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Acta Cryst. (2009). E65, m680    [ doi:10.1107/S1600536809018364 ]

Dibromido[(tert-butylamino)dimethyl(piperidin-1-ylmethyl)silane-[kappa]2N,N']zinc(II)

V. P. Colquhoun and C. Strohmann

Abstract top

The title compound, [ZnBr2(C12H28N2Si)], is an example of a neutral coordination compound of a bidentate ligand to a metal centre with the Zn atom being coordinated by two Br and two N atoms, yielding a slightly distorted tetrahedral coordination environment.

Comment top

The title compound, the adduct of the silazane ligand and zinc bromide crystallized from acetonitrile in the monoclinic crystal system, space group P21/c. The H atom H1n was refined freely. It is connected to N1 with a bond length of 0.853 (21) Å which is in the expected range for N—H bonds. Additionally, H1N is forming a weak intermolecular hydrogen bond to Br1i (i: –x, –y + 1, –z + 1). The H1···Br1i distance (2.828 (22) Å) and the N1—H1N—Br1i angle (166.1 (20) Å) are in the typical ranges of such hydrogen bonds (Farrugia et al., 2001). With a value of 1.791 (2) Å, the Si—N bond length is in the upper range of other known systems and is very close to the sum of the covalent radii of silicon and nitrogen (1.86 Å) (Lerner et al., 2005; Herrmann et al., 1992). The bond lengths of 2.128 (2) Å for N1—Zn and 2.110 (2) Å for N2—Zn are similar to other reported dative zinc-nitrogen bonds (Mimoun et al., 1999). The structure of the title compound is a neutral coordination compound of a bidentate ligand and zinc(II) bromide forming a five-membered ring with a typical envelope conformation similar to other known metalla heterocycles (Strohmann et al. 2002, 2005, 2006; Strohmann & Schildbach 2002; Ott et al. 2008). The tip of the envelope is formed by the Si atom with a distance of 0.8312 (7) Å to a least-squares plane through Zn, N1, N2, C3 and Si. The title compound may be regarded as a comparative model structure for a deprotonation transition state as the silazane ligand can also be deprotonated by more reactive organozinc reagents. Thereby new metal silazane compounds are formed which themselves are interesting as deprotonation or alkylation reagents in organic synthesis.

Related literature top

For the synthesis and structure of cis-(2-amino-1,1-dimethylethylamine)dichloropalladium(II) ethanol hemisolvate, see: Farrugia et al. (2001); for niobium and tantalum complexes of silylamides, see Herrmann et al. (1992); for the synthesis and structure of tBu2Si═N-SiCltBu2, see Lerner et al. (2005); for syntheses, structures and properties of chiral zinc halide catalysts, see Mimoun et al. (1999); for the structure and reactivity of lithiated benzylsilanes, see Ott et al. (2008); for syntheses and structures of bis{[diphenyl(piperidinomethyl)silyl]methyl}cadmium and -magnesium, see Strohmann & Schildbach (2002). For a highly diastereomerically enriched, silyl-substituted alkyl lithium, see Strohmann et al. (2005). For the synthesis and structure of a monolithiated allylsilane and its related 1,3-dilithiated allylsilane, see Strohmann et al. (2006); for the synthesis and structure of a lithiated [(benzylsilyl)methyl]amine, see Strohmann et al. (2002).

Experimental top

To 0.38 g (1.7 mmol) dry zinc(II) bromide dissolved in 10 ml dry acetonitrile, 0.38 g (1.7 mmol) N-tert-butyl-1,1-dimethyl-1-(piperidin-1-ylmethyl)silanamine were added and stored at room temperature. After 24 h a colourless crystalline solid of the title compound suitable for single-crystal x-ray studies had formed.

