Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104020293/jz1658sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104020293/jz1658Isup2.hkl |
CCDC reference: 254904
Under a nitrogen atmosphere, CoCl2 (0.500 g) was dissolved in tetrahydrofuran (THF; 10 ml) and cooled to 195 K. A solution of K[1,3-(SiMe3)2C3H3] (1.725 g; Harvey et al., 1999) dissolved in THF (15 ml) was added dropwise with stirring over 30 min. The dark-red mixture was then allowed to warm slowly to room temperature with stirring. The THF was removed under vacuum and the residue was extracted with small portions (5 ml) of hexanes. The extract was filtered and the solvent was removed under vacuum from the filtrate. The resulting nearly black oil crystallized over several days to yield yellow-orange crystals of (I) (1.23 g, 75% yield, m.p. 346 K). Analysis calculated for C18H42CoSi4: C 50.30, H 9.85%; found: C 50.30, H 9.81%. Principle IR bands (KBr, ν, cm−1): 2955 (s), 2899 (m), 2366 (w), 1698 (w), 1449 (m), 1400 (w), 1248 (s), 1028 (s), 1009 (s), 843 (s), 800 (s), 715 (w), 549 (w), 478 (br, w). Magnetic susceptibility (toluene-d8): corrµ = 1.8 BM at 298 K. The compound sublimes at 323 K under reduced pressure (10−2 Torr; 1 Torr = 133.322 Pa) and is soluble in ethers and hydrocarbons.
Methyl H atoms were placed in ideal positions and further refined as rigid groups allowed to rotate but not tip. The H atoms on atoms C1–C6 were found from the difference electron density map and allowed to refine freely. A residual peak of 1.1 e Å−3 was found at slightly less than 1 Å from the Co atom, possibly because of residual absorption errors or Fourier termination errors. Atoms C10 and C12 show somewhat high U values, but the use of a disorder model did not significantly improve the refinement.
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL.
Fig. 1. The crystal structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. |
[Co(C9H21Si2)2] | F(000) = 932 |
Mr = 429.81 | Dx = 1.079 Mg m−3 |
Monoclinic, P21/c | Melting point: 346 K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 12.341 (1) Å | Cell parameters from 3337 reflections |
b = 10.3381 (9) Å | θ = 1.7–25.1° |
c = 21.024 (2) Å | µ = 0.83 mm−1 |
β = 99.371 (2)° | T = 173 K |
V = 2646.5 (4) Å3 | Block, orange |
Z = 4 | 0.31 × 0.24 × 0.16 mm |
Siemens SMART Platform CCD area-detector diffractometer | 4688 independent reflections |
