metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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Di­bromidotris(di­methyl­amine)magnesium(II)

aInstitut 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

(Received 24 June 2009; accepted 26 June 2009; online 8 July 2009)

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[Lerner, H.-W., Scholz, S., Bolte, M., Wiberg, N., Nöth, H. & Krossing, I. (2003). Eur. J. Inorg. Chem. pp. 666-670.]) to six as in [MgBr2(THF)4] (Lorbach et al., 2007[Lorbach, A., Lerner, H.-W. & Bolte, M. (2007). Acta Cryst. C63, m174-m176.]).

[Scheme 1]

Experimental

Crystal data
  • [MgBr2(C2H7N)3]

  • Mr = 319.39

  • Hexagonal, P 32 21

  • 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[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]; Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.]) Tmin = 0.321, Tmax = 0.345 (expected range = 0.241–0.258)

  • 5279 measured reflections

  • 1285 independent reflections

  • 1223 reflections with I > 2σ(I)

  • Rint = 0.037

Refinement
  • R[F2 > 2σ(F2)] = 0.022

  • wR(F2) = 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[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 517 Friedel pairs

  • Flack parameter: −0.012 (17)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA 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) [-x+1, -x+y, -z+{\script{2\over 3}}]; (ii) [-x+y+1, -x+1, z+{\script{1\over 3}}].

Data collection: X-AREA (Stoe & Cie, 2001[Stoe & Cie (2001). X-AREA. Stoe & Cie, Darmstadt, Germany.]); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

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.

Related literature top

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 top

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 top

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.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA (Stoe & Cie, 2001); data reduction: X-AREA (Stoe & Cie, 2001); 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 (Sheldrick, 2008).

Figures top
[Figure 1] 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.
Dibromidotris(dimethylamine)magnesium(II) top
Crystal data top
[MgBr2(C2H7N)3]Dx = 1.537 Mg m3
Mr = 319.39Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P3221Cell parameters from 5127 reflections
Hall symbol: P 32 2"θ = 3.8–25.6°
a = 9.0951 (7) ŵ = 5.88 mm1
c = 14.4544 (12) ÅT = 173 K
V = 1035.49 (14) Å3Block, colourless
Z = 30.25 × 0.25 × 0.23 mm
F(000) = 480
Data collection top
Stoe IPDSII two-circle
diffractometer
1285 independent reflections
Radiation source: fine-focus sealed tube1223 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.037
ω scansθmax = 25.6°, θmin = 3.8°
Absorption correction: multi-scan
(MULABS; Spek, 2003; Blessing, 1995)
h = 118
Tmin = 0.321, Tmax = 0.345k = 711
5279 measured reflectionsl = 1717
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-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 = 0.96Δρmax = 0.25 e Å3
1285 reflectionsΔρmin = 0.34 e Å3
61 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0106 (8)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 517 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.012 (17)
Crystal data top
[MgBr2(C2H7N)3]Z = 3
Mr = 319.39Mo Kα radiation
Hexagonal, P3221µ = 5.88 mm1
a = 9.0951 (7) ÅT = 173 K
c = 14.4544 (12) Å0.25 × 0.25 × 0.23 mm
V = 1035.49 (14) Å3
Data collection top
Stoe IPDSII two-circle
diffractometer
1285 independent reflections
Absorption correction: multi-scan
(MULABS; Spek, 2003; Blessing, 1995)
1223 reflections with I > 2σ(I)
Tmin = 0.321, Tmax = 0.345Rint = 0.037
5279 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.022H-atom parameters constrained
wR(F2) = 0.049Δρmax = 0.25 e Å3
S = 0.96Δρmin = 0.34 e Å3
1285 reflectionsAbsolute structure: Flack (1983), 517 Friedel pairs
61 parametersAbsolute structure parameter: 0.012 (17)
0 restraints
Special details top

