supplementary materials


bt6904 scheme

Acta Cryst. (2013). E69, o905    [ doi:10.1107/S160053681301249X ]

N-[4-(Dimethylamino)benzylidene]-4-methylaniline

R. K. Balachandar, S. Kalainathan, S. M. Eappen and J. Podder

Abstract top

The molecules of the title compound, C16H18N2, exists in a trans conformation with respect to the C=N bond [1.270 (3) Å]. The least-squares plane of the dimethylamino group makes a dihedral angle of 1.3 (2)° with the ring to which it is attached. The dihedral angle between the two aromatic rings is 11.70 (2)°. The crystal structure features weak C-H...[pi] interactions.

Comment top

Schiff bases are among the most useful ligands in coordination chemistry as they readily form stable complexes with most transition metals (Xia et al., 2009). They are known to exibit potent anti-bacterial, anti-convulsant, anti-inflammatory and anti-cancer activities (Shah et al., 1992). In addition to that, they show Non-linear optical properties (Ünver et al., 2004). Therefore, successful application of Schiff bases requires a careful study of their characteristics.

The title compound, C16H18N2, exists in a trans configuration with respect to the CN bond[1.270 (3) Å]. The N1C8 bond length of 1.270 (3) Å is shorter than the N–C bond [1.413 (3) Å], indicating a typical imine double bond. The C–N–C angle is 120.6 (2) °. X-ray analysis confirms the molecular structure and atom connectivity as illustrated in Fig. 1.

The least square plane of the dimethylamine group has a dihedral angle of 1.31 (2) ° with the phenyl ring (C9–C14), which shows that they are almost coplanar to each other. The dimethylamine group attached phenyl ring (C9–C14) forms a dihedral angle of 11.70 (2) Å with the methyl group attached phenyl ring (C2–C7).

The crystal packing is stabilized by C11—H11···Cg1i inter-molecular interactions, where Cg1 is the center of gravity of (C8–C14) phenyl ring. The symmetry code is 1/2-X,-1/2+Y,Z.

Related literature top

For the uses and biological importance of diketones, see: Xia et al. (2009); Shah et al. (1992); Ünver et al. (2004). For related structures, see: Fun et al. (2011); Khalaji & Simpson (2009).

Experimental top

The title compound was synthesized by the reaction of p-dimethylaminobenzaldehyde (10 mmol, 1.14919 g) with p-toluidine (10 mmol, 1.0717 g) in ethanol (25 ml) under reflux condition for six hours. After filtering, drying the solid product was recrystallized from ethanol/THF (5:1 v/v). After five days yellow colour crystals were obtained Which were suitable for X-ray diffraction studies.

