Bis(η⁵-penta­methyl­cyclo­penta­dien­yl)cobalt(II)

Abstract

The crystal structure of the title compound, deca­methyl­cobaltocene, [Co(C₁₀H₁₅)₂], has been determined. High-quality single crystals were grown from a cold saturated hexa­methyl­disiloxane solution. The structure is related to the manganese and iron analogs. The molecule has D _5d symmetry, with the Co atom in a crystallographic 2/m position. The cobalt–centroid(C₅) distance is 1.71Å and the centroid(C₅)–Co–centroid(C₅) angle is 180°, by symmetry.

Related literature

For the synthesis of the title compound and its electrochemical and magnetic properties, see: Robbins et al. (1982 ▶). For its formal potential and use as a reducing agent, see: Connelly & Geiger (1996 ▶). For the isotypic manganese and iron structures, see: Struchkov et al. (1978 ▶); Freyburg et al. (1979 ▶); Augart et al. (1991 ▶); Arrais et al. (2003 ▶).

Experimental

Crystal data

• [Co(C₁₀H₁₅)₂]

• M _r = 329.37

• Orthorhombic,

• a = 15.0848 (16) Å

• b = 11.5031 (12) Å

• c = 10.0105 (10) Å

• V = 1737.0 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.98 mm⁻¹

• T = 100 K

• 0.28 × 0.28 × 0.14 mm

Data collection

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 2008a ▶) T _min = 0.771, T _max = 0.875

• 19672 measured reflections

• 2386 independent reflections

• 1903 reflections with I > 2σ(I)

• R _int = 0.046

Refinement

• R[F ² > 2σ(F ²)] = 0.031

• wR(F ²) = 0.089

• S = 1.07

• 2386 reflections

• 84 parameters

• All H-atom parameters refined

• Δρ_max = 0.70 e Å⁻³

• Δρ_min = −0.74 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b ▶); molecular graphics: SHELXTL (Sheldrick, 2008b ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Co1—C1	2.0914 (12)
Co1—C3	2.0956 (8)
Co1—C2	2.1113 (8)
C1—C2	1.4304 (12)
C1—C4	1.4961 (18)
C2—C3	1.4231 (12)
C2—C5	1.4935 (14)
C3—C6	1.4950 (13)

supplementary crystallographic information

Comment

The structure of (I) has been conspicuously absent from the literature, despite its being a widely used reducing agent (Connelly & Geiger, 1996). Robbins and co-workers referred to a structural determination in 1982 (Robbins et al., 1982), specifically its D_5d symmetry and its similarity to the manganese analog. However, no structural data were presented. Attempts to grow single crystals from toluene and hexane, the latter from which Robbins reported having grown crystals, resulted in very poor quality specimens that were unsuitable for X-ray diffraction experiments. A cold (-38 ° C) saturated hexamethyldisiloxane solution of (I) afforded excellent crystals that resulted in a high quality structural determination.

The structure is isomorphous to that of decamethylferrocene (refcodes DMFERR, Struchkov et al., 1978, DMFERR01, Freyburg et al., 1979, DMFERR02, Arrais et al., 2003) and the low temperature polymorph of decamethylmanganocene (refcodes DMCPMN01 and DMCPMN02, Augart et al., 1991), for which the metal atoms are in crystallographic 2/m positions.

Experimental

All operations were performed under an inert atmosphere (dinitrogen). Hexamethyldisiloxane was stirred over CaH₂ and vacuum transferred from sodium benzophenone ketyl. (I) was purchased from Sigma-Aldrich and used as is. Hexamethyldisiloxane (1 ml) was added to (I) (10 mg, 30 µmol), most of which dissolved over the course of a few hours at room temperature. After filtration through Celite, the filtrate was stored at -38 °C, resulting in dark yellow-brown crystals of (I) after a few hours.

Refinement

Hydrogen atoms were found from the difference Fourier map and refined independently from their respective carbon atoms with individual isotropic displacement parameters.

Figures

Fig. 1.

A displacement ellipsoid (50% probability) drawing of (I). The cobalt atom is in a crystallographic 2/m position.

