supplementary materials


rk2409 scheme

Acta Cryst. (2013). E69, o1496    [ doi:10.1107/S1600536813023921 ]

4,6-Dibromo-N-{3-[(4,6-dibromo-2,3-dimethylphenyl)imino]butan-2-ylidene}-2,3-dimethylaniline

L. Huang, Z. Du, W. Liu and F. Che

Abstract top

The title compound, C20H20Br4N2, is a product of the condensation reaction of 4,6-dibromo-2,3-dimethylaniline and butane-2,3-dione. The molecule has a center of symmetry at the mid-point of the central C-C bond. The dihedral angle between the benzene ring and the 1,4-diazabutadiene plane is 78.3 (2)°. Niether hydrogen bonding nor aromatic stacking is observed in the crystal structure.

Comment top

Since Brookhart and co–workers discovered nickel and palladium(II) aryl–substituted α–diimine catalysts for olefin polymerization (Johnson et al., 1995), late transition metal catalysis has attracted increasing attention due to their high functional group tolerance and their ability to produce branched or dendritic polymer (Gao et al., 2012; Sun et al., 2012; Popeney et al., 2012; Shi et al., 2012; Zhang & Ye, 2012; Killian et al., 1996; Yuan et al., 2005;2011). In this study, we designed and synthesized the title compound as abidentate ligand (Fig. 1).

The title molecule placed in center of symmetry (middle of C6—C6i bond). The dihedral angle between the benzene ring and 1,4–diazabutadiene plane is 78.3 (2)°. Niether hydrogen bonding nor aromatic stacking are observed in the crystal structure.

Related literature top

For applications of diimine–metal catalysts, see: Johnson et al. (1995). For related structures, see: Gao et al. (2012); Sun et al. (2012); Popeney et al. (2012); Shi et al. (2012); Zhang & Ye (2012); Killian et al. (1996); Yuan et al. (2005, 2011).

Experimental top

Formic acid (0.5 ml) was added to a stirred solution of 2,3–butanedione (0.09 g, 1.00 mmol) and 4,6–dibromo–2,3–dimethylaniline (0.61 g, 2.2 mmol) in ethanol (10 ml) (Fig. 2). The mixture was refluxed for 24 h, and then cooled and the precipitate was separated by filtration. The solid was recrystallized from EtOH/CH2Cl2 (v:v = 10:1), washed with cold ethanol and dried under vacuum to give the title compound1. Yield is 0.50 g (82%). Crystals suitable for X–ray structure determination were grown from a cyclohexane/dichloromethane (v:v = 1:2) solution. Anal. Calcd. for C20H20Br4N2: C, 39.51; H, 3.32; Br, 52.57; N, 4.61. Found: C, 39.49; H, 3.31; Br, 52.60 N, 4.60.

