Bis[μ-N-(tert-butyl-dimethyl-silyl)-N-(pyridin-2-ylmeth-yl)amido]-bis-[methyl-cobalt(II)].

The green title complex, [Co(2)(CH(3))(2)(C(12)H(21)N(2)Si)(2)], was obtained from bis-{[μ-N-tert-butyl-dimethyl-silyl-N-(pyridin-2-ylmeth-yl)amido]-chloridocobalt(II)} and methyl-lithium in diethyl ether at 195 K via a metathesis reaction. The dimeric cobalt(II) complex exhibits a crystallographic center of inversion in the middle of the Co(2)N(2) ring (average Co-N = 2.050 Å). The Co(II) atom shows a distorted tetra-hedral coordination sphere. The exocyclic Co-N bond length to the pyridyl group shows a similar value of 2.045 (4) Å. The exocyclic methyl group has a rather long Co-C bond length of 2.019 (5) Å.

Related literature

The metathetical conversion of a cobalt chloride functionality into a methyl cobalt fragment via the reaction with methyllithium was reported earlier for tetra-coordinate cobalt(II) complexes bound to three additional aza-bases, see: Au-Yeung et al. (2007 ▶); Bowman et al. (2010 ▶); Humphries et al. (2005 ▶); Kleigrewe et al. (2005 ▶), Wallenhorst et al. (2008 ▶). The synthesis of dialkyl cobalt complexes succeeds starting from hexa-coordinate [(L)4CoCl2] with L being a pyridyl base, see: Milani et al. (2003 ▶); Zhu et al. (2010 ▶). The coordination number of the final cobalt(II) complexes depends on intra­molecular steric strain yielding hexa-coordinate [(bpy)2CoMe2] (bpy = 2,2′-bipyridine) and tetra-coordinate [(py)2CoR 2] (R = CH2C(Me2)Ph). The formation of para-tolyl­cobalt complexes was reported by Zhu & Budzelaar (2010 ▶) who proposed a radical mechanism.

Experimental

Crystal data

[Co2(CH3)2(C12H21N2Si)2]

M = 590.72

Triclinic,

a = 8.4751 (8) Å

b = 9.8055 (12) Å

c = 10.6130 (6) Å

α = 72.837 (6)°

β = 83.450 (6)°

γ = 69.216 (6)°

V = 787.81 (13) Å3

Z = 1

Mo Kα radiation

μ = 1.15 mm−1

T = 183 K

0.06 × 0.06 × 0.04 mm

Data collection

Nonius KappaCCD diffractometer

5417 measured reflections

3551 independent reflections

1685 reflections with I > 2σ(I)

R int = 0.074

Refinement

R[F 2 > 2σ(F 2)] = 0.061

wR(F 2) = 0.129

S = 0.92

3551 reflections

160 parameters

H-atom parameters constrained

Δρmax = 0.39 e Å−3

Δρmin = −0.39 e Å−3

Data collection: COLLECT (Nonius, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶); data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL/PC (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812032321/im2393sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812032321/im2393Isup2.hkl

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

[Co2(CH3)2(C12H21N2Si)2]	Z = 1
Mr = 590.72	F(000) = 314
Triclinic, P1	Dx = 1.245 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.4751 (8) Å	Cell parameters from 5417 reflections
b = 9.8055 (12) Å	θ = 3.3–27.5°
c = 10.6130 (6) Å	µ = 1.15 mm−1
α = 72.837 (6)°	T = 183 K
β = 83.450 (6)°	Prism, green
γ = 69.216 (6)°	0.06 × 0.06 × 0.04 mm
V = 787.81 (13) Å3

