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

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ISSN: 2056-9890

(E)-4-Bromo-N-{(E)-3-[(4-bromo-2-methyl­phen­yl)imino]­butan-2-yl­­idene}-2-methyl­aniline

aKey Laboratory of Environmental Materials and Engineering of Jiangsu Province, Yangzhou University, Yangzhou 225009, People's Republic of China
*Correspondence e-mail: zhangxu@yzu.edu.cn

(Received 13 December 2012; accepted 30 December 2012; online 9 January 2013)

The title compound, C18H18Br2N2, is centrosymmetric with the mid-point of the central C—C bond of the butyl group located on an inversion center. The terminal benzene ring is approximately perpendicular to the central butyl plane [dihedral angle = 71.9 (8)°]. No hydrogen bonding or aromatic stacking is observed in the crystal.

Related literature

For applications of diimine-metal catalysts, see: Johnson et al. (1995[Johnson, L. K., Killian, C. M. & Brookhart, M. (1995). J. Am. Chem. Soc. 117, 6414-6415.]); Killian et al. (1996[Killian, C. M., Tempel, D. J., Johnson, L. K. & Brookhart, M. (1996). J. Am. Chem. Soc. 118, 11664-11665.]); Popeney & Guan (2010[Popeney, C. S. & Guan, Z. B. (2010). Macromolecules, 43, 4091-4097.]); Popeney et al. (2011[Popeney, C. S., Levins, C. M. & Guan, Z. B. (2011). Organometallics, 30, 2432-2452.]); Yuan et al. (2005[Yuan, J.-C., Silva, L. C., Gomes, P. T., Valerga, P., Campos, J. M., Ribeiro, M. R., Chien, J. C. W. & Marques, M. M. (2005). Polymer, 46, 2122-2132.]). For a related structure, see: Zhang et al. (2013[Zhang, C., Wu, G.-F., Huang, B.-M. & Lu, X.-Q. (2013). Acta Cryst. E69, o216.]).

[Scheme 1]

Experimental

Crystal data
  • C18H18Br2N2

  • Mr = 422.16

  • Orthorhombic, P b c a

  • a = 13.625 (13) Å

  • b = 7.495 (7) Å

  • c = 17.029 (17) Å

  • V = 1739 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 4.66 mm−1

  • T = 293 K

  • 0.21 × 0.20 × 0.15 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.441, Tmax = 0.542

  • 6368 measured reflections

  • 1541 independent reflections

  • 847 reflections with I > 2σ(I)

  • Rint = 0.104

Refinement
  • R[F2 > 2σ(F2)] = 0.052

  • wR(F2) = 0.113

  • S = 1.05

  • 1541 reflections

  • 103 parameters

  • H-atom parameters constrained

  • Δρmax = 0.70 e Å−3

  • Δρmin = −0.85 e Å−3

Data collection: APEX2 (Bruker, 2007[Bruker (2007). SAINT and APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). SAINT and APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

There is a considerable interest in the development of new late transition metal catalysts for the polymerization of α-olefins since Brookhart discovered highly active α-diimine nickel catalysts (Johnson et al., 1995; Killian et al., 1996). It is well known that the ligand structure had significant influence on the product properties and polymerization activities (Popeney & Guan, 2010; Popeney et al., 2011; Yuan et al., 2005).

In this study, we designed and synthesized the title compound as a bidentate ligand, and its molecular structure was characterized by X-ray diffraction. In the solid state, the ligand exhibits a -1 symmetry. The single bond of 1,4-diazabutadiene fragment is (E)-configured. The dihedral angle between the benzene ring and 1,4-diazabutadiene plane is 71.9 (8)°, similar to that found in a related compound (Zhang et al., 2013). In the crystal packing, there is no hydrogen-bond between the molecules.

Related literature top

For applications of diimine-metal catalysts, see: Johnson et al. (1995); Killian et al. (1996); Popeney & Guan (2010); Popeney et al. (2011); Yuan et al. (2005). For a related structure, see: Zhang et al. (2013).

Experimental top

Formic acid (0.5 ml) was added to a stirred solution of 2,3-butanedione (0.103 g, 1.2 mmol) and 4-bromo-2-methylaniline (0.447 g, 2.4 mmol) in methanol (25 ml). The mixture was refluxed for 24 h, then cooled and the precipitate was separated by filtration. The solid was recrystallized from dichloromethane/cyclohexane (v/v = 6:1), washed with cold ethanol and dried under vacuum to give the title ligand 0.37 g (87%). Anal. Calcd. for C18H18Br2N2: C, 51.21; H, 4.30; N, 6.64. Found: C, 51.18; H, 4.29; N, 6.68. Crystals suitable for X-ray structure determination were grown from a solution of the title compound in a mixture of cyclohexane/dichloromethane (1:4, v/v).

