supplementary materials


jj2112 scheme

Acta Cryst. (2012). E68, m81    [ doi:10.1107/S1600536811054602 ]

Bis[[mu]-N-(diethylamino-[kappa]N)dimethylsilylanilido-[kappa]2N:N]bis[chloridocobalt(II)]

J. Chen

Abstract top

In the title binuclear CoII complex, [Co2(C12H21N2Si)2Cl2], an inversion center is located at the mid-point between the two Co atoms in the dimeric molecule. The bidentate N-silylated anilide ligand coordinates the CoII atom in an N,N'-chelating mode and provides the anilide N atom as a bridge to link two CoII atoms. The two ends of the N-Si-N chelating unit exhibit different affinities for the metal atom. The Co-Nanilide bond is 2.031 (6) Å and Co-Namino bond is 2.214 (6) Å. The four-coordinate Co atom presents a distorted tetrahedral geometry, while the dimeric aggregation exhibits a (CoN)2 rhombus core with 1.998 (6) Å as the shortest sides and shows a ladder structure composed of Co, N and Si atoms.

Comment top

Metal amides are important substitutes for cyclopentadienyl derivatives and are found to have valuable applications in various industrial and biological processes (Holm et al., 1996; Kempe, 2000). Group 4 metal amides supported with N-silylated anilido ligands are active catalysts for olefin polymerization reactions (Gibson et al., 1998; Hill & Hitchcock, 2002). Recently, a class of monoionic N-silylated anilido ligands bearing a pendant amino group were the subject of focus presuming that the empty d-orbitals on silicon would interact with the lone-pair electrons on the p-orbital of nitrogen center through a d—pπ interaction throughout the N—Si—N motif. Analogous compounds with different metals including Zn (Schumann et al., 2000), Zr (Chen, 2009) and Fe (Chen, 2008) have been synthesized. In addition, a group of zirconium amides with a similar ligand were reported showing good performance in ethylene polymerization reactions (Yuan et al., 2010). In view of the importance of these compounds, the synthesis and crystal structure of a new cobalt(II) anilido complex, (I), is reported.

The title compound, [Co(C12H21N2Si)Cl]2, is a binuclear CoII complex with an inversion center located at the mid-point between two Co atoms in the dimeric molecule (Fig. 1). Each Co(II) atom is bound to three nitrogen atoms and one chlorine atom, resulting in a distorted tetrahedral geomety at the metal center. The bidentate N-silylated anilide ligand coordinates a metal center in an N,N'-chelating mode and provides the anilido nitrogen as a bridge to link the two Co atoms. The two ends of the N—Si—N chelating unit exhibit different affinities for the metal center. The Co—Co distance is 2.5682 (19) Å, which is similar to 2.583 (1) Å in [Co{N(SiMe3)2}2]2 and 2.566 (3) Å in [Co(NPh2)2]2 (Murray & Power, 1984; Hope et al., 1985). The N—Si—N angle is constrained to be 98.8 (3)°. The Co—Nanilido bond is 2.031 (2) Å and Co—Namino bond is 2.214 (6) Å. The four-coordinate Co atom presents a distorted tetrahedral geometry while the dimeric aggregation exhibits a (CoN)2 rhombus core with 2.0 Å sides and shows a ladder structure composed of Co, N and Si atoms.

Related literature top

For related reviews of metal amides, see: Holm et al. (1996); Kempe (2000). For catalytic applications of related N-silylated analido group 4 metal compounds towards olefin polymerization, see: Gibson et al. (1998); Hill & Hitchcock (2002); Yuan et al. (2010). For related organometallic compounds supported by analogous analido ligands, see: Schumann et al. (2000); Chen (2008, 2009). For related cobalt amides, see: Murray & Power (1984); Hope et al. (1985).

Experimental top

The title compound was prepared by a one-pot reaction of LiBun, N-[(diethylamino)dimethylsilyl]aniline and CoCl2 as follows: A solution of LiBun (1.6 M, 1.75 ml, 2.8 mmol) in hexane was slowly added into a solution of N-[(diethylamino)dimethylsilyl]aniline (0.62 g, 2.8 mmol) in Et2O (20 ml) at 273 K by syringe. The mixture was stirred at room temperature for two hours and then added to a stirring suspension of CoCl2 (0.37 g, 2.8 mmol) in Et2O (20 ml) at 273 K. The resulting mixture was stirred at room temperature for 8 h. Then all the volatiles were removed under vacuum. The residue was extracted with toluene (25 ml). The filtrate was concentrated and suitable green single-crystals of the title compound were obtained by recrystallization in toluene. (yield 0.25 g, 28%). Anal. Calc. for C24H42Cl2Co2N4Si2: C, 45.64; H, 6.70; N, 8.87%. Found: C, 45.48; H, 6.65; N, 9.05%.