Crystal data

[Co(C10H15)2]	F(000) = 708
Mr = 329.37	Dx = 1.259 Mg m−3
Orthorhombic, Cmca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2bc 2	Cell parameters from 4000 reflections
a = 15.0848 (16) Å	θ = 3.0–37.5°
b = 11.5031 (12) Å	µ = 0.98 mm−1
c = 10.0105 (10) Å	T = 100 K
V = 1737.0 (3) Å3	Block, dark yellow-brown
Z = 4	0.28 × 0.28 × 0.14 mm

Data collection

Bruker APEXII CCD diffractometer	2386 independent reflections
Radiation source: fine-focus sealed tube	1903 reflections with I > 2σ(I)
graphite	Rint = 0.046
φ and ω scans	θmax = 38.0°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a)	h = −25→25
Tmin = 0.771, Tmax = 0.875	k = −19→19
19672 measured reflections	l = −16→17

Refinement

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.089	All H-atom parameters refined
S = 1.07	w = 1/[σ2(Fo2) + (0.0525P)2 + 0.2743P] where P = (Fo2 + 2Fc2)/3
2386 reflections	(Δ/σ)max < 0.001
84 parameters	Δρmax = 0.70 e Å−3
0 restraints	Δρmin = −0.74 e Å−3

Special details

Experimental. The crystal was examined under N2 and affixed to the end of a glass capillary with viscous oil, which protected the crystal during transfer to the cold stream.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Co1	0.0000	0.0000	0.0000	0.01533 (7)
C1	0.0000	−0.17732 (10)	0.04617 (12)	0.0228 (2)
C2	−0.07677 (6)	−0.12416 (7)	0.10364 (8)	0.02149 (15)
C3	−0.04749 (5)	−0.03551 (7)	0.19244 (8)	0.01843 (13)
C4	0.0000	−0.27361 (12)	−0.05429 (14)	0.0348 (3)
H4A	0.0000	−0.352 (3)	−0.013 (2)	0.045 (8)*
H4B	−0.0486 (10)	−0.2711 (18)	−0.1133 (16)	0.063 (5)*
C5	−0.17089 (8)	−0.15651 (11)	0.07606 (12)	0.0340 (2)
H5A	−0.1798 (16)	−0.184 (2)	−0.0134 (18)	0.053 (6)*
H5B	−0.2119 (12)	−0.0926 (16)	0.0778 (19)	0.059 (5)*
H5C	−0.1896 (11)	−0.2189 (15)	0.1358 (16)	0.047 (4)*
C6	−0.10544 (7)	0.04079 (10)	0.27607 (9)	0.02731 (18)
H6A	−0.1134 (15)	0.0057 (13)	0.360 (3)	0.045 (6)*
H6B	−0.1638 (11)	0.0562 (13)	0.2287 (15)	0.039 (4)*
H6C	−0.0774 (11)	0.1158 (14)	0.2912 (14)	0.037 (4)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Co1	0.01811 (10)	0.01380 (9)	0.01409 (9)	0.000	0.000	−0.00032 (6)
C1	0.0353 (6)	0.0161 (4)	0.0170 (4)	0.000	0.000	−0.0004 (4)
C2	0.0245 (3)	0.0202 (3)	0.0198 (3)	−0.0054 (3)	−0.0013 (3)	0.0016 (3)
C3	0.0205 (3)	0.0180 (3)	0.0168 (3)	0.0002 (3)	0.0014 (2)	0.0006 (2)
C4	0.0653 (11)	0.0183 (5)	0.0206 (5)	0.000	0.000	−0.0029 (4)
C5	0.0290 (4)	0.0371 (5)	0.0359 (5)	−0.0147 (4)	−0.0069 (4)	0.0063 (4)
C6	0.0293 (4)	0.0292 (4)	0.0234 (4)	0.0056 (4)	0.0068 (3)	−0.0005 (3)

Geometric parameters (Å, °)