Nonius KappaCCD diffractometer	1685 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.074
Graphite monochromator	θmax = 27.5°, θmin = 3.3°
phi– + ω–scan	h = −10→9
5417 measured reflections	k = −10→12
3551 independent reflections	l = −13→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)] = 0.061	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.129	H-atom parameters constrained
S = 0.92	w = 1/[σ2(Fo2) + (0.0369P)2] where P = (Fo2 + 2Fc2)/3
3551 reflections	(Δ/σ)max < 0.001
160 parameters	Δρmax = 0.39 e Å−3
0 restraints	Δρmin = −0.39 e Å−3

Experimental. IR (in Nujol between KBr windows, cm-1): = 1715 w, 1583 m, 1273 m, 1244 s, 1146 m, 1080 m, 1036 m, 1008 m, 889 m, 828 s, 770 m, 736 m. MS (DEI, rel. intensity in brackets): m/z = 501 ([M - CoMe2]+, 11%), 165 ([Pyr-CH2-NHSiMe2]+, 100%). Elemental analysis (C26H48Co2N4Si2, 590,72): calcd.: C 52.86, H 8.19, N 9.48; found: C 49.47, H 7.70, N 9.03 (the rather large deviations are caused by extreme sensitivity of the complex towards moisture and air; the low carbon value is a consequence of carbide and carbonate formation despite the fact that V2O5 was added prior to combustion).

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	0.50875 (8)	0.62393 (8)	0.52394 (5)	0.0360 (2)
Si1	0.36965 (16)	0.43232 (17)	0.77488 (11)	0.0373 (4)
N1	0.2891 (5)	0.7874 (4)	0.4452 (3)	0.0342 (10)
N2	0.3562 (4)	0.4948 (4)	0.6037 (3)	0.0306 (9)
C1	0.2668 (7)	0.9328 (6)	0.3756 (4)	0.0466 (14)
H1A	0.3599	0.9681	0.3636	0.056*
C2	0.1139 (7)	1.0311 (6)	0.3217 (4)	0.0524 (15)
H2A	0.1017	1.1325	0.2732	0.063*
C3	−0.0218 (7)	0.9803 (7)	0.3391 (5)	0.0570 (16)
H3A	−0.1275	1.0452	0.3003	0.068*
C4	−0.0012 (6)	0.8329 (6)	0.4142 (4)	0.0429 (13)
H4A	−0.0938	0.7967	0.4294	0.052*
C5	0.1560 (6)	0.7389 (6)	0.4668 (4)	0.0349 (12)
C6	0.1808 (5)	0.5827 (6)	0.5525 (4)	0.0387 (12)
H6A	0.1501	0.5256	0.5020	0.046*
H6B	0.1020	0.5892	0.6286	0.046*
C7	0.2682 (6)	0.5989 (6)	0.8446 (4)	0.0529 (15)
H7A	0.3243	0.6742	0.8080	0.079*
H7B	0.2788	0.5648	0.9408	0.079*
H7C	0.1485	0.6445	0.8213	0.079*
C8	0.5975 (6)	0.3468 (6)	0.8222 (4)	0.0504 (15)
H8A	0.6571	0.4165	0.7746	0.076*
H8B	0.6479	0.2504	0.7993	0.076*
H8C	0.6067	0.3288	0.9174	0.076*
C9	0.2621 (6)	0.2877 (6)	0.8564 (4)	0.0430 (13)
C10	0.0704 (6)	0.3488 (6)	0.8314 (5)	0.0594 (16)
H10A	0.0208	0.2719	0.8808	0.089*
H10B	0.0505	0.3722	0.7370	0.089*
H10C	0.0180	0.4411	0.8606	0.089*
C11	0.3389 (6)	0.1452 (6)	0.8085 (4)	0.0502 (14)
H11A	0.2790	0.0739	0.8499	0.075*
H11B	0.4584	0.0976	0.8324	0.075*
H11C	0.3288	0.1728	0.7125	0.075*
C12	0.2873 (7)	0.2393 (7)	1.0077 (4)	0.0700 (19)
H12A	0.2415	0.1575	1.0491	0.105*
H12B	0.2284	0.3263	1.0430	0.105*
H12C	0.4080	0.2034	1.0267	0.105*
C13	0.6200 (6)	0.7259 (7)	0.6082 (4)	0.0580 (16)
H13A	0.6269	0.8189	0.5442	0.087*
H13B	0.7339	0.6571	0.6363	0.087*
H13C	0.5532	0.7510	0.6850	0.087*