Refinement top

The positions of hydrogen atoms were localized from the difference electron density maps and their distances were geometrically constrained. The H atoms bound to the C atoms were treated as riding atoms, with d(C–H) = 0.93 Å and Uiso(H) = 1.2Ueq(C) for aryl atoms; d(C–H) = 0.96 Å and Uiso(H) = 1.5Ueq(C) for methyl group. The methyl groups were allowed to rotate but not to tip.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT and XPREP (Bruker, 2004); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); 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 the atom numbering scheme, displacement ellipaoids are drawn at 30% probability level. H atoms are present as small spheres of arbitary radius.
[Figure 2] Fig. 2. The crystal packing of the title compound, viewed down a-axis, showing C11—H11···Cg1i inter-molecular interactions. The H atoms not involved in the bonding have been excluded for clarity.
N-[4-(Dimethylamino)benzylidene]-4-methylaniline top
Crystal data top
C16H18N2F(000) = 1024
Mr = 238.32Dx = 1.152 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 1737 reflections
a = 10.4814 (10) Åθ = 2.3–26.0°
b = 8.0528 (8) ŵ = 0.07 mm1
c = 32.571 (3) ÅT = 296 K
V = 2749.1 (4) Å3Block, yellow
Z = 80.30 × 0.25 × 0.20 mm
Data collection top
Bruker Kappa APEXII CCD
diffractometer
2692 independent reflections
Radiation source: fine-focus sealed tube1737 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.041
ω and φ scanθmax = 26.0°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Bruker, 2004)
h = 1212
Tmin = 0.980, Tmax = 0.987k = 97
17121 measured reflectionsl = 4040
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)] = 0.061H-atom parameters constrained
wR(F2) = 0.187 w = 1/[σ2(Fo2) + (0.0814P)2 + 0.8121P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max = 0.001
2692 reflectionsΔρmax = 0.21 e Å3
167 parametersΔρmin = 0.16 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: 0.0130 (19)
Crystal data top
C16H18N2V = 2749.1 (4) Å3
Mr = 238.32Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 10.4814 (10) ŵ = 0.07 mm1
b = 8.0528 (8) ÅT = 296 K
c = 32.571 (3) Å0.30 × 0.25 × 0.20 mm
Data collection top
Bruker Kappa APEXII CCD
diffractometer
2692 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2004)
1737 reflections with I > 2σ(I)
Tmin = 0.980, Tmax = 0.987Rint = 0.041
17121 measured reflectionsθmax = 26.0°
Refinement top
R[F2 > 2σ(F2)] = 0.061H-atom parameters constrained
wR(F2) = 0.187Δρmax = 0.21 e Å3
S = 1.08Δρmin = 0.16 e Å3
2692 reflectionsAbsolute structure: ?
167 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
C60.0030 (3)0.4888 (3)0.18005 (8)0.0768 (8)
H60.06580.52930.16510.092*
C140.0373 (2)0.2889 (2)0.03147 (7)0.0523 (6)
H140.01820.36710.04250.063*
C130.0307 (2)0.2534 (3)0.00941 (7)0.0528 (6)
H130.02970.30730.02550.063*
C150.1898 (3)0.0172 (4)0.08750 (8)0.0805 (8)
H15A0.27570.02430.08750.121*
H15B0.16290.03780.11520.121*
H15C0.18620.11870.07210.121*
C160.0139 (3)0.1841 (4)0.09499 (8)0.0809 (8)
H16A0.07050.15680.08570.121*
H16B0.02470.14680.12280.121*
H16C0.02580.30220.09380.121*
C100.2053 (2)0.0940 (2)0.03889 (7)0.0530 (6)
H100.26400.03800.05520.064*
C10.1192 (4)0.5064 (5)0.29002 (9)0.1148 (13)
H1A0.13670.62230.29390.172*
H1B0.18630.44160.30210.172*
H1C0.03950.47870.30290.172*
C30.2043 (3)0.3782 (4)0.22509 (9)0.0862 (9)
H30.27370.34000.24020.103*
C70.0115 (3)0.5248 (4)0.22110 (9)0.0831 (9)
H70.05210.58860.23330.100*
C40.1978 (3)0.3420 (4)0.18370 (8)0.0788 (8)
H40.26320.28230.17130.095*
C20.1112 (3)0.4694 (3)0.24474 (8)0.0791 (8)
C90.1257 (2)0.2105 (2)0.05712 (7)0.0482 (5)
C120.11276 (19)0.1375 (2)0.02776 (7)0.0477 (5)
C50.0941 (2)0.3941 (3)0.16042 (7)0.0607 (6)
N20.10664 (19)0.1037 (2)0.06899 (6)0.0632 (6)
N10.0775 (2)0.3645 (2)0.11798 (6)0.0630 (6)
C110.2007 (2)0.0582 (2)0.00217 (7)0.0527 (6)
H110.25670.01970.01310.063*
C80.1356 (2)0.2458 (3)0.10037 (7)0.0541 (6)
