Acta Crystallographica Section E: Structure Reports Online

Acta Crystallogr Sect E Struct Rep Online. 65(Pt 8): m888-m888

Dibromidotris(dimethylamine)magnesium(II)

Hannes Vitzea, Hans-Wolfram Lernera, Michael Boltea*

a. Institut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany

Correspondence e-mail: bolte@chemie.uni-frankfurt.de

© Vitze et al. 2009

DOI: 10.1107/S1600536809024702

Published online: 08 July 2009

Abstract

The Mg centre in the title compound, [MgBr₂(C₂H₇N)₃], is pentacoordinated in a trigonal-bipyramidal mode with the two Br atoms in axial positions and the N atoms of the dimethylamine ligands in equatorial positions. The MgII centre is located on a crystallographic twofold rotation axis. The crystal structure is stabilized by N—H⋯Br hydrogen bonds. The N atom and H atoms of one dimethylamine ligand are disordered over two equally occupied positions.

Related literature

The solid-state structures of Mg–Br compounds feature coordination numbers of the Mg center from four as in [MgBr(SitBu₃)(THF)]₂ (Lerner et al., 2003 ▶) to six as in [MgBr₂(THF)₄] (Lorbach et al., 2007 ▶).

Experimental

Crystal data

[MgBr₂(C₂H₇N)₃]

M r = 319.39

Hexagonal,

a = 9.0951 (7) Å

c = 14.4544 (12) Å

V = 1035.49 (14) Å³

Z = 3

Mo Kα radiation

μ = 5.88 mm⁻¹

T = 173 K

0.25 × 0.25 × 0.23 mm

Data collection

Stoe IPDSII two-circle diffractometer

Absorption correction: multi-scan (MULABS; Spek, 2003 ▶; Blessing, 1995 ▶) T min = 0.321, T max = 0.345 (expected range = 0.241–0.258)

5279 measured reflections

1285 independent reflections

1223 reflections with I > 2σ(I)

R int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.022

wR(F ²) = 0.049

S = 0.96

1285 reflections

61 parameters

H-atom parameters constrained

Δρmax = 0.25 e Å⁻³

Δρmin = −0.34 e Å⁻³

Absolute structure: Flack (1983 ▶), 517 Friedel pairs

Flack parameter: −0.012 (17)

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

See full table Table 1. Hydrogen-bond geometry (Å, °)

Supplementary Material

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Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: AT2830).

supplementary crystallographic information

Comment

The solid-state structures of Mg—Br compounds feature coordination numbers of the Mg center from four as in [MgBr(SitBu₃)(THF)]₂ (Lerner et al., 2003) to six as in [MgBr₂(THF)₄] (Lorbach et al., 2007). Most of the Mg—Br compounds possess an octahedral coordination sphere which surrounds the Mg cation whereas only a few compounds are found in the Cambridge Structural Database with four- and five-coordinated Mg centers. We report here the X-ray crystal structure analysis of [MgBr₂(NHMe₂)₃], the adduct of MgBr₂ with three dimethylamine molecules, which was obtained as a by-product from the reaction of C₆F₅MgBr with BrB(NMe₂) in Et₂O.

Experimental

At 273 K, BrB(NMe₂) (3.5 g, 19.6 mmol) was added to a solution of C₆F₅MgBr in Et₂O which was obtained from C₆F₅Br (4,6 g, 18.6 mmol) and Mg (0.5 g, 21.0 mmol) in 25 ml Et₂O. After distillation of C₆F₅B(NMe₂) (yield 73%) colourless crystals of the title compound were obtained as distillation residue.

Refinement

H atoms were geometrically positioned and refined using a riding model with fixed individual displacement parameters [Uiso(H) = 1.2 Ueq(N) or Uiso(H) = 1.5 Ueq(C)] and with N—H = 0.93Å and C—H = 0.98 Å. The N atom and H atoms of one dimethylamine ligand are disordered over two equally occupied positions.

Figures

Fig. 1.View larger versionFig. 1. Perspective view of the title compound with the atom numbering scheme; displacement ellipsoids are at the 50% probability level; H atoms are drawn as small spheres of arbitrary radii. Only one of the two disordered moieties is shown.

