Intramolecular rearrangement of the bridging σ,π-acetylide ligand in the Os3H(CO)9(L)(μ-η2-CCPh) (L = CO,PMe2Ph) clusters and crystal structure of Os3H(CO)9(PMe2Ph)(μ-η2-CCPh)

Clusters Os₃H(Cl)(CO)₉(L) (L= CO, PMe₂Ph) react with lithium phenyl-acetylide to yield Os₃H(CO)₉(L)(μ-η²-CCPh),which has a bridging acetylide ligand. The Os₃H(CO)₁₀(μ-η²-CCPh) complex (II) is fluxional owing to rapid π → σ, σ → π interchange of acetylide ligand between the bridged osmium atoms, whereas the phosphine-substituted derivative, Os₃H(CO)₉(PM₂Ph)(μ-η²-CCPh) (III), is stereochemically rigid and exists at room temperature in two isomeric forms. These isomers have been isolated as solids and have been characterized by ¹H and ³¹P{¹H} NMR spectroscopy. According to the spectroscopic data, in the major (IIIa) and minor (IIIb) isomers the phosphine ligand is coordinated to the metal atom which is σ- or π-bonded to the bridging acetylide group, respectively. The isomerization of IIIb into IIIa occurs only at 80°C. The structure of IIIa has been confirmed by an X-ray diffraction study.     

The reaction of H2Os3(CO)10 with trifluoroacetonitrile and the x-ray crystal structure of HOs3(CO)9(μ3-η2-HNCCF3)

The reaction of H₂Os₃(CO)₁₀ with CF₃CN in hexane at 80°C leads to two isomeric products. The isomer constituting the major product contains a 1,1,1-tri-fluoroethylidenimido ligand which bridges one edge of the Os₃ triangle via the nitrogen, atom and may be formulated as (μ-H)Os₃(CO)₁₀(μ-NC(H)CF₃) (I). The minor product, formulated as (μ-H)Os₃(CO)₁₀(μ-η²-HNCCF₃) (II), contains a 1,1,1-trifluoroacetimidoyl ligand which is also edge-bridging, being N-bonded to one Os atom and C-bonded to the other. Thermolysis of I and II in solution results in loss of a CO group in each case to give (μ-H)Os₃(CO)_9^? (μ₃-η²-NC(H)CF₃) (III) and (μ-H)Os₃(CO)₉(μ₃-η²-HNCCF₃) (IV), respectively, which, it is proposed, are structurally related to I and II, but with the CN group coordinated also to the third Os atom in place of a CO group. In the case of IV this proposal has been confirmed by an X-ray crystallographic analysis. The compound crystallises in space group C2/c with a = 14.258(7), b = 13.486(10), c = 18.193(8) Å, β = 92.68(4)°, and Z = 8. The structure was solved by a combination of direct methods and Fourier difference techniques, and refined by full-matrix least squares to R = 0.054 for 2489 unique observed diffractometer data. Reaction of I with Et₃P gives a 1 : 2 adduct which is formulated as (μ-H)Os₃(CO)₁₀[μ-N?C(H)(CF₃)PEt₃] (V) on the basis of NMR evidence.     

The synthesis and characterisation of some mixed-metal carbonyl hydrides containing tungsten: The X-ray crystal structure of [(Ph3P)2N][Os3WH(CO)14]

The mixed-metal cluster anion [Os₃W(μ-H)(μ-CO)(CO)₁₃]^? has been prepared by the reaction of [Os₃(μ-H)(CO)₁₁]^? with W(CO)₃(MeCN)₃, and the dianion, [Os₃W(CO)₁₄]^2?, may be obtained by subsequent deprotonation. An X-ray analysis of the monoanion shows that the metals adopt a closo-tetrahedral geometry with the W atom coordinated to four terminal and one bridging carbonyl groups. The neutral clusters [Os₃WH₂(CO)₁₄] and [Os₃WH(CO)₁₄] are formed upon treatment of the monoanion with sulphuric acid and iodine, respectively.     

Synthesis and characterization of the undecaosmium carbido carbonyl cluster: Crystal and molecular structures of [N(PPh3)2][Os11C(CO)27(μ-Cl)]

A chloro-derivative of undecaosmium carbido cluster [Os₁₁C(CO)₂₇(µ-Cl)]-1 anion has been prepared and fully characterized by spectroscopic and crystallographic methods. The structure1 is an important intermediate for the conversion of [Os₁₁C(CO)₂₇]² 2 dianion to [OS₁₀C(CO)₂₄]²-3 dianion.     

