Acta Cryst. (2009). E65, m1242 [ doi:10.1107/S1600536809037817 ]
![[eta]](/logos/entities/eta_rmgif.gif)
4-cycloocta-1,5-diene)bis(triphenylphosphine)osmium(II)The OsII atom in the title compound, [OsCl2(C8H12)(C18H15P)2], is located on a crystallographic twofold axis and adopts a distorted octahedral coordination geometry. The two triphenylphosphine ligands are trans to each other, while the two chlorine ligands are cis-disposed. The coordination is completed by the cyclooctadiene (COD) ligand with bonding to the two olefin double bonds. The C=C bond has a length of 1.403 (6) Å, which is significntly longer than a free olefinic double bond (![[asymptotically equal to]](/logos/entities/sime_rmgif.gif)
1.34 Å).
To a solution of OsCl2(PPh3)3 (0.52 g, 0.50 mmol) in toluene (10 ml) under nitrogen atmosphere was added cycloocta-1,5-diene (0.20 ml, 2.5 mmol). The reaction mixture was stirred at room temperature for 30 h to give the title compound as large amount of a yellow precipitate. The solid was collected by filtration, washed with toluene (2 × 5 ml) and diethyl ether (3 × 5 ml), and dried under vaccum. Yield: 0.38 g, 85%. Crystals suitable for X-ray analysis were obtained by layering a solution of the title compound with a solution of chloroform and hexane.
All non-hydrogen atoms were refined anisotropically. The hydrogen atoms were positioned geometrically (C—H =0.95, 1.00 or 0.99 Å for phenyl, tertiary or methylene H atoms, respectively) and were included in the refinement in the riding model approximation. The displacement parameters of H atoms were set to 1.2Ueq(C). In the final Fourier map the highest peak is 0.99 Å from atom Os1 and the deepest hole is 1.86 Å from atom C15.
Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
![[Figure 1]](./wm2258fig1thm.gif)
| Fig. 1. The structure of [OsCl2(C8H12)(C18H15P) 2] showing 40% probability displacement ellipsoids. H atoms have been omitted for clarity. Atoms with symmetry code letter A are related by -x + 1/2, -y + 1/2, z. |
| [OsCl2(C8H12)(PC18H15)2] | F(000) = 3568 |
| Mr = 893.82 | Dx = 1.628 Mg m−3 |
| Orthorhombic, Fdd2 | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: F 2 -2d | Cell parameters from 5605 reflections |
| a = 39.6505 (15) Å | θ = 2.3–32.5° |
| b = 10.4393 (5) Å | µ = 3.76 mm−1 |
| c = 17.6248 (8) Å | T = 173 K |
| V = 7295.3 (6) Å3 | Block, light yellow |
| Z = 8 | 0.15 × 0.15 × 0.12 mm |
| Oxford Diffraction Gemini S Ultra diffractometer | 2778 independent reflections |
| Radiation source: Enhance (Mo) X-ray Source | 2546 reflections with I > 2σ(I) |
