Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801017172/om6064sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801017172/om6064Isup2.hkl |
CCDC reference: 175980
Key indicators
- Single-crystal X-ray study
- T = 213 K
- Mean (F-B) = 0.002 Å
- Disorder in main residue
- R factor = 0.028
- wR factor = 0.084
- Data-to-parameter ratio = 12.1
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
Alert Level B:
PLAT_301 Alert B Main Residue Disorder ........................ 50.00 Perc.
Author response: The nature of the disorder is fully discussed in the comment section. |
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
0 Alert Level C = Please check
All synthetic procedures were carried out under a nitrogen atmosphere. Cobaltocene (51 mg, 0.27 mmol) and AgBF4 (52 mg, 0.27 mmol) were weighed into separate Schlenk flasks. Methylene chloride (10 ml) was added to each flask, and the cobaltocene solution was transferred to the flask containing the AgBF4 via cannula. The mixture was allowed to react, with stirring, for 1 h. The solution was then transferred with a filter-equipped cannula into a 50 ml Schlenk tube and layered with 20 ml hexanes. Crystals formed after one week.
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1996); software used to prepare material for publication: SHELXL97.
[Co(C5H5)2]·BF4 | Dx = 1.680 Mg m−3 |
Mr = 275.92 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Cccm | Cell parameters from 1619 reflections |
a = 7.3586 (7) Å | θ = 2.4–27.4° |
b = 11.9176 (11) Å | µ = 1.59 mm−1 |
c = 12.4369 (13) Å | T = 213 K |
V = 1090.68 (18) Å3 | Block, yellow |
Z = 4 | 0.30 × 0.28 × 0.20 mm |
F(000) = 552 |
Bruker SMART diffractometer | 665 independent reflections |
Radiation source: normal-focus sealed tube | 485 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.018 |
ω scans | θmax = 27.5°, θmin = 3.3° |
Absorption correction: multi-scan (SADABS; Blessing, 1995) | h = −9→9 |
Tmin = 0.609, Tmax = 0.727 | k = −15→10 |
3263 measured reflections | l = −16→13 |
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)] = 0.028 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.084 | H-atom parameters not refined |
S = 1.09 | w = 1/[σ2(Fo2) + (0.036P)2 + 0.6P] where P = (Fo2 + 2Fc2)/3 |
665 reflections | (Δ/σ)max = 0.003 |
55 parameters | Δρmax = 0.19 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
[Co(C5H5)2]·BF4 | V = 1090.68 (18) Å3 |
Mr = 275.92 | Z = 4 |
Orthorhombic, Cccm | Mo Kα radiation |
a = 7.3586 (7) Å | µ = 1.59 mm−1 |
b = 11.9176 (11) Å | T = 213 K |
c = 12.4369 (13) Å | 0.30 × 0.28 × 0.20 mm |
Bruker SMART diffractometer | 665 independent reflections |
Absorption correction: multi-scan (SADABS; Blessing, 1995) | 485 reflections with I > 2σ(I) |
Tmin = 0.609, Tmax = 0.727 | Rint = 0.018 |
3263 measured reflections |
R[F2 > 2σ(F2)] = 0.028 | 0 restraints |
wR(F2) = 0.084 | H-atom parameters not refined |
S = 1.09 | Δρmax = 0.19 e Å−3 |
665 reflections | Δρmin = −0.18 e Å−3 |
55 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 | Occ. (<1) | |
Co | 0.2500 | 0.2500 | 0.4821 (4) | 0.0622 (10) | 0.50 |
C1 | 0.3131 (4) | 0.4145 (3) | 0.4953 (10) | 0.0860 (16) | 0.50 |
H1 | 0.2311 | 0.4730 | 0.5050 | 0.103* | 0.50 |
C2 | 0.3970 (13) | 0.3527 (7) | 0.5769 (8) | 0.113 (4) | 0.50 |
H2 | 0.3806 | 0.3629 | 0.6504 | 0.136* | 0.50 |
C3 | 0.5098 (10) | 0.2730 (6) | 0.5287 (5) | 0.101 (7) | 0.50 |
H3 | 0.5817 | 0.2208 | 0.5645 | 0.122* | 0.50 |
C4 | 0.4956 (9) | 0.2854 (4) | 0.4173 (5) | 0.092 (4) | 0.50 |
H4 | 0.5563 | 0.2429 | 0.3659 | 0.110* | 0.50 |
C5 | 0.3740 (14) | 0.3729 (7) | 0.3967 (6) | 0.0721 (18) | 0.50 |
H5 | 0.3397 | 0.3989 | 0.3292 | 0.087* | 0.50 |
F | 0.1069 (3) | 0.4337 (2) | 0.18803 (19) | 0.1734 (10) | |
B | 0.0000 | 0.5000 | 0.2500 | 0.124 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co | 0.0360 (3) | 0.0488 (3) | 0.102 (3) | −0.00996 (18) | 0.000 | 0.000 |
C1 | 0.065 (2) | 0.0539 (17) | 0.139 (4) | −0.0181 (18) | −0.030 (9) | 0.008 (11) |
C2 | 0.095 (9) | 0.140 (11) | 0.104 (6) | −0.077 (7) | 0.000 (4) | −0.025 (5) |
C3 | 0.040 (2) | 0.096 (4) | 0.17 (2) | −0.023 (2) | −0.018 (5) | 0.043 (8) |
C4 | 0.050 (3) | 0.061 (3) | 0.164 (11) | −0.010 (2) | 0.025 (5) | 0.006 (4) |
C5 | 0.056 (3) | 0.051 (2) | 0.110 (5) | −0.012 (2) | 0.013 (3) | 0.005 (3) |
