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

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(Z)-N-[(Z)-3-(2,4-Di­methyl­phenyl­imino)­butan-2-yl­­idene]-2,4-di­methyl­aniline

aKey Laboratory of Eco-Environment-Related Polymer Materials of the Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070, People's Republic of China
*Correspondence e-mail: jianchaoyuan@nwnu.edu.cn

(Received 15 November 2011; accepted 10 December 2011; online 17 December 2011)

The asymmetric unit of the title compound, C20H24N2, contains one half -mol­ecule which exhibits a crystallographically imposed center of symmetry. The benzene rings are inclined to the 1,4-diaza­butadiene mean plane by 78.3 (2)°.

Related literature

The title compound was synthesized as a α-diimine ligand for NiII-α-diimine olefin polymerization catalysts. For applications of α-diimine ligands, 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.]). For the design and synthesis of new α-diimine derivatives, see: Yuan et al. (2005[Yuan, J. C., SiIva, 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.]); Popeney & Guan (2005[Popeney, C. S. & Guan, Z. B. (2005). Organometallics, 24, 1145-1155.], 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.]). The crystal structures of Re and Ni complexes with the title ligand were reported by Kia et al. (2005[Kia, R., Mirkhani, V., Deák, A. & Kálmán, A. (2005). Acta Cryst. E61, m566-m567.]) and Yuan et al. (2011[Yuan, J. C., Mei, T. J., Gomes, P. T., Marques, M. M., Wang, X. H., Liu, Y. F., Miao, C. P. & Xie, X. L. (2011). J. Organomet. Chem. 696, 3251-3256.]), respectively.

[Scheme 1]

Experimental

Crystal data
  • C20H24N2

  • Mr = 292.41

  • Orthorhombic, P b c a

  • a = 13.50 (1) Å

  • b = 7.571 (6) Å

  • c = 16.738 (12) Å

  • V = 1711 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 296 K

  • 0.23 × 0.20 × 0.14 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.985, Tmax = 0.991

  • 5143 measured reflections

  • 1592 independent reflections

  • 1043 reflections with I > 2σ(I)

  • Rint = 0.031

Refinement
  • R[F2 > 2σ(F2)] = 0.052

  • wR(F2) = 0.175

  • S = 1.05

  • 1592 reflections

  • 104 parameters

  • H-atom parameters constrained

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.15 e Å−3

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

Supporting information


Comment top

α-Diimine ligand nickel catalysts greatly attracted attention due to their high catalytic activity in ethylene polymerization (Johnson et al., 1995; Killian et al., 1996). Design and synthesis of the ligands is crucial (Popeney et al., 2005, 2010, 2011; Yuan et al., 2005). Herewith we present the title compound (I).

In (I) (Fig. 1), the single C—C bond in 1,4-diazabutadiene fragment is trans-configured and situated on inversion center. The dihedral angle between the benzene ring and 1,4-diazabutadiene plane is 78.3 (2)°. However, the trans-configured ligand can be transformed into cis-configured ligand in order to facilitate the formation of α-diimine-metal complexes, for examples, see Yuan et al. (2011) for Ni complex, and Kia et al. (2005) for Re complex.

Related literature top

For applications of α-diimine ligands, see: Johnson et al. (1995); Killian et al. (1996). For the design and synthesis of new α-diimine derivatives, see: Yuan et al. (2005); Popeney & Guan (2005, 2010); Popeney et al. (2011). The crystal structures of Re and Ni complexes with the title ligand were reported by Kia et al. (2005) and Yuan et al. (2011), respectively.

