Syntheses of double- and triple-decker clusters of osmium and cobalt metals linked by cyclotetradeca-1,8-diyne ligands

Photoirradiation of Os₃(CO)₁₀(C₁₄H₂₀) (1) in n-hexane produces the double-decker cluster [Os₃(CO)₉(C₂₈H₄₀)] [Os₃(CO)₁₀] (7), which can also be prepared from the reaction of Os₃(CO)₉(C₂₈H₄₀) (2) and Os₃(CO)₁₀(NCMe)₂. Further reaction of 7 with Os₃(CO)₁₀(NCMe)₂ affords the triple-decker cluster [Os₃(CO)₉(C₂₈H₄₀)][Os₃(CO)₁₀]₂ (8). The bis(diyne) complex Os₃(CO)₈(C₁₄H₂₀)₂ (3) reacts with Os₃(CO)₁₀(NCMe)₂ sequentially to yield the double-decker cluster [Os₃(CO)₈(C₁₄H₂₀)₂][Os₃(CO)₁₀] (4) and the triple-decker cluster [Os₃(CO)₈(C₁₄H₂₀)₂][Os₃(CO)₁₀]₂ (5). Treatment of 3 with Co₂(CO)₈ at room temperature leads to the mixed-metal triple-decker cluster [Os₃(CO)₈(C₁₄H₂₀)₂][Co₂(CO)₆]₂ (6), while the reaction of 2 and Co₂(CO)₈ produces [Os₃(CO)₉(C₂₈H₄₀)][Co₂(CO)₆]₂ (9) and [Os₂(CO)₆(C₂₈H₄₀)][Co₂(CO)₆]₂ (10). Compound 10, which involves cluster degradation from Os₃ to Os₂, has been structurally characterized by an X-ray diffraction study.     

Surface organometallic chemistry: Reductive carbonylation of OsCl3·3H2O supported on silica

The reductive carbonylation of silica-supported OsCl₃·3H₂O was investigated under atmospheric pressure of CO or of a mixture of CO and H₂O at relatively mild temperatures. Starting from OsCl₃·3H₂O a mixture of physisorbed α-[Os(CO)₃Cl₂]₂, cis-[Os(CO)₄Cl₂] and a species bound to the surface silanol groups, [Os(CO)₃Cl₂(HOSi)], is formed working at 100°C under CO. At higher temperatures [Os(CO)₃Cl₂(HOSi)] is the major surface species. Attempts to reduce further on the surface these Os^II chlorocarbonyl species failed due to their easy sublimation and to the difficult removal of the chloro ligands. However, when the silica is treated with a weak base such as NaHCO₃, α- or β-[Os(CO)₃Cl₂]₂ supported on silica may be reduced with CO to [Os₃(CO)₁₂], with CO and H₂O to a mixture of [OS₃(CO)₁₂] and [H₄Os₄(CO)₁₂], and finally with H₂ to [H₄Os₄(CO)₁₂]. These reduction processes occur via the anchored [Os(CO)₃(OSi)₂]_n species, as intermediate surface species.     

Synthesis of heterometallic cluster compounds from Fe3(μ3-Te)2(CO)9 and comparisons with analogous sulfide clusters