	U11	U22	U33	U12	U13	U23
Co1	0.0333 (4)	0.0450 (5)	0.0363 (4)	−0.0195 (3)	0.0038 (3)	−0.0147 (3)
Si1	0.0355 (8)	0.0459 (10)	0.0285 (7)	−0.0122 (8)	0.0012 (5)	−0.0098 (6)
N1	0.039 (2)	0.033 (3)	0.033 (2)	−0.015 (2)	0.0103 (16)	−0.0130 (19)
N2	0.026 (2)	0.036 (3)	0.0285 (17)	−0.009 (2)	−0.0019 (15)	−0.0068 (16)
C1	0.051 (4)	0.038 (4)	0.050 (3)	−0.017 (3)	0.020 (3)	−0.015 (3)
C2	0.059 (4)	0.037 (4)	0.048 (3)	−0.010 (3)	0.011 (3)	−0.004 (3)
C3	0.051 (4)	0.050 (4)	0.054 (3)	0.000 (3)	−0.005 (3)	−0.010 (3)
C4	0.032 (3)	0.045 (4)	0.046 (3)	−0.009 (3)	0.001 (2)	−0.010 (3)
C5	0.037 (3)	0.041 (3)	0.024 (2)	−0.012 (3)	0.0019 (19)	−0.008 (2)
C6	0.038 (3)	0.044 (4)	0.037 (2)	−0.022 (3)	0.003 (2)	−0.007 (2)
C7	0.061 (4)	0.057 (4)	0.045 (3)	−0.018 (3)	0.003 (2)	−0.024 (3)
C8	0.045 (3)	0.070 (4)	0.038 (3)	−0.014 (3)	−0.007 (2)	−0.020 (3)
C9	0.044 (3)	0.042 (4)	0.029 (2)	−0.005 (3)	0.005 (2)	−0.003 (2)
C10	0.050 (4)	0.054 (4)	0.068 (3)	−0.022 (3)	0.016 (3)	−0.009 (3)
C11	0.048 (3)	0.042 (4)	0.056 (3)	−0.018 (3)	0.010 (2)	−0.007 (3)
C12	0.084 (4)	0.064 (5)	0.040 (3)	−0.019 (4)	0.001 (3)	0.009 (3)
C13	0.055 (4)	0.089 (5)	0.055 (3)	−0.047 (4)	0.013 (3)	−0.034 (3)

