organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

(E)-2-(Benzyl­imino­meth­yl)-4,6-di­bromo­phenol

aCollege of Chemistry and Life Sciences, Maoming University, Guandu Second Road 139, Maoming 525000, People's Republic of China
*Correspondence e-mail: gdmmjw@yahoo.cn

(Received 22 June 2008; accepted 25 June 2008; online 5 July 2008)

The title compound, C14H11Br2NO, was prepared by the condensation of benzyl­amine and 3,5-dibromo-2-hydroxy­benzaldehyde. The crystal structure is stabilized by aromatic ππ stacking inter­actions between the phenol rings of neighbouring mol­ecules [centroid–centroid distance = 3.530 (5) Å]. In addition, the stacked mol­ecules exhibit inter­molecular C—H⋯π and intra­molecular O—H⋯N inter­actions.

Related literature

For details of the photochromism and thermochromism of Schiff base compounds, see: Cohen et al. (1964[Cohen, M. D., Schmidt, G. M. J. & Flavian, S. (1964). J. Chem. Soc. pp. 2041-2043.]).

[Scheme 1]

Experimental

Crystal data
  • C14H11Br2NO

  • Mr = 369.07

  • Monoclinic, P 21 /c

  • a = 12.086 (2) Å

  • b = 8.326 (1) Å

  • c = 13.576 (2) Å

  • β = 93.126 (2)°

  • V = 1364.1 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 5.93 mm−1

  • T = 296 (2) K

  • 0.34 × 0.30 × 0.25 mm

Data collection
  • Bruker APEXII area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2000[Sheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.]) Tmin = 0.156, Tmax = 0.231

  • 11566 measured reflections

  • 3156 independent reflections

  • 2339 reflections with I > 2σ(I)

  • Rint = 0.030

Refinement
  • R[F2 > 2σ(F2)] = 0.030

  • wR(F2) = 0.073

  • S = 1.01

  • 3156 reflections

  • 164 parameters

  • H-atom parameters constrained

  • Δρmax = 0.45 e Å−3

  • Δρmin = −0.55 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C7—H7ACgi 0.97 2.88 3.526 (3) 125
O—H1O⋯N 0.82 1.88 2.601 (3) 147
Symmetry code: (i) -x+1, -y+2, -z+1. Cg is the centroid of the C9–C14 ring.

Data collection: APEX2 (Bruker, 2004[Bruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2004[Bruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Compounds presenting photochromism, a reversible color change brought about in at least one direction, by the action of electromagnetic radiation, attract considerable attention from various fields of chemistry, physics and material science as potential candidates for practical applications. Since long time,the Schiff bases of salicylaldehyde with aromatic amines (anils or N-salicylideneaniline derivatives) are recognized as such compounds, which undergo enol-keto tautomerism and present common features in their structures and reaction mechanisms.The schiff base compounds show photochromism and thermochromism in the solid state by proton transfer from the hydroxyl O atom to the imine N atom (Cohen et al., 1964). The tautomerism involves proton transfer from the hydroxylic oxygen to the imino nitrogen atom that occurs intramolecularly via a six-membered ring, with the keto species showing bathochromically shifted spectra. As our continuing studies on the relation between the Schiff base geometry in the crystalline state and photochromism and/or thermochromism, here we report the crystal structure of the title compound, (E)-benzyliminomethyl-4,6-dibromophenol (Fig. 1).

The molecular structure is a typical salicylaldehyde schiff derivative with normal geometric parameters. The molecular packing (Fig. 2) is stabilized by ππ interactions between the phenol rings of neighbouring molecules. The Cg···Cgii distance is 3.530 (5) Å (Cg1 is the centroid of the C9-C14 ring, symmetry code as in Fig. 2). The crystal packing (Fig. 2) is further stabilized by the C—H···π interactions between a methylene H atom of the benzyl group and the phenol ring, i.e. with a C7–H7A···Cgi separation of 2.88 Å (Fig. 2 and Table 1; symmetry code as in Fig. 2). Additionally, intramolecular O—H···N interactions in the structure were observed (Fig. 2 and Table 1; symmetry code as in Fig. 2).

Related literature top

For details of the photochromism and thermochromism of Schiff base compounds, see: Cohen et al. (1964). Cg is the centroid of the C9–C14 ring.