Fe₃Te₂(CO)₉ is shown to be a useful precursor to a variety of heterometallic carbonyl clusters in reactions which appear to proceed via the intermediacy of Fe₂(Te₂)(CO)₆. Fe₃Te₂(CO)₉ decomposed in polar solvents to give Fe₂(Te₂)(CO)₆ which could be dimerized to Fe₄Te₄(CO)₁₂. Fe₃Te₂(CO)₉ reacted with C₅H₅Co(CO)₂ and Pt(C₂H₄)(PPh₃)₂ to give good yields of (C₅H₅CO)Fe₂Te₂(CO)₇ and Fe₂PtTe₂(CO)₆(PPh₃)₂, respectively. (C₅H₅Co)Fe₂Te₂(CO)₇ underwent reversible decarbonylation to give a mixture of two isomers of (C₅H₅Co)Fe₂Te₂(CO)₆ as established by ¹²⁵Te NMR spectroscopy. Upon reaction with Co₂(CO)₈, Fe₃Te₂(CO)₉ gave Co₂FeTe(CO)₉ or Co₄Te₂(CO)₁₁ depending on the reaction conditions. Co₄Te₂(CO)₁₁, like Fe₃Te₂(CO)₁₀ and (C₅H₅Co)Fe₂Te₂(CO)₇, can be reversibly decarbonylated. The assembly of Co₂FeTe(CO)₉ may be mechanistically related to the conversion of Fe₂(S₂)(CO)₆ to FeCo₂S(CO)₉ which was found to proceed via Co₂Fe₂S₂(CO)₁₁. Alternatively, Co₂Fe₂S₂(CO)₁₁ reacted photochemically with [C₅H₅Mo(CO)₃]₂ to give the known, chiral cluster (C₅H₅Mo)CoFeS(CO)₈. While Fe₂(Te₂)(CO)₆ thermally dimerized to Fe₄Te₄(CO)₁₂, Fe₂(S₂)(CO)₆ gave the analogous dimer only upon photolysis. In contrast to the stability of (C₅H₅CO)Fe₂Te₂(CO)₇, the reaction of C₅H₅Co(CO)₂ with Fe₂(S₂)(CO)₆ gave only (C₅H₅CO)Fe₂S₂(CO)₆ which is proposed to be structurally related to Fe₃S₂(CO)₉ and not (C₅H₅Co)₃S₂ or Fe₂PtS₂(CO)₆(PPh₃)₂.     

Chemistry of vinylidene complexes: IV. Synthesis and the crystal and molecular structure of (η5-C5H5)MnOs3(μ2-CHCHPh)(μ-H)(μ-CO)(CO)11, an unusual heterometallic cluster

By the reaction of Cp(CO)₂MnCCHPh (I) with H₂Os₃(CO)₁₀ (II) the tetranuclear mixed-metal complex CpMnOs₃(μ₂-CHCHPh)(μ-H)(μ-CO)(CO)₁₁ (III) was prepared. An X-ray study of the structure of III showed that it is a spiked, tetranuclear cluster with the Mn atom linked to one of the vertices of the osmium triangle; the MnOs bond is bridged by CO and CHCHPh groups, the latter being σ-bonded to Os and η²-coordinated by Mn. In the course of the formation of III, hydrogenation and n-π rearrangement of the initial phenylvinylidene ligand take place. In solution, complex III readily eliminates the [CpMn(CO)₂] fragment to give triosmium clusters containing unsaturated organic ligands: HOs₃(μ₂-CHCHPh)(CO)₁₀, H₂Os₃(μ₃-CHCPh)(CO)₉, and H₂Os₃(μ₃-CCHPh)(CO)₉.     

Reactions of metal carbonyl cluster complexes with multidentate phosphine ligands; preparation of bis(diphenylphosphino)methane derivatives of the trinuclear complexes M3(CO)12 (M = Fe,Ru and Os) and the X-ray crystal structure of Os3(CO)9(μ-dppm)(η1-dppm) (dppm = Ph2pch2ppH2)

The reaction of bis(diphenylphosphino)methane (dppm) with Fe₃(CO)₁₂ gave the known complexes Fe(CO)₄ (dppm), Fe₂(CO)₇ (dppm), in addition to Fe₂CO)₅(dppm)₂. Two new dppm derivatives of Ru₃CO)₁₂, Ru₃(CO)₉(μ-dppm)(η¹-dppm) and Ru₃(CO)₆(dppm)₃ have been isolated and spectroscopically characterised. From the reaction of Os₃(CO)₁₂ with dppm, the derivatives Os₃(CO)₁₀(dppm), Os₃(CO)₉(μ-dppm)(η¹-dppm) and Os₃(CO)₈(dppm)₂ have been isolated. The crystal structure of Os₃(CO)₉(μ-dppm)(η¹-dppm) has been determined.     

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.     

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.     

