Cluster Chemsitry. 96. Penta- and hexa-nuclear ruthenium cluster complexes derived from reactions of cyclopentadienes with Ru5(μ5-C2PPh2)(μ-PPh2)(CO)13

The reactions between Ru₅( ₅-C₂PPh₂)(gm-PPh₂(CO)₁₃ (1) and cyclopentadienes afforded the hexanuclear clusters Ru₆( ₆-C)( ₃-PPh₂)₂(CO)₁₀(-C₅ R ₅) [R ₅ = H₅ (2), H₄Me (3), Me₅ (4)] which contain an encapsulated carbide and a face-capping ₃-CH group, formed by cleavage of CC and CP bonds of the C₂PPh₂ moiety in1. In the reaction with cyclopentadiene, the unusual ligand C₁₃H₁₂O, formed by combination of C₂, CO and two molecules of C₅H₆ (or one molecule of dicyclopentadien), was characterized in the complex Ru₅( ₄-PPh) ( ₄-C₁₃H₁₂O)(-PPh₂(CO)₁₁(-C₅H₅) (5). In the reaction with pentamethylcyclopentadiene, the vinylidene complex Ru₅( ₃-CCHPh)( ₄-PPh)( ₄-PPh) (-PPh₂)(CO)₉(-C₅Me₅) (6) was also formed.     

Further studies of the reactions of PtRu5(μ6-C)(CO)16 with alkynes: The preparation and structural characterizations of PtRu5(CO)13(μ-EtC2Et)(μ3-EtC2Et)(μ5-C) and Pt2Ru6(CO)17(μ-η5-Et4C5)(μ3-EtC2Et) (μ6-C)

The reaction of PtRu₅(CO)₁₆(μ₆-C),1 with 3-hexyne in the presence of UV irradiation produced two new electron-rich platinum-ruthenium cluster complexes PtRu₅(CO)₁₃(μ-EtC₂Et)(μ₃-EtC₂Et)(μ₅-C),2 (20% yield) and Pt₂Ru₆(CO)₁₇(μ-η⁵-Et₄C₅)(μ₃-EtC₂Et) (μ₆-C),3 (7% yield). Both compounds were characterized by single-crystal X-ray diffraction analyses. Compound2 contains of a platinum capped square pyramidal cluster of five ruthenium atoms with the carbido ligand located in the center of the square pyramid. A EtC₂Et ligand bridges one of the PtRu₂ triangles and the Ru-Pt bond between the apical ruthenium atom and the platinum cap. The structure of compound3 consists of an octahedral PtRu₅ cluster with an interstitial carbido ligand and a platinum atom capping one of the PtRu₂ triangles. There is an additional Ru(CO)₂ group extending from the platinum atom in the PtRu₅ cluster that contains a metallated tetraethylcyclopentadienyl ligand that bridges to the platinum capping group. There is also a EtC₂Et ligand bridging one of the PtRu₂ triangular faces to the capping platinum atom. Compounds2 and3 both contain two valence electrons more than the number predicted by conventional electron counting theories, and both also possess unusually long metal-metal bonds that may be related to these anomalous electron configurations. Crystal data for2, space group Pna2₁,a=19.951(3) Å,b=9.905(2) Å,c=17.180(2) Å,Z=2, 1844 reflections,R=0.036; for3, space group Pna2₁,α=13.339(1) Å,b=14.671(2) Å,c=11.748(2) Å, α=100.18(1)°, β=95.79(1)°, γ=83.671(9)°,Z=2, 3127 reflections,R=0.026.     