Experimental top

Formic acid (1 ml) was added to a stirred solution of 2,3-butanedione (0.052 g, 0.6 mmol) and 2,4-dimethylaniline (0.144 g, 1.2 mmol) in methanol (30 ml). The mixture was refluxed for 24 h, then cooled and the precipitate was separated by filtration. The solid was recrystallized from ethanol/dichloromethane (v/v = 8:1), washed and dried under vacuum. Yield: 0.160 g (82%). Crystals suitable for X-ray structure determination were grown from a solution of the title compound in a mixture of cyclohexane/dichloromethane (1:2, 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, respectively. They were included in the refinement in a riding model approximation, with Uiso = 1.2-1.5 Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with the atom-labelling scheme [symmetry code: (a) 1 - x, 2 - y, 1 - z]. Displacement ellipsoids are shown at the 30% probability level.
(Z)-N-[(Z)-3-(2,4-Dimethylphenylimino)butan-2-ylidene]- 2,4-dimethylaniline top
Crystal data top
C20H24N2Dx = 1.135 Mg m3
Mr = 292.41Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PbcaCell parameters from 1144 reflections
a = 13.50 (1) Åθ = 2.9–23.2°
b = 7.571 (6) ŵ = 0.07 mm1
c = 16.738 (12) ÅT = 296 K
V = 1711 (2) Å3Block, yellow
Z = 40.23 × 0.20 × 0.14 mm
F(000) = 632
Data collection top
Bruker APEXII CCD
diffractometer
1592 independent reflections
Radiation source: fine-focus sealed tube1043 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.031
ϕ and ω scansθmax = 25.5°, θmin = 2.4°
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
h = 816
Tmin = 0.985, Tmax = 0.991k = 69
5143 measured reflectionsl = 1620
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) = 0.175 w = 1/[σ2(Fo2) + (0.0962P)2 + 0.2091P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
1592 reflectionsΔρmax = 0.21 e Å3
104 parametersΔρmin = 0.15 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.009 (4)
Crystal data top
C20H24N2V = 1711 (2) Å3
Mr = 292.41Z = 4
Orthorhombic, PbcaMo Kα radiation
a = 13.50 (1) ŵ = 0.07 mm1
b = 7.571 (6) ÅT = 296 K
c = 16.738 (12) Å0.23 × 0.20 × 0.14 mm
Data collection top
Bruker APEXII CCD
diffractometer
1592 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
1043 reflections with I > 2σ(I)
Tmin = 0.985, Tmax = 0.991Rint = 0.031
5143 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0520 restraints
wR(F2) = 0.175H-atom parameters constrained
S = 1.05Δρmax = 0.21 e Å3
1592 reflectionsΔρmin = 0.15 e Å3
104 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
C10.60082 (15)0.9674 (3)0.65918 (13)0.0471 (6)
C20.69975 (15)0.9165 (3)0.66744 (13)0.0464 (6)
C30.72926 (16)0.8473 (3)0.74028 (13)0.0528 (6)
H30.79460.81040.74600.063*
C40.66613 (18)0.8305 (3)0.80502 (13)0.0548 (6)
C50.56961 (18)0.8859 (3)0.79551 (14)0.0596 (7)
H50.52570.87820.83820.072*
C60.53728 (17)0.9527 (3)0.72328 (15)0.0579 (7)
H60.47170.98820.71780.070*
C70.77174 (18)0.9360 (3)0.59996 (15)0.0669 (8)
H7A0.74030.90260.55080.100*
H7B0.82800.86120.60920.100*
H7C0.79311.05670.59660.100*
C80.7013 (2)0.7515 (4)0.88279 (14)0.0795 (9)
H8A0.76420.69510.87470.119*
H8B0.65400.66590.90110.119*
H8C0.70810.84320.92200.119*
C90.51658 (15)0.9537 (3)0.53705 (12)0.0467 (6)
C100.48786 (19)0.7641 (3)0.54753 (15)0.0662 (7)
H10A0.51910.71770.59460.099*
H10B0.50880.69760.50170.099*
H10C0.41720.75550.55300.099*
N10.56812 (12)1.0428 (2)0.58600 (11)0.0516 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0501 (13)0.0426 (12)0.0487 (13)0.0029 (9)0.0084 (10)0.0010 (10)
C20.0488 (13)0.0429 (12)0.0476 (13)0.0017 (9)0.0048 (9)0.0027 (10)
C30.0475 (12)0.0526 (13)0.0583 (14)0.0050 (10)0.0116 (10)0.0000 (11)
C40.0658 (15)0.0504 (14)0.0483 (14)0.0026 (12)0.0108 (11)0.0014 (11)
C50.0630 (15)0.0636 (16)0.0523 (14)0.0035 (12)0.0046 (11)0.0049 (12)
C60.0482 (12)0.0610 (16)0.0646 (15)0.0054 (11)0.0008 (11)0.0083 (12)
C70.0624 (15)0.0685 (17)0.0697 (16)0.0067 (12)0.0087 (12)0.0054 (13)
C80.0911 (19)0.089 (2)0.0584 (16)0.0039 (15)0.0191 (14)0.0118 (15)
C90.0401 (11)0.0499 (14)0.0501 (13)0.0004 (9)0.0031 (9)0.0045 (10)
C100.0783 (17)0.0551 (15)0.0652 (16)0.0118 (12)0.0161 (12)0.0118 (12)
N10.0503 (11)0.0505 (11)0.0540 (12)0.0017 (8)0.0086 (9)0.0083 (9)
Geometric parameters (Å, º) top
C1—C61.378 (3)C7—H7A0.9600
C1—C21.397 (3)C7—H7B0.9600
C1—N11.421 (3)C7—H7C0.9600
C2—C31.385 (3)C8—H8A0.9600
C2—C71.497 (3)C8—H8B0.9600
C3—C41.384 (3)C8—H8C0.9600
C3—H30.9300C9—N11.269 (3)
C4—C51.378 (3)C9—C9i1.494 (4)
C4—C81.509 (3)C9—C101.497 (3)
C5—C61.381 (3)C10—H10A0.9600
C5—H50.9300C10—H10B0.9600
C6—H60.9300C10—H10C0.9600
C6—C1—C2119.7 (2)H7A—C7—H7B109.5
C6—C1—N1120.67 (19)C2—C7—H7C109.5
C2—C1—N1119.5 (2)H7A—C7—H7C109.5
C3—C2—C1117.8 (2)H7B—C7—H7C109.5
C3—C2—C7121.0 (2)C4—C8—H8A109.5
C1—C2—C7121.2 (2)C4—C8—H8B109.5
C4—C3—C2123.1 (2)H8A—C8—H8B109.5
C4—C3—H3118.4C4—C8—H8C109.5
C2—C3—H3118.4H8A—C8—H8C109.5
C5—C4—C3117.6 (2)H8B—C8—H8C109.5
C5—C4—C8121.2 (2)N1—C9—C9i116.8 (2)
C3—C4—C8121.2 (2)N1—C9—C10125.18 (19)
C4—C5—C6120.7 (2)C9i—C9—C10118.0 (2)
C4—C5—H5119.6C9—C10—H10A109.5
C6—C5—H5119.6C9—C10—H10B109.5
C1—C6—C5121.0 (2)H10A—C10—H10B109.5
C1—C6—H6119.5C9—C10—H10C109.5
C5—C6—H6119.5H10A—C10—H10C109.5
C2—C7—H7A109.5H10B—C10—H10C109.5
C2—C7—H7B109.5C9—N1—C1120.87 (19)
C6—C1—C2—C31.9 (3)C8—C4—C5—C6177.9 (2)
N1—C1—C2—C3178.55 (19)C2—C1—C6—C50.9 (4)
C6—C1—C2—C7178.0 (2)N1—C1—C6—C5177.5 (2)
N1—C1—C2—C71.4 (3)C4—C5—C6—C10.7 (4)
C1—C2—C3—C41.5 (3)C9i—C9—N1—C1178.3 (2)
C7—C2—C3—C4178.4 (2)C10—C9—N1—C12.4 (3)
C2—C3—C4—C50.0 (3)C6—C1—N1—C978.8 (3)
C2—C3—C4—C8179.0 (2)C2—C1—N1—C9104.6 (2)
C3—C4—C5—C61.1 (4)
Symmetry code: (i) x+1, y+2, z+1.