Radiation source: normal-focus sealed tube | 4033 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.025 |
ω scans | θmax = 25.1°, θmin = 1.7° |
Absorption correction: multi-scan (SADABS; Blessing, 1995) | h = −14→14 |
Tmin = 0.767, Tmax = 0.876 | k = −12→12 |
25453 measured reflections | l = −25→25 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.111 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0666P)2 + 1.7528P] where P = (Fo2 + 2Fc2)/3 |
4688 reflections | (Δ/σ)max = 0.001 |
244 parameters | Δρmax = 1.11 e Å−3 |
0 restraints | Δρmin = −0.30 e Å−3 |
[Co(C9H21Si2)2] | V = 2646.5 (4) Å3 |
Mr = 429.81 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.341 (1) Å | µ = 0.83 mm−1 |
b = 10.3381 (9) Å | T = 173 K |
c = 21.024 (2) Å | 0.31 × 0.24 × 0.16 mm |
β = 99.371 (2)° |
Siemens SMART Platform CCD area-detector diffractometer | 4688 independent reflections |
Absorption correction: multi-scan (SADABS; Blessing, 1995) | 4033 reflections with I > 2σ(I) |
Tmin = 0.767, Tmax = 0.876 | Rint = 0.025 |
25453 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.111 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | Δρmax = 1.11 e Å−3 |
4688 reflections | Δρmin = −0.30 e Å−3 |
244 parameters |
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 | ||
Co1 | 0.18098 (3) | 0.13807 (3) | 0.903736 (16) | 0.03271 (13) | |
C1 | 0.1727 (2) | −0.0534 (2) | 0.87120 (13) | 0.0379 (6) | |
H1A | 0.140 (2) | −0.029 (3) | 0.8258 (14) | 0.044 (7)* | |
C2 | 0.1049 (2) | −0.0271 (3) | 0.91821 (14) | 0.0390 (6) | |
H2A | 0.125 (2) | −0.067 (3) | 0.9636 (14) | 0.044 (7)* | |
C3 | 0.0279 (2) | 0.0740 (3) | 0.91395 (15) | 0.0426 (6) | |
H3A | 0.000 (3) | 0.100 (4) | 0.9569 (18) | 0.075 (11)* | |
C4 | 0.1772 (2) | 0.3217 (3) | 0.94014 (13) | 0.0383 (6) | |
H4A | 0.107 (3) | 0.374 (3) | 0.9276 (14) | 0.046 (8)* | |
C5 | 0.2442 (2) | 0.3134 (2) | 0.89148 (13) | 0.0365 (6) | |
H5A | 0.217 (2) | 0.354 (3) | 0.8501 (14) | 0.042 (8)* | |
C6 | 0.3308 (2) | 0.2242 (3) | 0.89329 (12) | 0.0356 (6) | |
H6A | 0.370 (2) | 0.194 (3) | 0.9389 (13) | 0.037 (7)* | |
Si1 | 0.27858 (7) | −0.18274 (7) | 0.88643 (4) | 0.0413 (2) | |
C7 | 0.2107 (3) | −0.3391 (3) | 0.89985 (19) | 0.0657 (10) | |
H7A | 0.1717 | −0.3307 | 0.9367 | 0.099* | |
H7B | 0.2664 | −0.4072 | 0.9087 | 0.099* | |
H7C | 0.1584 | −0.3617 | 0.8612 | 0.099* | |
C8 | 0.3806 (3) | −0.1454 (3) | 0.95930 (17) | 0.0621 (9) | |
H8A | 0.4204 | −0.0662 | 0.9520 | 0.093* | |
H8B | 0.4327 | −0.2173 | 0.9681 | 0.093* | |