New electron-deficient alkene and alkyne derivatives of Ru5(μ5-C)(CO)15: The syntheses and crystal structure analyses of Ru5(μ5-C)(CO)13 [C2H2(CO2Me)2] and Ru5(μ5-C)(CO)15 [C2(CO2Me)2]

Treatment of carbido cluster Ru₅(μ ₅-C)(CO)₁₅ with Me₃NO in acetonitrile solution followed by addition of dimethyl maleate or dimethyl acetylene dicarboxylate affords new clusters Ru₅(μ ₅-C)(CO)₁₃[C₂H₂(CO₂Me)₂] (1) and Ru₅(μ ₅-C)(CO)₁₅[C₂(CO₂Me)₂] (2), respectively. Single crystal X-ray structural studies reveal that both complexes contain a wingtip-bridged butterfly pentametallic skeleton. In complex1 the maleate fragment is coordinated to one wingtip Ru atom through its carbon-carbon double bond and to the adjacent Ru atom by the formation of two O → Ru dative bonding interactions, while the acetylene dicarboxylate fragment in2 is best considered as acis-dimetallated alkene, linking one hinge Ru atom and the nearby Ru atom at the bridged position. Crystal data for1: space group P 4₂/n;a=20.199(6),c=13.941(3) Å,Z=8; finalR _F=0.025,R _w=0.026 for 3963 reflections withI>2σ(I). Crystal data for2: space group P2₁/n;a=9.634(3),b=20.062(6),c=17.372(5) Å,β=90.62(2)°,Z=4; finalR _F=0 033,R _w=0.036 for 4683 reflections withI>3σ(I).     

Dinuclear Ruthenium(II) Carbonyl Complexes Doubly Bridged by a Bromine Atom and a C5H3N-2-C(O)CH2-6-CH2 (Q) Group. Crystal Structures of Ru2(μ-Br)(μ-Q)Br(CO)4(PPh3)(MeOH) and Ru2(μ-Br)(μ-Q)Br(CO)3(PPh3)2

The oxidative addition reaction of 2,6-bis(bromomethyl)pyridine to Ru₃(CO)₁₂ gave scarcely soluble {Ru₂Br₂(-Q)(CO)₄} _n , 1, [Q=C₅H₃N-2-C(O)CH₂-6-CH₂] or a mixture of 1 and the mononuclear complex RuBr(Q)(CO)₃, 2, [Q=C₅H₃N-2-C(O)CH₂-6-CH₂Br] according to the reactant's mole ratio. Further reactions of 1 with some N- and P-donor ligands (L) afforded readily soluble dinuclear complexes, Ru₂(-Br)(-Q)Br(CO) _n (L) _m [n=4, m=1, L=PPh₃ 3a, or py 3b; n=3, m=2, L=PPh₃ 5a, or PPh₂(o-tolyl) 5b]. In this paper, the characterization of these products by the elemental analyses and the spectroscopic methods are described. The X-ray crystal structures of Ru₂(-Br) (-Q)Br(CO)₄(PPh₃)(MeOH), 4, which was obtained by crystallization of 3a from MeOH, and of 5a · (2CHCl ₃ ) are also described. Each of the metal atoms in 4 has a distorted octahedral coordination, while in 5a · (2CHCl ₃ ) one metal atom takes a distorted octahedral geometry and the other pseudooctahedral, which is completed by presenting a Ru ··· Br secondary bonding interaction.     

Self-recognition by the iron chiral auxiliary [(η5-C5H5)Fe(CO)(PPh3] in the formation of (RR,SS)-[(η5-C5H5)FE(CO)(PPh3)COCH2]2CH2

Complete self-recognition of chirality is observed in the Michael addition of the enolate derived from R,S-[η⁵-C₅H₅Fe(CO)(PPh₃-COCH₃] to the acryloyl complex R,S-[(η⁵-C₅H₅Fe(CO)(PPh₃)-COCHCH₂)] to generate exclusively the single diastereoisomer of the glutaroyl complex RR,SS-[(η⁵-C₅H₅)Fe(CO)(PPh₃)COCH₂]₂CH₂.     

Synthesis and X-ray crystal structure of the electron-deficient metal carbonyl cluster [Os3(CO)5(μ3-H)(μ-H)(μ-PtBu2)2(μ-Ph2PCH2PPh2)]

The reaction of [Os₃(CO)₁₀(μ-dppm)] (1) with ^tBu₂PH in refluxing diglyme results in the electron-deficient metal cluster complex [Os₃(CO)₅(μ₃-H)(μ-P^tBu₂)₂(μ-dppm)] (2) (dppm = Ph₂PCH₂PPh₂) in good yields. The molecular structure of 2 has been established by a single crystal X-ray structure analysis. In contrast to the known homologue [Ru₃(μ-CO)(CO)₄(μ₃-H)(μ-H)(μ-P^tBu₂)₂(μ-dppm)] (3), no bridging carbonyl ligand was found in 2. The electronically unsaturated cluster 2 does not react with carbon monoxide under elevated pressure, therefore 2 seems to be coordinatively saturated by reason of the high steric demands of the phosphido ligands.     