Refinement top

The H atoms were refined in their ideal geometric positions using the riding model approximation with Uiso(H) = 1.5Ueq(C) for methyl H atoms and of Uiso(H) = 1.2Ueq(C) for all other H atoms except atom H1n (bonded to N1) which was refined freely.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Plot of the asymmetric unit of the title compound with displacement ellipsoids drawn at the 50% probability level.
Dibromido[(tert-butylamino)dimethyl(piperidin-1-ylmethyl)silane-\ κ2N,N']zinc(II) top
Crystal data top
[ZnBr2(C12H28N2Si)]F(000) = 912
Mr = 453.64Dx = 1.716 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 9282 reflections
a = 12.0284 (4) Åθ = 2.4–29.1°
b = 10.6505 (3) ŵ = 6.01 mm−1
c = 14.5633 (5) ÅT = 123 K
β = 109.752 (4)°Block, colourless
V = 1755.91 (10) Å30.40 × 0.20 × 0.20 mm
Z = 4
Data collection top
Oxford Diffraction Xcalibur S
diffractometer		2673 reflections with I > 2σ(I)
Radiation source: Enhance (Mo) X-ray SourceRint = 0.034
graphiteθmax = 26.0°, θmin = 2.4°
ω scansh = −14→14
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2006)		k = −13→13
Tmin = 0.698, Tmax = 1.000l = −17→17
17826 measured reflections1 standard reflections every 50 reflections
3440 independent reflections intensity decay: none
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)] = 0.020Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.035H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.012P)2]
where P = (Fo2 + 2Fc2)/3
3440 reflections(Δ/σ)max = 0.002
172 parametersΔρmax = 0.56 e Å−3
0 restraintsΔρmin = −0.43 e Å−3
Crystal data top
[ZnBr2(C12H28N2Si)]V = 1755.91 (10) Å3
Mr = 453.64Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.0284 (4) ŵ = 6.01 mm−1
b = 10.6505 (3) ÅT = 123 K
c = 14.5633 (5) Å0.40 × 0.20 × 0.20 mm
β = 109.752 (4)°
Data collection top
Oxford Diffraction Xcalibur S
diffractometer		2673 reflections with I > 2σ(I)
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2006)		Rint = 0.034
Tmin = 0.698, Tmax = 1.000θmax = 26.0°
17826 measured reflections1 standard reflections every 50 reflections
3440 independent reflections intensity decay: none
Refinement top
R[F2 > 2σ(F2)] = 0.020H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.035Δρmax = 0.56 e Å−3
S = 1.04Δρmin = −0.43 e Å−3
3440 reflectionsAbsolute structure: ?
172 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. CrysAlis RED, Oxford Diffraction Ltd. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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
Br10.034333 (19)0.34304 (2)0.425367 (16)0.02008 (7)
Br20.36966 (2)0.21717 (2)0.546307 (18)0.02735 (7)
C10.43775 (18)0.4264 (2)0.80678 (16)0.0251 (6)
H1A0.45370.36360.76370.038*
