Darstellung,Kristallstruktur, Schwingungsspektren und Normalkoordinatenanalyse von [Co(NH3)6][Os(SCN)6]

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of [Co(NH₃)₆][Os(SCN)₆] From the mixture of the linkage isomers [Os(NCS)_n(SCN)_6–n]^3–, n = 0–2, pure [Os(SCN)₆]^3– has been isolated by ion exchange chromatography on diethylaminoethyl cellulose. The X‐ray structure determination on a single crystal of [Co(NH₃)₆][Os(SCN)₆] (trigonal, space group R 3, a = 12.368(2), c = 11.830(2) Å, Z = 3) reveals that the thiocyanate ligands are exclusively S‐coordinated with the Os–S distance of 2.388 Å and the Os–S–C angle of 108.8°. The IR and Raman spectra of (n‐Bu₄N)₃[Os(SCN)₆] are assigned by normal coordinate analysis based on the molecular parameters of the X‐ray determination. The valence force constant f_d(OsS) is 1.42 mdyn/Å.     

Synthesis and structural characterization of a polar Os(II,III) complex,Os2(fhp)4Cl

The title compound was prepared by prolonged reaction of Os₂(CH₃COO)₄Cl₂ with Hfhp (Hfhp = 6-fluoro-2-hydroxypyridine) in refluxing toluene in the presence of LiCl. The product, Os₂(fhp)₄Cl (1), is a result of ligand displacement with a concomitant core reduction of Os₂⁶⁺ to Os₂⁵⁺. Crystals were grown by slow diffusion of hexane into a dichloromethane solution of 1. Crystallographic data are as follows: tetragonal crystal system, space group I4mm (No. 107), a = b = 11.000(3) Å, c = 13.142(2) Å, V= 1590(1) ų, Z = 2. The molecule possesses crystallographic 4mm symmetry, with the OsOs bonds lying along the four-fold axes. The four fhp ligands are arranged in a polar fashion around the diosmium core, blocking one axial site. The second axial position is occupied by a chloride ion. The principal distances in 1 are: Os(1)Os(2) = 2.341(1) Å, Os(1)N = 2.027(12) Å, Os(2)O = 2.014(5) Å, Os(2)Cl = 2.487(7) Å. The title compound was also investigated by several physical methods. The electrochemistry as determined by cyclic voltammetry revealed two processes: a reversible, one-electron reduction at E_ox = −0.63 V in dichloromethane and an irreversible oxidation at E_ox = +0.95 V in dichloromethane vs Ag-AgCl at room temperature. The electronic spectrum shows strong bands at 413 nm (ε = 4290 M⁻¹ cm⁻¹), 309 nm (ε = 23,560 M⁻¹ cm⁻¹) and at 294 nm (ε = 26,500 M⁻¹ cm⁻¹) as well as shoulders at 334 and 261 nm.     

Migratory-insertion reactions involving the thiocarbonyl ligand. dihapto-thioacyl complexes from the rearrangement of arylthiocarbonyl complexes of osmium(II). Structure of Os(η2-CSR)(η1-O2CCF3)(CO)(PPh3)2

Reaction of HgR₂ with OsHCl(CS)(PPh₃)₃ yields red, five-coordinate, OsRCl-(CS)(PPh₃)₂ (R = p-tolyl). From this have been derived the compounds OsRX(CS)(PPh₃)₂ with X = Br, I, S₂CNEt₂, O₂CMe, O₂CCF₃. These compounds add an additional ligand, MeCN, CO or CNR to form colourless, six coordinate arylthiocarbonyl complexes, which undergo migratory-insertion reactions to form red, dihapto-thioacyl complexes. The crystal structure of a representative example, Os(η²-CSR)(η¹-O₂CCF₃)(CO)PPh₃)₂ has been determined. The red equant crystals are orthorhombic, space group P2₁2₁2₁, a 11.584(1), b 19.184(2), c 18.90(1) Å, V 4199 ų, Z  4. The structure was solved by conventional heavy-atom methods and refined by full-matrix least-squares employing anisotropic thermal parameters for all non-hydrogen atoms except the carbon atoms of the triphenylphosphines. The final R factor is 0.057 for 2868 observed reflections.The coordination geometry in the monomeric complex is that of an octahedron distorted by the constraints of the ligands. The triphenyl phosphine ligands are mutually trans; the equatorial plane contains carbonyl, monohapto-trifluoroacetate, and dihapto-thioacyl ligands. Bond distances and angles are OsP 2.405, 2.407(4) Å; POsP 173.9(1)°; OsCO 1.83(2) Å; Os-O (trifluoroacetate) 2.206(11) Å; OsC (thioacyl) 1.91(2); OsS 2.513(6); CS 1.72 Å. The CS bond length implies a reduction in bond order from 2.0 to approx. 1.5 upon coordination to the metal.The η²-thioacyl ligand in Os(η²-CSR)Cl(CNR)(PPh³)₂ is methylated with methyl triflate and further reaction with LiCl produces the thiocarbene complex OsCl₂(C[SMe]R)(CNR)(PPh₃)₂.     