| graphite | Rint = 0.033 |
| Detector resolution: 16.1930 pixels mm-1 | θmax = 26.0°, θmin = 2.3° |
| ω scans | h = −48→48 |
| Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008) | k = −12→12 |
| Tmin = 0.860, Tmax = 1.000 | l = −21→16 |
| 6965 measured reflections |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.022 | H-atom parameters constrained |
| wR(F2) = 0.044 | w = 1/[σ2(Fo2) + (0.0184P)2] where P = (Fo2 + 2Fc2)/3 |
| S = 1.00 | (Δ/σ)max = 0.001 |
| 2778 reflections | Δρmax = 1.39 e Å−3 |
| 222 parameters | Δρmin = −0.74 e Å−3 |
| 1 restraint | Absolute structure: Flack (1983), 937 Friedel pairs |
| Primary atom site location: structure-invariant direct methods | Flack parameter: 0.009 (6) |
| [OsCl2(C8H12)(PC18H15)2] | V = 7295.3 (6) Å3 |
| Mr = 893.82 | Z = 8 |
| Orthorhombic, Fdd2 | Mo Kα radiation |
| a = 39.6505 (15) Å | µ = 3.76 mm−1 |
| b = 10.4393 (5) Å | T = 173 K |
| c = 17.6248 (8) Å | 0.15 × 0.15 × 0.12 mm |
| Oxford Diffraction Gemini S Ultra diffractometer | 2778 independent reflections |
| Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008) | 2546 reflections with I > 2σ(I) |
| Tmin = 0.860, Tmax = 1.000 | Rint = 0.033 |
| 6965 measured reflections | θmax = 26.0° |
| R[F2 > 2σ(F2)] = 0.022 | H-atom parameters constrained |
| wR(F2) = 0.044 | Δρmax = 1.39 e Å−3 |
| S = 1.00 | Δρmin = −0.74 e Å−3 |
| 2778 reflections | Absolute structure: Flack (1983), 937 Friedel pairs |
| 222 parameters | Flack parameter: 0.009 (6) |
| 1 restraint |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
| x | y | z | Uiso*/Ueq | ||
| Os1 | 0.2500 | 0.2500 | 0.134570 (16) | 0.01584 (6) | |
| Cl1 | 0.27183 (3) | 0.08574 (11) | 0.22020 (7) | 0.0225 (3) | |
| P1 | 0.19622 (3) | 0.14284 (12) | 0.17335 (8) | 0.0183 (3) | |
| C1 | 0.25093 (11) | 0.1050 (4) | 0.0444 (3) | 0.0232 (10) | |
| H1A | 0.2499 | 0.0145 | 0.0629 | 0.028* | |
| C2 | 0.28281 (11) | 0.1625 (5) | 0.0509 (3) | 0.0203 (10) | |
| H2A | 0.3005 | 0.1053 | 0.0728 | 0.024* | |
| C3 | 0.29572 (11) | 0.2541 (5) | −0.0092 (3) | 0.0243 (10) | |
| H3A | 0.2991 | 0.2067 | −0.0572 | 0.029* | |
| H3B | 0.3179 | 0.2882 | 0.0069 | 0.029* | |
| C4 | 0.27153 (12) | 0.3668 (5) | −0.0234 (3) | 0.0279 (12) | |
| H4A | 0.2849 | 0.4442 | −0.0357 | 0.033* | |
| H4B | 0.2572 | 0.3468 | −0.0678 | 0.033* | |
| C11 | 0.19375 (10) | −0.0268 (4) | 0.1464 (3) | 0.0222 (11) | |
| C12 | 0.18371 (11) | −0.0649 (5) | 0.0742 (3) | 0.0263 (12) | |
| H12A | 0.1759 | −0.0021 | 0.0393 | 0.032* | |
| C13 | 0.18481 (12) | −0.1911 (5) | 0.0520 (4) | 0.0342 (13) | |
