A New Preparation of Mo2(CO)8(μ-PPh2)2 and W2(CO)8(μ-PPh2)2 by a Phosphorus-Carbon Bond Cleavage Reaction. Crystal Structure of a New Polymorph of Mo2(CO)8(μ-PPh2)2

A new synthesis of Mo₂(CO)₈(-PPh₂)₂ and W₂(CO)₈(-PPh₂)₂ by the reaction of molybdenum and tungsten hexacarbonyls with a tetraazamacrocyclic ligand containing —CH₂PPh₂ side chains, comprising cleavage of the phosphorus-methylene bond has been performed. The complexes have been investigated by magnetic and spectroscopic measurements and by single-crystal structure analyses. The structural characterization of a new polymorph of Mo₂(CO)₈(-PPh₂)₂ has been described.     

Solid–Gas Hydrogenation of Hex-3-yne and 1,4-Cyclohexadiene in the Presence of Ru3(CO)9(μ-H)(μ-PPh2), Ru3(CO)10(μ-H)(μ-PPh2), Ru3(CO)7(μ-PPh2)2(C6H4), and Ru4(CO)11(μ4-PPh)(C6H4) Deposited on Pyrex Glass, Silica, and Alumina

The title complexes were tested in the hydrogenation of hex-3-yne and of 1,3- and 1,4-cyclohexadiene (CHD) under solid–gas conditions. The clusters were deposited on three “standard” supports, that is, pyrex glass, alumina, and silica. All the clusters, particularly (μ-H)Ru₃(CO)₁₀(PPh₂), show hydrogenation activity. However, they are not particularly selective toward the formation of monoenes; “disproportionation” of 1,3- and 1,4-CHD to hydrogenated products and benzene also occurs. The hydrogenation activity of the clusters is dependent on their nature, the type of substrate, and the characteristics of the supporting material; silica and pyrex glass are usually more active than alumina. Attempts at detecting the formation of organometallic intermediates or by-products (through IR spectroscopy) were made. HRTEM was used to check for eventual decomposition on some supports.     

Chemistry of iridium carbonyl cluster complexes. Synthesis,characterization and solid state structure of the phosphido carbonyl cluster [Ir6(CO)12(μ-CO)2(μ-PPh2)−

The phosphido-bridged cluster [Ir₆(CO)₁₄ PPh2]^– has been obtained by reaction of [Ir₆(CO)₁₅]^2– with PHPh₂, in the presence of ferrocenium cation, followed by deprotonation. The anion was isolated as a salt of [N(PPh₃)₂]⁺ or K⁺ and its structure was determined by single crystal X-ray data analysis. The salt [N(PPh₃)₂][Ir₆(CO)₁₄PPh₂] crystallizes in the triclinic space group P witha = 11.835(1) Å,b = 15.007(1) Å,c = 18.766(2)_ Å; = 78.779(7)°, = 87.260(8)°, = 75.794(6)°,V = 3169.3(7) Å,Z = 2. The structure was solved by Direct Methods and Difference Fourier techniques and refined down toR andR _w values of 0.034 and 0.036, respectively, for 8003 observed reflections havingl > 3(I). The octahedral anion, of idealized C₂ symmetry, possesses two distance Ir-P = 2.284 Å, formally acting as a three electron donor. Average bond distances (Å) and angles (degrees) are: Ir-Ir = 2.776, Ir-C _t = 1.87, Ir-C _b = 2.05, C _t -O _t = 1.14, C _b -O_b= 1.17, Ir-P-Ir = 74.3°, Ir-C _t -O _t = 177°, Ir-C _b -O _b = 138°, Ir-C _b -Ir = 84° (t = terminal,b = bridging).     

Synthesis and structural characterization of the first transition metal cluster containing a PPh2AuPPh3 ligand,Ir4(CO)8(μ-CO)3(PPh2AuPPh3), and its conversion into Ir4(CO)9(μ-CO)(μ-PPh2)(μ-AuPPh3)

Deprotonation of Ir₄(CO)₁₁PPh₂H (1) in the presence of [AuPPh₃][PF₆] yields the novel species Ir₄(CO)₁₁(PPh₂AuPPh₃) (2), which possesses a tetrahedral framework bearing a terminally bound PPh₂AuPPh₃ ligand. When heated in toluene, 2 is converted into the phosphido species Ir₄(CO)₁₀(μ-PPh₂)(μ-AuPPh₃).     

Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with azulenes

Reaction of the heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (1) with azulene under thermal activation afforded the novel clusters RuOs₃(μ-H)(CO)₉(μ₃,η⁵:η²:η²-C₁₀H₉) (3) and Ru₂Os₃(μ-H)₂(CO)₁₃(μ-CO)(μ₃,η⁵:σ²-C₁₀H₈) (5a), with 4,6,8-trimethylazulene to give RuOs₃(μ-H)(CO)₈(μ-CO)(μ,η⁵:η⁴-C₁₀H₆Me₃) (4) and Ru₂Os₃(μ-H)₂(CO)₁₃(μ-CO)(μ₃,η⁵:σ²-C₁₀H₅Me₃) (5b), and with guaiazulene to give Ru₂Os₃(CO)₁₁(μ₃,η⁵:η³:η³-C₁₀H₅Me₂ⁱPr) (6), respectively. In 3–5, cluster-to-ligand hydrogen transfer appears to have taken place, with the organic moiety capping a trimetallic face in 3, bridging a metal–metal bond in 4 and via a μ₃,η⁵:σ² bonding mode in 5a and 5b. Cluster 6 contains a trigonal bipyramidal metal framework with the guaiazulene ligand over a triangular metal face. All five clusters have been completely characterised, including by single-crystal X-ray diffraction analysis.     

Synthesis and molecular and crystal structure of the octanuclear palladium cluster Pd8(μ3-CO)2(μ2-CO)6(PMe3)7

Treatment of bis(dibenzylideneacetone)palladium with trimethylphosphine under a carbon monoxide atmosphere gives the title complex in good yield. X-ray crystallography has shown the structure of the complex to consist of an octahedron of palladium atoms which is bicapped by two further palladium atoms in an asymmetric fashion. Seven of the eight palladium centres carry terminal trimethylphosphine ligands. Two face-bridging and six edge-bridging CO molecules complete the ligand shell.     

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.     

Cluster chemistry. 85. Addition of a gold acetylide to an Ru5 cluster. X-ray structure of AuRu5(μ5-C2PPh2)(μ-C2Ph)(μ-PPh2)(CO)13(PPh3)

The reaction between Ru₅(₅-C₂PPh₂)(-PPh₂)(CO)₁₃ and Au(C₂Ph)(PPh₃) afforded AuRu₅(₅-C₂PPh₂)(-C₂Ph)(-PPh₂)(CO)₁₃ (PPh₃), in which the Ru₅ cluster has a scorpion geometry; the Au(PPh₃) group bridges one of the Ru-Ru bonds of the Ru₃ triangle, while the C₂Ph group bridges one of the tail Ru-Ru vectors.For Part 84, see Ref. 1.     

The preparation and structure of the tetranuclear ruthenium cluster [Ru4(CO)10(μ2-Cl)2(μ3-OEt)2]

The tetranuclear ruthenium cluster [Ru₄(CO)₁₀Cl₂(OEt)₂] has been prepared in low yield by the reaction of [Ru₃(CO)₁₂] with [N(PPh₃)₂]Cl in refluxing EtOH, followed by oxidation with either [NO][BF₄] or Ag[ClO₄]. A single-crystal X-ray analysis of the complex shows that the four metal atoms adopt a planar geometry with one ruthenium bonded by two μ₂-Cl ligands and two μ₃-OEt ligands to a trinuclear fragment. This complex crystallises in the monoclinic space group I2/c, with a 14.458(3), b 22.073(6), c 15.302(4) Å, β 99.54(2)°, Z = 8; 3113 observed data with F > 3σ(F) were refined by blocked full-matrix least squares to R = 0.031, R_w = 0.034.     

The insertion of acetylene into the formal ruthenium-phosphorus bonds of closo-[Ru4(μ4-PPh)2(μ2-CO)(CO)10. Crystal structure of [Ru4(μ4-PPh){μ4-η3-P(Ph)CHCH}(μ2-CO)(CO)10]

Treatment of closo-[Ru₄(μ₄-PPh)₂(μ₂-CO)(CO)₁₀] with acetylene under ambient conditions leads to the insertion of the acetylene into the skeletal framework of the cluster and the formation of [Ru₄(μ₄-PPh){μ₄-η³-P(Ph)CHCH}(μ₂-CO)(CO)₁₀], the structure of which has been determined X-ray crystallographically.     