La3Os2O10, a new compound containing isolated clusters Os2O10 with metal-metal bonds

The formula of a new compound isolated in the LaOsO system has been established by means of crystal structure determination. There are two La₃Os₂O₁₀ units in a face-centered monoclinic unit cell (S.G. $\text{C2}\text{m}$); a = 7.911(2) Å, b = 7.963(2) Å, c = 6.966(2)Å, β = 115.76(2)°;. For 1082 intensities, collected on an automated single-crystal diffractometer, the final R value was 0.025 after absorption corrections. The structure consists of isolated Os₂O₁₀ clusters composed of two edge-shared OsO₆ octahedra. These dimeric units are connected together by two types of La³⁺ ions in eightfold coordination. In view of the OsOs distance inside the pair (2.462 Å), La₃Os₂O₁₀ provides an example of metal-metal bonding involving a transition metal in a half-integral formal oxidation state of 5.5.     

Structural studies on osmium carbonyl hydrides: XXXI. Crystal and molecular structure of CpWOs3(CO)9(μ-H)(μ-O)(μ-CHCH2C6H4Me), a hydrido-alkylidene produced by hydrogenation of a μ3-alkylidyne

The complex CpWOs₃(CO)₉(μ-H)(μ-O)(μ-CHCH₂C₆H₄Me), previously prepared by hydrogenation of CpWOs₃(CO)₉(μ-O)(μ₃-CCH₂C₆H₄Me), has been subjected to a single-crystal X-ray diffraction study. The complex crystallizes in the non-centrosymmetric monoclinic space group Cc(C_s⁴; No. 9) with a 14.1510(27), b 13.9257(22), c 13.3179(19) Å, β 92.023(13)°, V 2622.8(7) ų and D(calcd) 3.06 g cm^?3 for Z = 4 and mol. wt. 1206.8. Single-crystal X-ray diffraction data were collected with a Syntex P2₁ automated four-circle diffractometer and the structure was refined to R 3.5% for all 2476 independent observations (Mo-K_α radiation, 2θ = 4.5–40.0°) and R 3.4% for those 2430 data with | F₀| > 3.0σ(| F₀|). The molecule contains a tetrahedral WOs₃ core associated with 60 valence electrons. Each osmium atom is associated with three terminal carbonyl ligands and the tungsten atom is linked to an η⁵-C₅H₅ ligand. In addition, the μ-oxo ligand is involved in a WO: → Os bridge (in which WO(B) 1.737(17), Os(3)← :O(B) 2.167(16) Å and WO(B)Os(3) 96.0(7)°), the μ-hydride ligand spans the Os(1)Os(3) linkage and the μ-CHCH₂C₆H₄Me ligand bridges the WOs(2) linkage (WC(1) 2.068(26) and Os(2)C(1) 2.281(26) Å).     

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.     

The X-ray structure of Os(CS)(PhCCPh)(PPh3)2, a complex containing a four-electron donor acetylene ligand

Os(CS)(PhC?CPh)(PPh₃)₂ is formed by the treatment of Os(CS)(CO)(PPh₃)₃ with diphenylacetylene and is an example of a complex containing a four-electron donor acetylene ligand. Os(CS)(PhC?CPh)(PPh₃)₂ crystallizes in the monoclinic space group P2₁/n with the cell dimensions a = 9.028(5), b = 25.256(2) and c = 19.22(2) Å with β = 103.8(7)°, V = 4260 ų, Z = 4 and d(calcd) = 1.461 g cm^?3 for mol.wt 937.09 g mol^?1. Diffraction data were collected with a Nonius CAD-4 diffractometer and refined to R = 4.05% and R_w = 4.19% for 1172 independent reflections. The structure can be described as a distorted trigonal bipyramid with the CS ligand occupying an axial position. The two cis-PPh₃ ligands are in equatorial sites with the acetylene occupying a position between the remaining axial and equatorial sites. The diphenylacetylene is symmetrically bound to the metal with an average Os? C distance of 2.04(3) Å. The Os? CS distance is unusually short at 1.79(2) Å.     