Triosmium-induced dehydrogenation of triethylamine. The crystal structure of HOs3 (CO)10 (−CHCH+NEt2)

The reaction of Os₃ (CO)₁₀(NCCH₃)₂ and triethylamine provides H₂ Os₃ (CO)₁₀ and HOs₃ (CO)₁₀(CHCHNEt₂) in equimolar amounts. The structure of the latter compound has been shown to involve an iminium ion center anchored to the Os₃ framework by a bridging (substituted) methylene moiety.     

The molecular structures of H2Os3(CO)10, H(SC2H5)Os3(CO)10 and (OCH3)2Os3(CO)10

X-ray crystallographic analyses of H₂Os₃(CO)₁₀, H(SC₂H₅)Os₃(CO)₁₀ and (OCH₃)₂Os₃(CO)₁₀ are reported. Although hydrogen atom positions have not been located, the essential isostructural nature of the three commplexes establishes the hydride ligands as bridging two metal atoms, separated by 2.670 Å, with a formal bond order of two; the bridging hydrido- and thiolato-ligands span an osmium---osmium bond of length 2.863 Å and formal bond order one; the two μ-methoxy ligands bridge two metal atoms separated by 3.078 Å which, by simple 18 electron rule counting, has a metal---metal bond order of zero. Some general comments are made on the structures of polynuclear transition metal carbonyls.     

The activation of tertiary amines by osmium cluster complexes: Further studies of the reaction of Os3(CO)10(NCMe)2 with triethylamine

The reactions of Os₃(CO)₁₂ and Os₃(CO)₁₀(NCMe)₂ with NEt₃ have been reinvestigated. Two new products, Os₃(CO)₁₀(μ-CH₂C(H)?NEt₂)(μ-H)) (2) and Os₃(CO)₁₀(syn-μ-η¹-CHCHNEt₂)(μ-H) (3) were obtained in low yields, 4% and 7%, in addition to the previously reported compound Os₃(CO)₁₀(anti-μ-η¹-CHCHNEt₂(μ-H) (1) (20% yield) when the reaction was conducted at 25°C using Os₃(CO)₁₀(NCMe)₂. Compounds 2 and 3 were characterized by IR, ¹H NMR and single-crystal X-ray diffraction analyses. Compound 2 contains a bridging methyl-metallated N-ethylimine ligand formed by the cleavage of one ethyl group from the NEt₃. Compound 3 is an isomer of 1 in which the bridging ligand has a syn conformation with respect to the cluster as compared with the anti conformation in 1. Compound 3 slowly isomerizes to 1. Compound 3 is de-carbonylated by exposure to UV radiation and is transformed to the new compound Os₃(CO)₉(μ₃-CC(H)?NEt₂)(μ-H)₂ (4) (58% yield) by an additional CH activation to form a triply bridging η¹-diethylaminovinylidene ligand. Compound 4 isomerizes to the compound Os₃(CO)₉(μ₃-HCCNEt₂)(μ-H)₂ (5) (70% yield) at 68°C. The latter contains a triply briding ynamine ligand which exhibits structural and reactivity features that are characteristic of a carbene ligand at the amine-substituted carbon atom. Crystal data: for 2, space group = P2₁/c, a = 9.236(2) Å, b = 12.469(2) Å, c = 18.107(3) Å, β = 104.67(1)°, Z = 4, 2518 reflections, R = 0.031; for 3, space group = P2₁/m, a = 7.644(1) Å, b = 12.706(2) Å, c = 11.912(2) Å, β = 108.02(1)°, Z = 2, 1295 reflections, R = 0.030; for 4, space group = P2₁/n, a = 10.233(2) Å, b = 14.834(4) Å, c = 14.538(2) Å, β = 99.88(2)°, Z = 4, 2403 reflections, R = 0.036.     

Negative ion mass spectra of Os3(CO)12X2 and Os3(CO)10X2 complexes (X = Br,I)

The negative-ion mass spectra at 70 eV of the compounds Os₃(CO)₁₂X₂ and Os₃(CO)₁₀X₂ (X =Br, I) are reported. Negative molecular ions are absent and only Os₃-containing fragments due to the loss of carbonyl groups are observed. [M  CO]^? is the base peak in the spectrum of Os₃(CO)₁₀I₂ and has a very high abundance in that of Os₃(CO)₁₀Br₂, whereas it is very weak in the spectra of Os₃(CO)₁₂X₂, where [M  3 CO]^? is the base peak. This change in the ionic intensities is related to the closed and open structure of the Os₃ unit in Os₃(CO)₁₀X₂ and Os₃(CO)₁₂X₂ respectively.     