Refinement top

All hydrogen atoms were placed in calculated positions with C—H distances of 0.93Å and 0.96Å for aryl and methyl H atoms. They were included in the refinement in a riding model approximation, respectively. The H atoms were assigned Uiso = 1.2Ueq(C) for aryl H and Uiso = 1.5Ueq(C) for methyl H.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis RED (Agilent, 2013); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: OLEX2 (Dolomanov et al., 2009); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Figures top
[Figure 1] Fig. 1. Molecular structure of title compound with the atom numbering scheme. Displacement ellipsoids are shown at the 50% probability level. H atoms are presented as a small spheres of arbitrary radius. Symmetry code: (i) -x+1, -y+1, -z+1.
[Figure 2] Fig. 2. A condensation reaction of 2,3–butanedione and 4,6–dibromo-2,3–dimethylaniline.
4,6-Dibromo-N-{3-[(4,6-dibromo-2,3-dimethylphenyl)imino]butan-2-ylidene}-2,3-dimethylaniline top
Crystal data top
C20H20Br4N2F(000) = 588
Mr = 607.98Dx = 1.922 Mg m3
Monoclinic, P21/nCu Kα radiation, λ = 1.5418 Å
a = 5.5582 (6) ÅCell parameters from 2210 reflections
b = 12.8881 (15) Åθ = 3.4–70.4°
c = 14.8377 (11) ŵ = 9.40 mm1
β = 98.782 (8)°T = 150 K
V = 1050.43 (19) Å3Block, clear light yellow
Z = 20.29 × 0.17 × 0.16 mm
Data collection top
Agilent SuperNova (Dual, Cu at zero, Eos)
diffractometer
1921 independent reflections
Radiation source: SuperNova (Cu) X-ray Source1777 reflections with I > 2σ(I)
Mirror monochromatorRint = 0.029
Detector resolution: 16.0733 pixels mm-1θmax = 68.2°, θmin = 4.6°
ω–scansh = 64
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)
k = 1515
Tmin = 0.688, Tmax = 1.000l = 1717
4675 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)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.135H-atom parameters constrained
S = 1.11 w = 1/[σ2(Fo2) + (0.0802P)2 + 2.2115P]
where P = (Fo2 + 2Fc2)/3
1921 reflections(Δ/σ)max < 0.001
121 parametersΔρmax = 0.70 e Å3
0 restraintsΔρmin = 1.04 e Å3
Crystal data top
C20H20Br4N2V = 1050.43 (19) Å3
Mr = 607.98Z = 2
Monoclinic, P21/nCu Kα radiation
a = 5.5582 (6) ŵ = 9.40 mm1
b = 12.8881 (15) ÅT = 150 K
c = 14.8377 (11) Å0.29 × 0.17 × 0.16 mm
β = 98.782 (8)°
Data collection top
Agilent SuperNova (Dual, Cu at zero, Eos)
diffractometer
1921 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)
1777 reflections with I > 2σ(I)
Tmin = 0.688, Tmax = 1.000Rint = 0.029
4675 measured reflectionsθmax = 68.2°
Refinement top
R[F2 > 2σ(F2)] = 0.044H-atom parameters constrained
wR(F2) = 0.135Δρmax = 0.70 e Å3
S = 1.11Δρmin = 1.04 e Å3
1921 reflectionsAbsolute structure: ?
121 parametersAbsolute structure parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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
Br20.84461 (11)0.31214 (5)0.68427 (4)0.0431 (2)
N10.5517 (8)0.5134 (4)0.6182 (3)0.0327 (9)
C20.2754 (9)0.4881 (4)0.8311 (3)0.0269 (9)
C30.6169 (9)0.3862 (4)0.7425 (3)0.0277 (10)
C40.4939 (9)0.4723 (4)0.7012 (3)0.0275 (10)
C50.3261 (10)0.5238 (4)0.7464 (3)0.0296 (10)
C60.4633 (10)0.4739 (4)0.5417 (3)0.0341 (11)
C70.5762 (9)0.3504 (4)0.8271 (3)0.0293 (10)
H70.66160.29390.85480.035*
C10.1862 (10)0.6189 (4)0.7022 (3)0.0341 (11)
H1A0.02000.59990.68130.051*
H1B0.26040.64220.65150.051*
H1C0.19120.67360.74630.051*
C80.2980 (12)0.3814 (5)0.5268 (3)0.0438 (14)
H8A0.14790.40100.48980.066*
H8B0.26540.35600.58450.066*
H8C0.37510.32780.49640.066*
C90.0867 (10)0.5414 (4)0.8773 (4)0.0378 (12)
H9A0.16160.59680.91480.057*
H9B0.01700.49240.91460.057*
H9C0.03880.56910.83210.057*
C100.4039 (9)0.4017 (4)0.8689 (3)0.0277 (10)
Br10.34078 (11)0.34478 (4)0.98167 (3)0.0379 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br20.0473 (4)0.0546 (4)0.0317 (3)0.0012 (3)0.0199 (3)0.0110 (2)