H8C | 0.3426 | −0.1332 | 0.9963 | 0.093* | |
C9 | 0.3480 (3) | −0.2036 (4) | 0.81468 (18) | 0.0667 (9) | |
H9A | 0.3812 | −0.1214 | 0.8048 | 0.100* | |
H9B | 0.2940 | −0.2307 | 0.7776 | 0.100* | |
H9C | 0.4054 | −0.2697 | 0.8239 | 0.100* | |
Si2 | −0.06703 (7) | 0.13597 (8) | 0.84189 (5) | 0.0484 (2) | |
C10 | −0.1579 (4) | 0.2542 (5) | 0.8762 (3) | 0.113 (2) | |
H10A | −0.1908 | 0.3140 | 0.8423 | 0.169* | |
H10B | −0.1142 | 0.3031 | 0.9113 | 0.169* | |
H10C | −0.2162 | 0.2071 | 0.8929 | 0.169* | |
C11 | −0.1524 (3) | 0.0031 (3) | 0.80038 (16) | 0.0611 (9) | |
H11A | −0.1045 | −0.0649 | 0.7881 | 0.092* | |
H11B | −0.1987 | 0.0371 | 0.7617 | 0.092* | |
H11C | −0.1991 | −0.0330 | 0.8295 | 0.092* | |
C12 | 0.0023 (4) | 0.2163 (6) | 0.7806 (2) | 0.123 (2) | |
H12A | 0.0501 | 0.1540 | 0.7636 | 0.184* | |
H12B | 0.0463 | 0.2889 | 0.8005 | 0.184* | |
H12C | −0.0531 | 0.2483 | 0.7454 | 0.184* | |
Si3 | 0.22330 (7) | 0.31203 (8) | 1.02931 (4) | 0.0427 (2) | |
C13 | 0.1004 (3) | 0.3441 (4) | 1.06878 (19) | 0.0783 (12) | |
H13A | 0.0662 | 0.4258 | 1.0527 | 0.118* | |
H13B | 0.1233 | 0.3497 | 1.1156 | 0.118* | |
H13C | 0.0474 | 0.2735 | 1.0587 | 0.118* | |
C14 | 0.2813 (3) | 0.1519 (3) | 1.05816 (16) | 0.0643 (9) | |
H14A | 0.3468 | 0.1338 | 1.0389 | 0.096* | |
H14B | 0.2263 | 0.0842 | 1.0456 | 0.096* | |
H14C | 0.3012 | 0.1534 | 1.1052 | 0.096* | |
C15 | 0.3318 (4) | 0.4356 (4) | 1.05332 (18) | 0.0833 (13) | |
H15A | 0.3914 | 0.4231 | 1.0283 | 0.125* | |
H15B | 0.3608 | 0.4266 | 1.0994 | 0.125* | |
H15C | 0.3004 | 0.5222 | 1.0450 | 0.125* | |
Si4 | 0.41081 (6) | 0.21876 (8) | 0.82541 (3) | 0.03845 (19) | |
C16 | 0.3240 (3) | 0.1646 (3) | 0.74922 (14) | 0.0545 (8) | |
H16A | 0.2952 | 0.0779 | 0.7553 | 0.082* | |
H16B | 0.3683 | 0.1624 | 0.7146 | 0.082* | |
H16C | 0.2627 | 0.2250 | 0.7377 | 0.082* | |
C17 | 0.5329 (3) | 0.1115 (4) | 0.84618 (16) | 0.0610 (9) | |
H17A | 0.5087 | 0.0242 | 0.8553 | 0.092* | |
H17B | 0.5807 | 0.1457 | 0.8843 | 0.092* | |
H17C | 0.5735 | 0.1084 | 0.8098 | 0.092* | |
C18 | 0.4588 (3) | 0.3877 (4) | 0.81262 (19) | 0.0716 (10) | |
H18A | 0.4974 | 0.3891 | 0.7754 | 0.107* | |
H18B | 0.5088 | 0.4163 | 0.8511 | 0.107* | |
H18C | 0.3954 | 0.4459 | 0.8046 | 0.107* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co1 | 0.0347 (2) | 0.0287 (2) | 0.0343 (2) | −0.00274 (14) | 0.00463 (14) | 0.00155 (14) |
C1 | 0.0484 (15) | 0.0282 (13) | 0.0359 (14) | −0.0047 (11) | 0.0038 (11) | 0.0007 (11) |
