N-[(E)-4-Chloro­benzyl­idene]-N′-phenyl­benzene-1,4-diamine

The title compound, C₁₉H₁₅ClN₂, adopts an E configuration with respect to the position of the chloro­benzene and diphenyl­amine groups on the C=N azomethine bond. The mol­ecule is not planar, the central six-membered ring making angles of 12.26 (10) and 44.18 (11)° with the 4-chloro­phenyl and phenyl rings, respectively. In the crystal structure, weak C—H...π inter­actions contribute to the stabilization of the packing.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.054
• wR factor = 0.127
• Data-to-parameter ratio = 14.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT420_ALERT_2_C D-H Without Acceptor       N2     -   H2A    ...          ?
PLAT717_ALERT_1_C D...A   Unknown or Inconsistent Label ..........    <I>CG</
PLAT717_ALERT_1_C D...A   Unknown or Inconsistent Label ..........    <I>CG</

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

The continuing study on Schiff bases are driven not only because of their application as ligands but also because of their biological (Singh & Dhakarey, 2009) and pharmaceutical properties and as corrosion inhibitors (Küstü et al., 2007).

The title compound, C₁₉H₁₅N₂Cl (I), is a Schiff base having chlorobenzylidene and phenyl groups attached at the terminal nitrogen atoms of the 1,4-diaminobenzene group (Fig.1). The whole molecule is not planar. Each benzene ring is planar with a maximum deviation of 0.011 (2) Å for the C6 atom from the (C1—C6) ring. The middle (C8—C13) ring makes angles of 12.26 (10)° and 44.18 (11)° with the (C1—C6) and (C14—C19) rings, respectively. The dihedral angle between (C1—C6) and (C14—C19) rings is 56.00 (11)°. The E conformation about the C7=N1 double bond is also observed in N,N' -bis(2-methoxybenzylidene)-p-phenylenediamine (II) with an angle of 12.10 (15)° between the mean planes of the benzene rings (Ojala et al., 2007). The bond lengths and angles are in normal ranges (Allen et al., 1987) and comparable to those in (II) and 2-{(4-(phenyldiazenyl)phenl]imino-methyl}phenol (Fun et al., 2008).

In the crystal structure, the molecule is stablized by C—H..π interactions, C1—H1B ···Cg3 (C14—C19) and C16—H16A···Cg1 (C1—C6) with H···Cg distances of 2.95 and 2.90 Å, and C—H···Cg angles of 135 and 136°, respectively.

Related literature

For related structures, see: Ojala et al. (2007); Fun et al. (2008). For standard bond lengths, see: Allen et al. (1987). For the biological activity of Schiff bases, see: Küstü et al. (2007) and for their pharmaceutical properties and applications as corrosion inhibitors, see: Singh & Dhakarey (2009).

S2. Experimental

4-Chlorobenzaldehyde (0.7029 g, 0.005 mol) in 15 ml of ethanol and N-phenyl-1,4-phenylenediamine (0.9212 g, 0.005 mol) in 10 ml of ethanol were mixed in a round bottom flask. The mixture was stirred for 30 minutes at about 30 °C. The mixture was left to cool down in an ice bath. A green solid was collected and washed with cold ethanol. Green crystals were obtained by recrystallization from toluene (yield 72%; melting point: 408–411 K; CHNS: C, 74.38; H, 4.93; N, 9.13. Found: C, 74.09; H, 4.91; N, 9.08. IR (cm^-1): C=N, 1592; N—H, 3408; C—Cl, 749.

S3. Refinement

The H atoms were positioned geometrically with C—H = 0.93 and N—H = 0.86 Å and constrained to ride on their parent atoms with U_iso(H)= 1.2 x U_eq (C or N).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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), PARST (Nardelli, 1995) and PLATON (Spek, 2009).

Figures

Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level.