F | 0.217 (3) | 0.1521 (18) | 0.1513 (18) | −0.0482 (15) | 0.0620 (17) | −0.0701 (14) |
B | 0.156 (8) | 0.119 (6) | 0.095 (5) | 0.000 | 0.000 | 0.000 |
Co—C1 | 2.021 (4) | C1—C5 | 1.397 (4) |
Co—C2 | 2.015 (11) | C2—C3 | 1.397 (4) |
Co—C3 | 2.016 (7) | C3—C4 | 1.397 (4) |
Co—C4 | 2.023 (7) | C4—C5 | 1.397 (4) |
Co—C5 | 2.027 (10) | B—F | 1.355 (2) |
C1—C2 | 1.397 (4) | ||
C1—C2—C3 | 108.0 | C2—C3—Co | 69.7 (3) |
C2—C3—C4 | 108.0 | C4—C3—Co | 70.0 (5) |
C3—C4—C5 | 108.0 | C5—C4—Co | 69.9 (3) |
C4—C5—C1 | 108.0 | C3—C4—Co | 69.5 (5) |
C2—C1—C5 | 108.0 | C1—C5—Co | 69.6 (3) |
C2—C1—Co | 69.5 (4) | C4—C5—Co | 69.70 (15) |
C5—C1—Co | 70.0 (4) | Fi—B—F | 108.7 (2) |
C1—C2—Co | 70.0 (3) | Fi—B—Fii | 110.7 (2) |
C3—C2—Co | 69.77 (15) | F—B—Fii | 109.05 (19) |
Symmetry codes: (i) −x, y, −z+1/2; (ii) x, −y+1, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [Co(C5H5)2]·BF4 |
Mr | 275.92 |
Crystal system, space group | Orthorhombic, Cccm |
Temperature (K) | 213 |
a, b, c (Å) | 7.3586 (7), 11.9176 (11), 12.4369 (13) |
V (Å3) | 1090.68 (18) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.59 |
Crystal size (mm) | 0.30 × 0.28 × 0.20 |
Data collection | |
Diffractometer | Bruker SMART diffractometer |
Absorption correction | Multi-scan (SADABS; Blessing, 1995) |
Tmin, Tmax | 0.609, 0.727 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3263, 665, 485 |
Rint | 0.018 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.028, 0.084, 1.09 |
No. of reflections | 665 |
No. of parameters | 55 |
H-atom treatment | H-atom parameters not refined |
Δρmax, Δρmin (e Å−3) | 0.19, −0.18 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2001), SAINT, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL (Siemens, 1996), SHELXL97.
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Cobaltocene has often been used as a convenient, mild reducing agent (Connelly & Geiger, 1996), thus leading to the appearance of the cobaltocenium cation in many crystal structures [over 80 times in the Cambridge Database (Allen & Kennard, 1993)]. We have also found the cobaltocenium cation to be useful as a mild oxidizing agent, and often use the BF4- salt whenever a weakly coordinating anion is desired in the target synthetic product. While structures of the Cp2Co+ ion with many different anions are known, the BF4- salt, (I), is not, and its structure is reported here.
Space group Cccm was strongly indicated by intensity statistics, and while the solution and refinement of the structure was expected to be straightforward, the initial solution from direct methods suggested a position for the Co atom that was on the twofold axis at 1/4, 1/4, z but only approximately 0.2 Å from the 2/m site at 1/4, 1/4, 1/2. (The BF4- anion resides on a site of 222 symmetry at 0, 1/2, 1/4 in a way that generates an almost perfectly tetrahedral moiety.) Fourier peaks corresponding to the C atoms of the Cp rings were therefore badly mixed by the symmetry operations. At this point, it seemed apparent that the mirror plane should be removed to reduce the symmetry and change the space group to Ccc2. However, two slightly separated positions for the Co atom persisted and the Cp rings continued to appear as a badly disordered cluster of atoms. The solution and refinement were therefore continued in space group Cccm, using a disordered model in which the Cp2Co+ unit resides on a twofold axis perpendicular to the main axis of the molecule, but slightly displaced from the mirror plane which almost contains the main molecular axis. A view of the model showing one orientation of the Cp2Co group is shown in Fig. 1.
In order to refine the model effectively, the Cp ring was constrained to be exactly pentagonal, but was allowed to shrink or expand freely. This resulted in a C—C distance of 1.397 (4) Å, which is shorter than the expected distance for π-bonded Cp, but is due to librational error. Librational analysis (Schomaker & Trueblood, 1968) of the Cp ring gives corrected C—C bond lengths of 1.42 Å, which is the expected value of the distances.
Atom C1 lies almost on the mirror plane and appears to be shared by both orientations in Fig. 2, although it is actually not. The Cp plane is 1.634 (1) Å from the Co atom, and the two Cp rings form an angle of 1.5 (4)°. The Cp rings are slightly staggered, with an approximate offset of 21°.