| H13A | 0.1779 | −0.2156 | 0.0024 | 0.041* | |
| C14 | 0.19615 (15) | −0.2814 (6) | 0.1031 (5) | 0.0346 (18) | |
| H14A | 0.1969 | −0.3689 | 0.0885 | 0.041* | |
| C15 | 0.20651 (14) | −0.2471 (6) | 0.1754 (5) | 0.0349 (18) | |
| H15A | 0.2142 | −0.3107 | 0.2099 | 0.042* | |
| C16 | 0.20554 (11) | −0.1196 (4) | 0.1973 (3) | 0.0257 (12) | |
| H16A | 0.2129 | −0.0952 | 0.2465 | 0.031* | |
| C21 | 0.18731 (10) | 0.1237 (4) | 0.2762 (3) | 0.0204 (10) | |
| C22 | 0.15626 (12) | 0.0737 (5) | 0.2961 (3) | 0.0270 (12) | |
| H22A | 0.1395 | 0.0618 | 0.2582 | 0.032* | |
| C23 | 0.14915 (12) | 0.0407 (5) | 0.3707 (4) | 0.0318 (14) | |
| H23A | 0.1276 | 0.0077 | 0.3835 | 0.038* | |
| C24 | 0.17309 (13) | 0.0556 (5) | 0.4255 (3) | 0.0317 (13) | |
| H24A | 0.1685 | 0.0310 | 0.4764 | 0.038* | |
| C25 | 0.20399 (12) | 0.1068 (5) | 0.4063 (3) | 0.0306 (13) | |
| H25A | 0.2207 | 0.1182 | 0.4444 | 0.037* | |
| C26 | 0.21088 (12) | 0.1414 (5) | 0.3332 (3) | 0.0259 (12) | |
| H26A | 0.2322 | 0.1780 | 0.3213 | 0.031* | |
| C31 | 0.15530 (10) | 0.2115 (4) | 0.1440 (3) | 0.0191 (12) | |
| C32 | 0.14963 (12) | 0.3414 (5) | 0.1543 (3) | 0.0240 (12) | |
| H32A | 0.1670 | 0.3930 | 0.1754 | 0.029* | |
| C33 | 0.11927 (12) | 0.3978 (5) | 0.1344 (4) | 0.0305 (13) | |
| H33A | 0.1161 | 0.4873 | 0.1414 | 0.037* | |
| C34 | 0.09364 (12) | 0.3237 (6) | 0.1046 (3) | 0.0323 (14) | |
| H34A | 0.0731 | 0.3622 | 0.0889 | 0.039* | |
| C35 | 0.09823 (12) | 0.1943 (6) | 0.0978 (3) | 0.0304 (13) | |
| H35A | 0.0802 | 0.1423 | 0.0800 | 0.037* | |
| C36 | 0.12872 (12) | 0.1382 (5) | 0.1165 (3) | 0.0246 (14) | |
| H36A | 0.1315 | 0.0484 | 0.1106 | 0.029* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Os1 | 0.01417 (9) | 0.01427 (10) | 0.01910 (11) | 0.00191 (17) | 0.000 | 0.000 |
| Cl1 | 0.0193 (5) | 0.0201 (6) | 0.0280 (7) | 0.0041 (4) | 0.0005 (5) | 0.0053 (6) |
| P1 | 0.0167 (5) | 0.0157 (6) | 0.0224 (7) | 0.0016 (5) | 0.0000 (5) | −0.0006 (6) |
| C1 | 0.027 (2) | 0.016 (2) | 0.027 (3) | 0.004 (2) | 0.007 (3) | −0.005 (2) |
| C2 | 0.022 (2) | 0.019 (3) | 0.019 (3) | −0.0009 (19) | 0.000 (2) | −0.005 (2) |
| C3 | 0.023 (2) | 0.027 (3) | 0.023 (2) | 0.001 (2) | 0.000 (2) | −0.003 (3) |
| C4 | 0.030 (2) | 0.026 (3) | 0.028 (3) | −0.002 (2) | −0.003 (2) | 0.003 (3) |
| C11 | 0.0164 (19) | 0.016 (2) | 0.034 (3) | −0.0028 (16) | 0.004 (2) | −0.007 (2) |
| C12 | 0.024 (2) | 0.023 (3) | 0.031 (3) | −0.001 (2) | 0.001 (2) | −0.003 (2) |
| C13 | 0.030 (3) | 0.031 (3) | 0.041 (3) | 0.004 (2) | 0.002 (3) | −0.014 (3) |