Synthesis and Characterization of an Unusual 68-Electrons Os4Se3 Carbonyl Phosphane Cluster

The 68-electrons, phosphane-substituted, osmium selenido-carbonyl cluster [Os₄Se₃(CO)₁₀(dppm)] (cluster 3; dppm = bis(diphenylphosphino)methane) has been obtained by reaction under mild experimental conditions between [Os₃(CO)₁₂] and the diphosphane diselenide dppmSe₂. Its crystal and molecular structure has been elucidated by X-ray diffraction methods. Cluster 3 contains only two Os–Os bonds as suggested by its electron count. It can be described as derived from the open-triangular nido cluster [Os₃(μ₃-Se)₂(CO)₉] through substitution of one CO ligand by the four-electrons donor osmiaselone fragment [CH₂(Ph₂P)₂](CO)₂Os=Se. The replacement of a two-electrons donor carbonyl with a four-electron donor fragment produces the cleavage of one Os–Os bond in the nido cluster. Under the adopted experimental conditions, other products of the reaction between [Os₃(CO)₁₂] and dppmSe₂ are the clusters [Os₃(μ₃-Se)₂(CO)₉] (1), [Os₃(μ₃-Se)₂(CO)₇(μ-dppm)] (2), and [Os₃(μ₃-Se)(CO)₈(μ-dppm)] (4), already described in the literature.     

Synthesis and characterization of triosmium and triruthenium pyrene clusters

The reaction between 1-pyrenecarboxaldehyde (C₁₆H₉CHO) and the labile triosmium cluster [Os₃(CO)₁₀(CH₃CN)₂] gives rise to the formation of two new compounds by competitive oxidative addition between the aldehydic group and an arene C-H bond, to afford the acyl complex [Os₃(CO)₁₀(μ-H)(μ-COC₁₆H₉)] (1) and the compound [Os₃(CO)₁₀(μ-H) (C₁₆H₈CHO)] (2), respectively. Thermolysis of [Os₃(CO)₁₀(μ-H)(μ-C₁₆H₉CO)] (1) in n-octane affords two new complexes in good yields, [Os₃(CO)₉(μ-H)₂(μ-COC₁₆H₈)] (3) and the pyryne complex [Os₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (4).In contrast, when 1-pyrenecarboxaldehyde reacts with [Ru₃(CO)₁₂] only one product is obtained, [Ru₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (5), a nonacarbonyl cluster bearing a pyrene ligand. All compounds were characterized by analytical and spectroscopic data, and crystal structures for 1, 2, 4 and 5 were obtained.     

IR frequencies and intensities of the vibrational modes of Cx Hy fragments bonded to metal complexes. Relationship with structure,bonding and reactivity

The following organometallic complexes were studied as models of the coordination between metal atoms and different C_x H_y ligands: Co₂Fe(CO)₉(CCH₂), Co₂Ru(CO)₉(CCH₂), Os₃(H)₂(CO)₉(CCH₂) and Co₂Fe(CO)₉(CC(H)CH₃) (η₃-η₂-vinylidene or μ₃-η₂-methylvinylidene group); Fe₂(C₅H₅)₂(CO)₃(CCH₂) (μ₂-η¹-vinylidene group); Os₃(μ-H)(CO)₉(CHCH₂) (μ₂-η²-vinyl group); CH₃Mn(CO)₅ (η¹-methyl group); Os₃(μ-H)₂(Co)₁₀(CH₂) and Fe₂(CO)₈(CH₂) (μ₂-η¹-methylene group); Co₃(CO)₉(CH) (μ₃-methyne group); CO₃(CO)₉(CCH₃) (μ₃-η¹-ethylidyne group); Os₃(H)(CO)₉(C₂H) (μ₃-η²-acetylide group). The infrared frequencies and intensities associated with the main vibrational modes of the ligands (CC and CH stretchings, CH deformations) were evaluated and compared with those of appropriate model molecules. Both the frequency and intensity data can be usefully correlated with structural parameters (e.g. CC and CH bond distances and HCH bond angles) and provide information on the charge distribution on the ligands. It is therefore possible to discuss the type of metal—ligand interaction and the balance between the σ and π contributions to the bond.     