Synthesis and structure of three isomeric cluster complexes (μ-H)Os3μ-O2CC5H4Mn(CO)3(PPh3)2(CO)8

The reaction of (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(CO)₁₀ with PPh₃ in the presence of Me₃NO gave mono- and disubstituted heterometallic complexes (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(PPh₃)(CO)₉ and (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃ (PPh₃)₂(CO)₈. Crystal structure determination was performed for three isomeric cluster complexes (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(PPh₃)₂(CO)₈, which are both geometrical and conformational isomers differing in color. The geometrical isomerism is due to the attachment of the PPh₃ group at different vertices of the Os₃ triangle relative to the O₂CC₅H₄Mn(CO)₃ bridging ligand. The conform ational isomerism implies that the molecules have the same arrangement of ligands and differ only in the values of bond angles between the planar fragments of the clusters.     

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.     

The synthesis and crystal structure of novel Mo-Sn tetranuclear cubane-like cluster [Mo3(SnBr3)(μ3-O)(μ3-S)3(dtp)3(py)3]·(CH2Cl2)

The synthesis and crystal structure of the first example for hybrid Sn-Mo tetranuclear cubane-like cluster compound containing S/O mixed triple capping atom [Mo₃(SnBr₃)(μ ₃-O)(μ ₃-S)₃(dtp)₃(py)₃]·(CH₂Cl₂) (A) (dtp=S₂P(OC₂H₅)₂) are reported. The compound is prepared by the reaction of [Mo₃(μ ₃-O)(μ-S)₃(dtp)₄·(H₂O)] with SnBr ₃ ^? . The molecular structure of the cluster can be described as a [Mo₃OS₃] core with the SnBr ₃ ^? fragment linked to {Mo₃} triangle by three (μ ₃-S). Three Mo-Mo bond lengths are 2.616(2), 2.620(2), 2.628(2) Å, respectively, and the molecule has approximately C_3v symmetry. There is no bonding between Sn and Mo atoms, however, the addition of SnBr ₃ ^? may cause electron transfer from Sn²⁺ to [Mo₃OS₃] core to result in the shortening of Mo-Mo bond distances. The compound crystallizes in the monoclinic space group P2₁/n with refined lattice parameters ofa=13.012(4),b=22.877(6),c=18.585(6) Å,β=96.34(3)°,V=5498(3)ų, andZ=4. Full matrix refinement converged with final agreement factor ofR=0.054,R _w=0.064.     

Reaction of HRu3(CO)10(μ-COMe) with bma: NMR and X-ray structural evidence for the formation of the Ph2PH-substituted cluster HRu3(CO)8(Ph2PH)[μ-PPh2C=CC(O)OC(O)]

Me₃NO activation of the methylidyne-bridged cluster HRu₃(CO)₁₀(μ-COMe) (1) in the presence of the unsaturated diphosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) furnishes the bma-substituted cluster HRu₃(CO)₈(bma)(μ-COMe) (2) and the diphenylphosphine-substituted cluster HRu₃(CO)₈(Ph₂PH)[μ-PPh₂C=CC(O)OC(O)] (3) as the major and minor products, respectively. The ¹H and ³¹P NMR data indicate that the bma ligand in cluster 2 is chelated to one of the ruthenium atoms that is bridged by the hydride and methylidyne ligands. Cluster 3 has been fully characterized in solution by IR and NMR spectroscopies, and the solid-state structure determined by X-ray crystallography. 3 crystallizes in the monoclinic space P2₁, a?=?12.1467(7)?Å, b?=?19.284(1)?Å, c?=?16.867(1)?Å, β?=?109.639(6)°, V?=?3721.0(4)?ų, Z?=?4, and d_calcd?=?1.774?g?cm^?3; R?=?0.0325, R _w?=?0.0383 for 3518 reflections with I?>?3σ(I). The X-ray data confirm that one of the P–C(maleic anhydride) bonds of the bma ligand has been cleaved and that cluster 3 contains Ph₂PH and μ-PPh₂C=CC(O)OC(O) ligands, the latter which functions as a face-capping ligand to all three ruthenium atoms. Control experiments indicate that cluster 2 does not function as a precursor to cluster 3 under the employed reaction conditions.     

Synthesis of 62-electron square planar clusters with group 15 and 16 main group atoms: Structural characterization of Ru4(CO)11(μ4-PPh)(μ4-S) and Ru4(CO)10(μ4-PPh)(μ4-Se)(PEt3): Bonding preferences in cappingNido Ru4(CO)13(μ3-PPh)

Thecloso octahedral cluster Ru₄(CO)₁₁(μ₄-PPh)(μ₄-S)1 and selenium and tellurium analogues, the first examples of unsaturated ruthenium clusters with a planar metal core and different main group 15 and 16 atoms have been synthesized fromnido Ru₄(CO)₁₃(μ₃-PPh). An X-ray analysis of1 and Ru₄(CO)₁₀(μ₄-PPh)(μ₄-Se)(PEt₃)2a has confirmed thetrans disposition of phosphorus and group 16 main group fragments.     