Generation of the dichloromethane complex [(η5-C5Me5)Re(NO)(PPh3)(ClCH2Cl]+ BF4−, and its conversion to the oxidative addition product [(η5-C5Me5)Re(NO)(PPh3)(Cl)(CH2Cl)]+ BF4−

Reaction of (η⁵-C₅Me₅)Re(NO)(PPh₃)(CH₃) and HBF₄ · OEt₂ in CH₂Cl₂ at −78°C gives the dichloromethane complex [η⁵-C₅Me₅Re(NO)(PPh₃)(ClCH₂Cl)]⁺ BF₄⁻, which undergoes the title transformation at −35°C. The ReClCH₂Cl carbon is attacked by halide nucleophiles (X⁻) to give XCH₂Cl and the chloride complex (η⁵-C₅Me₅)Re(NO)(PPh₃)(Cl), and exhibits a ¹³C NMR resonance that is coupled to phosphorus (d, ³J(CP) 5.0 Hz) and geminal hydrogens (t, ¹J(CH) 186 Hz).     

New Mixed Metal Cluster Complexes Containing Platinum. The Synthesis and Structural Characterizations of PtFe4(CO)12(COD)(μ5-C) and PtFe4(CO)12(PMe2Ph)2(μ5-C)

The new mixed metal carbide containing cluster compounds PtFe₄(CO)₁₂(COD)(₅-C) 1 and PtFe₄(CO)₁₂(PMe₂Ph)₂(₅-C), 2 were obtained by metal–metal exchange reactions between [Et₄N]₂[Fe₅(C)(CO)₁₄] with Pt(COD)Cl₂ in the presence of TIPF₆ and Pt(PMe₂Ph)₂Cl₂, respectively. Compound 1 was also obtained by the reaction of Fe₅(CO)₁₅(₅-C) with Pt(COD)₂ in the presence of UV irradiation but in a lower yield. Both compounds were characterized by a combination of IR, ¹H NMR and single crystal x-ray diffraction analyses. Both complexes consists of a square pyramidal cluster of five metal atoms with an interstitial carbido ligand in the center of the square base. The phosphine ligands in 2 undergo a dynamical intramolecular interchange at a rate that is fast on the ¹H NMR time scale at 45°C, G (at 318 K)=15.1 kcal/mol.     

Synthesis, Characterization and Crystal Structure of [Co2Mo2(μ4-C2HPh)(μ-CO)4(CO)4(η5-C5H4C(O)Me)2]

The reaction of μ-alkyne-bridged dimolybdenum compound [Mo2(μ-C2HPh)(CO)4(η5-C5H4C(O)Me)2] 1 with Co2(CO)8 in refluxing toluene gave a new butterfly compound [Co2Mo2(μ4-C2HPh)(μ-CO)4(CO)4(η5-C5H4C(O)Me)2] 2 which was fully characterized by elemental analysis, IR, 1H NMR and X-ray single crystal diffraction techniques. 2 crystallized in monoclinic system, C30H20Co2Mo2O10, Mr=850.23, space group P21/a(#14), a=14.165(5), b=12.498(2), c=16.204(2)(A), β = 96.50(2)°, V = 2850(1)(A)3, Z = 4, Dc = 1.981 g cm-3, F(000)=1672, μ(MoKα)=20.41 cm-1, final R=0.030, Rw=0.039 for 4831 observable reflections with I>2σ(I). The structure contains a Co2Mo2 butterfly core, and each Mo-Co bond is spanned by an asymmetric semi-bridging carbonyl ligand.     