Triosmium clusters with μ3-AsR group as a building block for hexaosmium-arsenic cluster synthesis. Synthesis and characterisation of [(CO)11Os3As(Os3(CO)9H3)] and [(CO)9H3Os3As(Os3(CO)9H3)]. Crystal structure of [(CO)11Os3As(Os3(CO)9H3)]

Reaction of the activated cluster [Os₃(CO)₁₁(CNMe)] with primary arsine AsH₃ forms the arsinidine compound [H₂Os₃(μ₃-AsH)(CO)₁₁] (1a, 1b), which on further reaction with [Os₃(CO)₁₁(NCMe)] yields [(CO)₁₁Os₃As(Os₃(CO)₉H₃)] (2) and with [H₂Os₃(CO)₁₀] yields [H₂Os₃(CO)₉As(Os₃(CO)₉H₂)] (3). Similarly [H₂Os₃(CO)₁₀] reacts with AsH₃ at room temperature to afford 3 in good yields. Thermal degradation and rearrangement of 2 gives the pentanuclear cluster [H₂Os₅(CO)₁₇AsH] (4).     

The reduction of triosmium dodecacarbonyl by sodium borohydride. The preparation and X-ray structure of the cluster anion [H2Os4(CO)12]2−

The reduction of Os₃(CO)₁₂ by NaBH₄ in tetrahydrofuran has been studied, and the formation of the anionic clusters [HOs₃(CO)₁₁]^?, [H₃Os₄(CO)₁₂]^? and [H₂Os₄(CO)₁₂]^2? observed. The previously unreported dianion [H₂Os₄(CO)₁₂]^2? was prepared in satisfactory yield, and characterised as the bis(triphenylphosphine)iminium salt. This compound crystallizes in the space group P$\text{1}$, with Z = 1, and cell dimensions of a 11.014(2), b 14.751(3), c 15.168(3) Å, α 123.95(2)°, β 95.77(2)°, γ 98.73(2)°. The structure was solved by a combination of multisolution sign expansion and Fourier methods, and final residuals were R 0.067 and R_W 0.066 for 5972 observed intensity data. The dianion comprises a distorted tetrahedron of osmium atoms, each metal also bonding to three terminal carbonyl ligands, which as staggered with respect to the metalmetal bonds. Unlike the cation, the cluster anion is statistically disordered between two centrosymmetrically related sites.     

Two modes of C-H bond activation of tris(2-thienyl)phosphine in trinuclear osmium carbonyl clusters

Tris(2-thienyl)phosphine, P(C₄H₃S)₃, reacts with [Os₃(CO)₁₂] at 110 °C to give the phosphine-substituted derivatives [Os₃(CO)₁₁{P(C₄H₃S)₃}] (1), [Os₃(CO)₁₀{P(C₄H₃S)₃}₂] (2) and [Os₃(CO)₉{P(C₄H₃S)₃}₃] (4), as well as the C-H activated product [Os₃(μ-H)(CO)₉{μ-P(C₄H₂S)(C₄H₃S)₂}{P(C₄H₃S)₃}] (3), in which the bridging ligand is equatorially coordinated to two osmium atoms. Thermolysis of 2 in refluxing toluene results in the formation of 3. Compound 1 can also be prepared in high yield from [Os₃(CO)₁₁(NCMe)]. The reaction of [Os₃(μ-H)₂(CO)₁₀] with tris(2-thienyl)phosphine at room temperature afforded [Os₃(μ-H)₂(CO)₉{P(C₄H₃S)₃}] (5) and [Os₃H(μ-H)(CO)₁₀{P(C₄H₃S)₃}] (6), with the ligand coordinated through the phosphorus atom whereas at elevated temperature the cyclometallated compounds [Os₃(μ-H)(CO)₉{μ₃-P(C₄H₂S)(C₄H₃S)₂}] (7) and [Os₃(μ-H)(CO)₈{μ₃-P(C₄H₂S)(C₄H₃S)₂{P(C₄H₃S)₃}] (8) were obtained in addition to 5. Heating 6 in refluxing heptane furnished 5 via loss of one carbonyl ligand. Thermolysis of 1 and 3 in refluxing toluene gives 7 and 8, respectively, in good yields. In 3, the μ-P(C₄H₂S)(C₄H₃S)₂ ligand is coordinated through the phosphorus to one Os atom and through a σ-Os-C bond to the second osmium atom. Compound 7 contains the μ₃-P(C₄H₂S)(C₄H₃S)₂ ligand bound through phosphorus to one Os atom, through a σ-Os-C bond to another and by an η² (π)-interaction to the third osmium atom. Compounds 1, 2 and 4 contain the ligand coordinated exclusively through the phosphorus atom. The crystal and molecular structures of 2, 3, 5, 6 and 7 are reported.     