N10.043 (2)0.043 (2)0.0129 (18)0.0155 (19)0.0064 (16)0.0029 (17)
C20.035 (2)0.030 (2)0.017 (2)0.0044 (19)0.0075 (17)0.0020 (17)
C30.038 (2)0.032 (2)0.015 (2)0.005 (2)0.0109 (17)0.0075 (18)
C40.042 (3)0.032 (2)0.0096 (19)0.012 (2)0.0066 (17)0.0023 (17)
C50.047 (3)0.026 (2)0.015 (2)0.006 (2)0.0046 (19)0.0011 (18)
C60.047 (3)0.044 (3)0.013 (2)0.016 (2)0.0102 (19)0.001 (2)
C70.042 (3)0.025 (2)0.022 (2)0.003 (2)0.007 (2)0.0012 (17)
C10.053 (3)0.029 (2)0.019 (2)0.004 (2)0.001 (2)0.0107 (19)
C80.061 (4)0.058 (3)0.013 (2)0.031 (3)0.007 (2)0.000 (2)
C90.045 (3)0.042 (3)0.029 (3)0.005 (2)0.015 (2)0.003 (2)
C100.044 (3)0.030 (2)0.0102 (18)0.004 (2)0.0077 (17)0.0000 (17)
Br10.0605 (4)0.0407 (4)0.0159 (3)0.0013 (2)0.0171 (2)0.00654 (19)
Geometric parameters (Å, º) top
Br2—C31.895 (5)C7—H70.9300
N1—C41.422 (6)C7—C101.385 (7)
N1—C61.273 (6)C1—H1A0.9600
C2—C51.406 (6)C1—H1B0.9600
C2—C91.504 (7)C1—H1C0.9600
C2—C101.395 (7)C8—H8A0.9600
C3—C41.395 (7)C8—H8B0.9600
C3—C71.388 (6)C8—H8C0.9600
C4—C51.397 (7)C9—H9A0.9600
C5—C11.543 (7)C9—H9B0.9600
C6—C6i1.518 (9)C9—H9C0.9600
C6—C81.501 (7)C10—Br11.908 (4)
C6—N1—C4121.1 (4)C5—C1—H1B109.5
C5—C2—C9120.5 (5)C5—C1—H1C109.5
C10—C2—C5117.4 (4)H1A—C1—H1B109.5
C10—C2—C9122.1 (4)H1A—C1—H1C109.5
C4—C3—Br2121.1 (3)H1B—C1—H1C109.5
C7—C3—Br2117.2 (4)C6—C8—H8A109.5
C7—C3—C4121.6 (4)C6—C8—H8B109.5
C3—C4—N1121.1 (4)C6—C8—H8C109.5
C3—C4—C5119.1 (4)H8A—C8—H8B109.5
C5—C4—N1119.6 (4)H8A—C8—H8C109.5
C2—C5—C1118.9 (5)H8B—C8—H8C109.5
C4—C5—C2120.9 (4)C2—C9—H9A109.5
C4—C5—C1120.2 (4)C2—C9—H9B109.5
N1—C6—C6i115.8 (6)C2—C9—H9C109.5
N1—C6—C8126.4 (4)H9A—C9—H9B109.5
C8—C6—C6i117.8 (5)H9A—C9—H9C109.5
C3—C7—H7121.1H9B—C9—H9C109.5
C10—C7—C3117.8 (5)C2—C10—Br1120.6 (4)
C10—C7—H7121.1C7—C10—C2123.2 (4)
C5—C1—H1A109.5C7—C10—Br1116.2 (4)
Br2—C3—C4—N16.1 (6)C5—C2—C10—C70.1 (7)
Br2—C3—C4—C5179.4 (3)C5—C2—C10—Br1178.0 (4)
Br2—C3—C7—C10177.8 (4)C6—N1—C4—C382.4 (7)
N1—C4—C5—C2176.5 (4)C6—N1—C4—C5103.1 (6)
N1—C4—C5—C15.7 (7)C7—C3—C4—N1174.7 (4)
C3—C4—C5—C21.9 (7)C7—C3—C4—C50.2 (7)
C3—C4—C5—C1179.7 (4)C9—C2—C5—C4177.4 (5)
C3—C7—C10—C21.5 (7)C9—C2—C5—C10.4 (7)
C3—C7—C10—Br1176.5 (4)C9—C2—C10—C7179.1 (5)
C4—N1—C6—C6i179.2 (6)C9—C2—C10—Br11.2 (7)
C4—N1—C6—C81.5 (10)C10—C2—C5—C41.8 (7)
C4—C3—C7—C101.5 (7)C10—C2—C5—C1179.6 (4)
Symmetry code: (i) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC20H20Br4N2
Mr607.98
Crystal system, space groupMonoclinic, P21/n
Temperature (K)150
a, b, c (Å)5.5582 (6), 12.8881 (15), 14.8377 (11)
β (°) 98.782 (8)
V3)1050.43 (19)
Z2
Radiation typeCu Kα
µ (mm1)9.40
Crystal size (mm)0.29 × 0.17 × 0.16
Data collection
DiffractometerAgilent SuperNova (Dual, Cu at zero, Eos)
diffractometer
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2013)
Tmin, Tmax0.688, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
4675, 1921, 1777
Rint0.029
(sin θ/λ)max1)0.602
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.135, 1.11
No. of reflections1921
No. of parameters121
No. of restraints0
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.70, 1.04

Computer programs: CrysAlis PRO (Agilent, 2013), CrysAlis RED (Agilent, 2013), SUPERFLIP (Palatinus & Chapuis, 2007), OLEX2 (Dolomanov et al., 2009).

Acknowledgements top

We gratefully acknowledge the Natural Science Foundation of China (20702042, 21262028), the Program for Changjiang Scholars and Innovative Research Teams in Universities of the Ministry of Education of China (IRT1177), the Natural Science Foundation of Gansu Province (1208RJZA140) and the NWNU Young Teachers Reseach Improving Program (NWNU–LKQN–10–11) for financial support.

references
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