C2 | 0.0413 (15) | 0.0308 (13) | 0.0452 (15) | −0.0076 (11) | 0.0076 (12) | 0.0045 (11) |
C3 | 0.0360 (14) | 0.0375 (15) | 0.0557 (17) | −0.0055 (12) | 0.0111 (12) | 0.0046 (13) |
C4 | 0.0440 (15) | 0.0281 (13) | 0.0419 (15) | −0.0004 (11) | 0.0040 (12) | −0.0027 (11) |
C5 | 0.0433 (15) | 0.0269 (12) | 0.0378 (14) | −0.0068 (11) | 0.0023 (11) | 0.0019 (11) |
C6 | 0.0389 (14) | 0.0348 (13) | 0.0323 (13) | −0.0068 (11) | 0.0035 (11) | 0.0033 (11) |
Si1 | 0.0493 (4) | 0.0296 (4) | 0.0453 (4) | 0.0032 (3) | 0.0090 (3) | −0.0009 (3) |
C7 | 0.080 (2) | 0.0326 (16) | 0.086 (3) | 0.0016 (15) | 0.016 (2) | 0.0099 (16) |
C8 | 0.063 (2) | 0.059 (2) | 0.060 (2) | 0.0165 (16) | −0.0041 (16) | −0.0009 (16) |
C9 | 0.082 (2) | 0.056 (2) | 0.068 (2) | 0.0090 (18) | 0.0301 (19) | −0.0064 (17) |
Si2 | 0.0358 (4) | 0.0387 (4) | 0.0669 (5) | −0.0015 (3) | −0.0027 (4) | 0.0040 (4) |
C10 | 0.082 (3) | 0.094 (3) | 0.143 (4) | 0.041 (3) | −0.040 (3) | −0.057 (3) |
C11 | 0.069 (2) | 0.060 (2) | 0.0545 (19) | −0.0134 (17) | 0.0088 (16) | −0.0090 (16) |
C12 | 0.076 (3) | 0.169 (5) | 0.108 (4) | −0.053 (3) | −0.036 (3) | 0.102 (4) |
Si3 | 0.0505 (5) | 0.0413 (4) | 0.0370 (4) | −0.0012 (3) | 0.0091 (3) | −0.0035 (3) |
C13 | 0.077 (3) | 0.100 (3) | 0.064 (2) | 0.015 (2) | 0.029 (2) | −0.016 (2) |
C14 | 0.090 (3) | 0.063 (2) | 0.0408 (17) | 0.0180 (19) | 0.0140 (17) | 0.0088 (15) |
C15 | 0.101 (3) | 0.084 (3) | 0.057 (2) | −0.040 (2) | −0.012 (2) | 0.002 (2) |
Si4 | 0.0404 (4) | 0.0448 (4) | 0.0308 (4) | −0.0047 (3) | 0.0075 (3) | 0.0020 (3) |
C16 | 0.065 (2) | 0.064 (2) | 0.0331 (15) | 0.0051 (16) | 0.0036 (14) | −0.0027 (14) |
C17 | 0.0425 (17) | 0.090 (3) | 0.0511 (18) | 0.0113 (17) | 0.0090 (14) | 0.0044 (17) |
C18 | 0.088 (3) | 0.062 (2) | 0.073 (2) | −0.0255 (19) | 0.034 (2) | 0.0045 (18) |
Co1—C1 | 2.091 (3) | Si2—C10 | 1.881 (4) |
Co1—C2 | 1.996 (3) | C10—H10A | 0.9800 |
Co1—C3 | 2.046 (3) | C10—H10B | 0.9800 |
Co1—C4 | 2.050 (3) | C10—H10C | 0.9800 |
Co1—C5 | 2.006 (3) | C11—H11A | 0.9800 |
Co1—C6 | 2.096 (3) | C11—H11B | 0.9800 |
C1—C2 | 1.421 (4) | C11—H11C | 0.9800 |
C1—Si1 | 1.861 (3) | C12—H12A | 0.9800 |
C1—H1A | 1.01 (3) | C12—H12B | 0.9800 |
C2—C3 | 1.407 (4) | C12—H12C | 0.9800 |
C2—H2A | 1.03 (3) | Si3—C15 | 1.860 (4) |
C3—Si2 | 1.871 (3) | Si3—C14 | 1.865 (3) |
C3—H3A | 1.05 (4) | Si3—C13 | 1.873 (4) |
C4—C5 | 1.419 (4) | C13—H13A | 0.9800 |
C4—Si3 | 1.871 (3) | C13—H13B | 0.9800 |
C4—H4A | 1.01 (3) | C13—H13C | 0.9800 |