Experimental top

Benzylamine (0.02 mol, 2.14 g) and 3,5-dibromo-2-hydroxybenzaldehyde(0.02 mol, 5.498 g) were dissolved in ethanol and the solution was refluxed for 3 h. After evaporation, a crude product was recrystallized twice from ethanol to give a pure yellow product. Yield: 82.5%. Calcd. for C14H11Br2NO: C, 45.56; H, 3.00; N, 3.80; Found: C, 45.21; H, 2.858; N, 3.67%.

Refinement top

All H atoms were located from difference Fourier syntheses, H atoms from the C—H groups and O—H group were placed in geometrically idealized positions and constrained to ride on their parent atoms (C—H = 0.93 %A, 0.96 %A, 0.97 %A; O—H = 0.82 Å) and Uiso(H) values equal to 1.2 Ueq(C) or 1.5Ueq(O).

Computing details top

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 top
[Figure 1] Fig. 1. The structure of (I), showing displacement ellipsoids drawn at the 30% probability level.
[Figure 2] Fig. 2. π···π, C—H···π and N—H···O interactions (dotted lines) in the title compound. Cg denotes the ring centroids. [Symmetry code: (i) -x+1, -y+2, -z+1; (ii) -x+1, -y+1, -z+1.]
(E)-2-(Benzyliminomethyl)-4,6-dibromophenol top
Crystal data top
C14H11Br2NOF(000) = 720
Mr = 369.07Dx = 1.797 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1859 reflections
a = 12.086 (2) Åθ = 1.0–27.6°
b = 8.326 (1) ŵ = 5.93 mm1
c = 13.576 (2) ÅT = 296 K
β = 93.126 (2)°Block, yellow
V = 1364.1 (3) Å30.34 × 0.30 × 0.25 mm
Z = 4
Data collection top
Bruker APEXII area-detector
diffractometer
3156 independent reflections
Radiation source: fine-focus sealed tube2339 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
Detector resolution: 10.00 pixels mm-1θmax = 27.6°, θmin = 1.7°
ϕ and ω scansh = 1515
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)
k = 1010
Tmin = 0.156, Tmax = 0.231l = 1717
11566 measured reflections
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)] = 0.030H-atom parameters constrained
wR(F2) = 0.073 w = 1/[σ2(Fo2) + (0.0301P)2 + 0.6854P]
where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max = 0.001
3156 reflectionsΔρmax = 0.45 e Å3
164 parametersΔρmin = 0.55 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: 0.0030 (4)
Crystal data top
C14H11Br2NOV = 1364.1 (3) Å3
Mr = 369.07Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.086 (2) ŵ = 5.93 mm1
b = 8.326 (1) ÅT = 296 K
c = 13.576 (2) Å0.34 × 0.30 × 0.25 mm
β = 93.126 (2)°
Data collection top
Bruker APEXII area-detector
diffractometer
3156 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)
2339 reflections with I > 2σ(I)
Tmin = 0.156, Tmax = 0.231Rint = 0.030
11566 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0300 restraints
wR(F2) = 0.073H-atom parameters constrained
S = 1.01Δρmax = 0.45 e Å3
3156 reflectionsΔρmin = 0.55 e Å3
164 parameters
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
Br10.75214 (3)0.53350 (5)0.72206 (2)0.07826 (14)