N-[(E)-4-Chlorobenzylidene]-N'-phenylbenzene-1,4-diamine

Crystal data

C19H15ClN2	F(000) = 640
Mr = 306.78	Dx = 1.327 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1956 reflections
a = 10.3353 (15) Å	θ = 1.9–25.5°
b = 17.045 (3) Å	µ = 0.25 mm^−1
c = 8.7893 (13) Å	T = 298 K
β = 97.384 (3)°	Block, colourless
V = 1535.5 (4) Å^3	0.50 × 0.39 × 0.12 mm
Z = 4

Data collection

Bruker SMART APEX CCD area-detector diffractometer	2860 independent reflections
Radiation source: fine-focus sealed tube	2076 reflections with I > 2/s(I)
Graphite monochromator	Rint = 0.038
Detector resolution: 83.66 pixels mm^-1	θmax = 25.5°, θmin = 1.9°
ω scan	h = −11→12
Absorption correction: multi-scan (SADABS; Bruker, 2000)	k = −14→20
Tmin = 0.886, Tmax = 0.971	l = −10→9
8939 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.127	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0491P)^2 + 0.388P] where P = (Fo^2 + 2Fc^2)/3
2860 reflections	(Δ/σ)max = 0.001
199 parameters	Δρmax = 0.22 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.49291 (8)	0.14092 (4)	1.51538 (8)	0.0878 (3)
N1	0.19891 (17)	0.12993 (11)	0.7853 (2)	0.0563 (5)
N2	−0.00657 (18)	0.08239 (12)	0.1689 (2)	0.0649 (6)
H2A	0.0363	0.0492	0.1212	0.078*
C1	0.3831 (2)	0.03701 (13)	1.1159 (3)	0.0595 (6)
H1B	0.3918	−0.0123	1.0730	0.071*
C2	0.4384 (2)	0.05077 (14)	1.2645 (3)	0.0614 (6)
H2B	0.4851	0.0116	1.3210	0.074*
C3	0.4233 (2)	0.12328 (14)	1.3281 (3)	0.0568 (6)
C4	0.3532 (2)	0.18165 (13)	1.2465 (3)	0.0583 (6)
H4A	0.3421	0.2301	1.2915	0.070*
C5	0.2997 (2)	0.16732 (13)	1.0975 (3)	0.0540 (6)
H5A	0.2526	0.2067	1.0418	0.065*
C6	0.3150 (2)	0.09492 (13)	1.0290 (2)	0.0502 (5)
C7	0.2607 (2)	0.07919 (13)	0.8699 (3)	0.0556 (6)
H7A	0.2723	0.0296	0.8296	0.067*
C8	0.1486 (2)	0.11346 (13)	0.6310 (2)	0.0506 (5)
C9	0.0617 (2)	0.16743 (13)	0.5585 (3)	0.0565 (6)
H9A	0.0388	0.2110	0.6130	0.068*
C10	0.0079 (2)	0.15853 (13)	0.4074 (3)	0.0574 (6)
H10A	−0.0497	0.1960	0.3615	0.069*
C11	0.0396 (2)	0.09396 (13)	0.3239 (3)	0.0514 (5)
C12	0.1269 (2)	0.03969 (14)	0.3963 (3)	0.0575 (6)
H12A	0.1493	−0.0040	0.3418	0.069*
C13	0.1808 (2)	0.04887 (13)	0.5455 (3)	0.0561 (6)
H13A	0.2395	0.0117	0.5907	0.067*
C14	−0.1137 (2)	0.11789 (12)	0.0811 (3)	0.0500 (5)