H22E0.18740.17780.11630.065*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C60.0832 (19)0.0809 (18)0.0664 (17)0.0181 (15)0.0077 (14)0.0081 (14)
C140.0464 (12)0.0402 (11)0.0703 (15)0.0053 (9)0.0058 (11)0.0021 (10)
C130.0470 (13)0.0445 (11)0.0669 (14)0.0029 (9)0.0055 (11)0.0087 (10)
C150.0811 (19)0.0882 (19)0.0721 (16)0.0062 (15)0.0070 (15)0.0134 (14)
C160.099 (2)0.0781 (18)0.0657 (16)0.0016 (15)0.0108 (15)0.0086 (13)
C100.0463 (13)0.0431 (11)0.0696 (14)0.0046 (9)0.0046 (11)0.0095 (10)
C10.147 (3)0.132 (3)0.0655 (18)0.002 (3)0.001 (2)0.0060 (18)
C30.094 (2)0.091 (2)0.0741 (18)0.0121 (17)0.0165 (16)0.0009 (15)
C70.092 (2)0.085 (2)0.0722 (18)0.0140 (16)0.0183 (17)0.0006 (15)
C40.077 (2)0.0833 (19)0.0759 (17)0.0150 (15)0.0038 (15)0.0099 (14)
C20.103 (2)0.0753 (18)0.0593 (16)0.0054 (16)0.0072 (16)0.0052 (13)
C90.0459 (12)0.0381 (11)0.0607 (13)0.0047 (8)0.0043 (10)0.0078 (9)
C120.0422 (12)0.0411 (11)0.0597 (13)0.0066 (8)0.0038 (10)0.0035 (9)
C50.0697 (17)0.0530 (13)0.0592 (14)0.0018 (11)0.0053 (12)0.0076 (11)
N20.0613 (13)0.0650 (12)0.0632 (12)0.0064 (10)0.0013 (10)0.0009 (10)
N10.0684 (14)0.0608 (12)0.0599 (12)0.0050 (10)0.0046 (10)0.0042 (9)
C110.0443 (13)0.0429 (11)0.0710 (14)0.0051 (9)0.0024 (11)0.0004 (10)
C80.0524 (13)0.0428 (12)0.0670 (14)0.0018 (9)0.0016 (11)0.0110 (10)
Geometric parameters (Å, º) top
C6—C71.371 (4)C1—C21.507 (4)
C6—C51.378 (3)C1—H1A0.9600
C6—H60.9300C1—H1B0.9600
C14—C131.364 (3)C1—H1C0.9600
C14—C91.398 (3)C3—C21.379 (4)
C14—H140.9300C3—C41.381 (4)
C13—C121.403 (3)C3—H30.9300
C13—H130.9300C7—C21.373 (4)
C15—N21.439 (3)C7—H70.9300
C15—H15A0.9600C4—C51.390 (3)
C15—H15B0.9600C4—H40.9300
C15—H15C0.9600C9—C81.441 (3)
C16—N21.443 (3)C12—N21.372 (3)
C16—H16A0.9600C12—C111.397 (3)
C16—H16B0.9600C5—N11.413 (3)
C16—H16C0.9600N1—C81.270 (3)
C10—C111.369 (3)C11—H110.9300
C10—C91.389 (3)C8—H22E0.9300
C10—H100.9300
C7—C6—C5121.6 (3)C2—C3—H3119.0
C7—C6—H6119.2C4—C3—H3119.0
C5—C6—H6119.2C6—C7—C2121.8 (3)
C13—C14—C9121.5 (2)C6—C7—H7119.1
C13—C14—H14119.3C2—C7—H7119.1
C9—C14—H14119.3C3—C4—C5120.5 (3)
C14—C13—C12121.6 (2)C3—C4—H4119.8
C14—C13—H13119.2C5—C4—H4119.8
C12—C13—H13119.2C7—C2—C3116.8 (3)
N2—C15—H15A109.5C7—C2—C1121.8 (3)
N2—C15—H15B109.5C3—C2—C1121.4 (3)
H15A—C15—H15B109.5C10—C9—C14116.6 (2)
N2—C15—H15C109.5C10—C9—C8120.6 (2)
H15A—C15—H15C109.5C14—C9—C8122.8 (2)
H15B—C15—H15C109.5N2—C12—C11121.6 (2)
N2—C16—H16A109.5N2—C12—C13121.4 (2)
N2—C16—H16B109.5C11—C12—C13117.1 (2)
H16A—C16—H16B109.5C6—C5—C4117.1 (2)
N2—C16—H16C109.5C6—C5—N1117.5 (2)
H16A—C16—H16C109.5C4—C5—N1125.3 (2)
H16B—C16—H16C109.5C12—N2—C15121.1 (2)
C11—C10—C9122.6 (2)C12—N2—C16121.1 (2)
C11—C10—H10118.7C15—N2—C16117.7 (2)
C9—C10—H10118.7C8—N1—C5120.6 (2)
C2—C1—H1A109.5C10—C11—C12120.6 (2)
C2—C1—H1B109.5C10—C11—H11119.7
H1A—C1—H1B109.5C12—C11—H11119.7
C2—C1—H1C109.5N1—C8—C9123.8 (2)
H1A—C1—H1C109.5N1—C8—H22E118.1
H1B—C1—H1C109.5C9—C8—H22E118.1
C2—C3—C4122.0 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···Cg1i0.932.943.670 (2)137
Symmetry code: (i) x, y+3/2, z1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···Cg1i0.932.943.670 (2)137
Symmetry code: (i) x, y+3/2, z1/2.
Acknowledgements top

The author acknowledges the STIC, Cochin 682 022, for the single-crystal XRD facility. The authors also thank Mr P. Narayanan and Dr K.Sethusankar, RKM Vivekananda College (Autonomous), Chennai 600 004, and VIT University for providing the excellent research facilities.

references
References top

Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343–350.

Bruker (2004). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.

Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.

Fun, H.-K., Quah, C. K., Huang, C. & Yu, H. (2011). Acta Cryst. E67, o1273–o1274.

Khalaji, A. D. & Simpson, J. (2009). Acta Cryst. E65, o553.

Shah, S., Vyas, R. & Mehta, R. H. (1992). J. Indian Chem. Soc. 69, 590–590.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Ünver, H., Karakas, A. & Elmali, A. (2004). J. Mol. Struct. 702, 49–54.

Xia, D.-G., Ye, Y.-F. & Lei, K.-W. (2009). Acta Cryst. E65, o3168.