Kristallstrukturen und Schwingungsspektren von Tetrahalogenoacetylacetonatoosmaten(IV), [OsX4(acac)]−, X  Cl,Br, I

Crystal Structures and Vibrational Spectra of Tetrahalogenoacetylacetonatoosmates(IV), [OsX₄(acac)]^?, X ? Cl, Br, I By reaction of the hexahalogenoosmates(IV) with acetylacetone the tetrahalogenoacetylacetonatoosmates(IV) [OsX₄(acac)]^? (X = Cl, Br, I) are formed, which have been purified by chromatography and precipitated from aqueous solution as tetraphenylphosphonium (Ph₄P) or cesium salts. X-ray structure determinations on single crystals have been performed of (Ph₄P)[OsCl₄(acac)] ( 1 ) (triclinic, space group P1 , a = 9.9661(6), b = 11.208(2), c = 13.4943(7) Å, α = 101.130(9), β = 91.948(6), γ = 96.348(8)°, Z = 2), (Ph₄P)[OsBr₄(acac)] ( 2 ) (monoclinic, space group P2₁/n, a = 9.0251(8), b = 12.423(2), c = 27.834(2) Å, β = 94.259(7)°, Z = 4) and (Ph₄P)[OsI₄(acac)] ( 3 ) (monoclinic, space group P2₁/c, a = 18.294(3), b = 10.664(2), c = 18.333(3) Å, β = 117.68(2)°, Z = 4). Due to the increasing trans influence in the series O < Cl < Br < I the Os? O^. distances of O^.? Cl? X′ axes are lengthened and the OsO^. stretching vibrations are shifted to lower frequencies. The Os? X′ bond lenghts are shorter as compared with symmetrically coordinated X? Os? X axes.     

Structure of ammonium decachloro-μ-oxodiosmate(IV) (NH4)4[Os2OCl10] and its behavior in solutions

The structure of (NH₄)₄[OS₂OCl₁₀] has been determined by X-ray diffraction. The crystals are tetragonal, space group I4/mmm, a = 7.292(1) Å, c = 17.157(3) Å, Z = 2. The binuclear anion has D _4h symmetry; the osmium atom is coordinated to five chlorine atoms and the oxygen atom. The Os-O distances are 1.8242(5) Å; Os-Cl_eqv, 2.3743(18) Å; Os-Cl_ax, 2.335(3) Å; the Cl₁OsCl₂ angle is 86.84(4)°. The anion has been established spectrophotometrically to remain structurally unchanged in freshly prepared aqueous and hydrochloric acid solutions. Slow aquation with retention of a binuclear structure occurs with time in 1 and 6 M HCl. At 75 or 90°C, the process is faster with the disrupture of the Os-O-Os bond and the formation [OsCl₆]^2? ions in 6 M HCl and a mixture of [OsCl₆]^2? and [Os(H₂O)Cl₅]^? ions in 1 M HCl.     

Synthesis,Spectroscopic and Electrochemical Studies of Isomeric Dichloro-bis-[ N (1)-Alkyl-2-(Arylazo)Imidazole]-Osmium(II). Single Crystal X-ray Structures of Blue-Violet Dichloro-Bis-[ N (1)-Methyl-2-(Arylazo)Imidazole]-Osmium(II) Species

1-Alkyl-2-(arylazo)imidazoles (p-R-C₆H₄-N=N-C₃H₂N₂X, abbreviated as RaaiX, R = H(a), CH₃(b), Cl(c); X = N(1)-CH₃ (1), N(1)-CH₂-C₆H₅ (2)) have been reacted with (NH₄)₂[OsCl₆] and OsCl₂(RaaiX)₂ species isolated in two isomeric forms, blue-violet (3, 5) and red-violet (4, 6). IR spectra show two x (Os-Cl) modes and support a cis-OsCl₂ configuration. X-ray diffraction methods were used to determine structures of blue-violet isomers. In terms of the three coordination pairs around Os(II), Cl, Cl, N, N (N(imidazole), N) and N', N' (N(azo), N') the blue-violet isomers have a cis-trans-cis (ctc) configuration. ¹H NMR data for the red-violet complexes (isomers B) and results concerning analogous ruthenium(II) complexes indicate isomer B to have cis-cis-cis (ccc) configuration. Absorption spectra show an intense MLCT band at ca 580 nm along with two weak bands at 800 and 1000 nm. Cyclic voltammetry shows quasi-reversible Os(III)/Os(II) and Os(IV)/Os(III) couples at 0.4-0.6 V and 1.3-1.5 V versus SCE and ill-defined azo reductions. The X-Ray structures show unusually long N=N bond lengths, 1.31-1.32 Å, elongated by some 0.06 Å compared to the free ligand value. Os(II) prefers to bind N(azo) (Os-N(azo), 1.98 Å) rather than N(imidazole) (Os-N(imidazole), 2.03 Å). EHMO calculations of ctc-OsCl₂ (MeaaiMe) and comparison with the ruthenium(II) complex account for the MLCT transitions in terms of a metal-dominated HOMO to a ligand-dominated LUMO shift.     

