N-[(E)-4-Bromo­benzyl­idene]-2,3-di­methyl­aniline

The title compound, C₁₅H₁₄BrN, has an E conformation about the C=N bond and the dihedral angle between the benzene rings is 50.7 (2)°. In the crystal, mol­ecules are linked via C—H...π inter­actions, forming columns propagating along [010].

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.042
• wR factor = 0.112
• Data-to-parameter ratio = 16.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         46 Perc.
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C3     --  C4      ..        5.2 su
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C3
PLAT341_ALERT_3_C Low Bond Precision on  C-C Bonds ...............     0.0068 Ang
PLAT905_ALERT_3_C Negative K value in the Analysis of Variance ...    -11.780
PLAT905_ALERT_3_C Negative K value in the Analysis of Variance ...     -1.050
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         18

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF          ?
PLAT128_ALERT_4_G Alternate Setting of Space-group P21/c   .......      P21/n

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   8 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   2 ALERT level G = General information/check it is not something unexpected

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

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S1. Comment

Schiff base ligands have received much more attention during the past years. They have many pharmaceutical activities, such as antifungal effects (Aziz et al., 2010), radical scavenging activity (Lu et al., 2012), inhibition of enzyme activity (Schmidt et al., 2009), and antibacterial activities (Shi et al., 2010). We report herein on the crystal structure of a new Schiff base compound.

In the title molecule, Fig. 1, the bond lengths (Allen et al., 1987) and angles are normal and comparable to the values observed in similar compounds (Sun et al., 2011a,b; Guo et al., 2011). The molecule has an E conformation about the C7═N1 bond and is twisted with the dihedral angle between the two aromatic rings being 50.7 (2) °.

In the crystal, molecules are linked via C-H···π interactions (Table 1).

Related literature

Schiff base derivativies have many pharmaceutical activities. For their antifungal effects, see: Aziz et al. (2010), for their radical scavenging activity, see: Lu et al. (2012), for their inhibition of enzyme activity, see: Schmidt et al. (2009) and for their antibacterial activity, see: Shi et al. (2010). For related structures, see: Sun et al. (2011a,b); Guo et al. (2011). For standard bond lengths, see: Allen et al. (1987).

S2. Experimental

A mixture of 4-bromobenzaldehyde (5 mmol), 2,3-dimethylaniline (5 mmol) and methanol (50 ml) was refluxed for 6 h. The mixture was then allowed to cool and filtered. Recrystallization of the crude product from methanol yielded yellow block-like crystals.

S3. Refinement

H atoms were positioned geometrically and refined using the riding-model approximation: C—H = 0.93 and 0.96 Å for CH and CH₃ H atoms, respectively, with U_iso(H) = 1.5U_eq(C-methyl) and = 1.2U_eq(C) for other H atoms.

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); 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

Fig. 1. The molecular structure of the title molecule, with atom labelling. The displacement ellipsoids are drawn at the 50% probability level.

N-[(E)-4-Bromobenzylidene]-2,3-dimethylaniline

Crystal data

C15H14BrN	F(000) = 584
Mr = 288.18	Dx = 1.414 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2505 reflections
a = 12.945 (9) Å	θ = 2.7–25.5°
b = 7.857 (5) Å	µ = 3.02 mm^−1
c = 14.497 (10) Å	T = 296 K
β = 113.384 (8)°	Block, yellow
V = 1353.3 (16) Å^3	0.25 × 0.20 × 0.19 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer	2525 independent reflections
Radiation source: fine-focus sealed tube	1154 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.058
φ and ω scans	θmax = 25.5°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −15→10
Tmin = 0.519, Tmax = 0.598	k = −9→7
5865 measured reflections	l = −15→17

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.042	H-atom parameters constrained
wR(F^2) = 0.112	w = 1/[σ^2(Fo^2) + (0.0477P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.94	(Δ/σ)max < 0.001
2525 reflections	Δρmax = 0.35 e Å^−3
157 parameters	Δρmin = −0.25 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0298 (19)