H1B0.43970.38630.86790.038*
H1C0.49800.49240.82090.038*
C20.2739 (2)0.6418 (2)0.80978 (17)0.0296 (6)
H2A0.34180.69690.81750.044*
H2B0.27030.62070.87420.044*
H2C0.20110.68500.77140.044*
C30.16458 (18)0.3884 (2)0.74214 (15)0.0168 (5)
H3A0.17200.36540.80980.020*
H3B0.08940.43490.71380.020*
C40.03415 (18)0.2212 (2)0.65665 (15)0.0178 (5)
H4A−0.02020.28160.61170.021*
H4B0.01160.21480.71590.021*
C50.0203 (2)0.0941 (2)0.60787 (16)0.0234 (6)
H5A0.03800.10130.54650.028*
H5B−0.06250.06560.59120.028*
C60.10247 (19)−0.0026 (2)0.67401 (17)0.0246 (6)
H6A0.0809−0.01590.73310.029*
H6B0.0954−0.08370.63940.029*
C70.22848 (19)0.0459 (2)0.70248 (17)0.0215 (6)
H7A0.2824−0.01320.74900.026*
H7B0.25220.05040.64370.026*
C80.23979 (19)0.1747 (2)0.74873 (15)0.0176 (5)
H8A0.22320.16800.81070.021*
H8B0.32220.20430.76460.021*
C90.32287 (19)0.5977 (2)0.56932 (16)0.0198 (5)
C100.2842 (2)0.5668 (2)0.46137 (16)0.0271 (6)
H10A0.30380.47930.45290.041*
H10B0.32500.62230.42950.041*
H10C0.19870.57900.43200.041*
C110.2945 (2)0.7356 (2)0.58157 (17)0.0275 (6)
H11A0.20900.74890.55330.041*
H11B0.33490.78930.54810.041*
H11C0.32140.75690.65110.041*
C120.45464 (18)0.5736 (2)0.61593 (17)0.0283 (6)
H12A0.48150.60380.68350.042*
H12B0.49730.61820.57920.042*
H12C0.47010.48330.61520.042*
H1N0.1857 (18)0.544 (2)0.5961 (15)0.024 (7)*
N10.25541 (17)0.51356 (18)0.61717 (13)0.0169 (5)
N20.15788 (14)0.26976 (16)0.68447 (12)0.0126 (4)
Si0.29025 (5)0.49627 (6)0.74618 (5)0.01692 (15)
Zn0.20862 (2)0.32732 (2)0.565755 (18)0.01447 (7)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.01765 (13)0.02519 (15)0.01490 (13)−0.00001 (11)0.00222 (10)0.00006 (11)
Br20.02695 (14)0.02831 (15)0.03360 (15)0.01126 (12)0.01917 (12)0.00731 (13)
C10.0218 (14)0.0238 (15)0.0254 (15)−0.0039 (11)0.0025 (12)0.0022 (12)
C20.0291 (15)0.0299 (16)0.0306 (16)−0.0056 (12)0.0112 (13)−0.0105 (12)
C30.0175 (13)0.0198 (14)0.0152 (13)0.0025 (11)0.0081 (11)−0.0013 (11)
C40.0144 (12)0.0245 (14)0.0156 (13)−0.0032 (11)0.0062 (11)0.0008 (11)
C50.0199 (14)0.0276 (16)0.0214 (14)−0.0114 (12)0.0052 (12)−0.0033 (12)
C60.0311 (15)0.0174 (14)0.0265 (15)−0.0076 (12)0.0115 (13)−0.0007 (11)
C70.0254 (14)0.0150 (14)0.0252 (14)0.0025 (11)0.0099 (12)0.0047 (11)
C80.0152 (12)0.0183 (14)0.0175 (13)0.0015 (11)0.0030 (10)0.0054 (11)
C90.0178 (13)0.0194 (14)0.0220 (14)−0.0037 (11)0.0065 (11)0.0027 (11)
C100.0347 (16)0.0228 (15)0.0268 (15)−0.0032 (12)0.0144 (13)0.0059 (12)
C110.0279 (15)0.0201 (15)0.0353 (16)−0.0060 (12)0.0118 (13)−0.0006 (12)
C120.0176 (14)0.0345 (17)0.0342 (16)−0.0016 (12)0.0106 (13)0.0053 (12)
N10.0135 (11)0.0187 (12)0.0190 (11)−0.0038 (9)0.0064 (10)−0.0013 (9)
N20.0101 (10)0.0145 (11)0.0121 (10)−0.0007 (8)0.0023 (8)−0.0006 (8)