Experimental details

Crystal data
Chemical formulaC20H24N2
Mr292.41
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)296
a, b, c (Å)13.50 (1), 7.571 (6), 16.738 (12)
V3)1711 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.23 × 0.20 × 0.14
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2008)
Tmin, Tmax0.985, 0.991
No. of measured, independent and
observed [I > 2σ(I)] reflections
5143, 1592, 1043
Rint0.031
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.052, 0.175, 1.05
No. of reflections1592
No. of parameters104
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.15

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

We thank the National Natural Science Foundation of China (grant No. 20964003) for funding. We also thank the Key Laboratory of Eco Environment-Related Polymer Materials of the Ministry of Education and Key Laboratory of Polymer Materials of Gansu Province (Northwest Normal University) for financial support.

References

First citationBruker (2008). APEX2, SAINT and SADABS. 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 citationKia, R., Mirkhani, V., Deák, A. & Kálmán, A. (2005). Acta Cryst. E61, m566–m567.  Web of Science CSD CrossRef IUCr Journals
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. (2005). Organometallics, 24, 1145–1155.  Web of Science CrossRef CAS
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., Mei, T. J., Gomes, P. T., Marques, M. M., Wang, X. H., Liu, Y. F., Miao, C. P. & Xie, X. L. (2011). J. Organomet. Chem. 696, 3251–3256.  Web of Science CSD CrossRef CAS
First citationYuan, J. C., SiIva, 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

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