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ISSN: 2056-9890

N,N′-Bis[(E)-2,4,6-tri­methyl­benzyl­­idene]ethane-1,2-di­amine

aNelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth 6031, South Africa
*Correspondence e-mail: richard.betz@webmail.co.za

(Received 12 July 2011; accepted 20 July 2011; online 30 July 2011)

The title compound, C22H28N2, which is a double imine derived from ethane-1,2-diamine and mesityl aldehyde, has crystallographic inversion symmetry, with both C=N bonds E configured. The dihedral angle between the mesityl ring system and the imide functional group is 23.89 (17)°.

Related literature

For background to applications of chelate complexes, see: Gade (1998[Gade, L. H. (1998). Koordinationschemie, 1. Auflage. Weinheim: Wiley-VCH.]). For the crystal structure of a palladium coord­ination compound involving the title compound as a ligand, see: Arici et al. (2006[Arici, C., Ülkü, D., Özdemir, I., Demir, S. & Cetinkaya, B. (2006). J. Coord. Chem. 59, 797-802.]).

[Scheme 1]

Experimental

Crystal data
  • C22H28N2

  • Mr = 320.46

  • Monoclinic, P 21 /c

  • a = 11.1346 (5) Å

  • b = 5.2082 (2) Å

  • c = 15.9958 (7) Å

  • β = 93.154 (2)°

  • V = 926.21 (7) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 200 K

  • 0.21 × 0.09 × 0.07 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • 8541 measured reflections

  • 2298 independent reflections

  • 1205 reflections with I > 2σ(I)

  • Rint = 0.066

Refinement
  • R[F2 > 2σ(F2)] = 0.047

  • wR(F2) = 0.113

  • S = 0.89

  • 2298 reflections

  • 112 parameters

  • H-atom parameters constrained

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.18 e Å−3

Data collection: APEX2 (Bruker, 2010[Bruker (2010). APEX2 and SAINT Bruker AXS Inc., Madison, USA.]); cell refinement: SAINT (Bruker, 2010[Bruker (2010). APEX2 and SAINT Bruker AXS Inc., Madison, 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: ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Chelate ligands have found widespread use in coordination chemistry due to the enhanced thermodynamic stability of resultant metal complexes in relation to those compounds involving comparable monodentate ligands exclusively (Gade, 1998). In our continuing efforts in elucidating the rules governing the formation of metal complexes with nitrogen-containing chelate ligands, we determined the structure of the title compound, C22H28N2, to allow comparative studies on designed coordination compounds. Structural information on a palladium(II) complex featuring the title compound as a ligand is found in the literature (Arici et al., 2006).

The title compound has crystallographic inversion symmetry, the asymmetric unit comprising half a molecule, with both double-bonds (E)-configured (Fig. 1). Mesomeric interaction between the aromatic systems and the imine groups is hampered by the presence of the bulky methyl groups in the mesityl moiety which is evident in the out-of-plane orientation of the functional group of the Schiff-base. The dihedral angle between the least-squares planes defined by the carbon atoms of the mesityl group and those of the imine functional group (C—NC) is 23.89 (17)°.

In the crystal structure, no significant intermolecular interactions are present (Fig. 2). The shortest inter-centroid distance between two aromatic ring systems was found to be 5.6101 (9) Å.

Related literature top

For backgroundto applications of chelate complexes, see: Gade (1998). For the crystal structure of a palladium coordination compound involving the title compound as a ligand, see: Arici et al. (2006).

Experimental top

The title compound was prepared from the reaction of ethylenediamine (0.017 mol) and 2,4,6-trimethylbenzaldehyde (0.034 mol) at room temperature for two hours. The colourless title compound was filtered and recrystallized from methanol.

Refinement top

Carbon-bound H atoms were placed in calculated positions (C—H = 0.95–0.99 Å) and were included in the refinement in the riding model approximation, with Uiso(H) set to 1.2Ueq(aromatic and methylene C) or 1.5Ueq(methyl C). The H atoms of the methyl groups were allowed to rotate.

