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

Yumata, N.; Gerber, T.; Hosten, E.; Betz, R.

doi:10.1107/S1600536811029424

organic compounds

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ISSN: 2056-9890

Volume 67| Part 8| August 2011| Page o2175

doi:10.1107/S1600536811029424

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

Nonzaliseko Yumata,^a Thomas Gerber,^a Eric Hosten ^a and Richard Betz ^a ^*

^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 ). For the crystal structure of a palladium coordination compound involving the title compound as a ligand, see: Arici et al. (2006 ).

Experimental

Crystal data

C₂₂H₂₈N₂
M_r = 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)
R_int = 0.066

Refinement

R[F² > 2σ(F²)] = 0.047
wR(F²) = 0.113
S = 0.89
2298 reflections
112 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: APEX2 (Bruker, 2010 ); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT; 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 and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811029424/zs2130sup1.cif

Supporting information file. DOI: 10.1107/S1600536811029424/zs2130Isup2.cdx

Structure factors: contains datablock I. DOI: 10.1107/S1600536811029424/zs2130Isup3.hkl

Supporting information file. DOI: 10.1107/S1600536811029424/zs2130Isup4.cml

checkCIF report

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—N═C) 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.

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

	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.
	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

C₂₂H₂₈N₂	F(000) = 348
M_r = 320.46	D_x = 1.149 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1409 reflections
a = 11.1346 (5) Å	θ = 2.6–25.2°
b = 5.2082 (2) Å	µ = 0.07 mm⁻¹
c = 15.9958 (7) Å	T = 200 K
β = 93.154 (2)°	Rod, colourless
V = 926.21 (7) Å³	0.21 × 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 tube	R_int = 0.066
Graphite monochromator	θ_max = 28.3°, θ_min = 1.8°
ϕ and ω scans	h = −14→14
8541 measured reflections	k = −6→6
2298 independent reflections	l = −21→21

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.113	H-atom parameters constrained
S = 0.89	w = 1/[σ²(F_o²) + (0.0511P)²] where P = (F_o² + 2F_c²)/3
2298 reflections	(Δ/σ)_max < 0.001
112 parameters	Δρ_max = 0.21 e Å⁻³
0 restraints	Δρ_min = −0.18 e Å⁻³

Crystal data top

C₂₂H₂₈N₂	V = 926.21 (7) Å³
M_r = 320.46	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 11.1346 (5) Å	µ = 0.07 mm⁻¹
b = 5.2082 (2) Å	T = 200 K
c = 15.9958 (7) Å	0.21 × 0.09 × 0.07 mm
β = 93.154 (2)°

Data collection top

Bruker APEXII CCD diffractometer	1205 reflections with I > 2σ(I)
8541 measured reflections	R_int = 0.066
2298 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.047	0 restraints
wR(F²) = 0.113	H-atom parameters constrained
S = 0.89	Δρ_max = 0.21 e Å⁻³
2298 reflections	Δρ_min = −0.18 e Å⁻³
112 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
N1	0.37236 (13)	0.1259 (3)	0.05808 (8)	0.0384 (4)
C1	0.34978 (14)	0.0574 (3)	0.13110 (10)	0.0315 (4)
H1	0.3771	−0.1078	0.1486	0.038*
C2	0.43958 (14)	−0.0558 (3)	0.00940 (10)	0.0400 (5)
H2A	0.3934	−0.0954	−0.0437	0.048*
H2B	0.4514	−0.2177	0.0412	0.048*
C11	0.28497 (13)	0.2094 (3)	0.19186 (9)	0.0275 (4)
C12	0.20161 (14)	0.4033 (3)	0.16864 (9)	0.0297 (4)
C13	0.14202 (14)	0.5283 (3)	0.23055 (9)	0.0340 (4)
H13	0.0859	0.6593	0.2147	0.041*
C14	0.16123 (14)	0.4694 (3)	0.31499 (10)	0.0322 (4)
C15	0.24383 (14)	0.2802 (3)	0.33654 (9)	0.0320 (4)
H15	0.2584	0.2385	0.3940	0.038*
C16	0.30645 (14)	0.1486 (3)	0.27741 (9)	0.0290 (4)
C17	0.17222 (15)	0.4778 (3)	0.07837 (10)	0.0398 (5)
H17A	0.1050	0.5996	0.0756	0.060*
H17B	0.1498	0.3240	0.0458	0.060*
H17C	0.2428	0.5579	0.0552	0.060*
C18	0.09542 (17)	0.6100 (3)	0.38071 (11)	0.0487 (5)
H18A	0.1299	0.5635	0.4364	0.073*
H18B	0.0101	0.5625	0.3762	0.073*
H18C	0.1034	0.7955	0.3723	0.073*
C19	0.39721 (15)	−0.0503 (3)	0.30684 (10)	0.0394 (4)
H19A	0.4074	−0.0454	0.3681	0.059*
H19B	0.4744	−0.0142	0.2827	0.059*
H19C	0.3689	−0.2209	0.2889	0.059*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0414 (8)	0.0446 (9)	0.0303 (8)	0.0052 (7)	0.0114 (6)	−0.0025 (7)
C1	0.0324 (9)	0.0305 (9)	0.0319 (9)	−0.0017 (7)	0.0039 (7)	−0.0024 (7)
C2	0.0443 (11)	0.0457 (11)	0.0308 (9)	0.0052 (9)	0.0099 (8)	−0.0067 (8)
C11	0.0271 (8)	0.0303 (9)	0.0255 (8)	−0.0059 (7)	0.0049 (7)	−0.0009 (7)
C12	0.0297 (9)	0.0327 (9)	0.0267 (9)	−0.0040 (7)	0.0023 (7)	0.0001 (7)
C13	0.0332 (9)	0.0365 (10)	0.0321 (9)	0.0045 (8)	0.0014 (7)	−0.0005 (8)
C14	0.0330 (9)	0.0355 (10)	0.0286 (9)	−0.0016 (8)	0.0058 (7)	−0.0048 (7)
C15	0.0372 (10)	0.0367 (10)	0.0224 (8)	−0.0068 (8)	0.0035 (7)	0.0017 (7)
C16	0.0309 (9)	0.0283 (9)	0.0281 (9)	−0.0051 (7)	0.0037 (7)	0.0022 (7)
C17	0.0418 (10)	0.0490 (11)	0.0288 (9)	0.0045 (9)	0.0028 (8)	0.0044 (8)
C18	0.0547 (12)	0.0546 (13)	0.0377 (11)	0.0095 (10)	0.0118 (9)	−0.0082 (9)
C19	0.0425 (10)	0.0408 (10)	0.0349 (10)	0.0029 (9)	0.0024 (8)	0.0065 (8)