Products of the reaction of H2Os3(CO)10 with cyclonona-1,2diene

Treatment of H₂Os₃(CO)₁₀ with cyclonona-l,2-diene produced HOs₃(CO)₉C₉H₁₃ and Os₂(CO)₆(C₉H₄)₂. Single crystal X ray analysis has shown that the latter is not isostructural with Fe₂(CO)₆(C₉H₁₄)₂.     

Reactions of dodecacarbonyltriosmium with dienic ligands

Dodecacabonyltriosmium reacts with diene ligands (D) such as 2,4-trans, trans- and 2,4-cis, trans-hexadiene and 1,6- and 1,5-heptadiene to give H₂Os₃D(CO)₉, H₄Os₄(CO)₁₂ and two isomers of molecular formula HOs₃-(D  H)(CO)₉ in addition to Os₂(D  2H)(CO)₆ and OsD(CO)₃. The structures of the trimetal complexes show that dehydrogenation, isomerization and rearrangement of the organic substrates occur before the coordination to the metal cluster. 2,3-Dimethyl-1,3-butadiene and dodecacabonyltriosmium give only the well known bi- and mono-metal complexes. The results are compared with those obtained in the reactions of the some organic molecules with dodecacabonyltriruthenium.     

Products from the reaction of M3(CO)12 (M = Ru or Os) with water

Reaction of the carbonyl Ru₃(CO)₁₂ with water leads to the formation of polynuclear hydrides α-H₄Ru₄(CO)₁₂, α-H₂Ru₄(CO)₁₃; the corresponding reaction with Os₃(CO)₁₂ yields the complexes (H)(OH)Os₃(CO)₁₀, H₂Os₄(CO)₁₃, H₄Os₄(CO)₁₂, H₂Os₅(CO)₁₆, H₂Os₅(CO)₁₅, H₂Os₆(CO)₁₈ and H₂Os₇(CO)₁₉C.     

Os(CO)2(η-SC5H4N(O))(η-SC5H4N): structural evidence for the transformation of pyridine-2-thione N-oxide to pyridine-2-thiolate in osmium complexes

The reaction of Os₃(CO)₁₂ with an excess of 1-hydroxypyridine-2-thione and Me₃NO gives three mononuclear osmium complexes Os(CO)₂(η²-SC₅H₄N(O))₂ (1), Os(CO)₂(η²-SC₅H₄N(O))(η²-SC₅H₄N) (2), and Os(CO)₂(η²-SC₅H₄N)₂ (3). The results of single-crystal X-ray analyses reveal that complex 1 contains two O,S-chelate pyridine-2-thione N-oxide (PyOS) ligands, whereas complex 2 contains one O,S-chelate PyOS and one N,S-chelate pyridine-2-thiolate group. The unique structure of 2 provides evidence of the pathway for this transformation. When this reaction was monitored by ¹H NMR spectroscopy the triosmium complexes Os₃(CO)₁₀(μ-H)(μ-η¹-S-C₅H₄N(O)) (4) and Os₃(CO)₉(μ-H)(μ-η¹:η²-SC₅H₄N(O)) (5) were identified as intermediates in the formation of the mononuclear final products 1-3. The proposed pathway is further supported by the observation of several dinuclear osmium intermediates by electrospray ionization mass spectrometry. In addition, the reaction of Os₃(CO)₁₂ with 1-hydroxypyridine-2-thione in the absence of Me₃NO at 90 °C generated mononuclear complex 2 as the major product along with smaller amounts of complexes 1 and 3. These results suggest that the N-oxide facilitates the decarbonylation reaction. Crystal data for 1: monoclinic, space group C2/c, a = 26.9990(5) Å, b = 7.6230(7) Å, c = 14.2980(13) Å, β = 101.620(2)°, V = 2882.4(4) ų, Z = 8. Crystal data for 2: monoclinic, space group C2/c, a = 5.7884(3) Å, b = 13.9667(7) Å, c = 17.2575(9) Å, β = 96.686(1)°, V = 1385.69(12) ų, Z = 4.     