Refinement top

All of the H atoms were placed in their geometrically idealized positions and constrained to ride on their parent atoms with calculated positions and then refined using the riding model with Atom—H lengths of 0.93Å (CH), 0.97 Å (CH2) or 0.96Å (CH3). Isotropic displacement parameters for these atoms were set to 1.2 (CH, CH2) or 1.5 (CH3) times Ueq of the parent atom. The N—Si—N angle is constrained to be 98.8 (3)°.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. An inversion center is located at the mid-point between two Co atoms in the dimeric molecule. H atoms have been omitted for clarity.
\ Bis[µ-N-(diethylamino-κN)dimethylsilylanilido- κ2N:N]bis[chloridocobalt(II)] top
Crystal data top
[Co2(C12H21N2Si)2Cl2]F(000) = 1320
Mr = 631.56Dx = 1.371 Mg m3
Orthorhombic, PccnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ab 2acCell parameters from 3365 reflections
a = 12.180 (1) Åθ = 2.3–26.3°
b = 15.6753 (13) ŵ = 1.36 mm1
c = 16.0235 (13) ÅT = 293 K
V = 3059.3 (4) Å3Block, green
Z = 40.20 × 0.15 × 0.10 mm
Data collection top
Bruker SMART area-detector
diffractometer
2885 independent reflections
Radiation source: fine-focus sealed tube1795 reflections with I > 2σ(I)
graphiteRint = 0.093
Detector resolution: 7.9 pixels mm-1θmax = 25.6°, θmin = 2.1°
φ and ω scanh = 1414
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
k = 1719
Tmin = 0.773, Tmax = 0.876l = 1319
16361 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.072Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.227H-atom parameters constrained
S = 1.17 w = 1/[σ2(Fo2) + (0.0945P)2 + 13.3754P]
where P = (Fo2 + 2Fc2)/3
2885 reflections(Δ/σ)max < 0.001
154 parametersΔρmax = 1.97 e Å3
48 restraintsΔρmin = 0.51 e Å3
Crystal data top
[Co2(C12H21N2Si)2Cl2]V = 3059.3 (4) Å3
Mr = 631.56Z = 4
Orthorhombic, PccnMo Kα radiation
a = 12.180 (1) ŵ = 1.36 mm1
b = 15.6753 (13) ÅT = 293 K
c = 16.0235 (13) Å0.20 × 0.15 × 0.10 mm
Data collection top
Bruker SMART area-detector
diffractometer
2885 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1795 reflections with I > 2σ(I)
Tmin = 0.773, Tmax = 0.876Rint = 0.093
16361 measured reflectionsθmax = 25.6°
Refinement top
R[F2 > 2σ(F2)] = 0.072 w = 1/[σ2(Fo2) + (0.0945P)2 + 13.3754P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.227Δρmax = 1.97 e Å3
S = 1.17Δρmin = 0.51 e Å3
2885 reflectionsAbsolute structure: ?
154 parametersFlack parameter: ?
48 restraintsRogers parameter: ?
H-atom parameters constrained
Special details top

Experimental. MS (EI, 70 eV): m/z 632 [M]+.