Osmium(IV) thiocarbamide complexes. Synthesis and crystal and molecular structures of [Os(Thio)<Subscript>2</Subscript>Cl<Subscript>4</Subscript>] · 2H<Subscript>2</Subscript>O

Tetrachlorobis(thiocarbamide)osmium(IV) dehydrate, [Os(Thio)₂Cl₄] · 2H₂O, was synthesized by the reaction of K₂[OsO₂(OH)₄] with thiocarbamide in 6 M HCl. The compound was characterized by chemical analysis and IR, UV, and X-ray photoelectron spectroscopies. The structure was determined by X-ray diffraction analysis. The coordination polyhedron of the osmium atom lying in the axis 2 is a distorted cis-octahedron formed by four chlorine atoms and two sulfur atoms of two monodentate thiocarbamide ligands: Os-S 2.3075(18) Å and Os-Cl 2.3625(18) Å (trans to Cl) and 2.4294(19) Å (trans to S). The conditions for the formation of the osmium(IV) thiocarbamide complexes in HCl solutions were determined using spectrophotometry, and the spectral characteristics of [Os(Thio)Cl₅]^? were obtained.     

Kristallstrukturen,Schwingungsspektren und Normalkoordinatenanalyse von (n‐Bu4N)2[Os(NCS)6] und (n‐Bu4N)3[Os(NCS)6]

Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of ( n ‐Bu₄N)₂[Os(NCS)₆] and ( n ‐Bu₄N)₃[Os(NCS)₆] By tempering the solid mixture of the linkage isomers (n‐Bu₄N)₃[Os(NCS)_n(SCN)_6–n] n = 0–5 for a longer time at temperatures increasing from 60 to 140 °C the homoleptic (n‐Bu₄N)₃[Os(NCS)₆] is formed, which on oxidation with (NH₄)₂[Ce(NO₃)₆] in acetone yields the corresponding Os^IV complex (n‐Bu₄N)₂[Os(NCS)₆]. X‐ray structure determinations on single crystals of (n‐Bu₄N)₂[Os(NCS)₆] (1) (triclinic, space group P 1, a = 12.596(5), b = 12.666(5), c = 16.026(5) Å, α = 88.063(5), β = 80.439(5), γ = 88.637(5)°, Z = 2) and (n‐Bu₄N)₃[Os(NCS)₆] ( 2 ) (cubic, space group Pa 3, a = 24.349(4) Å, Z = 8) have been performed. The nearly linear thiocyanate groups are coordinated with Os–N–C angles of 172.3–177.7°. Based on the molecular parameters of the X‐ray determinations the IR and Raman spectra are assigned by normal coordinate analysis. The valence force constant f_d(OsN) is 2.3 ( 1 ) and 2.10 mdyn/Å ( 2 ).     

The reactions of (η5-C5H5)NiO(s)3(μ-H)3(CO)9 with group V donor ligands. Spectroscopic characterization of the disubstituted derivatives,and crystal structure of (η5-C5H5)NiO(s)3(μ-H)3(CO)7(PMe2Ph)2

The complex (η⁵-C₅H₅NiO(s)₃(μ-H)₃(CO)₉ (1 reacts with phosphines in the presence of Me₃NO to give monosubsituted derivatives, the main products, along with smaller amounts of disubstituted derivatives. The IR and NMR spectroscopic characterizations of two representative disubstituted derivatives are described.The crystal structure of (η⁵-C₅H₅)NiO(s)(μ-H)₃(CO)₇(PMe₂Ph)₂ has been determined by X-ray diffraction. The crystals are monoclinic, space group P2₁/a with Z = 4 in a unit cell of dimensions a 18.198(8), b 20.865(8), c 8.656(5) Å, β 99.67(2)°. The structure was solved by direct and Fourier methods and refined by full-matrix least-squares to R = 0.061 for 3139 observed reflections. The structure can be regarded as derived from that of 1 (which has a tetrahedral NiO(s) core with three hydride hydrogen atoms bridging the OsOs edges, a cyclopentadienyl group coordinated to the Ni atom,and nine terminal carbonyls bound to the Os atoms, three for each Os atom) by replacing two axial carbonyls by two PMe₂Ph ligands.     