C5—C6 | 1.407 (4) | C14—H14A | 0.9800 |
C5—H5A | 0.97 (3) | C14—H14B | 0.9800 |
C6—Si4 | 1.864 (3) | C14—H14C | 0.9800 |
C6—H6A | 1.05 (3) | C15—H15A | 0.9800 |
Si1—C8 | 1.858 (3) | C15—H15B | 0.9800 |
Si1—C7 | 1.863 (3) | C15—H15C | 0.9800 |
Si1—C9 | 1.865 (3) | Si4—C16 | 1.862 (3) |
C7—H7A | 0.9800 | Si4—C17 | 1.864 (3) |
C7—H7B | 0.9800 | Si4—C18 | 1.878 (3) |
C7—H7C | 0.9800 | C16—H16A | 0.9800 |
C8—H8A | 0.9800 | C16—H16B | 0.9800 |
C8—H8B | 0.9800 | C16—H16C | 0.9800 |
C8—H8C | 0.9800 | C17—H17A | 0.9800 |
C9—H9A | 0.9800 | C17—H17B | 0.9800 |
C9—H9B | 0.9800 | C17—H17C | 0.9800 |
C9—H9C | 0.9800 | C18—H18A | 0.9800 |
Si2—C12 | 1.854 (4) | C18—H18B | 0.9800 |
Si2—C11 | 1.860 (3) | C18—H18C | 0.9800 |
C2—Co1—C5 | 174.23 (11) | H9B—C9—H9C | 109.5 |
C2—Co1—C3 | 40.70 (11) | C12—Si2—C11 | 107.2 (2) |
C5—Co1—C3 | 133.68 (11) | C12—Si2—C3 | 114.64 (15) |
C2—Co1—C4 | 134.05 (11) | C11—Si2—C3 | 111.06 (15) |
C5—Co1—C4 | 40.94 (11) | C12—Si2—C10 | 110.3 (3) |
C3—Co1—C4 | 100.51 (12) | C11—Si2—C10 | 109.40 (19) |
C2—Co1—C1 | 40.62 (11) | C3—Si2—C10 | 104.22 (19) |
C5—Co1—C1 | 144.32 (11) | Si2—C10—H10A | 109.5 |
C3—Co1—C1 | 74.42 (11) | Si2—C10—H10B | 109.5 |
C4—Co1—C1 | 174.62 (11) | H10A—C10—H10B | 109.5 |
C2—Co1—C6 | 145.54 (11) | Si2—C10—H10C | 109.5 |
C5—Co1—C6 | 40.05 (11) | H10A—C10—H10C | 109.5 |
C3—Co1—C6 | 173.72 (11) | H10B—C10—H10C | 109.5 |
C4—Co1—C6 | 73.74 (11) | Si2—C11—H11A | 109.5 |
C1—Co1—C6 | 111.40 (11) | Si2—C11—H11B | 109.5 |
C2—C1—Si1 | 119.6 (2) | H11A—C11—H11B | 109.5 |
C2—C1—Co1 | 66.10 (14) | Si2—C11—H11C | 109.5 |
Si1—C1—Co1 | 128.95 (14) | H11A—C11—H11C | 109.5 |
C2—C1—H1A | 114.7 (16) | H11B—C11—H11C | 109.5 |
Si1—C1—H1A | 120.6 (16) | Si2—C12—H12A | 109.5 |
Co1—C1—H1A | 93.4 (16) | Si2—C12—H12B | 109.5 |
C3—C2—C1 | 124.5 (3) | H12A—C12—H12B | 109.5 |
C3—C2—Co1 | 71.55 (15) | Si2—C12—H12C | 109.5 |
C1—C2—Co1 | 73.28 (15) | H12A—C12—H12C | 109.5 |
C3—C2—H2A | 114.5 (16) | H12B—C12—H12C | 109.5 |
C1—C2—H2A | 119.1 (16) | C15—Si3—C14 | 107.5 (2) |
Co1—C2—H2A | 115.7 (16) | C15—Si3—C4 | 108.88 (15) |
C2—C3—Si2 | 129.3 (2) | C14—Si3—C4 | 114.27 (14) |
C2—C3—Co1 | 67.74 (15) | C15—Si3—C13 | 110.9 (2) |
Si2—C3—Co1 | 105.75 (13) | C14—Si3—C13 | 107.96 (19) |
C2—C3—H3A | 117 (2) | C4—Si3—C13 | 107.34 (17) |
Si2—C3—H3A | 111 (2) | Si3—C13—H13A | 109.5 |
Co1—C3—H3A | 116 (2) | Si3—C13—H13B | 109.5 |
C5—C4—Si3 | 126.9 (2) | H13A—C13—H13B | 109.5 |
C5—C4—Co1 | 67.87 (14) | Si3—C13—H13C | 109.5 |