| C14 | 0.027 (3) | 0.017 (3) | 0.060 (5) | 0.004 (2) | 0.005 (3) | −0.011 (3) |
| C15 | 0.022 (3) | 0.027 (3) | 0.055 (5) | 0.008 (2) | 0.000 (3) | 0.007 (4) |
| C16 | 0.021 (2) | 0.020 (3) | 0.035 (3) | −0.0002 (19) | −0.003 (2) | −0.001 (2) |
| C21 | 0.021 (2) | 0.019 (2) | 0.022 (3) | 0.0058 (18) | 0.005 (2) | 0.005 (2) |
| C22 | 0.023 (2) | 0.028 (3) | 0.030 (3) | 0.000 (2) | −0.001 (2) | 0.005 (3) |
| C23 | 0.029 (2) | 0.031 (3) | 0.035 (4) | −0.0005 (18) | 0.005 (3) | 0.007 (3) |
| C24 | 0.043 (3) | 0.029 (3) | 0.024 (3) | 0.008 (2) | 0.004 (3) | 0.005 (3) |
| C25 | 0.030 (3) | 0.039 (3) | 0.023 (3) | 0.004 (2) | −0.002 (2) | −0.003 (3) |
| C26 | 0.025 (2) | 0.025 (3) | 0.028 (3) | 0.004 (2) | 0.004 (2) | −0.005 (2) |
| C31 | 0.0143 (18) | 0.021 (3) | 0.022 (4) | 0.0026 (15) | 0.000 (2) | −0.003 (3) |
| C32 | 0.022 (2) | 0.022 (3) | 0.028 (3) | 0.003 (2) | 0.001 (2) | −0.006 (2) |
| C33 | 0.028 (2) | 0.029 (3) | 0.035 (3) | 0.015 (2) | 0.007 (3) | −0.004 (3) |
| C34 | 0.016 (2) | 0.042 (4) | 0.039 (4) | 0.004 (2) | 0.000 (2) | 0.002 (3) |
| C35 | 0.017 (2) | 0.044 (3) | 0.030 (3) | −0.006 (2) | −0.001 (2) | −0.010 (3) |
| C36 | 0.020 (3) | 0.022 (3) | 0.032 (4) | −0.003 (2) | 0.001 (3) | −0.005 (3) |
| Os1—C2i | 2.169 (5) | C14—C15 | 1.386 (8) |
| Os1—C2 | 2.169 (5) | C14—H14A | 0.9500 |
| Os1—C1 | 2.195 (5) | C15—C16 | 1.387 (7) |
| Os1—C1i | 2.195 (5) | C15—H15A | 0.9500 |
| Os1—Cl1i | 2.4429 (12) | C16—H16A | 0.9500 |
| Os1—Cl1 | 2.4429 (12) | C21—C22 | 1.382 (6) |
| Os1—P1 | 2.5031 (12) | C21—C26 | 1.384 (7) |
| Os1—P1i | 2.5031 (12) | C22—C23 | 1.387 (8) |
| P1—C11 | 1.836 (4) | C22—H22A | 0.9500 |
| P1—C31 | 1.848 (4) | C23—C24 | 1.364 (8) |
| P1—C21 | 1.858 (5) | C23—H23A | 0.9500 |
| C1—C2 | 1.404 (6) | C24—C25 | 1.379 (7) |
| C1—C4i | 1.519 (7) | C24—H24A | 0.9500 |
| C1—H1A | 1.0000 | C25—C26 | 1.365 (7) |
| C2—C3 | 1.516 (7) | C25—H25A | 0.9500 |
| C2—H2A | 1.0000 | C26—H26A | 0.9500 |
| C3—C4 | 1.538 (7) | C31—C32 | 1.386 (7) |
| C3—H3A | 0.9900 | C31—C36 | 1.390 (7) |
| C3—H3B | 0.9900 | C32—C33 | 1.385 (7) |
| C4—C1i | 1.519 (7) | C32—H32A | 0.9500 |
| C4—H4A | 0.9900 | C33—C34 | 1.381 (7) |
| C4—H4B | 0.9900 | C33—H33A | 0.9500 |
| C11—C12 | 1.392 (7) | C34—C35 | 1.368 (7) |
| C11—C16 | 1.400 (7) | C34—H34A | 0.9500 |
| C12—C13 | 1.375 (7) | C35—C36 | 1.383 (7) |
| C12—H12A | 0.9500 | C35—H35A | 0.9500 |
| C13—C14 | 1.380 (9) | C36—H36A | 0.9500 |
| C13—H13A | 0.9500 | ||
| C2i—Os1—C2 | 94.3 (3) | C3—C4—H4B | 109.1 |
| C2i—Os1—C1 | 78.95 (18) | H4A—C4—H4B | 107.8 |
| C2—Os1—C1 | 37.52 (16) | C12—C11—C16 | 118.9 (4) |