Co1—C1i	2.0914 (12)	C2—C3	1.4231 (12)
Co1—C1	2.0914 (12)	C2—C5	1.4935 (14)
Co1—C3ii	2.0955 (8)	C3—C3ii	1.4328 (17)
Co1—C3	2.0956 (8)	C3—C6	1.4950 (13)
Co1—C3i	2.0956 (8)	C4—H4A	0.99 (3)
Co1—C3iii	2.0956 (8)	C4—H4B	0.942 (16)
Co1—C2iii	2.1113 (8)	C5—H5A	0.960 (18)
Co1—C2	2.1113 (8)	C5—H5B	0.962 (18)
Co1—C2ii	2.1113 (8)	C5—H5C	0.976 (17)
Co1—C2i	2.1113 (8)	C6—H6A	0.94 (2)
C1—C2	1.4304 (12)	C6—H6B	1.016 (16)
C1—C2ii	1.4304 (12)	C6—H6C	0.973 (16)
C1—C4	1.4961 (18)
C1i—Co1—C1	180.0	C3—Co1—C2i	140.46 (3)
C1i—Co1—C3ii	113.16 (4)	C3i—Co1—C2i	39.54 (3)
C1—Co1—C3ii	66.84 (4)	C3iii—Co1—C2i	66.67 (3)
C1i—Co1—C3	113.16 (4)	C2iii—Co1—C2i	66.53 (5)
C1—Co1—C3	66.84 (4)	C2—Co1—C2i	180.0
C3ii—Co1—C3	39.98 (5)	C2ii—Co1—C2i	113.47 (5)
C1i—Co1—C3i	66.84 (4)	C2—C1—C2ii	108.12 (10)
C1—Co1—C3i	113.16 (4)	C2—C1—C4	125.94 (5)
C3ii—Co1—C3i	140.02 (5)	C2ii—C1—C4	125.93 (5)
C3—Co1—C3i	180.0	C2—C1—Co1	70.85 (6)
C1i—Co1—C3iii	66.84 (4)	C2ii—C1—Co1	70.85 (6)
C1—Co1—C3iii	113.16 (4)	C4—C1—Co1	124.99 (9)
C3ii—Co1—C3iii	180.0	C3—C2—C1	107.84 (8)
C3—Co1—C3iii	140.02 (5)	C3—C2—C5	126.09 (9)
C3i—Co1—C3iii	39.98 (5)	C1—C2—C5	126.07 (9)
C1i—Co1—C2iii	39.79 (3)	C3—C2—Co1	69.63 (5)
C1—Co1—C2iii	140.21 (3)	C1—C2—Co1	69.36 (6)
C3ii—Co1—C2iii	140.46 (3)	C5—C2—Co1	126.81 (7)
C3—Co1—C2iii	113.34 (3)	C2—C3—C3ii	108.08 (5)
C3i—Co1—C2iii	66.66 (3)	C2—C3—C6	126.09 (8)
C3iii—Co1—C2iii	39.54 (3)	C3ii—C3—C6	125.78 (5)
C1i—Co1—C2	140.21 (3)	C2—C3—Co1	70.82 (5)
C1—Co1—C2	39.79 (3)	C3ii—C3—Co1	70.01 (2)
C3ii—Co1—C2	66.67 (3)	C6—C3—Co1	126.88 (6)
C3—Co1—C2	39.54 (3)	C1—C4—H4A	112.8 (13)
C3i—Co1—C2	140.46 (3)	C1—C4—H4B	113.5 (11)
C3iii—Co1—C2	113.33 (3)	H4A—C4—H4B	107.0 (15)
C2iii—Co1—C2	113.47 (5)	C2—C5—H5A	112.8 (15)
C1i—Co1—C2ii	140.21 (3)	C2—C5—H5B	114.7 (11)
C1—Co1—C2ii	39.79 (3)	H5A—C5—H5B	100.5 (18)
C3ii—Co1—C2ii	39.54 (3)	C2—C5—H5C	110.1 (9)
C3—Co1—C2ii	66.67 (3)	H5A—C5—H5C	106.7 (16)
C3i—Co1—C2ii	113.33 (3)	H5B—C5—H5C	111.4 (14)
C3iii—Co1—C2ii	140.46 (3)	C3—C6—H6A	109.0 (11)
C2iii—Co1—C2ii	180.0	C3—C6—H6B	110.4 (9)
C2—Co1—C2ii	66.53 (5)	H6A—C6—H6B	112.4 (16)
C1i—Co1—C2i	39.79 (3)	C3—C6—H6C	110.7 (9)
C1—Co1—C2i	140.21 (3)	H6A—C6—H6C	107.2 (15)
C3ii—Co1—C2i	113.33 (3)	H6B—C6—H6C	107.2 (13)
C1i—Co1—C1—C2	22.38 (12)	C2iii—Co1—C2—C1	141.96 (6)
C3ii—Co1—C1—C2	80.81 (6)	C2ii—Co1—C2—C1	−38.04 (6)