Si3—C4—Co1 | 107.64 (13) | H13A—C13—H13C | 109.5 |
C5—C4—H4A | 114.5 (17) | H13B—C13—H13C | 109.5 |
Si3—C4—H4A | 113.4 (17) | Si3—C14—H14A | 109.5 |
Co1—C4—H4A | 117.6 (17) | Si3—C14—H14B | 109.5 |
C6—C5—C4 | 123.3 (2) | H14A—C14—H14B | 109.5 |
C6—C5—Co1 | 73.41 (15) | Si3—C14—H14C | 109.5 |
C4—C5—Co1 | 71.18 (15) | H14A—C14—H14C | 109.5 |
C6—C5—H5A | 117.1 (17) | H14B—C14—H14C | 109.5 |
C4—C5—H5A | 117.5 (17) | Si3—C15—H15A | 109.5 |
Co1—C5—H5A | 115.0 (17) | Si3—C15—H15B | 109.5 |
C5—C6—Si4 | 119.60 (19) | H15A—C15—H15B | 109.5 |
C5—C6—Co1 | 66.54 (14) | Si3—C15—H15C | 109.5 |
Si4—C6—Co1 | 130.82 (14) | H15A—C15—H15C | 109.5 |
C5—C6—H6A | 117.0 (15) | H15B—C15—H15C | 109.5 |
Si4—C6—H6A | 118.0 (14) | C16—Si4—C6 | 111.42 (14) |
Co1—C6—H6A | 93.3 (15) | C16—Si4—C17 | 110.65 (16) |
C8—Si1—C1 | 110.81 (14) | C6—Si4—C17 | 110.33 (13) |
C8—Si1—C7 | 108.44 (17) | C16—Si4—C18 | 107.91 (17) |
C1—Si1—C7 | 109.23 (15) | C6—Si4—C18 | 107.47 (15) |
C8—Si1—C9 | 110.61 (18) | C17—Si4—C18 | 108.95 (19) |
C1—Si1—C9 | 110.26 (15) | Si4—C16—H16A | 109.5 |
C7—Si1—C9 | 107.41 (17) | Si4—C16—H16B | 109.5 |
Si1—C7—H7A | 109.5 | H16A—C16—H16B | 109.5 |
Si1—C7—H7B | 109.5 | Si4—C16—H16C | 109.5 |
H7A—C7—H7B | 109.5 | H16A—C16—H16C | 109.5 |
Si1—C7—H7C | 109.5 | H16B—C16—H16C | 109.5 |
H7A—C7—H7C | 109.5 | Si4—C17—H17A | 109.5 |
H7B—C7—H7C | 109.5 | Si4—C17—H17B | 109.5 |
Si1—C8—H8A | 109.5 | H17A—C17—H17B | 109.5 |
Si1—C8—H8B | 109.5 | Si4—C17—H17C | 109.5 |
H8A—C8—H8B | 109.5 | H17A—C17—H17C | 109.5 |
Si1—C8—H8C | 109.5 | H17B—C17—H17C | 109.5 |
H8A—C8—H8C | 109.5 | Si4—C18—H18A | 109.5 |
H8B—C8—H8C | 109.5 | Si4—C18—H18B | 109.5 |
Si1—C9—H9A | 109.5 | H18A—C18—H18B | 109.5 |
Si1—C9—H9B | 109.5 | Si4—C18—H18C | 109.5 |
H9A—C9—H9B | 109.5 | H18A—C18—H18C | 109.5 |
Si1—C9—H9C | 109.5 | H18B—C18—H18C | 109.5 |
H9A—C9—H9C | 109.5 | ||
C5—Co1—C1—C2 | −175.14 (18) | C1—Co1—C5—C6 | −46.8 (3) |
C3—Co1—C1—C2 | −27.88 (17) | C3—Co1—C5—C4 | 44.3 (2) |
C6—Co1—C1—C2 | 154.61 (16) | C1—Co1—C5—C4 | 178.20 (18) |
C2—Co1—C1—Si1 | −109.7 (2) | C6—Co1—C5—C4 | −135.0 (2) |
C5—Co1—C1—Si1 | 75.2 (3) | C4—C5—C6—Si4 | 178.2 (2) |
C3—Co1—C1—Si1 | −137.5 (2) | Co1—C5—C6—Si4 | 124.96 (18) |
C6—Co1—C1—Si1 | 44.9 (2) | C4—C5—C6—Co1 | 53.2 (2) |
Si1—C1—C2—C3 | 175.3 (2) | C2—Co1—C6—C5 | −177.61 (19) |
Co1—C1—C2—C3 | 52.6 (2) | C4—Co1—C6—C5 | −28.86 (16) |
Si1—C1—C2—Co1 | 122.62 (18) | C1—Co1—C6—C5 | 152.83 (16) |