Synthesis,structure, and properties of the thermolysis products of [Os(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>Cl][ReCl<Subscript>6</Subscript>]

The crystal structure of [Os(NH₃)₅Cl][ReCl₆] has been refined by X-ray powder analysis: a = 11.645(3) Å, b = 8.3788(2) Å, c = 15.277(4) Å, β = 91.029(6)°, V = 1490(1) ų, d _x = 3.163 g/cm³, space group P2₁/m, Z = 4. The thermolysis product of the salt in a hydrogen atmosphere is a solid substitution solution Os_0.5Re_0.5: a = 2.753(2) Å, c = 4.366(3) Å, space group P6₃/mmc; coherent scattering region (CSR) is ～230 Å.     

Inorganic Chemistry Concepts,Vol. 6. Inorganic Stereochemistry : by D.L. Kepert,Springer-Verlag,Berlin; 227 pages,DM 154

The paramagnetic compounds [Os₂(OCOR)₄Cl₂] (R = n-C₃H₇, C₂H₇, C₂H₅, CH₂Cl) have been synthesized by reaction of [Os(OCOCH₃)₂Cl]_n with the appropriate acids and the binuclear tetracarboxylate bridged structure confirmed by X-ray analysis for R = n-C₃H₇, (OsOs distance 2.301 Å, cf. the related [Os₂(hp)₄Cl₂](CH₃CN)₂; OsOs, 2.357 Å) (hp = 2-hydroxypyridine anion).     

Mechanism of Elimination Reactions : by W.H. Saunders Jr., and A.F. Cockerill,Wiley, New York,London, 1973,x + 641 pages. ß11.15.

The structure of H₃Os₃(CO)₉CCH₃ has been determined by a combination of nematic-phase PMR and X-ray powder photography; the compound is iso-structural with the analogous H₃Ru₃(CO)₉CCH₃, with an osmium to (bridging) hydride proton distance of 1.82 Å and an OsHOs angle of 103°.     

Synthesis, characterization, and crystal structures of the osmium triflate complexes CpOs(P-P)(OTf) and [CpOs(P-P)(OH2)][OTf]

Treatment of the osmium(II) hydrides Cp^∗Os(P-P)H (Cp^∗ = pentamethylcyclopentadienyl) with methyl trifluoromethanesulfonate (MeOTf) affords osmium(II) triflate complexes with the general formula Cp^∗Os(P-P)(OTf), where P-P = bis(dimethylphosphino)methane (dmpm), bis(diphenylphosphino)methane (dppm), or 1,2-bis(dimethylphosphino)ethane (dmpe). The aqua complexes [Cp^∗Os(dmpm)(OH₂)][OTf] and [Cp^∗Os(dppm)(OH₂)][OTf] are synthesized by the addition of water to the corresponding anhydrous triflates. The complexes Cp^∗Os(dppm)(OTf) and [Cp^∗Os(dmpm)(OH₂)][OTf] have been examined crystallographically, and all compounds have been characterized by NMR spectroscopy.     

Fluorescence and lifetime studies of Ho3+: CaF2

Four fluorescence groups in the wavelength region 4775–7590 Å have been recorded in Ho³⁺: CaF₂ single crystals in the concentration range from 0.01 to 0.1 wt% of Ho³⁺. The observed variation of the relative intensities of various fluorescence lines with concentration indicate the presence of more than one Ho³⁺ site in CaF₂. This has been further substantiated by the observation of three different fluorescent decay times. The increase in the fluorescent decay times with concentration above 373 K is explained as probably being due to reabsorption of fluorescence radiation.     

Kinetics and mechanism of Os(VIII)-catalyzed hexacyanoferrate(III) oxidation of α amino acids in alkaline medium

The kinetics of the Os(VIII)-catalyzed oxidation of glycine, alanine, valine, phenylalanine, isoleucine, lycine, and glutamic acid by alkaline hexacyanoferrate(III) reveal that these reactions are zero order in hexacyanoferrate(III) and first order in Os(VIII). The order in amino acid as well as in alkali is 1 at [amino acid] ?2.5 × 10^?2M and [OH^?] ?1.3 × 10^?M, but less than unity at higher concentrations of amino acids or alkali. The active oxidizing species under the experimental conditions is OsO₄(H₂O) (OH)^?. The ferricyanide is merely used up to regenerate the Os(VIII) species from Os(VI) formed during the reaction. The structural influence of amino acids on the reactivity has been discussed. The amino acids during oxidation are shown to be degraded through intermediate keto acids. The kinetic data are accommodated by considering the interaction between the conjugate base of the amino acids and the active oxidizing species of Os(VIII) to form a transient complex in the primary rate-determining step. The catalytic effect of hexacyanoferrate(II) has been rationalized.