Cluster synthesis. 42. The synthesis and crystal and molecular structures of the sulfur-bridged platinum-ruthenium carbonyl cluster compounds PtRu3(CO)9 L(PPh3)(μ3-S)2 (L=CO,PPh3) and PtRu4(CO)12(PPh3)(μ4-S)2

Two new mixed metal cluster complexes PtRu₃(CO)₁₀(PPh₃)(₃-S)₂,3 14% yield and PtRu₃(CO)₉(PPh₃)₂(₃-S)₂,4 23% yield were obtained from the reaction of Ru₃(CO)₉(₃-S)₂,1 with Pt(PPh₃)₂(C₂H₄) at 0°C. The cluster of4 consists of a spiked triangle of four metal atoms with two triply bridging sulfido ligands. The reaction of Ru₄(CO)₁₁(₄-S)₂,2 with Pt(PPh₃)₂(C₂H₄) yielded the expanded mixed-metal cluster complex PtRu₄(CO)₁₂(PPh₃)(₄-S)₂,5 in 12% yield. The structure of the cluster5 can be described as a pentagonal bipyramid of five metal atoms and two sulfido ligands with one metal-metal bond missing. Compounds4 and5 were characterized by a single-crystal X-ray diffraction analyses.     

Enantioselective synthesis: Catalysis of the aldol reaction by neutral gold(I)-chiral ferrocenylphosphine complexes. Crystal structure of the complex [{(η5-C5H4PPh2)(η5-C5H3(PPh2)CH(Me)N(Me)CH2CH2NMe2)Fe}2(AuCl)3] · Et2O

The chiral aminoferrocenylphosphine [(η⁵-C₅H₄PPh₂)(η⁵-C₅H₃(PPh₂)CH(CH₃)-N(CH₃)CH₂CH₂N(CH₃)₂)Fe] (1) reacts with (H₃C)₂SAuCl to give neutral gold(I) complexes that are active catalysts for the enantioselective coupling of isocyanoacetate esters with aldehydes, forming dihydrooxazoles. The structure of the trimeric complex [(rac-1)₂(AuCl)₃] · Et₂O has been determined by X-ray diffraction.     

Reactions of [Rh(Tp*)(PPh3)2] (Tp*=hydrotris(3,5-dimethylpyrazolyl)-borate) involving fragmentation or loss of Tp*. Structures of [Rh(Cl)2(H)(PPh3)2(pz*)], [(PPh3)2Rh(μ-SC6F5)2Rh(SC6F5)(H)(PPh3)(pz*)] (pz*=3,5-dimethylpyrazole) and [{Rh(Cl)2(PPh3)2}2Hg]

The complex [Rh(Tp*)(PPh₃)₂] reacts with dichloromethane to give [Rh(Cl)(H)₂(PPh₃)₂(pz*)] (1) and [Rh(Cl)₂(H)(PPh₃)₂(pz*)] (2), with C₆F₅SH to give [(PPh₃)₂Rh(μ-SC₆F₅)₂Rh(SC₆F₅)(H)(PPh₃)(pz*)] (3) and with HgCl₂ to give [{Rh(Cl)₂(PPh₃)₂}₂Hg] (4), all under mild conditions. The crystal structures show that 2 has a slightly distorted octahedral geometry, 3 has approximately square planar Rh(I) and octahedral Rh(III) geometries, with an angle of 160.7° between the two RhS₂ planes and 4 has rhodium with a square pyramidal geometry where mercury occupies a position at the apex of the pyramid; the Rh–Hg–Rh geometry is linear and, with respect to the Rh–Hg–Rh axis, the ligands (Cl, PPh₃) on one rhodium are offset by approximately 42° relative to their counterparts on the second rhodium. In 2 an intramolecular hydrogen bond exists between the pyrazole NH and one of the chloride ligands. Structure 4 is unusual in that it contains an unsupported mercury bridge.     