Refinement top

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

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure of the title compound, using 30% probability level ellipsoids.
(E)-4-Bromo-N-{(E)-3-[(4-bromo-2- methylphenyl)imino]butan-2-ylidene}-2-methylaniline top
Crystal data top
C18H18Br2N2F(000) = 840
Mr = 422.16Dx = 1.612 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 951 reflections
a = 13.625 (13) Åθ = 2.8–20.3°
b = 7.495 (7) ŵ = 4.66 mm1
c = 17.029 (17) ÅT = 293 K
V = 1739 (3) Å3Block, yellow
Z = 40.21 × 0.20 × 0.15 mm
Data collection top
Bruker APEXII CCD
diffractometer
1541 independent reflections
Radiation source: fine-focus sealed tube847 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.104
ϕ and ω scansθmax = 25.3°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 1515
Tmin = 0.441, Tmax = 0.542k = 95
6368 measured reflectionsl = 2018
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.052H-atom parameters constrained
wR(F2) = 0.113 w = 1/[σ2(Fo2) + (0.0106P)2 + 5.9013P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
1541 reflectionsΔρmax = 0.70 e Å3
103 parametersΔρmin = 0.85 e Å3
0 restraintsExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0038 (5)
Crystal data top
C18H18Br2N2V = 1739 (3) Å3
Mr = 422.16Z = 4
Orthorhombic, PbcaMo Kα radiation
a = 13.625 (13) ŵ = 4.66 mm1
b = 7.495 (7) ÅT = 293 K
c = 17.029 (17) Å0.21 × 0.20 × 0.15 mm
Data collection top
Bruker APEXII CCD
diffractometer
1541 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
847 reflections with I > 2σ(I)
Tmin = 0.441, Tmax = 0.542Rint = 0.104
6368 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0520 restraints
wR(F2) = 0.113H-atom parameters constrained
S = 1.05Δρmax = 0.70 e Å3
1541 reflectionsΔρmin = 0.85 e Å3
103 parameters
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*/Ueq
Br10.30195 (6)0.23158 (11)0.40014 (4)0.0631 (4)
C10.4677 (5)0.4420 (8)0.2188 (4)0.0398 (17)
H10.53300.47280.21070.048*
C20.4386 (5)0.3772 (9)0.2914 (4)0.0444 (19)
H20.48360.36530.33210.053*
C30.3421 (5)0.3308 (8)0.3021 (4)0.0374 (17)
C40.2742 (5)0.3508 (7)0.2429 (4)0.0341 (16)
H40.20920.31880.25180.041*
C50.3017 (5)0.4189 (7)0.1692 (3)0.0277 (14)
C60.3998 (4)0.4617 (7)0.1574 (4)0.0299 (15)
C70.4845 (4)0.4520 (8)0.0370 (4)0.0307 (15)
C80.5198 (5)0.2627 (8)0.0474 (4)0.0451 (17)
H8A0.47650.20060.08250.068*
H8B0.58500.26360.06890.068*
H8C0.52050.20350.00260.068*
C90.2258 (4)0.4423 (8)0.1053 (4)0.0452 (18)
H9A0.25410.50740.06230.068*
H9B0.17060.50710.12570.068*
H9C0.20450.32730.08720.068*
N10.4299 (4)0.5380 (6)0.0839 (3)0.0331 (13)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0619 (6)0.0768 (6)0.0505 (5)0.0068 (5)0.0143 (4)0.0208 (5)
C10.017 (4)0.044 (4)0.058 (5)0.003 (3)0.004 (3)0.006 (4)
C20.040 (5)0.048 (5)0.045 (4)0.005 (4)0.007 (3)0.004 (4)
C30.033 (4)0.031 (4)0.048 (4)0.001 (3)0.003 (4)0.000 (3)
C40.021 (4)0.030 (3)0.051 (4)0.001 (3)0.009 (3)0.002 (3)
C50.024 (4)0.019 (3)0.041 (4)0.001 (3)0.002 (3)0.001 (3)
C60.027 (4)0.021 (3)0.042 (4)0.001 (3)0.012 (3)0.000 (3)
C70.012 (3)0.028 (4)0.052 (4)0.005 (3)0.004 (3)0.008 (3)
C80.043 (4)0.033 (4)0.060 (4)0.012 (4)0.015 (4)0.012 (3)
C90.033 (5)0.043 (4)0.059 (5)0.002 (3)0.003 (4)0.003 (4)
N10.021 (3)0.030 (3)0.048 (4)0.000 (3)0.006 (3)0.006 (3)
Geometric parameters (Å, º) top
Br1—C31.908 (7)C6—N11.436 (7)
C1—C21.386 (9)C7—N11.268 (7)
C1—C61.403 (8)C7—C81.509 (8)
C1—H10.9300C7—C7i1.510 (11)
C2—C31.372 (9)C8—H8A0.9600
C2—H20.9300C8—H8B0.9600
C3—C41.375 (9)C8—H8C0.9600
C4—C51.406 (8)C9—H9A0.9600
C4—H40.9300C9—H9B0.9600
C5—C61.390 (8)C9—H9C0.9600
C5—C91.512 (8)
C2—C1—C6120.8 (6)C1—C6—N1120.2 (5)
C2—C1—H1119.6N1—C7—C8126.2 (5)
C6—C1—H1119.6N1—C7—C7i116.6 (7)
C3—C2—C1118.8 (6)C8—C7—C7i117.2 (7)
C3—C2—H2120.6C7—C8—H8A109.5
C1—C2—H2120.6C7—C8—H8B109.5
C2—C3—C4121.3 (6)H8A—C8—H8B109.5
C2—C3—Br1119.3 (5)C7—C8—H8C109.5
C4—C3—Br1119.4 (5)H8A—C8—H8C109.5
C3—C4—C5120.9 (6)H8B—C8—H8C109.5
C3—C4—H4119.5C5—C9—H9A109.5
C5—C4—H4119.5C5—C9—H9B109.5
C6—C5—C4118.0 (6)H9A—C9—H9B109.5
C6—C5—C9121.8 (6)C5—C9—H9C109.5
C4—C5—C9120.2 (6)H9A—C9—H9C109.5
C5—C6—C1120.1 (6)H9B—C9—H9C109.5
C5—C6—N1119.5 (6)C7—N1—C6120.9 (5)
C6—C1—C2—C30.6 (10)C4—C5—C6—N1177.6 (5)
C1—C2—C3—C41.3 (10)C9—C5—C6—N12.9 (8)
C1—C2—C3—Br1177.3 (5)C2—C1—C6—C51.1 (9)
C2—C3—C4—C50.3 (9)C2—C1—C6—N1176.6 (5)
Br1—C3—C4—C5178.3 (4)C8—C7—N1—C63.9 (10)
C3—C4—C5—C61.4 (8)C7i—C7—N1—C6177.3 (6)
C3—C4—C5—C9179.2 (6)C5—C6—N1—C7112.5 (7)
C4—C5—C6—C12.0 (8)C1—C6—N1—C771.9 (8)
C9—C5—C6—C1178.5 (5)
Symmetry code: (i) x+1, y+1, z.