C4—Co1—C2—C3 | 42.7 (2) | C2—Co1—C6—Si4 | 72.7 (3) |
C1—Co1—C2—C3 | −136.3 (2) | C5—Co1—C6—Si4 | −109.7 (2) |
C6—Co1—C2—C3 | 178.81 (18) | C1—Co1—C6—Si4 | 43.1 (2) |
C3—Co1—C2—C1 | 136.3 (2) | C2—C1—Si1—C8 | −61.2 (3) |
C4—Co1—C2—C1 | 178.98 (16) | Co1—C1—Si1—C8 | 20.8 (2) |
C6—Co1—C2—C1 | −44.9 (3) | C2—C1—Si1—C7 | 58.2 (3) |
C1—C2—C3—Si2 | 39.2 (4) | Co1—C1—Si1—C7 | 140.16 (19) |
Co1—C2—C3—Si2 | 92.5 (2) | C2—C1—Si1—C9 | 176.0 (2) |
C1—C2—C3—Co1 | −53.4 (2) | Co1—C1—Si1—C9 | −102.0 (2) |
C5—Co1—C3—C2 | −178.04 (17) | C2—C3—Si2—C12 | −67.4 (4) |
C4—Co1—C3—C2 | −150.30 (17) | Co1—C3—Si2—C12 | 6.5 (3) |
C1—Co1—C3—C2 | 27.83 (17) | C2—C3—Si2—C11 | 54.2 (3) |
C2—Co1—C3—Si2 | −126.6 (2) | Co1—C3—Si2—C11 | 128.13 (16) |
C5—Co1—C3—Si2 | 55.4 (2) | C2—C3—Si2—C10 | 171.9 (3) |
C4—Co1—C3—Si2 | 83.12 (15) | Co1—C3—Si2—C10 | −114.2 (2) |
C1—Co1—C3—Si2 | −98.76 (15) | C5—C4—Si3—C15 | 54.8 (3) |
C2—Co1—C4—C5 | −175.81 (16) | Co1—C4—Si3—C15 | 130.02 (19) |
C3—Co1—C4—C5 | −149.10 (17) | C5—C4—Si3—C14 | −65.3 (3) |
C6—Co1—C4—C5 | 28.29 (16) | Co1—C4—Si3—C14 | 9.9 (2) |
C2—Co1—C4—Si3 | 60.7 (2) | C5—C4—Si3—C13 | 175.0 (3) |
C5—Co1—C4—Si3 | −123.5 (2) | Co1—C4—Si3—C13 | −109.82 (19) |
C3—Co1—C4—Si3 | 87.43 (15) | C5—C6—Si4—C16 | −65.5 (2) |
C6—Co1—C4—Si3 | −95.18 (14) | Co1—C6—Si4—C16 | 17.9 (2) |
Si3—C4—C5—C6 | 41.8 (4) | C5—C6—Si4—C17 | 171.1 (2) |
Co1—C4—C5—C6 | −54.2 (2) | Co1—C6—Si4—C17 | −105.4 (2) |
Si3—C4—C5—Co1 | 95.9 (2) | C5—C6—Si4—C18 | 52.5 (3) |
C3—Co1—C5—C6 | 179.29 (16) | Co1—C6—Si4—C18 | 135.9 (2) |
C4—Co1—C5—C6 | 135.0 (2) |
Experimental details
Crystal data | |
Chemical formula | [Co(C9H21Si2)2] |
Mr | 429.81 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 12.341 (1), 10.3381 (9), 21.024 (2) |
β (°) | 99.371 (2) |
V (Å3) | 2646.5 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.83 |
Crystal size (mm) | 0.31 × 0.24 × 0.16 |
Data collection | |
Diffractometer | Siemens SMART Platform CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Blessing, 1995) |
Tmin, Tmax | 0.767, 0.876 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 25453, 4688, 4033 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.596 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.111, 1.02 |
No. of reflections | 4688 |
No. of parameters | 244 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 1.11, −0.30 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 1999), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1998), SHELXTL.