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with atom labels and anisotropic displacement ellipsoids (drawn at the 50% probability level). For symmetry code (i): -x + 1, -y, -z.
[Figure 2] Fig. 2. Molecular packing of the title compound, viewed along [0 1 0] (anisotropic displacement ellipsoids drawn at the 50% probability level).
N,N'-Bis[(E)-2,4,6-trimethylbenzylidene]ethane-1,2-diamine top
Crystal data top
C22H28N2F(000) = 348
Mr = 320.46Dx = 1.149 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1409 reflections
a = 11.1346 (5) Åθ = 2.6–25.2°
b = 5.2082 (2) ŵ = 0.07 mm1
c = 15.9958 (7) ÅT = 200 K
β = 93.154 (2)°Rod, colourless
V = 926.21 (7) Å30.21 × 0.09 × 0.07 mm
Z = 2
Data collection top
Bruker APEXII CCD
diffractometer
1205 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.066
Graphite monochromatorθmax = 28.3°, θmin = 1.8°
ϕ and ω scansh = 1414
8541 measured reflectionsk = 66
2298 independent reflectionsl = 2121
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)] = 0.047Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.113H-atom parameters constrained
S = 0.89 w = 1/[σ2(Fo2) + (0.0511P)2]
where P = (Fo2 + 2Fc2)/3
2298 reflections(Δ/σ)max < 0.001
112 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.18 e Å3
Crystal data top
C22H28N2V = 926.21 (7) Å3
Mr = 320.46Z = 2
Monoclinic, P21/cMo Kα radiation
a = 11.1346 (5) ŵ = 0.07 mm1
b = 5.2082 (2) ÅT = 200 K
c = 15.9958 (7) Å0.21 × 0.09 × 0.07 mm
β = 93.154 (2)°
Data collection top
Bruker APEXII CCD
diffractometer
1205 reflections with I > 2σ(I)
8541 measured reflectionsRint = 0.066
2298 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0470 restraints
wR(F2) = 0.113H-atom parameters constrained
S = 0.89Δρmax = 0.21 e Å3
2298 reflectionsΔρmin = 0.18 e Å3
112 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.37236 (13)0.1259 (3)0.05808 (8)0.0384 (4)
C10.34978 (14)0.0574 (3)0.13110 (10)0.0315 (4)
H10.37710.10780.14860.038*
C20.43958 (14)0.0558 (3)0.00940 (10)0.0400 (5)
H2A0.39340.09540.04370.048*
H2B0.45140.21770.04120.048*
C110.28497 (13)0.2094 (3)0.19186 (9)0.0275 (4)
C120.20161 (14)0.4033 (3)0.16864 (9)0.0297 (4)
C130.14202 (14)0.5283 (3)0.23055 (9)0.0340 (4)
H130.08590.65930.21470.041*
C140.16123 (14)0.4694 (3)0.31499 (10)0.0322 (4)
C150.24383 (14)0.2802 (3)0.33654 (9)0.0320 (4)
H150.25840.23850.39400.038*
C160.30645 (14)0.1486 (3)0.27741 (9)0.0290 (4)
C170.17222 (15)0.4778 (3)0.07837 (10)0.0398 (5)
H17A0.10500.59960.07560.060*
H17B0.14980.32400.04580.060*
H17C0.24280.55790.05520.060*
C180.09542 (17)0.6100 (3)0.38071 (11)0.0487 (5)
H18A0.12990.56350.43640.073*
H18B0.01010.56250.37620.073*
H18C0.10340.79550.37230.073*
C190.39721 (15)0.0503 (3)0.30684 (10)0.0394 (4)
H19A0.40740.04540.36810.059*
H19B0.47440.01420.28270.059*
H19C0.36890.22090.28890.059*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0414 (8)0.0446 (9)0.0303 (8)0.0052 (7)0.0114 (6)0.0025 (7)
C10.0324 (9)0.0305 (9)0.0319 (9)0.0017 (7)0.0039 (7)0.0024 (7)
C20.0443 (11)0.0457 (11)0.0308 (9)0.0052 (9)0.0099 (8)0.0067 (8)
C110.0271 (8)0.0303 (9)0.0255 (8)0.0059 (7)0.0049 (7)0.0009 (7)
C120.0297 (9)0.0327 (9)0.0267 (9)0.0040 (7)0.0023 (7)0.0001 (7)
C130.0332 (9)0.0365 (10)0.0321 (9)0.0045 (8)0.0014 (7)0.0005 (8)
C140.0330 (9)0.0355 (10)0.0286 (9)0.0016 (8)0.0058 (7)0.0048 (7)
C150.0372 (10)0.0367 (10)0.0224 (8)0.0068 (8)0.0035 (7)0.0017 (7)