Crystal data

See full table

Data collection

See full table

Refinement

See full table

Special details

See full table

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²)

See full table

Atomic displacement parameters (Å²)

See full table

Geometric parameters (Å, °)

See full table

Symmetry codes: (i) y, x, −z+1.

Hydrogen-bond geometry (Å, °)

See full table

Symmetry codes: (ii) −x+1, −x+y, −z+2/3; (iii) −x+y+1, −x+1, z+1/3.

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References

Blessing, R. H. (1995). Acta Cryst. A51, 33–38.

Flack, H. D. (1983). Acta Cryst. A39, 876–881.

Lerner, H.-W., Scholz, S., Bolte, M., Wiberg, N., Nöth, H. & Krossing, I. (2003). Eur. J. Inorg. Chem. pp. 666–670.

Lorbach, A., Lerner, H.-W. & Bolte, M. (2007). Acta Cryst. C63, m174–m176.

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

Spek, A. L. (2003). J. Appl. Cryst.36, 7–13.

Stoe & Cie (2001). X-AREA Stoe & Cie, Darmstadt, Germany.

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Fig. 1.

Perspective view of the title compound with the atom numbering scheme; displacement ellipsoids are at the 50% probability level; H atoms are drawn as small spheres of arbitrary radii. Only one of the two disordered moieties is shown.

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[MgBr₂(C₂H₇N)₃] | Dx = 1.537 Mg m⁻³
Mr = 319.39 | Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P3₂21 | Cell parameters from 5127 reflections
Hall symbol: P 32 2" | θ = 3.8–25.6°
a = 9.0951 (7) Å | µ = 5.88 mm⁻¹
c = 14.4544 (12) Å | T = 173 K
V = 1035.49 (14) Å³ | Block, colourless
Z = 3 | 0.25 × 0.25 × 0.23 mm
F(000) = 480 |

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Stoe IPDSII two-circle diffractometer | 1285 independent reflections
Radiation source: fine-focus sealed tube | 1223 reflections with I > 2σ(I)
graphite | Rint = 0.037
ω scans | θmax = 25.6°, θmin = 3.8°
Absorption correction: multi-scan (MULABS; Spek, 2003; Blessing, 1995) | h = −11→8
Tmin = 0.321, Tmax = 0.345 | k = −7→11
5279 measured reflections | l = −17→17

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Refinement on F² | Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full | H-atom parameters constrained
R[F² > 2σ(F²)] = 0.022 | w = 1/[σ²(Fo²) + (0.0277P)² + 0.2606P] where P = (Fo² + 2Fc²)/3
wR(F²) = 0.049 | (Δ/σ)max = 0.001
S = 0.96 | Δρmax = 0.25 e Å⁻³
1285 reflections | Δρmin = −0.33 e Å⁻³
61 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc²λ³/sin(2θ)]-1/4
0 restraints | Extinction coefficient: 0.0106 (8)
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 517 Friedel pairs
Secondary atom site location: difference Fourier map | Flack parameter: −0.012 (17)

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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.

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| x | y | z | Uiso*/Ueq | Occ. (<1)
Br1 | 0.39287 (4) | 0.37977 (4) | 0.318621 (17) | 0.03405 (12) |
Mg1 | 0.41479 (13) | 0.41479 (13) | 0.5000 | 0.0231 (3) |
N1 | 0.4463 (3) | 0.1927 (3) | 0.50042 (15) | 0.0301 (5) |
H1 | 0.4887 | 0.1897 | 0.4423 | 0.036* |
C1 | 0.5661 (5) | 0.1872 (5) | 0.5683 (2) | 0.0441 (9) |
H1A | 0.6768 | 0.2910 | 0.5630 | 0.066* |
H1B | 0.5789 | 0.0883 | 0.5556 | 0.066* |
H1C | 0.5217 | 0.1787 | 0.6310 | 0.066* |
C2 | 0.2791 (5) | 0.0368 (4) | 0.5070 (3) | 0.0474 (9) |
H2A | 0.2012 | 0.0419 | 0.4620 | 0.071* |
H2B | 0.2334 | 0.0270 | 0.5695 | 0.071* |
H2C | 0.2916 | −0.0621 | 0.4939 | 0.071* |
N2 | 0.6685 (6) | 0.6265 (6) | 0.5188 (3) | 0.0293 (12) | 0.50
H2 | 0.7183 | 0.5896 | 0.5623 | 0.035* | 0.50
C3 | 0.6750 (5) | 0.7809 (4) | 0.5616 (2) | 0.0444 (8) |
H3A | 0.7933 | 0.8716 | 0.5684 | 0.067* | 0.50
H3B | 0.6206 | 0.7508 | 0.6226 | 0.067* | 0.50
H3C | 0.6143 | 0.8201 | 0.5218 | 0.067* | 0.50
H3D | 0.7715 | 0.8920 | 0.5457 | 0.067* | 0.50
H3E | 0.5785 | 0.7940 | 0.5803 | 0.067* | 0.50
H3F | 0.7063 | 0.7309 | 0.6125 | 0.067* | 0.50