Experimental details

Crystal data
Chemical formulaC18H18Br2N2
Mr422.16
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)293
a, b, c (Å)13.625 (13), 7.495 (7), 17.029 (17)
V3)1739 (3)
Z4
Radiation typeMo Kα
µ (mm1)4.66
Crystal size (mm)0.21 × 0.20 × 0.15
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.441, 0.542
No. of measured, independent and
observed [I > 2σ(I)] reflections
6368, 1541, 847
Rint0.104
(sin θ/λ)max1)0.601
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.052, 0.113, 1.05
No. of reflections1541
No. of parameters103
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.70, 0.85

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXTL (Sheldrick, 2008).

 

References

First citationBruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationBruker (2007). SAINT and APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationJohnson, L. K., Killian, C. M. & Brookhart, M. (1995). J. Am. Chem. Soc. 117, 6414–6415.  CrossRef CAS Web of Science
First citationKillian, C. M., Tempel, D. J., Johnson, L. K. & Brookhart, M. (1996). J. Am. Chem. Soc. 118, 11664–11665.  CrossRef CAS Web of Science
First citationPopeney, C. S. & Guan, Z. B. (2010). Macromolecules, 43, 4091–4097.  Web of Science CrossRef CAS
First citationPopeney, C. S., Levins, C. M. & Guan, Z. B. (2011). Organometallics, 30, 2432–2452.  Web of Science CrossRef CAS
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationYuan, J.-C., Silva, L. C., Gomes, P. T., Valerga, P., Campos, J. M., Ribeiro, M. R., Chien, J. C. W. & Marques, M. M. (2005). Polymer, 46, 2122–2132.  Web of Science CSD CrossRef CAS
First citationZhang, C., Wu, G.-F., Huang, B.-M. & Lu, X.-Q. (2013). Acta Cryst. E69, o216.  CSD CrossRef IUCr Journals

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ISSN: 2056-9890
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