Fragmentierung des schwefeldiimidsystems in tBu2PN=S=NPtBu2 an dreikernigen osmiumclustern. Synthese,feströrperstruktur und dynamische eigenschaften von Os3(CO)11[PtBu2(NH2)] und HOs3(CO)9PtBu2N(H)S]

The phosphino-substituted sulphur diimide, S(NP^tBu₂)₂, reacts with the trinuclear osmium clusters Os₃(CO)₁₁(NCMe) and H₂Os₃(CO)₁₀ with cleavage of one of the NS bonds to give the cluster compounds Os₃(CO)₁₁[P^tBu₂(NH₂)] (I) and HOs₃(CO)₉[P^tBu₂N(H)S] (II), respectively. In the solid state, I contains a closed Os₃ triangle with the phosphine ligand bonded equatorially to an osmium atom through the phosphorus. In solution intramolecular dynamic processes are observed which are explained by carbonyl migration and pseudoration mechanisms. The osmium cluster II, in the solid state, forms an irregular Os₃ triangle which is bridged by a [P^tBu₂N(H)S] system, and the longest edge of which is bridged by a μ₂-hydride. In contrast to I, molecule II is relatively rigid in solution; only pseudorotations are observed as dynamic phenomena.     

Syntheses of the new trinuclear ions [Ru3(CO)11]2− and [Os3(CO)11]2−

Stoichiometric reduction of Os₃CO)₁₂ and Ru₃(CO)₁₂ with K and Ca, respectively; yields the two new cluster dianions [Os₃(CO)₁₁]^2? and [Ru₃(CO)₁₁]^2? which have been isolated and characterized. Temperature-dependent ¹³C NMR spectra for [Os₃(CO)₁₁]^2? and infrared spectra of [Os₃(CO)₁₁]^2? and [Ru₃(CO)₁₁]^2? suggest a similar structure for these dianions in which there is a single edge-bridging carbonyl.     

A platina-allenyl ligand coordinated to a triosmium cluster: X-ray structure of the acetylide complex Os3Pt(μ-H)(μ4-η-CCPh)(CO)10(PCy3)

The spiked triangular triosmium-platinum cluster complex Os₃Pt(μ-H)(μ₄-η²-CCPh)(CO)₁₀(PCy₃) has been synthesised by treatment of the unsaturated Os₃Pt(μ-H)₂(CO)₁₀(PCy₃) with LiCCPh followed by protonation. Crystallographic analysis reveals an unusual twisted configuration of the μ₄-η²-CCPh ligand about the triosmium framework such that the complex may be regarded as a platina-allenyl moiety coordinated to an Os₃(μ-H)(CO)₉ unit.     

Cluster Build-up Reactions using Di-gold Cationic Fragments: Synthesis and Structural Characterization of [Os7(CO)19(Au2dppm)]

The reaction of the di-gold cation [Au₂(dppx)]²⁺ with the heptanuclear cluster dianion [Os₇(CO)₂₀]^2– affords the mixed metal cluster [Os₇(CO)₂₀{Au₂(dppx)}] (x=m (1), e (2), b (3)). On standing, in solution, this complex undergoes decarbonylation to give the cluster [Os₇(CO)₁₉{Au₂(dppx)}] (x=m (4), e (5), b (6)). The complexes have been characterised spectroscopically, and an X-ray structure determination of the dppm derivative shows that it contains a metal core based on an Os₇ edge-bridged bicapped tetrahedron with the two ₃-Au atoms capping adjacent triangular Os₃ faces of the central tetrahedron. In an analogous reaction, the carbido anion [Os₇(H)C(CO)₁₉]^– affords the neutral cluster [Os₇C(CO)₁₉{Au₂(dppm)}] (7) when treated with [Au₂(dppm)]²⁺ in the presence of base.     

Synthesis and structural characterisation of an unsaturated osmium-gold cluster HOs3Au(CO)10(PR3) (R  Et,Ph); x-ray crystal structures of HOs3Au(CO)10(PPh3) and Os3Au(CO)10(PPh3)(SCN)

The reaction of [HOs₃(CO)₁₁]^? with AuClPR₃ (R  Et, Ph) yields the complex HOs₃Au(CO)₁₀(PR₃), and the PPh₃ derivative has been characterised by an X-ray analysis; the structure is compared with that of Os₃Au(CO)₁₀(PPh₃)-(SCN) and is shown to contain a formally unsaturated OsOs bond.     