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| U ¹¹ | U ²² | U ³³ | U ¹² | U ¹³ | U ²³
Br1 | 0.0453 (2) | 0.04152 (19) | 0.02015 (14) | 0.02533 (16) | 0.00289 (12) | −0.00057 (12)
Mg1 | 0.0233 (5) | 0.0233 (5) | 0.0200 (5) | 0.0096 (6) | 0.0012 (2) | −0.0012 (2)
N1 | 0.0368 (15) | 0.0336 (14) | 0.0232 (12) | 0.0199 (12) | 0.0007 (12) | −0.0026 (11)
C1 | 0.055 (2) | 0.057 (2) | 0.0385 (17) | 0.041 (2) | −0.0087 (17) | −0.0075 (17)
C2 | 0.048 (2) | 0.0276 (17) | 0.057 (2) | 0.0121 (16) | 0.0043 (18) | −0.0044 (15)
N2 | 0.027 (2) | 0.027 (3) | 0.028 (3) | 0.010 (2) | −0.0027 (19) | 0.005 (2)
C3 | 0.054 (2) | 0.0249 (16) | 0.0425 (18) | 0.0111 (16) | −0.0098 (17) | −0.0037 (14)

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Br1—Mg1 | 2.6365 (4) | C2—H2B | 0.9800
Mg1—N2 | 2.159 (5) | C2—H2C | 0.9800
Mg1—N2i | 2.159 (5) | N2—N2i | 0.856 (9)
Mg1—N1 | 2.177 (3) | N2—C3i | 1.463 (6)
Mg1—N1i | 2.177 (3) | N2—C3 | 1.508 (6)
Mg1—Br1i | 2.6365 (4) | N2—H2 | 0.9300
N1—C2 | 1.475 (4) | C3—N2i | 1.463 (6)
N1—C1 | 1.486 (4) | C3—H3A | 0.9800
N1—H1 | 0.9300 | C3—H3B | 0.9800
C1—H1A | 0.9800 | C3—H3C | 0.9800
C1—H1B | 0.9800 | C3—H3D | 0.9788
C1—H1C | 0.9800 | C3—H3E | 0.9803
C2—H2A | 0.9800 | C3—H3F | 0.9780
N2—Mg1—N2i | 22.9 (2) | C3i—N2—C3 | 110.5 (4)
N2—Mg1—N1 | 104.45 (16) | N2i—N2—Mg1 | 78.57 (12)
N2i—Mg1—N1 | 122.07 (17) | C3i—N2—Mg1 | 116.3 (3)
N2—Mg1—N1i | 122.07 (17) | C3—N2—Mg1 | 114.1 (3)
N2i—Mg1—N1i | 104.45 (16) | N2i—N2—H2 | 175.2
N1—Mg1—N1i | 133.08 (16) | C3i—N2—H2 | 104.6
N2—Mg1—Br1i | 88.69 (13) | C3—N2—H2 | 105.1
N2i—Mg1—Br1i | 102.44 (14) | Mg1—N2—H2 | 105.0
N1—Mg1—Br1i | 89.66 (6) | N2i—C3—H3A | 119.2
N1i—Mg1—Br1i | 85.86 (6) | N2—C3—H3A | 109.9
N2—Mg1—Br1 | 102.44 (14) | N2i—C3—H3B | 125.9
N2i—Mg1—Br1 | 88.69 (13) | N2—C3—H3B | 109.2
N1—Mg1—Br1 | 85.86 (6) | H3A—C3—H3B | 109.5
N1i—Mg1—Br1 | 89.66 (6) | N2i—C3—H3C | 76.1
Br1i—Mg1—Br1 | 168.72 (5) | N2—C3—H3C | 109.3
C2—N1—C1 | 110.2 (3) | H3A—C3—H3C | 109.5