Co1—C1 | 2.091 (3) | Co1—C6 | 2.096 (3) |
Co1—C2 | 1.996 (3) | C1—C2 | 1.421 (4) |
Co1—C3 | 2.046 (3) | C2—C3 | 1.407 (4) |
Co1—C4 | 2.050 (3) | C4—C5 | 1.419 (4) |
Co1—C5 | 2.006 (3) | C5—C6 | 1.407 (4) |
C3—C2—C1 | 124.5 (3) | C6—C5—C4 | 123.3 (2) |
The only homoleptic allyl compound of cobalt to be characterized to date is the tris(allyl) species (C3H5)3Co (Wilke et al., 1996), which decomposes at 233 K and of which the structure is unknown. It is possible to increase the thermal stability of allyl compounds by using substituted ligands, and several bis(η3-allyl)metal complexes of the first-row transition metals have been prepared with the bulky bis(1,3-trimethylsilyl)allyl ligand which have no counterparts with unsubstituted ligands, such as [η3-1,3-(SiMe3)2C3H3]2Cr and [η3-1,3-(SiMe3)2C3H3]2Fe (Smith et al., 2001). We have found that this ligand also effectively stabilizes a compound with cobalt. Specifically, the title compound, (I), a formally 15-electron species, [1,3-(SiMe3)2C3H3]2Co, can be isolated as an air- and moisture-sensitive solid (m.p. 346 K) which is far more thermally robust than (C3H5)3Co. We present here the structure of (I). \sch
Compound (I) is a yellow-orange complex which crystallizes as a monomer with approximate C2 symmetry. The two substituted allyl ligands are arranged about the metal in a staggered configuration (Fig. 1), with an angle between the C3 allyl planes of 5.5 (5)°. The ligands are bound in a trihapto manner to the Co center, with Co—C bond lengths varying from 1.996 (3) to 2.096 (3) Å (Table 1). The SiMe3 groups are in a syn,anti arrangement on each allyl ligand, similar to that found in [η3-1,3-(SiMe3)2C3H3]2Cr and [η3-1,3-(SiMe3)2C3H3]2Fe (Smith et al., 2001). The anti Si atoms display large displacements out of the C3 allyl plane, with torsion angles of 39.2 (4)° (C1—C2—C3—Si3) and 41.8 (4)° (Si3—C4—C5—C6). The syn Si atoms, in contrast, lie much closer to the allyl planes [Si1—C1—C2—C3 175.3 (2) and C4—C5—C6—Si4 178.2 (2)°]. There is a slight lateral shift of the allyl ligands, with the C atoms bearing the syn SiMe3 groups (atoms C1 and C6) further from the metal [2.091 (3) and 2.096 (3) Å, respectively] than those with the anti SiMe3 groups [atoms C3 and C4 at 2.046 (3) and 2.050 (3) Å, respectively]. This slippage pattern also exists in the Cr and Fe counterparts.
The range of bond distances in (I) is somewhat larger than the range 1.918–1.948 Å observed in the cobalt(II) compound (η3-C3H5)(η5-Me5C5)Co, for example, which suggests that steric encumbrance from the allyl ligands may be contributing to bond lengthening. Nevertheless, there is no evidence for agostic interactions (Brookhart & Green, 1983) with the H atoms of the ligand SiMe3 groups and the metal. There are also no intramolecular Me–Me contacts closer than the sum of their van der Waals radii (4.0 Å; Pauling, 1960).