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 (Å2) top
xyzUiso*/Ueq
Co10.55911 (8)0.48017 (6)0.43654 (6)0.0307 (3)
Si10.37762 (17)0.55954 (13)0.36970 (13)0.0356 (5)
Cl10.71974 (18)0.48946 (17)0.37397 (16)0.0617 (7)
N10.4612 (5)0.5831 (4)0.4563 (4)0.0328 (14)
N20.4195 (5)0.4511 (4)0.3528 (4)0.0303 (13)
C10.4863 (7)0.6714 (5)0.4684 (6)0.0472 (14)
C20.5770 (8)0.7089 (5)0.4330 (6)0.0534 (14)
H2A0.62300.67700.39880.064*
C30.6006 (9)0.7956 (6)0.4482 (6)0.0601 (15)
H3A0.66270.82070.42500.072*
C40.5322 (9)0.8417 (6)0.4969 (6)0.0620 (15)
H4A0.54740.89910.50590.074*
C50.4443 (8)0.8075 (6)0.5320 (7)0.0607 (15)
H5A0.39970.84080.56600.073*
C60.4175 (8)0.7207 (5)0.5182 (6)0.0536 (14)
H6A0.35490.69710.54200.064*
C70.2306 (8)0.5722 (7)0.3939 (8)0.079 (4)
H7A0.19630.60640.35160.119*
H7B0.22260.59960.44720.119*
H7C0.19620.51710.39570.119*
C80.4136 (10)0.6277 (6)0.2788 (6)0.073 (3)
H8A0.34840.65410.25730.109*
H8B0.44650.59320.23610.109*
H8C0.46460.67100.29600.109*
C90.4621 (7)0.4311 (5)0.2680 (5)0.0456 (18)
H9A0.51530.47420.25230.055*
H9B0.40190.43380.22850.055*
C100.5154 (8)0.3447 (6)0.2621 (6)0.057 (2)
H10A0.54070.33550.20600.085*
H10B0.46290.30140.27650.085*
H10C0.57650.34200.29980.085*
C110.3406 (7)0.3856 (5)0.3839 (5)0.0468 (19)
H11A0.31190.40420.43740.056*
H11B0.38000.33260.39300.056*
C120.2441 (8)0.3683 (6)0.3251 (6)0.056 (2)
H12A0.19710.32570.34920.083*
H12B0.27140.34830.27240.083*
H12C0.20320.42000.31690.083*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co10.0344 (5)0.0272 (5)0.0305 (6)0.0036 (4)0.0043 (4)0.0027 (4)
Si10.0450 (12)0.0250 (11)0.0369 (12)0.0043 (9)0.0108 (10)0.0007 (9)
Cl10.0470 (12)0.0727 (17)0.0655 (15)0.0029 (11)0.0246 (11)0.0051 (12)
N10.040 (3)0.023 (3)0.036 (4)0.005 (2)0.006 (3)0.001 (2)
N20.045 (3)0.018 (3)0.028 (3)0.000 (2)0.004 (3)0.002 (2)
C10.064 (3)0.024 (3)0.053 (3)0.001 (2)0.020 (3)0.003 (2)
C20.069 (3)0.030 (3)0.061 (3)0.004 (2)0.019 (3)0.006 (2)
C30.077 (3)0.035 (3)0.068 (3)0.006 (3)0.022 (3)0.007 (3)
C40.082 (3)0.035 (3)0.069 (3)0.001 (3)0.025 (3)0.002 (2)
C50.081 (3)0.036 (3)0.066 (3)0.007 (3)0.022 (3)0.003 (2)
C60.072 (3)0.030 (3)0.059 (3)0.005 (2)0.020 (3)0.001 (2)
C70.058 (6)0.079 (8)0.100 (9)0.027 (6)0.024 (6)0.027 (7)
C80.139 (10)0.036 (5)0.042 (5)0.014 (6)0.035 (6)0.010 (4)
C90.060 (5)0.043 (4)0.034 (4)0.003 (4)0.005 (3)0.001 (3)
C100.074 (5)0.051 (5)0.046 (4)0.004 (4)0.007 (4)0.011 (4)
C110.056 (4)0.036 (4)0.048 (4)0.008 (3)0.012 (4)0.006 (3)
C120.062 (4)0.043 (4)0.062 (5)0.014 (4)0.017 (4)0.007 (4)
Geometric parameters (Å, °) top
Co1—N1i1.998 (6)C5—C61.416 (12)
Co1—N12.031 (6)C5—H5A0.9300
Co1—Cl12.203 (2)C6—H6A0.9300
Co1—N22.214 (6)C7—H7A0.9600
Co1—Co1i2.5682 (19)C7—H7B0.9600
Co1—Si12.754 (2)C7—H7C0.9600
Si1—N11.760 (6)C8—H8A0.9600
Si1—N21.795 (6)C8—H8B0.9600
Si1—C71.843 (10)C8—H8C0.9600
Si1—C81.859 (9)C9—C101.505 (12)
N1—C11.431 (9)C9—H9A0.9700
N1—Co1i1.998 (6)C9—H9B0.9700
N2—C91.487 (10)C10—H10A0.9600
N2—C111.492 (10)C10—H10B0.9600
C1—C21.375 (13)C10—H10C0.9600
C1—C61.391 (13)C11—C121.531 (11)
C2—C31.410 (12)C11—H11A0.9700
C2—H2A0.9300C11—H11B0.9700
C3—C41.351 (14)C12—H12A0.9600
C3—H3A0.9300C12—H12B0.9600
C4—C51.323 (14)C12—H12C0.9600
C4—H4A0.9300
N1i—Co1—N1100.8 (2)C5—C4—C3121.9 (10)
N1i—Co1—Cl1122.26 (18)C5—C4—H4A119.1
N1—Co1—Cl1122.67 (19)C3—C4—H4A119.1
N1i—Co1—N2108.9 (2)C4—C5—C6120.6 (10)
N1—Co1—N278.9 (2)C4—C5—H5A119.7
Cl1—Co1—N2114.83 (18)C6—C5—H5A119.7
N1i—Co1—Co1i50.96 (17)C1—C6—C5119.0 (9)
N1—Co1—Co1i49.84 (17)C1—C6—H6A120.5
Cl1—Co1—Co1i147.37 (10)C5—C6—H6A120.5
N2—Co1—Co1i95.69 (16)Si1—C7—H7A109.5
N1i—Co1—Si1117.33 (18)Si1—C7—H7B109.5
N1—Co1—Si139.67 (17)H7A—C7—H7B109.5
Cl1—Co1—Si1120.40 (9)Si1—C7—H7C109.5
N2—Co1—Si140.57 (15)H7A—C7—H7C109.5
Co1i—Co1—Si175.44 (6)H7B—C7—H7C109.5
N1—Si1—N298.8 (3)Si1—C8—H8A109.5
N1—Si1—C7111.9 (4)Si1—C8—H8B109.5
N2—Si1—C7114.2 (4)H8A—C8—H8B109.5
N1—Si1—C8111.2 (4)Si1—C8—H8C109.5
N2—Si1—C8111.0 (4)H8A—C8—H8C109.5
C7—Si1—C8109.4 (6)H8B—C8—H8C109.5
N1—Si1—Co147.44 (19)N2—C9—C10113.5 (7)
N2—Si1—Co153.33 (19)N2—C9—H9A108.9
C7—Si1—Co1138.3 (4)C10—C9—H9A108.9
C8—Si1—Co1112.0 (4)N2—C9—H9B108.9
C1—N1—Si1115.7 (5)C10—C9—H9B108.9
C1—N1—Co1i112.9 (5)H9A—C9—H9B107.7
Si1—N1—Co1i120.1 (3)C9—C10—H10A109.5
C1—N1—Co1131.6 (5)C9—C10—H10B109.5
Si1—N1—Co192.9 (3)H10A—C10—H10B109.5
Co1i—N1—Co179.2 (2)C9—C10—H10C109.5
C9—N2—C11112.6 (6)H10A—C10—H10C109.5
C9—N2—Si1115.9 (5)H10B—C10—H10C109.5
C11—N2—Si1114.7 (5)N2—C11—C12114.2 (7)
C9—N2—Co1109.2 (5)N2—C11—H11A108.7
C11—N2—Co1115.7 (4)C12—C11—H11A108.7
Si1—N2—Co186.1 (2)N2—C11—H11B108.7
C2—C1—C6118.9 (8)C12—C11—H11B108.7
C2—C1—N1122.0 (8)H11A—C11—H11B107.6
C6—C1—N1119.2 (8)C11—C12—H12A109.5
C1—C2—C3120.4 (10)C11—C12—H12B109.5
C1—C2—H2A119.8H12A—C12—H12B109.5
C3—C2—H2A119.8C11—C12—H12C109.5
C4—C3—C2119.3 (10)H12A—C12—H12C109.5
C4—C3—H3A120.4H12B—C12—H12C109.5
C2—C3—H3A120.4
Symmetry codes: (i) −x+1, −y+1, −z+1.
Acknowledgements top

