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

Yao, J.-L.; Zhang, X.; Li, H.-Y.; Ye, J.-Q.

doi:10.1107/S1600536812052087

organic compounds

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ISSN: 2056-9890

Volume 69| Part 2| February 2013| Page o199

doi:10.1107/S1600536812052087

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

Jin-Li Yao,^a Xu Zhang,^a ^* Hong-Yan Li ^a and Jian-Qing Ye ^a

^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 ); 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

Crystal data

C₁₈H₁₈Br₂N₂
M_r = 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 ) T_min = 0.441, T_max = 0.542
6368 measured reflections
1541 independent reflections
847 reflections with I > 2σ(I)
R_int = 0.104

Refinement

R[F² > 2σ(F²)] = 0.052
wR(F²) = 0.113
S = 1.05
1541 reflections
103 parameters
H-atom parameters constrained
Δρ_max = 0.70 e Å⁻³
Δρ_min = −0.85 e Å⁻³

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

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812052087/xu5666sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812052087/xu5666Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812052087/xu5666Isup3.cml

checkCIF report

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).

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

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

C₁₈H₁₈Br₂N₂	F(000) = 840
M_r = 422.16	D_x = 1.612 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 951 reflections
a = 13.625 (13) Å	θ = 2.8–20.3°
b = 7.495 (7) Å	µ = 4.66 mm⁻¹
c = 17.029 (17) Å	T = 293 K
V = 1739 (3) Å³	Block, yellow
Z = 4	0.21 × 0.20 × 0.15 mm

Data collection top

Bruker APEXII CCD diffractometer	1541 independent reflections
Radiation source: fine-focus sealed tube	847 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.104
ϕ and ω scans	θ_max = 25.3°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −15→15
T_min = 0.441, T_max = 0.542	k = −9→5
6368 measured reflections	l = −20→18

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.052	H-atom parameters constrained
wR(F²) = 0.113	w = 1/[σ²(F_o²) + (0.0106P)² + 5.9013P] where P = (F_o² + 2F_c²)/3
S = 1.05	(Δ/σ)_max < 0.001
1541 reflections	Δρ_max = 0.70 e Å⁻³
103 parameters	Δρ_min = −0.85 e Å⁻³
0 restraints	Extinction correction: SHELXTL (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0038 (5)

Crystal data top

C₁₈H₁₈Br₂N₂	V = 1739 (3) Å³
M_r = 422.16	Z = 4
Orthorhombic, Pbca	Mo Kα radiation
a = 13.625 (13) Å	µ = 4.66 mm⁻¹
b = 7.495 (7) Å	T = 293 K
c = 17.029 (17) Å	0.21 × 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)
T_min = 0.441, T_max = 0.542	R_int = 0.104
6368 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.052	0 restraints
wR(F²) = 0.113	H-atom parameters constrained
S = 1.05	Δρ_max = 0.70 e Å⁻³
1541 reflections	Δρ_min = −0.85 e Å⁻³
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

	x	y	z	U_iso*/U_eq
Br1	0.30195 (6)	0.23158 (11)	0.40014 (4)	0.0631 (4)
C1	0.4677 (5)	0.4420 (8)	0.2188 (4)	0.0398 (17)
H1	0.5330	0.4728	0.2107	0.048*
C2	0.4386 (5)	0.3772 (9)	0.2914 (4)	0.0444 (19)
H2	0.4836	0.3653	0.3321	0.053*
C3	0.3421 (5)	0.3308 (8)	0.3021 (4)	0.0374 (17)
C4	0.2742 (5)	0.3508 (7)	0.2429 (4)	0.0341 (16)
H4	0.2092	0.3188	0.2518	0.041*
C5	0.3017 (5)	0.4189 (7)	0.1692 (3)	0.0277 (14)
C6	0.3998 (4)	0.4617 (7)	0.1574 (4)	0.0299 (15)
C7	0.4845 (4)	0.4520 (8)	0.0370 (4)	0.0307 (15)
C8	0.5198 (5)	0.2627 (8)	0.0474 (4)	0.0451 (17)
H8A	0.4765	0.2006	0.0825	0.068*
H8B	0.5850	0.2636	0.0689	0.068*
H8C	0.5205	0.2035	−0.0026	0.068*
C9	0.2258 (4)	0.4423 (8)	0.1053 (4)	0.0452 (18)
H9A	0.2541	0.5074	0.0623	0.068*
H9B	0.1706	0.5071	0.1257	0.068*
H9C	0.2045	0.3273	0.0872	0.068*
N1	0.4299 (4)	0.5380 (6)	0.0839 (3)	0.0331 (13)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0619 (6)	0.0768 (6)	0.0505 (5)	0.0068 (5)	0.0143 (4)	0.0208 (5)
C1	0.017 (4)	0.044 (4)	0.058 (5)	−0.003 (3)	0.004 (3)	0.006 (4)
C2	0.040 (5)	0.048 (5)	0.045 (4)	−0.005 (4)	−0.007 (3)	0.004 (4)
C3	0.033 (4)	0.031 (4)	0.048 (4)	0.001 (3)	0.003 (4)	0.000 (3)
C4	0.021 (4)	0.030 (3)	0.051 (4)	−0.001 (3)	0.009 (3)	−0.002 (3)
C5	0.024 (4)	0.019 (3)	0.041 (4)	−0.001 (3)	0.002 (3)	−0.001 (3)
C6	0.027 (4)	0.021 (3)	0.042 (4)	0.001 (3)	0.012 (3)	0.000 (3)
C7	0.012 (3)	0.028 (4)	0.052 (4)	−0.005 (3)	0.004 (3)	0.008 (3)
C8	0.043 (4)	0.033 (4)	0.060 (4)	0.012 (4)	0.015 (4)	0.012 (3)
C9	0.033 (5)	0.043 (4)	0.059 (5)	−0.002 (3)	0.003 (4)	0.003 (4)
N1	0.021 (3)	0.030 (3)	0.048 (4)	0.000 (3)	0.006 (3)	0.006 (3)