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*/UeqOcc. (<1)
Br10.39287 (4)0.37977 (4)0.318621 (17)0.03405 (12)
Mg10.41479 (13)0.41479 (13)0.50000.0231 (3)
N10.4463 (3)0.1927 (3)0.50042 (15)0.0301 (5)
H10.48870.18970.44230.036*
C10.5661 (5)0.1872 (5)0.5683 (2)0.0441 (9)
H1A0.67680.29100.56300.066*
H1B0.57890.08830.55560.066*
H1C0.52170.17870.63100.066*
C20.2791 (5)0.0368 (4)0.5070 (3)0.0474 (9)
H2A0.20120.04190.46200.071*
H2B0.23340.02700.56950.071*
H2C0.29160.06210.49390.071*
N20.6685 (6)0.6265 (6)0.5188 (3)0.0293 (12)0.50
H20.71830.58960.56230.035*0.50
C30.6750 (5)0.7809 (4)0.5616 (2)0.0444 (8)
H3A0.79330.87160.56840.067*0.50
H3B0.62060.75080.62260.067*0.50
H3C0.61430.82010.52180.067*0.50
H3D0.77150.89200.54570.067*0.50
H3E0.57850.79400.58030.067*0.50
H3F0.70630.73090.61250.067*0.50
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0453 (2)0.04152 (19)0.02015 (14)0.02533 (16)0.00289 (12)0.00057 (12)
Mg10.0233 (5)0.0233 (5)0.0200 (5)0.0096 (6)0.0012 (2)0.0012 (2)
N10.0368 (15)0.0336 (14)0.0232 (12)0.0199 (12)0.0007 (12)0.0026 (11)
C10.055 (2)0.057 (2)0.0385 (17)0.041 (2)0.0087 (17)0.0075 (17)
C20.048 (2)0.0276 (17)0.057 (2)0.0121 (16)0.0043 (18)0.0044 (15)
N20.027 (2)0.027 (3)0.028 (3)0.010 (2)0.0027 (19)0.005 (2)
C30.054 (2)0.0249 (16)0.0425 (18)0.0111 (16)0.0098 (17)0.0037 (14)
Geometric parameters (Å, º) top
Br1—Mg12.6365 (4)C2—H2B0.9800
Mg1—N22.159 (5)C2—H2C0.9800
Mg1—N2i2.159 (5)N2—N2i0.856 (9)
Mg1—N12.177 (3)N2—C3i1.463 (6)
Mg1—N1i2.177 (3)N2—C31.508 (6)
Mg1—Br1i2.6365 (4)N2—H20.9300
N1—C21.475 (4)C3—N2i1.463 (6)
N1—C11.486 (4)C3—H3A0.9800
N1—H10.9300C3—H3B0.9800
C1—H1A0.9800C3—H3C0.9800
C1—H1B0.9800C3—H3D0.9788
C1—H1C0.9800C3—H3E0.9803
C2—H2A0.9800C3—H3F0.9780
N2—Mg1—N2i22.9 (2)C3i—N2—C3110.5 (4)
N2—Mg1—N1104.45 (16)N2i—N2—Mg178.57 (12)
N2i—Mg1—N1122.07 (17)C3i—N2—Mg1116.3 (3)
N2—Mg1—N1i122.07 (17)C3—N2—Mg1114.1 (3)
N2i—Mg1—N1i104.45 (16)N2i—N2—H2175.2
N1—Mg1—N1i133.08 (16)C3i—N2—H2104.6
N2—Mg1—Br1i88.69 (13)C3—N2—H2105.1
N2i—Mg1—Br1i102.44 (14)Mg1—N2—H2105.0
N1—Mg1—Br1i89.66 (6)N2i—C3—H3A119.2
N1i—Mg1—Br1i85.86 (6)N2—C3—H3A109.9
N2—Mg1—Br1102.44 (14)N2i—C3—H3B125.9
N2i—Mg1—Br188.69 (13)N2—C3—H3B109.2
N1—Mg1—Br185.86 (6)H3A—C3—H3B109.5
N1i—Mg1—Br189.66 (6)N2i—C3—H3C76.1
Br1i—Mg1—Br1168.72 (5)N2—C3—H3C109.3
C2—N1—C1110.2 (3)H3A—C3—H3C109.5
C2—N1—Mg1110.0 (2)H3B—C3—H3C109.5
C1—N1—Mg1118.2 (2)N2i—C3—H3D109.6
C2—N1—H1105.9N2—C3—H3D117.5
C1—N1—H1105.9H3B—C3—H3D124.5
Mg1—N1—H1105.9H3C—C3—H3D82.1
N1—C1—H1A109.5N2i—C3—H3E109.2
N1—C1—H1B109.5N2—C3—H3E127.2
H1A—C1—H1B109.5H3A—C3—H3E122.9
N1—C1—H1C109.5H3B—C3—H3E55.2
H1A—C1—H1C109.5H3C—C3—H3E54.3
H1B—C1—H1C109.5H3D—C3—H3E109.5
N1—C2—H2A109.5N2i—C3—H3F109.2
N1—C2—H2B109.5N2—C3—H3F76.2
H2A—C2—H2B109.5H3A—C3—H3F82.1
N1—C2—H2C109.5H3B—C3—H3F54.4
H2A—C2—H2C109.5H3C—C3—H3F163.4
H2B—C2—H2C109.5H3D—C3—H3F109.7
N2i—N2—C3i76.2 (6)H3E—C3—H3F109.6
N2i—N2—C370.4 (6)
N2—Mg1—N1—C2168.6 (2)Br1—Mg1—N2—N2i54.3 (8)
N2i—Mg1—N1—C2175.4 (2)N2i—Mg1—N2—C3i68.2 (7)
N1i—Mg1—N1—C23.95 (19)N1—Mg1—N2—C3i75.0 (3)
Br1i—Mg1—N1—C280.0 (2)N1i—Mg1—N2—C3i111.4 (3)
Br1—Mg1—N1—C289.6 (2)Br1i—Mg1—N2—C3i164.3 (3)
N2—Mg1—N1—C140.9 (3)Br1—Mg1—N2—C3i13.9 (4)
N2i—Mg1—N1—C156.8 (3)N2i—Mg1—N2—C362.2 (7)
N1i—Mg1—N1—C1131.7 (2)N1—Mg1—N2—C3154.6 (3)
Br1i—Mg1—N1—C147.7 (2)N1i—Mg1—N2—C319.0 (4)
Br1—Mg1—N1—C1142.7 (2)Br1i—Mg1—N2—C365.3 (3)
N1—Mg1—N2—N2i143.2 (7)Br1—Mg1—N2—C3116.5 (3)
N1i—Mg1—N2—N2i43.2 (8)C3i—N2—C3—N2i66.2 (5)
Br1i—Mg1—N2—N2i127.5 (7)Mg1—N2—C3—N2i67.0 (4)
Symmetry code: (i) y, x, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Br1ii0.932.903.638 (2)137
N2—H2···Br1iii0.932.703.554 (5)153
Symmetry codes: (ii) x+1, x+y, z+2/3; (iii) x+y+1, x+1, z+1/3.