| C2i—Os1—C1i | 37.52 (16) | C12—C11—P1 | 121.8 (4) |
| C2—Os1—C1i | 78.95 (18) | C16—C11—P1 | 118.9 (4) |
| C1—Os1—C1i | 87.3 (3) | C13—C12—C11 | 121.7 (5) |
| C2i—Os1—Cl1i | 84.95 (14) | C13—C12—H12A | 119.2 |
| C2—Os1—Cl1i | 158.22 (12) | C11—C12—H12A | 119.2 |
| C1—Os1—Cl1i | 159.61 (12) | C12—C13—C14 | 118.6 (6) |
| C1i—Os1—Cl1i | 87.54 (13) | C12—C13—H13A | 120.7 |
| C2i—Os1—Cl1 | 158.22 (12) | C14—C13—H13A | 120.7 |
| C2—Os1—Cl1 | 84.95 (14) | C13—C14—C15 | 121.4 (6) |
| C1—Os1—Cl1 | 87.54 (13) | C13—C14—H14A | 119.3 |
| C1i—Os1—Cl1 | 159.61 (12) | C15—C14—H14A | 119.3 |
| Cl1i—Os1—Cl1 | 103.69 (6) | C14—C15—C16 | 119.7 (6) |
| C2i—Os1—P1 | 82.14 (12) | C14—C15—H15A | 120.2 |
| C2—Os1—P1 | 120.55 (12) | C16—C15—H15A | 120.2 |
| C1—Os1—P1 | 84.48 (13) | C15—C16—C11 | 119.7 (6) |
| C1i—Os1—P1 | 119.44 (12) | C15—C16—H16A | 120.1 |
| Cl1i—Os1—P1 | 80.97 (4) | C11—C16—H16A | 120.1 |
| Cl1—Os1—P1 | 79.60 (4) | C22—C21—C26 | 117.9 (5) |
| C2i—Os1—P1i | 120.55 (12) | C22—C21—P1 | 117.2 (4) |
| C2—Os1—P1i | 82.14 (12) | C26—C21—P1 | 124.4 (3) |
| C1—Os1—P1i | 119.44 (12) | C21—C22—C23 | 121.0 (5) |
| C1i—Os1—P1i | 84.48 (13) | C21—C22—H22A | 119.5 |
| Cl1i—Os1—P1i | 79.60 (4) | C23—C22—H22A | 119.5 |
| Cl1—Os1—P1i | 80.97 (4) | C24—C23—C22 | 120.1 (5) |
| P1—Os1—P1i | 148.31 (6) | C24—C23—H23A | 120.0 |
| C11—P1—C31 | 104.8 (2) | C22—C23—H23A | 120.0 |
| C11—P1—C21 | 98.0 (2) | C23—C24—C25 | 119.3 (5) |
| C31—P1—C21 | 98.5 (2) | C23—C24—H24A | 120.4 |
| C11—P1—Os1 | 113.95 (14) | C25—C24—H24A | 120.4 |
| C31—P1—Os1 | 119.87 (15) | C26—C25—C24 | 120.8 (5) |
| C21—P1—Os1 | 118.45 (15) | C26—C25—H25A | 119.6 |
| C2—C1—C4i | 120.5 (4) | C24—C25—H25A | 119.6 |
| C2—C1—Os1 | 70.2 (3) | C25—C26—C21 | 120.9 (4) |
| C4i—C1—Os1 | 115.2 (3) | C25—C26—H26A | 119.5 |
| C2—C1—H1A | 114.5 | C21—C26—H26A | 119.5 |
| C4i—C1—H1A | 114.5 | C32—C31—C36 | 117.5 (4) |
| Os1—C1—H1A | 114.5 | C32—C31—P1 | 119.0 (4) |
| C1—C2—C3 | 121.2 (4) | C36—C31—P1 | 123.3 (4) |
| C1—C2—Os1 | 72.3 (3) | C31—C32—C33 | 121.6 (5) |
| C3—C2—Os1 | 114.3 (3) | C31—C32—H32A | 119.2 |
| C1—C2—H2A | 114.2 | C33—C32—H32A | 119.2 |
| C3—C2—H2A | 114.2 | C34—C33—C32 | 119.8 (5) |
| Os1—C2—H2A | 114.2 | C34—C33—H33A | 120.1 |
| C2—C3—C4 | 112.7 (4) | C32—C33—H33A | 120.1 |
| C2—C3—H3A | 109.1 | C35—C34—C33 | 119.2 (5) |
| C4—C3—H3A | 109.1 | C35—C34—H34A | 120.4 |
| C2—C3—H3B | 109.1 | C33—C34—H34A | 120.4 |
| C4—C3—H3B | 109.1 | C34—C35—C36 | 120.9 (5) |
| H3A—C3—H3B | 107.8 | C34—C35—H35A | 119.5 |
| C1i—C4—C3 | 112.7 (4) | C36—C35—H35A | 119.5 |