ESR study of reactivity of the complex (η2-C60)Os(CO)(PPh3)2(CNBut) toward free radicals

Addition of the ^·P(O)(OPrⁱ)₂, Me^·, Et^·, ^·Bu^t, and Cl₃C^· radicals to the (ν²-C₆₀)Os(CO)-(PPh₃)₂(CNBu^t) complex (1) was studied by ESR spectroscopy. The spectral parameters of the spin-adducts of these radicals with complex 1 were determined. The predominant direction of the attack by the ^·P(O)(OPrⁱ)₂, ^·Bu^t, and Cl₃C^· radicals are the cis-1 and cis-2 bonds of the fullerene molecule. The stability of the spin-adducts depends substantially on the nature of the added radical. The addition rate constants of the ^·P(O)(OPrⁱ)₂, ^·But, and Cl₃C^· radicals to complex 1 and the dimerization rate constants for these spin-adducts were determined. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 301–307, February, 2008.     

Addition of HCl to a Cluster-Bound Vinylidene Ligand: Preparation and Structure of Ru5(μ3-SMe)(μ3-CMe)(μ-Cl)(μ-SMe)(μ-PPh2)2(CO)9·PhMe

Addition of aqueous HCl to Ru₅( ₃-C=CH₂)(-SMe)₂(-PPh₂)₂(CO)₁₀ afforded the structurally characterized carbyne complex Ru₅( ₃-SMe)( ₃-CMe)(-Cl)(-SMe)(-PPh₂)₂(CO)₉, formed by addition of H to the vinylidene ligand; a Cl atom bridges an Ru–Ru bond.     

Tantalocene complexes as bidentate métalloligands: (C5Me5)(C5H4X)Ta(H2)(PPh2) (C5Me5) (C5H4X)Ta(CO) (PPh2) (X = PPh2, CH2CH2NMe2)

The synthesis of new bidentate métalloligands derived from tantalocene(C₅Me₅)(C₅H₄X)Ta(H₂)(PPh₂) (X = PPh₂, 2P; X = CH₂CH₂NMe₂2N) and (C₅Me₅)(C₅H₄X)Ta(CO)(PPh₂) 4(P,N) is described. When opposed to chromium unsaturated fragments the phosphino functionalised complexes 2P and 4P act as chelating bidentate ligands affording Ta(V) (C₅Me₅)(C₅H₄PPh₂)Ta(CH₂) (μ-PPh₂)Cr(CO)₄ or Ta(III) (C₅Me₅)(C₅H₄PPh₂)Ta(CO)(μ-PPh₂)Cr(CO)₄ bimetallic complexes. The same reaction carried out starting from 2N gives rise to a μ-phosphido, μ-hydrido dibridged complex Cp*(C₅H₄CH₂CH₂NMe₂)TaH(μ-H)(μ-PPh₂)Cr(CO)₄.     

Triphospha-Ferrocenes as Ligands. Crystal Structures of [Fe(η5-C5Me5)(η5-C2 TBu2P3)M(CO)5)], (M= Cr,MO, W) and the Novel ruthenium and Nickel Complexes [Fe(η5-C5Me5) (η5-C2 TBu2P3)Ru3(CO)9] and [Fe(η5-C5Me5)(η5-C2 tBu2P3)Ni(Co)2]2

Abstract

Syntheses and structures of penta- and hexaphosphorus analogues of ferrocene have been described recently¹. Unlike their simple ferrocene analogues, these complexes have further ligating potential towards other transition metal centres by virtue of the availability of the ring phosphorus lone-pair electrons that are not involved in the η⁵-coordination. We now describe the first examples of coordination compounds of the triphospha-ferrocene [Fe(η⁵-C₅Me₅) (η⁵-C₂ ^tBu₂P₃]. In the ruthenium complex [Fe(η⁵-C₅Me₅)(η⁵-C₂ ^tBu₂P₃) Ru₃(CO)₉] ² two adjacent phosphorus atoms of the η⁵-C₂ ^tBu₂P₃ ring are interlinked by a ruthenium carbonyl cluster in which all three ruthenium atoms interact with the phosphorus atoms. The tetrametallic nickel complex [Fe(η⁵-C₅Me₅)(η⁵-C₂ ^tBu₂P₃)Ni(CO)₂]₂ ³ represents the first example of intermolecular interlinkage of two phospha-ferrocene systems by two metal centres.     