A comparative study of the reactivity of unsaturated triosmium clusters [Os3(CO)8{μ3-Ph2PCH2P(Ph)C6H4}(μ-H)] and [Os3(CO)9{μ3-η-C7H3(2-Me)NS}(μ-H)] with BuNC

Treatment of unsaturated [Os₃(CO)₈{μ₃-Ph₂PCH₂P(Ph)C₆H₄}(μ-H)] (2) with ^tBuNC at room temperature gives [Os₃(CO)₈(CNBu^t)){μ₃-Ph₂PCH₂P(Ph)C₆H₄}(μ-H)] (3) which on thermolysis in refluxing toluene furnishes [Os₃(CO)₇(CNBu^t){μ₃-Ph₂PCHP(Ph)C₆H₄}(μ-H)₂] (4). Reaction of the labile complex [Os₃(CO)₉(μ-dppm)(NCMe)] (5) with ^tBuNC at room temperature affords the substitution product [Os₃(CO)₉(μ-dppm)(CNBu^t)] (6). Thermolysis of 6 in refluxing toluene gives 4. On the other hand, the reaction of unsaturated [Os₃(CO)₉{μ₃-η²-C₇H₃(2-Me)NS}(μ-H)] (7) with ^tBuNC yields the addition product [Os₃(CO)₉(CNBu^t){μ-η²-C₇H₃(2-Me)NS}(μ-H)] (8) which on decarbonylation in refluxing toluene gives unsaturated [Os₃(CO)₈(CNBu^t){μ₃-η²-C₇H₃(2-Me)NS}(μ-H)] (9). Compound 9 reacts with PPh₃ at room temperature to give the adduct [Os₃(CO)₈(PPh₃)(CNBu^t){μ-η²-C₇H₃(2-Me)NS(μ-H)] (10). Compound 8 exists as two isomers in solution whereas 10 occurs in four isomeric forms. The molecular structures of 3, 6, 8, and 10 have been determined by X-ray diffraction studies.     

Darstellung,Kristallstruktur, Schwingungsspektren und Normalkoordinatenanalyse von K2[OsCl5(CO)] · H2O

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of K₂[OsCl₅(CO)] · H₂O The X-ray structure determination of K₂[OsCl₅(CO)] · H₂O (monoclinic, space group P2₁/c a = 13.600(2), b = 7.122(1), c = 22.186(11) Å, β = 98.66(3)°, Z = 8) revealed two crystallographic independent bat very similar complex anions [OsCl₅(CO)]^2? with rough C_4v point symmetry. Due to the stronger trans influence of the carbonyl group the bond lengths in the Cl? Os? CO axis Os? Cl = 2.449(2), 2.430(2) Å are langer as compared with the octahedron basis Os? Cl = 2.340-2.370 Å. The water of crystallization is coordinated to potassium (K? OH₂ = 2.625-2.815 Å). Using the molecular parameters the IR and Raman spectra are assigned by normal coordinate analysis. The valence force constants are f_d(CO) = 15.30, f_d(OsC) = 3.88, f_d(OsCl) = 1.81, f_d(OsCl) = 1.36, f_d(OH) = 7.65, 7.82, 7.79 mdyn/Å. The strengthening of the Os? C bond by stronger back donation of the Os^III(d⁵) complex in comparison with the isostructural Os^IV (d⁴) compound is discussed.