Experimental details

Crystal data
Chemical formula[MgBr2(C2H7N)3]
Mr319.39
Crystal system, space groupHexagonal, P3221
Temperature (K)173
a, c (Å)9.0951 (7), 14.4544 (12)
V3)1035.49 (14)
Z3
Radiation typeMo Kα
µ (mm1)5.88
Crystal size (mm)0.25 × 0.25 × 0.23
Data collection
DiffractometerStoe IPDSII two-circle
diffractometer
Absorption correctionMulti-scan
(MULABS; Spek, 2003; Blessing, 1995)
Tmin, Tmax0.321, 0.345
No. of measured, independent and
observed [I > 2σ(I)] reflections
5279, 1285, 1223
Rint0.037
(sin θ/λ)max1)0.608
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.022, 0.049, 0.96
No. of reflections1285
No. of parameters61
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.25, 0.34
Absolute structureFlack (1983), 517 Friedel pairs
Absolute structure parameter0.012 (17)

Computer programs: X-AREA (Stoe & Cie, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL-Plus (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Br1i0.932.903.638 (2)137.2
N2—H2···Br1ii0.932.703.554 (5)153.3
Symmetry codes: (i) x+1, x+y, z+2/3; (ii) x+y+1, x+1, z+1/3.
 

References

First citationBlessing, R. H. (1995). Acta Cryst. A51, 33–38.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationLerner, H.-W., Scholz, S., Bolte, M., Wiberg, N., Nöth, H. & Krossing, I. (2003). Eur. J. Inorg. Chem. pp. 666–670.  CSD CrossRef Google Scholar
First citationLorbach, A., Lerner, H.-W. & Bolte, M. (2007). Acta Cryst. C63, m174–m176.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationStoe & Cie (2001). X-AREA. Stoe & Cie, Darmstadt, Germany.  Google Scholar

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