The cleavage of a coordinated SCNR group in [Fe(CO)2L2(η2-SCNR)] by [Co(η-C5H5)(PPh3)2] to give complexes containing μ3-CNR ligand. The preparation and structure of [{Co(η-C5H5)}2{Fe(CO)2(PPh3)}(μ3-S){μ3-CNC(O)C6H5}]

The reaction of [Fe(CO)₂(PPh₃)₂{η²-SCNC(O)Ph}] with [Co(η-C₅H₅)(PPh₃)₂] in benzene solution at room temperature results in the facile cleavage of the CS bond of the SCNC(O)Ph ligand to give [{Co(η-C₅H₅)}₂{Fe(CO)₂(PPh₃)}(μ₃-S{μ₃-CNC(O)Ph}], whereas [Fe(CO)₂(PPh₃)₂(η²-SCNMe)] gives [{Co(η-C₅H₅)} ₂₂{Fe(CO)(CNMe)(PPh₃)(μ₃-S)(μ₃-CO)]. The structure of [{Co(η-C₅H₅)}₂{Fe(CO)₂(PPh₃)} (μ₃-CNC(O)Ph}] has been confirmed by X-ray diffraction.     

Application of electron-transfer chain catalysis: preparation of bridged 〚{(η5-C5H5)Fe(CO)2}2(μ-diphosphine)2+〛 complexes without chelated 〚(η5-C5H5)Fe(CO)(η2-diphosphine)+〛 byproducts

The ligand substitution by diphosphine L–L on (η⁵-C₅H₅)Fe(CO)₂I usually results in the chelated 〚(η⁵-C₅H₅)Fe(CO)(η²-L–L)⁺〛〚I^–〛 product exclusively. One could suppress the chelated complexes and selectively prepare the bridged 〚{(η⁵-C₅H₅)Fe(CO)₂}₂(μ-L–L)²⁺〛 complexes by application of the electron-transfer chain catalysis with a chemical initiation. Introducing a catalytic amount of reductant at low temperature to the mixture of 2:1 (η⁵-C₅H₅)Fe(CO)₂I/L–L in THF selectively produces the bridged complexes in 78–93% isolated yields where L–L is Ph₂P(CH₂)_nPPh₂, n = 1–4, or (η⁵-C₅H₄PPh₂)₂Fe.     

Synthesis of the gold-dirhenium ferrocenylacetylide cluster. The crystal structure of Re2(μ-C≡CFc){Au(PPh3)}(CO)8

The thermal reaction of Re₂(CO)₈(NCMe)₂ with Au(CCFc)PPh₃ afforded the cluster Re₂(-CCFc){Au(PPh₃)}(CO)₈, which was characterized by X-ray diffraction analysis.     

Formation and isomerization of cis,cis-Ir(H)2(--Ph)(CO)(PPh3)2 and cis,cis-Ir(H)(--Ph)2(CO)(PPh3)2 in oxidative addition of hydrogen and phenylacetylene to trans-Ir(CO)(--Ph)(PPh3)2

Oxidative addition of H–R (H--Ph and H₂) to trans-Ir(--Ph)(CO)(PPh₃)₂ (2) gives the initial products, cis, cis-Ir(H)(--Ph)₂(CO)(PPh₃)₂ (3a) and cis, cis-Ir(H)₂(--Ph)(CO)(PPh₃)₂ (3b), respectively. Both cis-bis(PPh₃) complexes, 3a and 3b undergo isomerization to give the trans-bis(PPh₃) complexes, trans, trans-Ir(H)(--Ph)₂(CO)(PPh₃)₂ (4a) and cis, trans-Ir(H)₂(--Ph)(CO)(PPh₃)₂ (4b). The isomerization, 3b→4b is first order with respect to 3b with k₁=6.37×10⁻⁴ s⁻¹ at 25°C under N₂ in CDCl₃. The reaction rate (k₁) seems independent of the concentration of H₂. A large negative entropy of activation (ΔS^≠=−24.9±5.7 cal deg⁻¹ mol⁻¹) and a relatively small enthalpy of activation (ΔH^≠=14.5±3.3 kcal mol⁻¹) were obtained in the temperature range 15∼35°C for the isomerization, 3b→4b under 1 atm of H₂.