Co1—C13	2.019 (5)	C6—H6B	0.9900
Co1—N2i	2.032 (3)	C7—H7A	0.9800
Co1—N1	2.045 (4)	C7—H7B	0.9800
Co1—N2	2.067 (4)	C7—H7C	0.9800
Co1—Co1i	2.6812 (14)	C8—H8A	0.9800
Si1—N2	1.741 (3)	C8—H8B	0.9800
Si1—C8	1.873 (4)	C8—H8C	0.9800
Si1—C7	1.877 (5)	C9—C11	1.528 (7)
Si1—C9	1.898 (5)	C9—C10	1.544 (6)
N1—C5	1.345 (5)	C9—C12	1.551 (6)
N1—C1	1.354 (6)	C10—H10A	0.9800
N2—C6	1.499 (5)	C10—H10B	0.9800
N2—Co1i	2.032 (3)	C10—H10C	0.9800
C1—C2	1.376 (6)	C11—H11A	0.9800
C1—H1A	0.9500	C11—H11B	0.9800
C2—C3	1.381 (7)	C11—H11C	0.9800
C2—H2A	0.9500	C12—H12A	0.9800
C3—C4	1.388 (7)	C12—H12B	0.9800
C3—H3A	0.9500	C12—H12C	0.9800
C4—C5	1.390 (6)	C13—H13A	0.9800
C4—H4A	0.9500	C13—H13B	0.9800
C5—C6	1.487 (6)	C13—H13C	0.9800
C6—H6A	0.9900
C13—Co1—N2i	119.40 (17)	N2—C6—H6B	108.5
C13—Co1—N1	105.8 (2)	H6A—C6—H6B	107.5
N2i—Co1—N1	112.97 (13)	Si1—C7—H7A	109.5
C13—Co1—N2	130.97 (16)	Si1—C7—H7B	109.5
N2i—Co1—N2	98.30 (12)	H7A—C7—H7B	109.5
N1—Co1—N2	84.19 (15)	Si1—C7—H7C	109.5
C13—Co1—Co1i	151.34 (17)	H7A—C7—H7C	109.5
N2i—Co1—Co1i	49.71 (10)	H7B—C7—H7C	109.5
N1—Co1—Co1i	102.57 (11)	Si1—C8—H8A	109.5
N2—Co1—Co1i	48.59 (10)	Si1—C8—H8B	109.5
N2—Si1—C8	108.95 (18)	H8A—C8—H8B	109.5
N2—Si1—C7	109.2 (2)	Si1—C8—H8C	109.5
C8—Si1—C7	108.4 (2)	H8A—C8—H8C	109.5
N2—Si1—C9	114.74 (19)	H8B—C8—H8C	109.5
C8—Si1—C9	108.4 (2)	C11—C9—C10	107.8 (4)
C7—Si1—C9	107.0 (2)	C11—C9—C12	107.5 (4)
C5—N1—C1	119.0 (4)	C10—C9—C12	107.5 (4)
C5—N1—Co1	113.7 (3)	C11—C9—Si1	111.1 (3)
C1—N1—Co1	127.3 (3)	C10—C9—Si1	113.3 (3)
C6—N2—Si1	114.5 (2)	C12—C9—Si1	109.4 (3)
C6—N2—Co1i	109.3 (2)	C9—C10—H10A	109.5
Si1—N2—Co1i	125.9 (2)	C9—C10—H10B	109.5
C6—N2—Co1	108.8 (3)	H10A—C10—H10B	109.5
Si1—N2—Co1	111.27 (17)	C9—C10—H10C	109.5
Co1i—N2—Co1	81.70 (12)	H10A—C10—H10C	109.5
N1—C1—C2	122.1 (5)	H10B—C10—H10C	109.5
N1—C1—H1A	118.9	C9—C11—H11A	109.5
C2—C1—H1A	118.9	C9—C11—H11B	109.5
C1—C2—C3	119.1 (5)	H11A—C11—H11B	109.5
C1—C2—H2A	120.4	C9—C11—H11C	109.5
C3—C2—H2A	120.4	H11A—C11—H11C	109.5
C2—C3—C4	119.0 (5)	H11B—C11—H11C	109.5
C2—C3—H3A	120.5	C9—C12—H12A	109.5
C4—C3—H3A	120.5	C9—C12—H12B	109.5
C3—C4—C5	119.4 (5)	H12A—C12—H12B	109.5
C3—C4—H4A	120.3	C9—C12—H12C	109.5
C5—C4—H4A	120.3	H12A—C12—H12C	109.5
N1—C5—C4	121.3 (4)	H12B—C12—H12C	109.5
N1—C5—C6	117.8 (4)	Co1—C13—H13A	109.5
C4—C5—C6	120.8 (4)	Co1—C13—H13B	109.5
C5—C6—N2	115.1 (4)	H13A—C13—H13B	109.5
C5—C6—H6A	108.5	Co1—C13—H13C	109.5
N2—C6—H6A	108.5	H13A—C13—H13C	109.5
C5—C6—H6B	108.5	H13B—C13—H13C	109.5