Synthesis and X-ray structure of the osmium carbonyl anion [HOs3(CO)10 · O2C · Os6(CO)20]−

The reaction of [HOs₃(CO)₁₁]⁻¹¹ with [Os₃(CO)₁₀(MeCN)₂] in acetone gives the green-blue anion [HOs₃(CO)₁₀·O₂C·Os₆(CO)₂₀]⁻ (1) amongst several other products; this anion has been structurally characterised by a single crystal X-ray study of its Bu₄P⁺ salt.     

Reactions of triosmium clusters with organic azides; x-ray crystal structures of [Os3(CO)10(NCMe)(N3COPh)], [Os3(μ-H)(CO)10(HN3Ph)], and [Os3(μ-H)2(CO)9(μ3-NPh)]

Organic azides [N₃R] react with [Os₃(CO)₁₁(NCMe)] and with [Os₃(μ-H)₂(CO)₁₀] to form [Os₃(CO)₁₀(NCMe)(N₃COR)] (R  Ph) and [Os₃(μ-H)(CO)₁₀(HN₃R)] (R  Ph, n-Bu, CH₂Ph, cyclo-C₆H₁₁), respectively; the latter may be converted to [Os₃(μ-H)₂(CO)₉(μ₃-NR)] by thermolysis; the molecular structure of the phenyl derivative of each class of compound has been confirmed by x-ray analysis.     

Ein cyclisches Arsinoschwefeldiimid als intramolekularer Brückenligand: Synthese und Röntgenstrukturanalyse von Os3(CO)10[μ-(t-Bu)As(NSN)2As(t-Bu)]

A Cyclic Arsino Sulfur Diimide as an Intramolecular Bridging Ligand: Synthesis and X-Ray Structure Analysis of Os₃(CO)₁₀[μ-(t-Bu)As(NSN)₂As(t-Bu)] The eight-membered sulfur diimide heterocycle (t-Bu)As(NSN)₂As(t-Bu) ( 8 ) can be incorporated into a trinuclear carbonylosmium cluster either as a mono- or as a bidentate ligand. Reaction of the kinetically labile acetonitrile complex Os₃(CO)₁₁(CH₃CN) with 8 in CH₂Cl₂ solution leads to a monosubstituted derivative of Os₃(CO)₁₂ of composition Os₃(CO)₁₁[(t-Bu)As(NSN)₂As(t-Bu)] ( 9 ) which still contains one uncoordinated arsenic atom; addition of a second [Os₃(CO)₁₁] fragment to 9 was not observed. However, Me₃NO-induced substitution of a carbonyl group in 9 results in coordination of the ligand 8 to the triosmium cluster through both arsenic atoms. The structure of the product Os₃(CO)₁₀[μ-(t-Bu)As(NSN)₂As(t-Bu)](10)¹ was determined by an X-ray structure analysis. I n the triangulo-triosmiumcarbonyl cluster 10 , the ligand 8 occupies two equatorial positions at two adjacent osmium atoms, being coordinated through the arsenic atoms with O s ? As distances of 2.403(1) Å The cluster molecule 10 possesses a 2-symmetry of crystallographic origin. The [Os₃(CO)₁₀] fragment and the eight-membered heterocyclic ligand are not changed significantly in their structures as compared with Os₃(CO)₁₀ and free 8 , respectively. Nevertheless, coordination of 8 imposes its lower 2-symmetry upon the [Os₃(CO)₁₀] fragment. The reduction of mm2- to 2-symmetry (C_2v to C₂) for the cyclic arsino sulfur diimide 8 is more pronounced in the complex 10 than in the free state. The As …? As distance in 10 (8.878(4) A) is considerably enlarged its compared to 8 (3.683(1) Å).     

Reaction of Os3(μ-Cl)2(CO)10 with Ph2PCH2PPh2. The formation of a novel 12-membered macrocycle containing C, P, Cl, and Os atoms in the ring

The reaction of Os₃(μ-Cl)₂(CO)₁₀ (1) with Ph₂PCH₂PPh₂ (dppm) in a toluene solution at 65°C results in novel osmium complexes [Os₃(μ-Cl)₂(CO)₉]₂(dppm) (2) and [Os₃(μ-Cl)₂(CO)₈]₂(dppm)₂ (3). Compounds 2 and 3 were characterized by¹H and³¹P NMR, and IR spectroscopy and their structures were established by X-ray analysis. In both compounds, dppm is a bridging ligand between the two cluster units. Molecule3 can be considered as an unusual 12-membered macrocycle containing C, P, Cl, and Os atoms in the ring. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1844–1851, September, 1998.     