Geometric parameters (Å, º) top

N1—C1	1.2597 (19)	C14—C18	1.504 (2)
N1—C2	1.458 (2)	C15—C16	1.387 (2)
C1—C11	1.473 (2)	C15—H15	0.9500
C1—H1	0.9500	C16—C19	1.505 (2)
C2—C2ⁱ	1.511 (3)	C17—H17A	0.9800
C2—H2A	0.9900	C17—H17B	0.9800
C2—H2B	0.9900	C17—H17C	0.9800
C11—C12	1.408 (2)	C18—H18A	0.9800
C11—C16	1.412 (2)	C18—H18B	0.9800
C12—C13	1.385 (2)	C18—H18C	0.9800
C12—C17	1.513 (2)	C19—H19A	0.9800
C13—C14	1.390 (2)	C19—H19B	0.9800
C13—H13	0.9500	C19—H19C	0.9800
C14—C15	1.379 (2)

C1—N1—C2	116.49 (14)	C14—C15—H15	118.8
N1—C1—C11	126.14 (15)	C16—C15—H15	118.8
N1—C1—H1	116.9	C15—C16—C11	119.02 (15)
C11—C1—H1	116.9	C15—C16—C19	118.77 (15)
N1—C2—C2ⁱ	110.22 (17)	C11—C16—C19	122.19 (14)
N1—C2—H2A	109.6	C12—C17—H17A	109.5
C2ⁱ—C2—H2A	109.6	C12—C17—H17B	109.5
N1—C2—H2B	109.6	H17A—C17—H17B	109.5
C2ⁱ—C2—H2B	109.6	C12—C17—H17C	109.5
H2A—C2—H2B	108.1	H17A—C17—H17C	109.5
C12—C11—C16	119.39 (14)	H17B—C17—H17C	109.5
C12—C11—C1	123.46 (14)	C14—C18—H18A	109.5
C16—C11—C1	117.12 (14)	C14—C18—H18B	109.5
C13—C12—C11	118.92 (14)	H18A—C18—H18B	109.5
C13—C12—C17	118.36 (15)	C14—C18—H18C	109.5
C11—C12—C17	122.71 (14)	H18A—C18—H18C	109.5
C12—C13—C14	122.47 (16)	H18B—C18—H18C	109.5
C12—C13—H13	118.8	C16—C19—H19A	109.5
C14—C13—H13	118.8	C16—C19—H19B	109.5
C15—C14—C13	117.75 (14)	H19A—C19—H19B	109.5
C15—C14—C18	121.14 (15)	C16—C19—H19C	109.5
C13—C14—C18	121.11 (16)	H19A—C19—H19C	109.5
C14—C15—C16	122.43 (15)	H19B—C19—H19C	109.5

C2—N1—C1—C11	179.13 (14)	C12—C13—C14—C15	0.5 (2)
C1—N1—C2—C2ⁱ	−115.7 (2)	C12—C13—C14—C18	179.66 (16)
N1—C1—C11—C12	25.0 (2)	C13—C14—C15—C16	−0.4 (2)
N1—C1—C11—C16	−156.94 (15)	C18—C14—C15—C16	−179.55 (16)
C16—C11—C12—C13	−0.5 (2)	C14—C15—C16—C11	−0.1 (2)
C1—C11—C12—C13	177.53 (15)	C14—C15—C16—C19	178.47 (15)
C16—C11—C12—C17	−179.17 (14)	C12—C11—C16—C15	0.6 (2)
C1—C11—C12—C17	−1.2 (2)	C1—C11—C16—C15	−177.54 (14)
C11—C12—C13—C14	−0.1 (2)	C12—C11—C16—C19	−177.96 (14)
C17—C12—C13—C14	178.66 (14)	C1—C11—C16—C19	3.9 (2)

Symmetry code: (i) −x+1, −y, −z.

Experimental details

Crystal data
Chemical formula	C₂₂H₂₈N₂
M_r	320.46
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	200
a, b, c (Å)	11.1346 (5), 5.2082 (2), 15.9958 (7)
β (°)	93.154 (2)
V (Å³)	926.21 (7)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.07
Crystal size (mm)	0.21 × 0.09 × 0.07

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	8541, 2298, 1205
R_int	0.066
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.047, 0.113, 0.89
No. of reflections	2298
No. of parameters	112
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	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

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