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
Br1	0.07853 (5)	0.88838 (7)	0.11686 (4)	0.0919 (4)
C1	0.0611 (4)	0.8732 (5)	0.3942 (3)	0.0581 (13)
H1	0.0091	0.9056	0.4205	0.070*
C2	0.0362 (4)	0.8999 (5)	0.2939 (3)	0.0643 (13)
H2	−0.0315	0.9504	0.2529	0.077*
C3	0.1122 (5)	0.8513 (5)	0.2554 (3)	0.0547 (12)
C4	0.2111 (4)	0.7767 (7)	0.3137 (4)	0.0736 (15)
H4	0.2616	0.7431	0.2860	0.088*
C5	0.2363 (4)	0.7508 (6)	0.4154 (3)	0.0682 (15)
H5	0.3042	0.7002	0.4557	0.082*
C6	0.1617 (4)	0.7992 (5)	0.4572 (3)	0.0477 (11)
C7	0.1882 (4)	0.7675 (5)	0.5637 (3)	0.0513 (12)
H7	0.2592	0.7258	0.6036	0.062*
C8	0.1554 (4)	0.7691 (5)	0.7095 (3)	0.0434 (11)
C9	0.2578 (4)	0.8290 (6)	0.7761 (3)	0.0582 (13)
H9	0.3060	0.8842	0.7525	0.070*
C10	0.2887 (4)	0.8071 (7)	0.8781 (3)	0.0713 (14)
H10	0.3586	0.8452	0.9231	0.086*
C11	0.2169 (4)	0.7295 (6)	0.9130 (3)	0.0602 (13)
H11	0.2382	0.7163	0.9818	0.072*
C12	0.1130 (4)	0.6702 (5)	0.8474 (3)	0.0500 (12)
C13	0.0802 (3)	0.6918 (5)	0.7437 (3)	0.0449 (11)
C14	0.0371 (4)	0.5812 (6)	0.8890 (4)	0.0776 (16)
H14A	0.0750	0.5718	0.9607	0.116*
H14B	0.0191	0.4695	0.8602	0.116*
H14C	−0.0309	0.6457	0.8726	0.116*
C15	−0.0326 (4)	0.6292 (6)	0.6700 (3)	0.0758 (15)
H15A	−0.0869	0.6384	0.6995	0.114*
H15B	−0.0262	0.5124	0.6535	0.114*
H15C	−0.0564	0.6970	0.6100	0.114*
N1	0.1199 (3)	0.7938 (4)	0.6039 (2)	0.0501 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.1350 (6)	0.0914 (5)	0.0529 (3)	−0.0264 (4)	0.0410 (3)	0.0038 (3)
C1	0.064 (3)	0.061 (3)	0.052 (3)	0.015 (3)	0.025 (3)	0.005 (2)
C2	0.075 (4)	0.054 (3)	0.061 (3)	0.021 (3)	0.024 (3)	0.008 (3)
C3	0.069 (3)	0.050 (3)	0.044 (2)	−0.006 (3)	0.023 (3)	0.005 (2)
C4	0.069 (4)	0.104 (4)	0.061 (3)	−0.012 (3)	0.039 (3)	−0.015 (3)
C5	0.051 (3)	0.095 (4)	0.060 (3)	0.013 (3)	0.024 (3)	0.000 (3)
C6	0.051 (3)	0.047 (3)	0.048 (3)	−0.001 (2)	0.023 (2)	−0.001 (2)
C7	0.058 (3)	0.047 (3)	0.050 (3)	0.002 (2)	0.022 (3)	0.000 (2)
C8	0.047 (3)	0.034 (3)	0.049 (3)	0.004 (2)	0.018 (2)	0.001 (2)
C9	0.062 (3)	0.055 (3)	0.063 (3)	−0.015 (3)	0.030 (3)	−0.005 (2)
C10	0.065 (3)	0.089 (4)	0.057 (3)	−0.024 (3)	0.021 (3)	−0.020 (3)
C11	0.072 (4)	0.066 (4)	0.044 (3)	−0.004 (3)	0.024 (3)	−0.002 (2)
C12	0.062 (3)	0.043 (3)	0.053 (3)	0.002 (2)	0.032 (3)	0.003 (2)
C13	0.051 (3)	0.037 (3)	0.046 (2)	0.002 (2)	0.018 (2)	−0.005 (2)
C14	0.093 (4)	0.080 (4)	0.070 (3)	−0.008 (3)	0.042 (3)	0.009 (3)
C15	0.059 (3)	0.100 (4)	0.062 (3)	−0.015 (3)	0.018 (3)	−0.005 (3)
N1	0.061 (2)	0.048 (2)	0.048 (2)	0.004 (2)	0.028 (2)	0.0032 (17)

Geometric parameters (Å, º)