Geometric parameters (Å, º) top

Br1—C3	1.908 (7)	C6—N1	1.436 (7)
C1—C2	1.386 (9)	C7—N1	1.268 (7)
C1—C6	1.403 (8)	C7—C8	1.509 (8)
C1—H1	0.9300	C7—C7ⁱ	1.510 (11)
C2—C3	1.372 (9)	C8—H8A	0.9600
C2—H2	0.9300	C8—H8B	0.9600
C3—C4	1.375 (9)	C8—H8C	0.9600
C4—C5	1.406 (8)	C9—H9A	0.9600
C4—H4	0.9300	C9—H9B	0.9600
C5—C6	1.390 (8)	C9—H9C	0.9600
C5—C9	1.512 (8)

C2—C1—C6	120.8 (6)	C1—C6—N1	120.2 (5)
C2—C1—H1	119.6	N1—C7—C8	126.2 (5)
C6—C1—H1	119.6	N1—C7—C7ⁱ	116.6 (7)
C3—C2—C1	118.8 (6)	C8—C7—C7ⁱ	117.2 (7)
C3—C2—H2	120.6	C7—C8—H8A	109.5
C1—C2—H2	120.6	C7—C8—H8B	109.5
C2—C3—C4	121.3 (6)	H8A—C8—H8B	109.5
C2—C3—Br1	119.3 (5)	C7—C8—H8C	109.5
C4—C3—Br1	119.4 (5)	H8A—C8—H8C	109.5
C3—C4—C5	120.9 (6)	H8B—C8—H8C	109.5
C3—C4—H4	119.5	C5—C9—H9A	109.5
C5—C4—H4	119.5	C5—C9—H9B	109.5
C6—C5—C4	118.0 (6)	H9A—C9—H9B	109.5
C6—C5—C9	121.8 (6)	C5—C9—H9C	109.5
C4—C5—C9	120.2 (6)	H9A—C9—H9C	109.5
C5—C6—C1	120.1 (6)	H9B—C9—H9C	109.5
C5—C6—N1	119.5 (6)	C7—N1—C6	120.9 (5)

C6—C1—C2—C3	0.6 (10)	C4—C5—C6—N1	−177.6 (5)
C1—C2—C3—C4	−1.3 (10)	C9—C5—C6—N1	2.9 (8)
C1—C2—C3—Br1	177.3 (5)	C2—C1—C6—C5	1.1 (9)
C2—C3—C4—C5	0.3 (9)	C2—C1—C6—N1	176.6 (5)
Br1—C3—C4—C5	−178.3 (4)	C8—C7—N1—C6	3.9 (10)
C3—C4—C5—C6	1.4 (8)	C7ⁱ—C7—N1—C6	−177.3 (6)
C3—C4—C5—C9	−179.2 (6)	C5—C6—N1—C7	−112.5 (7)
C4—C5—C6—C1	−2.0 (8)	C1—C6—N1—C7	71.9 (8)
C9—C5—C6—C1	178.5 (5)

Symmetry code: (i) −x+1, −y+1, −z.

Experimental details

Crystal data
Chemical formula	C₁₈H₁₈Br₂N₂
M_r	422.16
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	293
a, b, c (Å)	13.625 (13), 7.495 (7), 17.029 (17)
V (Å³)	1739 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	4.66
Crystal size (mm)	0.21 × 0.20 × 0.15

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.441, 0.542
No. of measured, independent and observed [I > 2σ(I)] reflections	6368, 1541, 847
R_int	0.104
(sin θ/λ)_max (Å⁻¹)	0.601

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.052, 0.113, 1.05
No. of reflections	1541
No. of parameters	103
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.70, −0.85

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

References

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