C15	−0.2251 (2)	0.13990 (12)	0.1426 (3)	0.0532 (6)
H15A	−0.2297	0.1331	0.2468	0.064*
C16	−0.3291 (2)	0.17186 (13)	0.0496 (3)	0.0581 (6)
H16A	−0.4032	0.1871	0.0920	0.070*
C17	−0.3251 (2)	0.18156 (14)	−0.1047 (3)	0.0649 (6)
H17A	−0.3957	0.2034	−0.1667	0.078*
C18	−0.2160 (3)	0.15871 (14)	−0.1662 (3)	0.0650 (6)
H18A	−0.2133	0.1642	−0.2710	0.078*
C19	−0.1107 (2)	0.12777 (14)	−0.0752 (3)	0.0592 (6)
H19A	−0.0368	0.1133	−0.1185	0.071*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.1158 (6)	0.0755 (5)	0.0653 (4)	−0.0226 (4)	−0.0141 (4)	0.0041 (3)
N1	0.0524 (11)	0.0529 (11)	0.0630 (12)	0.0028 (9)	0.0051 (9)	−0.0015 (10)
N2	0.0588 (12)	0.0757 (14)	0.0600 (12)	0.0135 (10)	0.0066 (10)	−0.0130 (10)
C1	0.0701 (15)	0.0421 (12)	0.0673 (16)	0.0003 (11)	0.0133 (12)	0.0000 (11)
C2	0.0662 (15)	0.0529 (14)	0.0643 (15)	0.0013 (12)	0.0057 (12)	0.0133 (12)
C3	0.0604 (14)	0.0540 (14)	0.0555 (14)	−0.0116 (11)	0.0057 (11)	0.0039 (11)
C4	0.0668 (15)	0.0431 (13)	0.0659 (15)	−0.0022 (11)	0.0121 (12)	−0.0037 (11)
C5	0.0508 (13)	0.0477 (13)	0.0633 (14)	0.0054 (10)	0.0072 (11)	0.0043 (11)
C6	0.0457 (12)	0.0469 (13)	0.0594 (14)	−0.0024 (10)	0.0116 (10)	0.0018 (11)
C7	0.0589 (14)	0.0455 (13)	0.0628 (15)	−0.0044 (11)	0.0092 (11)	−0.0050 (11)
C8	0.0451 (12)	0.0494 (13)	0.0573 (14)	−0.0045 (10)	0.0066 (10)	−0.0005 (10)
C9	0.0581 (14)	0.0464 (13)	0.0653 (15)	0.0028 (11)	0.0083 (11)	−0.0064 (11)
C10	0.0578 (14)	0.0478 (13)	0.0645 (15)	0.0046 (11)	0.0005 (11)	0.0023 (11)
C11	0.0426 (12)	0.0540 (14)	0.0583 (14)	−0.0037 (10)	0.0091 (10)	−0.0028 (11)
C12	0.0481 (13)	0.0568 (14)	0.0677 (15)	0.0041 (11)	0.0082 (11)	−0.0126 (12)
C13	0.0460 (12)	0.0538 (14)	0.0681 (15)	0.0056 (11)	0.0056 (11)	−0.0019 (12)
C14	0.0481 (12)	0.0453 (12)	0.0562 (13)	−0.0049 (10)	0.0052 (10)	−0.0059 (10)
C15	0.0550 (13)	0.0522 (13)	0.0535 (13)	−0.0032 (11)	0.0119 (10)	−0.0031 (10)
C16	0.0528 (13)	0.0527 (14)	0.0691 (16)	0.0027 (11)	0.0087 (11)	−0.0079 (12)
C17	0.0684 (16)	0.0557 (14)	0.0676 (16)	0.0073 (12)	−0.0033 (13)	−0.0016 (12)
C18	0.0788 (17)	0.0640 (16)	0.0519 (14)	−0.0021 (13)	0.0072 (12)	−0.0003 (12)
C19	0.0574 (14)	0.0626 (15)	0.0603 (15)	−0.0054 (12)	0.0175 (11)	−0.0071 (12)