C3—Co1—C1—C2	37.16 (5)	C2i—Co1—C2—C1	−59.99 (6)
C3i—Co1—C1—C2	−142.84 (5)	C1i—Co1—C2—C5	59.74 (11)
C3iii—Co1—C1—C2	−99.18 (6)	C1—Co1—C2—C5	−120.26 (11)
C2iii—Co1—C1—C2	−62.03 (10)	C3ii—Co1—C2—C5	158.44 (10)
C2ii—Co1—C1—C2	117.97 (10)	C3—Co1—C2—C5	120.46 (11)
C2i—Co1—C1—C2	180.0	C3i—Co1—C2—C5	−59.54 (11)
C1i—Co1—C1—C2ii	−95.59 (13)	C3iii—Co1—C2—C5	−21.56 (10)
C3ii—Co1—C1—C2ii	−37.16 (5)	C2iii—Co1—C2—C5	21.70 (8)
C3—Co1—C1—C2ii	−80.82 (6)	C2ii—Co1—C2—C5	−158.30 (8)
C3i—Co1—C1—C2ii	99.18 (6)	C2i—Co1—C2—C5	179.75 (9)
C3iii—Co1—C1—C2ii	142.84 (5)	C1—C2—C3—C3ii	−1.34 (8)
C2iii—Co1—C1—C2ii	180.0	C5—C2—C3—C3ii	178.27 (8)
C2—Co1—C1—C2ii	−117.97 (10)	Co1—C2—C3—C3ii	−60.38 (2)
C2i—Co1—C1—C2ii	62.03 (10)	C1—C2—C3—C6	−178.77 (9)
C1i—Co1—C1—C4	143.40 (12)	C5—C2—C3—C6	0.85 (14)
C3ii—Co1—C1—C4	−158.17 (3)	Co1—C2—C3—C6	122.20 (9)
C3—Co1—C1—C4	158.17 (3)	C1—C2—C3—Co1	59.04 (7)
C3i—Co1—C1—C4	−21.83 (3)	C5—C2—C3—Co1	−121.35 (9)
C3iii—Co1—C1—C4	21.83 (3)	C1i—Co1—C3—C2	142.61 (5)
C2iii—Co1—C1—C4	58.98 (5)	C1—Co1—C3—C2	−37.39 (5)
C2—Co1—C1—C4	121.01 (5)	C3ii—Co1—C3—C2	−118.44 (5)
C2ii—Co1—C1—C4	−121.01 (5)	C3i—Co1—C3—C2	−112.12 (6)
C2i—Co1—C1—C4	−58.99 (5)	C3iii—Co1—C3—C2	61.56 (5)
C2ii—C1—C2—C3	2.17 (13)	C2iii—Co1—C3—C2	99.14 (7)
C4—C1—C2—C3	−179.08 (11)	C2ii—Co1—C3—C2	−80.87 (7)
Co1—C1—C2—C3	−59.21 (6)	C2i—Co1—C3—C2	180.0
C2ii—C1—C2—C5	−177.44 (7)	C1i—Co1—C3—C3ii	−98.952 (19)
C4—C1—C2—C5	1.30 (17)	C1—Co1—C3—C3ii	81.049 (19)
Co1—C1—C2—C5	121.18 (9)	C3i—Co1—C3—C3ii	6.32 (2)
C2ii—C1—C2—Co1	61.38 (8)	C3iii—Co1—C3—C3ii	180.0
C4—C1—C2—Co1	−119.87 (12)	C2iii—Co1—C3—C3ii	−142.43 (3)
C1i—Co1—C2—C3	−60.72 (8)	C2—Co1—C3—C3ii	118.44 (5)
C1—Co1—C2—C3	119.28 (8)	C2ii—Co1—C3—C3ii	37.57 (3)
C3ii—Co1—C2—C3	37.98 (5)	C2i—Co1—C3—C3ii	−61.56 (5)
C3i—Co1—C2—C3	180.0	C1i—Co1—C3—C6	21.37 (9)
C3iii—Co1—C2—C3	−142.02 (5)	C1—Co1—C3—C6	−158.63 (9)
C2iii—Co1—C2—C3	−98.77 (5)	C3ii—Co1—C3—C6	120.32 (8)
C2ii—Co1—C2—C3	81.24 (5)	C3i—Co1—C3—C6	126.64 (8)
C2i—Co1—C2—C3	59.29 (5)	C3iii—Co1—C3—C6	−59.68 (8)
C1i—Co1—C2—C1	180.0	C2iii—Co1—C3—C6	−22.11 (9)
C3ii—Co1—C2—C1	−81.30 (6)	C2—Co1—C3—C6	−121.24 (10)
C3—Co1—C2—C1	−119.28 (8)	C2ii—Co1—C3—C6	157.89 (9)
C3i—Co1—C2—C1	60.72 (8)	C2i—Co1—C3—C6	58.76 (10)
C3iii—Co1—C2—C1	98.70 (6)

Symmetry codes: (i) −x, −y, −z; (ii) −x, y, z; (iii) x, −y, −z.