| C1i—C4—H4A | 109.1 | C35—C36—C31 | 120.8 (5) |
| C3—C4—H4A | 109.1 | C35—C36—H36A | 119.6 |
| C1i—C4—H4B | 109.1 | C31—C36—H36A | 119.6 |
| Symmetry codes: (i) −x+1/2, −y+1/2, z. |
| Os1—C2 | 2.169 (5) | Os1—Cl1 | 2.4429 (12) |
| Os1—C1 | 2.195 (5) | Os1—P1 | 2.5031 (12) |
The authors acknowledge financial support from the Young Talent Project of Fujian Provincial Department of Science & Technology (grant No. 2007 F3095).
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The ruthenium polymer [RuCl2(COD)]x (COD = cycloocta-1,5-diene), which can be readily prepared in 30–40% yield from RuCl3.3H2O and COD in boiling ethanol (Bennett & Wilkinson, 1959; Albers et al., 1989), has proved to be a useful precursor for a wide variety of ruthenium compounds (Cucullu et al., 1999; Coalter & Caulton, 2001; Alvarez et al., 2001). Although the analogous osmium polymer [OsCl2(COD)]x is also known, its utility as a starting material has remained relatively unexplored partially due to the difficuly in its preparation (Winkhaus et al., 1966; Schrock et al., 1974; Dickinson & Girolami, 2006). In our search for other potential precusors for the synthesis of osmium compounds, we have prepared [OsCl2(η4– COD)(PPh3)2] readily from the reaction of OsCl2(PPh3)3 with COD.
The title compound crystallizes in the non-centrosymmetric orthorhombic space group Fdd2. As shown in Fig.1, the structure possesses a crystallographic 2-fold axis passing through the osmium atom, thus the asymmetric unit contains half of a molecule. The OsII centre adopts a distorted octahedral geometry with the two triphenylphosphine ligands trans to each other (P(1)—Os(1)—P(1 A) 148.31 (6)°), while the two chlorine ligands are cis-disposed (Cl(1)—Os(1)—Cl(1 A) 103.69 (6)°) (symmetry code: -x + 1/2, -y + 1/2, z). The coordination is completed by the two olefin double bonds of the cyclooctadiene ligand. The Os(1)—C(1) and Os(1)—C(2) bond lengths (2.195 (5) and 2.168 (5) Å, respectively) are similar to the related Os—C bond lengths reported for other COD coordinated OsII complexes such as [H(EtOH)2[{OsCl(η4-COD)}2(µ-H)(µ-Cl)2] (2.129–2.152 Å) (Esteruelas et al., 2006) and TpOs(η4-COD)OMe (Tp = trispyrazolylborate) (2.141–2.198 Å) (Dickinson & Girolami, 2006). The C(1)—C(2) (1.403 (6) Å) bond length is significntly longer than a free olefinic double bond (≈ 1.34 Å) (Orpen et al., 1989) and is typical for a coordinated C═C double bond, which is also close to the C═C bond lengths found in [H(EtOH)2[{OsCl(η4-COD)}2(µ-H)(µ-Cl)2] (1.393–1.422 Å) and TpOs(η4-COD)OMe (1.396 (5) and 1.399 (5) Å).