Geometric parameters (Å, º)

Cl1—C3	1.736 (2)	C9—C10	1.381 (3)
N1—C7	1.260 (3)	C9—H9A	0.9300
N1—C8	1.417 (3)	C10—C11	1.385 (3)
N2—C11	1.399 (3)	C10—H10A	0.9300
N2—C14	1.402 (3)	C11—C12	1.388 (3)
N2—H2A	0.8600	C12—C13	1.367 (3)
C1—C2	1.377 (3)	C12—H12A	0.9300
C1—C6	1.384 (3)	C13—H13A	0.9300
C1—H1B	0.9300	C14—C15	1.385 (3)
C2—C3	1.373 (3)	C14—C19	1.389 (3)
C2—H2B	0.9300	C15—C16	1.376 (3)
C3—C4	1.377 (3)	C15—H15A	0.9300
C4—C5	1.376 (3)	C16—C17	1.373 (3)
C4—H4A	0.9300	C16—H16A	0.9300
C5—C6	1.391 (3)	C17—C18	1.368 (3)
C5—H5A	0.9300	C17—H17A	0.9300
C6—C7	1.463 (3)	C18—C19	1.370 (3)
C7—H7A	0.9300	C18—H18A	0.9300
C8—C9	1.382 (3)	C19—H19A	0.9300
C8—C13	1.397 (3)
C7—N1—C8	121.7 (2)	C9—C10—C11	120.2 (2)
C11—N2—C14	128.39 (19)	C9—C10—H10A	119.9
C11—N2—H2A	115.8	C11—C10—H10A	119.9
C14—N2—H2A	115.8	C10—C11—C12	118.1 (2)
C2—C1—C6	121.4 (2)	C10—C11—N2	123.6 (2)
C2—C1—H1B	119.3	C12—C11—N2	118.2 (2)
C6—C1—H1B	119.3	C13—C12—C11	121.6 (2)
C3—C2—C1	119.0 (2)	C13—C12—H12A	119.2
C3—C2—H2B	120.5	C11—C12—H12A	119.2
C1—C2—H2B	120.5	C12—C13—C8	120.7 (2)
C2—C3—C4	121.2 (2)	C12—C13—H13A	119.6
C2—C3—Cl1	119.14 (19)	C8—C13—H13A	119.6
C4—C3—Cl1	119.66 (19)	C15—C14—C19	118.6 (2)
C5—C4—C3	119.2 (2)	C15—C14—N2	122.7 (2)
C5—C4—H4A	120.4	C19—C14—N2	118.7 (2)
C3—C4—H4A	120.4	C16—C15—C14	120.0 (2)
C4—C5—C6	121.0 (2)	C16—C15—H15A	120.0
C4—C5—H5A	119.5	C14—C15—H15A	120.0
C6—C5—H5A	119.5	C17—C16—C15	121.0 (2)
C1—C6—C5	118.2 (2)	C17—C16—H16A	119.5
C1—C6—C7	120.1 (2)	C15—C16—H16A	119.5
C5—C6—C7	121.7 (2)	C18—C17—C16	119.1 (2)
N1—C7—C6	122.8 (2)	C18—C17—H17A	120.4
N1—C7—H7A	118.6	C16—C17—H17A	120.4
C6—C7—H7A	118.6	C17—C18—C19	120.8 (2)
C9—C8—C13	117.5 (2)	C17—C18—H18A	119.6
C9—C8—N1	116.5 (2)	C19—C18—H18A	119.6
C13—C8—N1	126.0 (2)	C18—C19—C14	120.5 (2)
C10—C9—C8	121.8 (2)	C18—C19—H19A	119.8
C10—C9—H9A	119.1	C14—C19—H19A	119.8
C8—C9—H9A	119.1
C6—C1—C2—C3	1.1 (4)	C9—C10—C11—N2	−177.3 (2)
C1—C2—C3—C4	0.7 (4)	C14—N2—C11—C10	−18.4 (4)
C1—C2—C3—Cl1	−179.97 (17)	C14—N2—C11—C12	164.8 (2)
C2—C3—C4—C5	−1.4 (3)	C10—C11—C12—C13	0.1 (3)
Cl1—C3—C4—C5	179.28 (17)	N2—C11—C12—C13	177.0 (2)
C3—C4—C5—C6	0.3 (3)	C11—C12—C13—C8	0.5 (3)
C2—C1—C6—C5	−2.1 (3)	C9—C8—C13—C12	−0.5 (3)
C2—C1—C6—C7	178.2 (2)	N1—C8—C13—C12	−179.1 (2)
C4—C5—C6—C1	1.4 (3)	C11—N2—C14—C15	−32.5 (3)
C4—C5—C6—C7	−178.9 (2)	C11—N2—C14—C19	150.9 (2)
C8—N1—C7—C6	179.28 (18)	C19—C14—C15—C16	−0.9 (3)
C1—C6—C7—N1	−179.3 (2)	N2—C14—C15—C16	−177.6 (2)
C5—C6—C7—N1	1.0 (3)	C14—C15—C16—C17	0.8 (3)
C7—N1—C8—C9	167.8 (2)	C15—C16—C17—C18	0.2 (4)
C7—N1—C8—C13	−13.6 (3)	C16—C17—C18—C19	−1.2 (4)
C13—C8—C9—C10	0.1 (3)	C17—C18—C19—C14	1.0 (4)
N1—C8—C9—C10	178.8 (2)	C15—C14—C19—C18	0.0 (3)
C8—C9—C10—C11	0.5 (3)	N2—C14—C19—C18	176.8 (2)
C9—C10—C11—C12	−0.6 (3)

Hydrogen-bond geometry (Å, º)

Cg1 and Cg3 are the centroids of the C1–C6 and C14–C19 rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1B···Cg3^i	0.93	2.95	3.661 (2)	135
C16—H16A···Cg1^ii	0.93	2.90	3.624 (2)	136

Symmetry codes: (i) −x, −y, −z+1; (ii) x−1, y, z−1.