Br1—C3	1.901 (4)	C8—N1	1.426 (5)
C1—C2	1.375 (6)	C9—C10	1.380 (6)
C1—C6	1.387 (5)	C9—H9	0.9300
C1—H1	0.9300	C10—C11	1.366 (6)
C2—C3	1.365 (6)	C10—H10	0.9300
C2—H2	0.9300	C11—C12	1.383 (6)
C3—C4	1.355 (6)	C11—H11	0.9300
C4—C5	1.393 (6)	C12—C13	1.401 (5)
C4—H4	0.9300	C12—C14	1.513 (6)
C5—C6	1.382 (5)	C13—C15	1.509 (6)
C5—H5	0.9300	C14—H14A	0.9600
C6—C7	1.464 (5)	C14—H14B	0.9600
C7—N1	1.253 (5)	C14—H14C	0.9600
C7—H7	0.9300	C15—H15A	0.9600
C8—C9	1.377 (5)	C15—H15B	0.9600
C8—C13	1.395 (5)	C15—H15C	0.9600
C2—C1—C6	121.6 (4)	C10—C9—H9	120.1
C2—C1—H1	119.2	C11—C10—C9	120.1 (4)
C6—C1—H1	119.2	C11—C10—H10	120.0
C3—C2—C1	119.1 (4)	C9—C10—H10	120.0
C3—C2—H2	120.5	C10—C11—C12	121.0 (4)
C1—C2—H2	120.5	C10—C11—H11	119.5
C4—C3—C2	121.5 (4)	C12—C11—H11	119.5
C4—C3—Br1	119.2 (4)	C11—C12—C13	119.6 (4)
C2—C3—Br1	119.3 (4)	C11—C12—C14	119.3 (4)
C3—C4—C5	119.3 (4)	C13—C12—C14	121.0 (4)
C3—C4—H4	120.4	C8—C13—C12	118.5 (4)
C5—C4—H4	120.4	C8—C13—C15	120.3 (4)
C6—C5—C4	120.9 (4)	C12—C13—C15	121.1 (4)
C6—C5—H5	119.6	C12—C14—H14A	109.5
C4—C5—H5	119.6	C12—C14—H14B	109.5
C5—C6—C1	117.7 (4)	H14A—C14—H14B	109.5
C5—C6—C7	120.2 (4)	C12—C14—H14C	109.5
C1—C6—C7	122.1 (4)	H14A—C14—H14C	109.5
N1—C7—C6	123.3 (4)	H14B—C14—H14C	109.5
N1—C7—H7	118.4	C13—C15—H15A	109.5
C6—C7—H7	118.4	C13—C15—H15B	109.5
C9—C8—C13	120.8 (4)	H15A—C15—H15B	109.5
C9—C8—N1	121.1 (4)	C13—C15—H15C	109.5
C13—C8—N1	117.9 (4)	H15A—C15—H15C	109.5
C8—C9—C10	119.9 (4)	H15B—C15—H15C	109.5
C8—C9—H9	120.1	C7—N1—C8	119.4 (4)
C6—C1—C2—C3	0.4 (7)	C9—C10—C11—C12	0.6 (8)
C1—C2—C3—C4	0.4 (7)	C10—C11—C12—C13	−0.8 (7)
C1—C2—C3—Br1	−179.8 (3)	C10—C11—C12—C14	178.5 (4)
C2—C3—C4—C5	−0.7 (7)	C9—C8—C13—C12	−2.6 (6)
Br1—C3—C4—C5	179.5 (4)	N1—C8—C13—C12	−178.6 (4)
C3—C4—C5—C6	0.3 (7)	C9—C8—C13—C15	179.0 (4)
C4—C5—C6—C1	0.4 (7)	N1—C8—C13—C15	3.0 (6)
C4—C5—C6—C7	178.6 (4)	C11—C12—C13—C8	1.7 (6)
C2—C1—C6—C5	−0.8 (7)	C14—C12—C13—C8	−177.6 (4)
C2—C1—C6—C7	−178.9 (4)	C11—C12—C13—C15	−179.9 (4)
C5—C6—C7—N1	−173.1 (4)	C14—C12—C13—C15	0.9 (6)
C1—C6—C7—N1	4.9 (7)	C6—C7—N1—C8	−176.2 (4)
C13—C8—C9—C10	2.5 (6)	C9—C8—N1—C7	44.6 (6)
N1—C8—C9—C10	178.4 (4)	C13—C8—N1—C7	−139.3 (4)
C8—C9—C10—C11	−1.5 (7)

Hydrogen-bond geometry (Å, º)

Cg1 and Cg2 are the centroids of the C8–C13 and C1–C6 rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···Cg2^i	0.93	2.99	3.830 (6)	151
C15—H15B···Cg1^ii	0.96	2.99	3.781 (6)	140

Symmetry codes: (i) −x, −y+2, −z+1; (ii) −x, −y+1, −z+1.