C2—N1—Mg1 | 110.0 (2) | H3B—C3—H3C | 109.5
C1—N1—Mg1 | 118.2 (2) | N2i—C3—H3D | 109.6
C2—N1—H1 | 105.9 | N2—C3—H3D | 117.5
C1—N1—H1 | 105.9 | H3B—C3—H3D | 124.5
Mg1—N1—H1 | 105.9 | H3C—C3—H3D | 82.1
N1—C1—H1A | 109.5 | N2i—C3—H3E | 109.2
N1—C1—H1B | 109.5 | N2—C3—H3E | 127.2
H1A—C1—H1B | 109.5 | H3A—C3—H3E | 122.9
N1—C1—H1C | 109.5 | H3B—C3—H3E | 55.2
H1A—C1—H1C | 109.5 | H3C—C3—H3E | 54.3
H1B—C1—H1C | 109.5 | H3D—C3—H3E | 109.5
N1—C2—H2A | 109.5 | N2i—C3—H3F | 109.2
N1—C2—H2B | 109.5 | N2—C3—H3F | 76.2
H2A—C2—H2B | 109.5 | H3A—C3—H3F | 82.1
N1—C2—H2C | 109.5 | H3B—C3—H3F | 54.4
H2A—C2—H2C | 109.5 | H3C—C3—H3F | 163.4
H2B—C2—H2C | 109.5 | H3D—C3—H3F | 109.7
N2i—N2—C3i | 76.2 (6) | H3E—C3—H3F | 109.6
N2i—N2—C3 | 70.4 (6) |  |
N2—Mg1—N1—C2 | 168.6 (2) | Br1—Mg1—N2—N2i | 54.3 (8)
N2i—Mg1—N1—C2 | −175.4 (2) | N2i—Mg1—N2—C3i | −68.2 (7)
N1i—Mg1—N1—C2 | −3.95 (19) | N1—Mg1—N2—C3i | 75.0 (3)
Br1i—Mg1—N1—C2 | 80.0 (2) | N1i—Mg1—N2—C3i | −111.4 (3)
Br1—Mg1—N1—C2 | −89.6 (2) | Br1i—Mg1—N2—C3i | 164.3 (3)
N2—Mg1—N1—C1 | 40.9 (3) | Br1—Mg1—N2—C3i | −13.9 (4)
N2i—Mg1—N1—C1 | 56.8 (3) | N2i—Mg1—N2—C3 | 62.2 (7)
N1i—Mg1—N1—C1 | −131.7 (2) | N1—Mg1—N2—C3 | −154.6 (3)
Br1i—Mg1—N1—C1 | −47.7 (2) | N1i—Mg1—N2—C3 | 19.0 (4)
Br1—Mg1—N1—C1 | 142.7 (2) | Br1i—Mg1—N2—C3 | −65.3 (3)
N1—Mg1—N2—N2i | 143.2 (7) | Br1—Mg1—N2—C3 | 116.5 (3)
N1i—Mg1—N2—N2i | −43.2 (8) | C3i—N2—C3—N2i | 66.2 (5)
Br1i—Mg1—N2—N2i | −127.5 (7) | Mg1—N2—C3—N2i | −67.0 (4)

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D—H···A | D—H | H···A | D···A | D—H···A
N1—H1···Br1ii | 0.93 | 2.90 | 3.638 (2) | 137
N2—H2···Br1iii | 0.93 | 2.70 | 3.554 (5) | 153

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Table 1. Hydrogen-bond geometry (Å, °)

D—H⋯A | D—H | H⋯A | D⋯A | D—H⋯A
N1—H1⋯Br1i | 0.93 | 2.90 | 3.638 (2) | 137
N2—H2⋯Br1ii | 0.93 | 2.70 | 3.554 (5) | 153

Symmetry codes: (i) ; (ii) .

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