Bulk polymerization of rac-lactide initiated by guanidinate alkoxide complexes of rare earth metals. The molecular structure of the cluster [{(Me3Si)2NC(NPri)2}Nd]4(μ3-OPri)8Li7(μ2-Cl)3(μ3-Cl)2(μ4-Cl)2

The complexes {(Me₃Si)₂NC(NPrⁱ)₂}₂LnOBu^t (Ln = Y (1), Lu (2)) initiate the bulk polymerization of racemic lactide (LA) at 130 °C. At the monomer: initiator molar ratio ([LA]: 1) equal to 1000: 1, the quantitative conversion of the monomer is achieved within 6 h. The resulting polymers are characterized by a rather narrow monomodal molecular weight distribution (M _w/M _n = 1.46–1.82) and molecular weights up to 33400 g mol^?1. The molecular weights of the resulting polylactides measured by gel permeation chromatography are 3–11 times lower than the values calculated from the monomer: initiator ratio on the assumption of one growing polymer chain per catalytic center. The reaction of the in-situ prepared complex [(Me₃Si)₂NC(NPrⁱ)₂]NdCl₂ with 2 equiv. of PrⁱOLi produced the 11-nuclear cluster [{(Me₃Si)₂NC(NPrⁱ)₂}Nd]₄(μ³-OPrⁱ)₈Li₇(μ²-Cl)₃(μ³-Cl)₂(μ⁴-Cl)₂ (3), which was isolated in 62% yield. The structure of compound 3 was established by X-ray diffraction. Complex 3 initiates both the bulk and solution polymerization of rac-lactide. In the bulk polymerization at the molar ratio [LA]: [Nd] = 500: 1, the 89% conversion of the monomer was achieved within one hour. The polylactide thus synthesized has the molecular weight M _n = 19720 g mol^?1 and a rather narrow polydispersity M _w/M _n = 1.54.     

Synthesis and structure of Os3(μ-H)3(CO)9(μ3-Sn)Os3(μ-H)(CO)10(PEt2Ph): The first osmium cluster containing a face-capping tin atom

Pyrolysis a the cluster Os₃(µ-H h (CO)₁₀ (SnMe2 H) produced an as yet unidentified purple duster, which upon reaction with PEt₂Ph at room temperature, gave essentially a quantitative yield of the cluster Os₃(µ-H)₃(CO)₉(µ₃-Sn) Os₃(µ-H)(CO)₁₀(PEt₂Ph), 4. The X-ray structure of 4 (as the toluene solvate) shows that it consists Or two Os, triangles linked through a µ₄-Sn unit, such that one of the Os₃ triangle is µ₃-bonded to the Sn atom (Os-Sn range 2.689(2)–2.707(2) Å) and the other is bonded via a single covalent bond (Os-Sn = 2.643(2) Å). The phosphine ligand occupies the equatorial site on a second osmium atom a be latter Os₃ moiety that is syn to the Sn atom; the unique bridging hydride ligarid is believed to occupy a site that Acis to both the P and Sn atoms. Crystallographic data for compound4. 0.5C₇H₈: space group,P ; ca= 11862(4) Å,b = 12.940(4) Å,c = 16.513(5) Å, =68.96(3),=80.60(3)°,=62.49(2).R=0.029, 4118 observed reflections.     

Heterometallic “butterfly” cluster [Fe3(CO)9(μ3-OBut)Au(PPh3)]

Alkylation of the [Fe₃(μ₃-O)(CO)₉]²⁻ dianion withtert-butyl iodide afforded the [Fe₃(μ₃OBu¹)(CO)₉]⁻ monoanion. The reaction of the latter with Au(PPh₃)Cl in the presence of TIBF₄ yielded the new heterometallic “butterfly” cluster [Fe₃(CO)₉(μ₃-OBu^t)Au(PPh₃)]. According to the X-ray data, both clusters synthesized contain the unchanged Fe₃(μ₃-O) fragment of the initial dianion. The addition of the Au(PPh₃) fragment to the monoanion occurred in such a way as to minimize steric changes. As a result, a “turned inside out” heterometallic “butterfly”, which contains the μ₃-O ligand on the outside rather than on the inside, was obtained. The dihedral angle characterizing the “butterfly” is 151°. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1779–1783, September, 1999.