This work was sponsored by the Natural Science Foundation of China (20702029) and the Natural Science Foundation of Shanxi Province (2008011024).

references
References top

Bruker (2000). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Chen, J. (2008). Acta Cryst. E64, m938.

Chen, J. (2009). Acta Cryst. E65, m1307.

Gibson, V. C., Kimberley, B. S., White, A. J. P., Willianms, D. J. & Howard, P. (1998). Chem. Commun. pp. 313–314.

Hill, M. S. & Hitchcock, P. B. (2002). Organometallics, 21, 3258–3262.

Holm, R. H., Kenneppohl, P. & Solomon, E. I. (1996). Chem. Rev. 96, 2239–2314.

Hope, H., Olmstead, M. M., Murray, B. D. & Power, P. P. (1985). J. Am. Chem. Soc. 107, 712–713.

Kempe, R. (2000). Angew. Chem. Int. Ed. 39, 468–493.

Murray, B. D. & Power, P. P. (1984). Inorg. Chem. 23, 4584–4588.

Schumann, H., Gottfriedsen, J., Dechert, S. & Girgsdies, F. (2000). Z. Anorg. Allg. Chem. 626, 747–758.

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Yuan, S. F., Wei, X. H., Tong, H. B., Zhang, L. P., Liu, D. S. & Sun, W. H. (2010). Organometallics, 29, 2085–2092.