C160.0309 (9)0.0283 (9)0.0281 (9)0.0051 (7)0.0037 (7)0.0022 (7)
C170.0418 (10)0.0490 (11)0.0288 (9)0.0045 (9)0.0028 (8)0.0044 (8)
C180.0547 (12)0.0546 (13)0.0377 (11)0.0095 (10)0.0118 (9)0.0082 (9)
C190.0425 (10)0.0408 (10)0.0349 (10)0.0029 (9)0.0024 (8)0.0065 (8)
Geometric parameters (Å, º) top
N1—C11.2597 (19)C14—C181.504 (2)
N1—C21.458 (2)C15—C161.387 (2)
C1—C111.473 (2)C15—H150.9500
C1—H10.9500C16—C191.505 (2)
C2—C2i1.511 (3)C17—H17A0.9800
C2—H2A0.9900C17—H17B0.9800
C2—H2B0.9900C17—H17C0.9800
C11—C121.408 (2)C18—H18A0.9800
C11—C161.412 (2)C18—H18B0.9800
C12—C131.385 (2)C18—H18C0.9800
C12—C171.513 (2)C19—H19A0.9800
C13—C141.390 (2)C19—H19B0.9800
C13—H130.9500C19—H19C0.9800
C14—C151.379 (2)
C1—N1—C2116.49 (14)C14—C15—H15118.8
N1—C1—C11126.14 (15)C16—C15—H15118.8
N1—C1—H1116.9C15—C16—C11119.02 (15)
C11—C1—H1116.9C15—C16—C19118.77 (15)
N1—C2—C2i110.22 (17)C11—C16—C19122.19 (14)
N1—C2—H2A109.6C12—C17—H17A109.5
C2i—C2—H2A109.6C12—C17—H17B109.5
N1—C2—H2B109.6H17A—C17—H17B109.5
C2i—C2—H2B109.6C12—C17—H17C109.5
H2A—C2—H2B108.1H17A—C17—H17C109.5
C12—C11—C16119.39 (14)H17B—C17—H17C109.5
C12—C11—C1123.46 (14)C14—C18—H18A109.5
C16—C11—C1117.12 (14)C14—C18—H18B109.5
C13—C12—C11118.92 (14)H18A—C18—H18B109.5
C13—C12—C17118.36 (15)C14—C18—H18C109.5
C11—C12—C17122.71 (14)H18A—C18—H18C109.5
C12—C13—C14122.47 (16)H18B—C18—H18C109.5
C12—C13—H13118.8C16—C19—H19A109.5
C14—C13—H13118.8C16—C19—H19B109.5
C15—C14—C13117.75 (14)H19A—C19—H19B109.5
C15—C14—C18121.14 (15)C16—C19—H19C109.5
C13—C14—C18121.11 (16)H19A—C19—H19C109.5
C14—C15—C16122.43 (15)H19B—C19—H19C109.5
C2—N1—C1—C11179.13 (14)C12—C13—C14—C150.5 (2)
C1—N1—C2—C2i115.7 (2)C12—C13—C14—C18179.66 (16)
N1—C1—C11—C1225.0 (2)C13—C14—C15—C160.4 (2)
N1—C1—C11—C16156.94 (15)C18—C14—C15—C16179.55 (16)
C16—C11—C12—C130.5 (2)C14—C15—C16—C110.1 (2)
C1—C11—C12—C13177.53 (15)C14—C15—C16—C19178.47 (15)
C16—C11—C12—C17179.17 (14)C12—C11—C16—C150.6 (2)
C1—C11—C12—C171.2 (2)C1—C11—C16—C15177.54 (14)
C11—C12—C13—C140.1 (2)C12—C11—C16—C19177.96 (14)
C17—C12—C13—C14178.66 (14)C1—C11—C16—C193.9 (2)
Symmetry code: (i) x+1, y, z.

Experimental details

Crystal data
Chemical formulaC22H28N2
Mr320.46
Crystal system, space groupMonoclinic, P21/c
Temperature (K)200
a, b, c (Å)11.1346 (5), 5.2082 (2), 15.9958 (7)
β (°) 93.154 (2)
V3)926.21 (7)
Z2
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.21 × 0.09 × 0.07
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
8541, 2298, 1205
Rint0.066
(sin θ/λ)max1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.047, 0.113, 0.89
No. of reflections2298
No. of parameters112
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.18

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

 

Acknowledgements

The authors thank Mr Gunther Hufnagel for helpful discussions.

References

First citationArici, C., Ülkü, D., Özdemir, I., Demir, S. & Cetinkaya, B. (2006). J. Coord. Chem. 59, 797–802.  Web of Science CSD CrossRef CAS Google Scholar
First citationBruker (2010). APEX2 and SAINT Bruker AXS Inc., Madison, USA.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationGade, L. H. (1998). Koordinationschemie, 1. Auflage. Weinheim: Wiley–VCH.  Google Scholar
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CrossRef CAS 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. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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