Ligand Dynamics in H2Os3(CO)10 and H2Os3(CO)10L

The variable temperature ¹³C NMR spectra of H₂Os₃(CO)₁₀ and H₂Os₃(CO)₁₀L (L P(C₆H₅)₃, P(O-i_C₃H₇)s3) and P(i_C₃H₇)₃) have been recorded and the results interpreted in terms of a localized exchange process involving concerted motion of the hydride and the carbonyl ligands. Taken along with previously reported variable temperature ¹H NMR data the results provide a complete picture of the ligand dynamics in these systems.     

Activation of the carbon—nitrogen triple bond of benzonitrile in the presence of triosmium clusters and acetic acid. Crystal structure of (μ-H)Os3(CO)10(μ-O2CCH3), a product of the reaction

The activation of the CN triple bond of benzonitrile in the presence of acetic acid and of Os₃(CO)₁₂ or H₂Os₃(CO)₁₀ has been studied. When Os₃(CO)₁₂ reacts with PhCN and acetic acid in refluxing n-octane the three main products are (μ-H)Os₃(CO)₁₀(μ-O₂CCH₃) (I), (μ-H)Os₃(CO)₁₀(μ-NCHPh) (II) and (μ-H)Os₃(CO)₁₀(μ-NHCH₂Ph) (III); II and III are analogues of (μ-H)Ru₃(CO)₁₀(μ-NCHPh) and (μ-H)Ru₃(CO)₁₀(μ-NHCH₂Ph) obtained from PhCN, Ru₃(CO)₁₂ or H₄Ru₄(CO)]₁₂, and acetic acid. In contrast to the reaction with ruthenium clusters, Os₃(CO)₁₂ and H₂Os₃(CO)₁₀ also give the adduct Os₃(CO)₁₀(CH₃COOH) (I). The structure of I has been fully elucidated by X-ray diffraction. Crystals of I are monoclinic, space group P2₁/m, with unit cell parameters a 7.858(6), b 12.542(8), c 9.867(6) Å, β 109.92(2)°, Z = 2. In I an edge of the triangular cluster of osmium atoms is doubly bridged by a hydride and an acetate ligand. Ten terminal carbonyl groups are bonded to the metal atoms.     

Triosmium clusters containing bridging dppm and EPh (E = S,Te) ligands: X-ray structures of [(μ-H)Os3(CO)7(μ-SPh){μ3-η4-Ph2PCHP(Ph)C6H4}], [Os3(CO)8(μ-SPh)2(μ-dppm)] and [Os3(CO)8(μ-TePh)2(μ-dppm)]

Heating [Os₃(CO)₁₀(μ-dppm)] (1) with two equivalents of PhSSPh in toluene under reflux provided three new triosmium compounds [(μ-H)Os₃(CO)₇(μ-SPh){μ₃-η⁴-Ph₂PCHP(Ph)C₆H₄}] (2), [Os₃(CO)₈(μ-SPh)₂(μ-dppm)] (3) and [(μ-H)Os₃(CO)₇(μ-η²-SC₆H₄)(μ-SPh)(μ-dppm)] (4) in 20%, 21% and 26% yields, respectively. In contrast, a similar reaction of 1 with two equivalents of PhTeTePh in refluxing toluene gave the binuclear compound [Os₂(CO)₄(μ-TePh)₂(μ-dppm)] (6) in 15% yield, and two 50 electron isomeric compounds 5 and 7 with the formula [Os₃(CO)₈(μ-TePh)₂(μ-dppm)] in 20% and 23% yields, respectively. Thermolysis of 3 at 110 °C afforded 4 in 53% yield which on further thermolysis in refluxing octane at 128 °C gave 2 in 45% yield. Thermolysis of 3 in refluxing octane also gave 2 in 50% yield. The new compounds, 2–7, were all spectroscopically characterized, and the X-ray structures of 2, 3 and 7 have been determined. Compound 2 contains a bridging SPh ligand and a μ₃,η⁴-Ph₂PCHP(Ph)C₆H₄ ligand, formed by two kinds of C–H activation, including orthometallation of a phenyl group as well as an unusual activation of the methylene group of the dppm ligand. The molecular structure of 3 reveals that two SPh groups span the open Os–Os edge of the Os₃ triangle, while the dppm ligand bridges one of the closed Os–Os edges. In compound 7, one TePh group spans the open Os–Os edge, while the other spans one of the two closed Os–Os edges and the dppm ligand bridges the third Os–Os vector.