Si0.0168 (4)0.0177 (4)0.0158 (4)−0.0018 (3)0.0049 (3)−0.0033 (3)
Zn0.01415 (14)0.01651 (15)0.01335 (15)0.00006 (12)0.00541 (12)−0.00062 (12)
Geometric parameters (Å, °) top
Br1—Zn2.3887 (4)C7—C81.513 (3)
Br2—Zn2.3622 (3)C7—H7A0.9900
C1—Si1.850 (2)C7—H7B0.9900
C1—H1A0.9800C8—N21.500 (2)
C1—H1B0.9800C8—H8A0.9900
C1—H1C0.9800C8—H8B0.9900
C2—Si1.850 (2)C9—C101.517 (3)
C2—H2A0.9800C9—C121.520 (3)
C2—H2B0.9800C9—N11.526 (3)
C2—H2C0.9800C9—C111.532 (3)
C3—N21.504 (3)C10—H10A0.9800
C3—Si1.884 (2)C10—H10B0.9800
C3—H3A0.9900C10—H10C0.9800
C3—H3B0.9900C11—H11A0.9800
C4—N21.496 (2)C11—H11B0.9800
C4—C51.512 (3)C11—H11C0.9800
C4—H4A0.9900C12—H12A0.9800
C4—H4B0.9900C12—H12B0.9800
C5—C61.524 (3)C12—H12C0.9800
C5—H5A0.9900N1—Si1.7909 (19)
C5—H5B0.9900N1—Zn2.1276 (19)
C6—C71.520 (3)N1—H1N0.85 (2)
C6—H6A0.9900N2—Zn2.1096 (16)
C6—H6B0.9900
Si—C1—H1A109.5C10—C9—C12109.55 (19)
Si—C1—H1B109.5C10—C9—N1108.78 (18)
H1A—C1—H1B109.5C12—C9—N1109.40 (18)
Si—C1—H1C109.5C10—C9—C11109.01 (19)
H1A—C1—H1C109.5C12—C9—C11110.46 (19)
H1B—C1—H1C109.5N1—C9—C11109.62 (17)
Si—C2—H2A109.5C9—C10—H10A109.5
Si—C2—H2B109.5C9—C10—H10B109.5
H2A—C2—H2B109.5H10A—C10—H10B109.5
Si—C2—H2C109.5C9—C10—H10C109.5
H2A—C2—H2C109.5H10A—C10—H10C109.5
H2B—C2—H2C109.5H10B—C10—H10C109.5
N2—C3—Si114.88 (13)C9—C11—H11A109.5
N2—C3—H3A108.5C9—C11—H11B109.5
Si—C3—H3A108.5H11A—C11—H11B109.5
N2—C3—H3B108.5C9—C11—H11C109.5
Si—C3—H3B108.5H11A—C11—H11C109.5
H3A—C3—H3B107.5H11B—C11—H11C109.5
N2—C4—C5112.22 (17)C9—C12—H12A109.5
N2—C4—H4A109.2C9—C12—H12B109.5
C5—C4—H4A109.2H12A—C12—H12B109.5
N2—C4—H4B109.2C9—C12—H12C109.5
C5—C4—H4B109.2H12A—C12—H12C109.5
H4A—C4—H4B107.9H12B—C12—H12C109.5
C4—C5—C6111.29 (19)C9—N1—Si124.57 (15)
C4—C5—H5A109.4C9—N1—Zn120.32 (13)
C6—C5—H5A109.4Si—N1—Zn102.34 (9)
C4—C5—H5B109.4C9—N1—H1N102.9 (15)
C6—C5—H5B109.4Si—N1—H1N105.6 (14)
H5A—C5—H5B108.0Zn—N1—H1N96.6 (16)
C7—C6—C5108.47 (18)C4—N2—C8108.62 (16)
C7—C6—H6A110.0C4—N2—C3107.58 (15)
C5—C6—H6A110.0C8—N2—C3108.60 (16)
C7—C6—H6B110.0C4—N2—Zn114.54 (13)
C5—C6—H6B110.0C8—N2—Zn113.37 (12)
H6A—C6—H6B108.4C3—N2—Zn103.75 (12)
C8—C7—C6111.13 (18)N1—Si—C1112.86 (10)
C8—C7—H7A109.4N1—Si—C2114.35 (10)
C6—C7—H7A109.4C1—Si—C2110.18 (11)
C8—C7—H7B109.4N1—Si—C397.42 (9)
C6—C7—H7B109.4C1—Si—C3113.57 (10)
H7A—C7—H7B108.0C2—Si—C3107.88 (10)
N2—C8—C7113.13 (18)N2—Zn—N195.62 (7)
N2—C8—H8A109.0N2—Zn—Br2115.47 (5)
C7—C8—H8A109.0N1—Zn—Br2112.03 (5)
N2—C8—H8B109.0N2—Zn—Br1107.97 (5)
C7—C8—H8B109.0N1—Zn—Br1106.69 (5)
H8A—C8—H8B107.8Br2—Zn—Br1116.759 (13)
Acknowledgements top

This work was supported by the Deutsche Forschungsgemeinschaft. The authors furthermore acknowledge Wacker Chemie AG and Chemetall for providing special chemicals.

references
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