complex CoD(CO)(R₂PCH₂)₃CCH₃ was also synthesized. The new compounds were characterized, as much as possible, by their IR, ¹H NMR and ³¹P NMR data.     

CATALYTIC BEHAVIOR OF SILICA-SUPPORTED POLY-γ- AMINOPROPYL- SILOXANE-Co-Ru BIMETALLIC COMPLEX FOR THE HYDROFORMYLATION OF CYCLOHEXENE

The cobalt and ruthenium bimetallic complex of poly-γ-amino-propylsiloxane( abbr. as Si-CH_2-Co-Ru) was prepared, and it was found that it can catalyze the hydroformylation of cyclobexene effectively with the conversion amounting to over 90%. Cyclohexanecarboxaldehyde was first formed in the hydroformylation, and then further hydrogenated to form cylcohexanemethanol. The coversion was affected obviously by the Co/Ru ratio.When Co/Ru molar ratio was 100-150, i.e. in the very low content of noble metal Ru, the catalytic activity of Si-NH_2 -Co-Ru was also very high. The product composition was affected by CO/H_2 ratio in the reaction gas. Aldehyde can be got high selectively by controlling CO/H_2 ratio. Compared with other catalyst system, the Si-NH_2-Co-Ru catalyst has higher catalytic activity and efficiency with very low Ru/Co ratio. The total turnover number was more than 28,800 (based on the amount of ruthenium used).