Br20.67394 (2)0.50575 (4)0.31003 (2)0.05547 (11)
O0.48779 (13)0.7332 (2)0.35440 (11)0.0493 (4)
H1O0.43160.78160.36820.074*
N0.35471 (16)0.8850 (2)0.46645 (16)0.0460 (5)
C10.0119 (3)0.7850 (6)0.3456 (3)0.0974 (13)
H10.01680.77380.28100.117*
C20.0382 (3)0.7132 (5)0.4196 (4)0.0908 (12)
H20.10270.65440.40630.109*
C30.0041 (3)0.7256 (5)0.5129 (3)0.0836 (11)
H30.03110.67540.56380.100*
C40.0993 (2)0.8125 (4)0.5333 (2)0.0612 (7)
H40.12860.81890.59790.073*
C50.15180 (19)0.8895 (3)0.46034 (19)0.0450 (6)
C60.1066 (2)0.8759 (5)0.3656 (2)0.0778 (10)
H60.13980.92810.31440.093*
C70.2567 (2)0.9840 (3)0.4827 (3)0.0575 (7)
H7A0.25721.07810.44070.069*
H7B0.25911.02000.55080.069*
C80.41771 (19)0.8452 (3)0.54029 (19)0.0426 (6)
H80.40140.88240.60250.051*
C90.51473 (17)0.7434 (3)0.53116 (16)0.0353 (5)
C100.54482 (17)0.6901 (3)0.43760 (16)0.0361 (5)
C110.63563 (18)0.5885 (3)0.43328 (16)0.0359 (5)
C120.69736 (18)0.5414 (3)0.51723 (17)0.0401 (5)
H120.75800.47360.51270.048*
C130.66716 (19)0.5970 (3)0.60777 (17)0.0418 (5)
C140.57710 (19)0.6958 (3)0.61547 (17)0.0422 (5)
H140.55770.73110.67720.051*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0719 (2)0.1044 (3)0.05549 (19)0.01255 (19)0.02322 (15)0.00917 (17)
Br20.05471 (18)0.0672 (2)0.04574 (16)0.00181 (13)0.01445 (12)0.00697 (12)
O0.0414 (9)0.0656 (12)0.0408 (9)0.0077 (8)0.0003 (7)0.0096 (8)
N0.0298 (10)0.0410 (12)0.0675 (14)0.0021 (8)0.0053 (9)0.0040 (10)
C10.053 (2)0.156 (4)0.082 (3)0.000 (2)0.0136 (18)0.022 (3)
C20.0439 (18)0.100 (3)0.129 (4)0.0135 (19)0.009 (2)0.029 (3)
C30.064 (2)0.079 (3)0.109 (3)0.0202 (18)0.026 (2)0.010 (2)
C40.0560 (17)0.0622 (19)0.0658 (18)0.0063 (14)0.0082 (14)0.0068 (14)
C50.0305 (12)0.0431 (14)0.0618 (15)0.0078 (10)0.0070 (11)0.0023 (12)
C60.0477 (17)0.121 (3)0.065 (2)0.0031 (18)0.0077 (15)0.0122 (19)
C70.0386 (13)0.0434 (16)0.091 (2)0.0027 (11)0.0084 (14)0.0010 (14)
C80.0348 (12)0.0384 (13)0.0555 (15)0.0075 (10)0.0107 (11)0.0058 (11)
C90.0293 (11)0.0349 (12)0.0420 (12)0.0083 (9)0.0040 (9)0.0002 (10)
C100.0310 (11)0.0368 (12)0.0406 (12)0.0077 (9)0.0036 (9)0.0040 (10)
C110.0321 (11)0.0367 (13)0.0394 (12)0.0079 (9)0.0075 (9)0.0003 (10)
C120.0316 (12)0.0364 (13)0.0522 (14)0.0026 (9)0.0016 (10)0.0033 (10)
C130.0356 (12)0.0479 (15)0.0407 (12)0.0065 (11)0.0070 (9)0.0050 (11)
C140.0391 (13)0.0480 (14)0.0394 (12)0.0102 (11)0.0025 (10)0.0060 (10)
Geometric parameters (Å, º) top
Br1—C131.889 (2)C5—C61.375 (4)
Br2—C111.890 (2)C5—C71.509 (4)
O—C101.340 (3)C6—H60.9300
O—H1O0.8200C7—H7A0.9700
N—C81.269 (3)C7—H7B0.9700
N—C71.469 (3)C8—C91.458 (3)
C1—C21.343 (5)C8—H80.9300
C1—C61.386 (5)C9—C141.393 (3)
C1—H10.9300C9—C101.412 (3)
C2—C31.343 (5)C10—C111.390 (3)
C2—H20.9300C11—C121.384 (3)
C3—C41.375 (4)C12—C131.381 (3)
C3—H30.9300C12—H120.9300
C4—C51.364 (4)C13—C141.373 (3)
C4—H40.9300C14—H140.9300
C10—O—H1O109.5C5—C7—H7B109.5
C8—N—C7118.8 (2)H7A—C7—H7B108.1
C2—C1—C6119.9 (3)N—C8—C9122.4 (2)
C2—C1—H1120.1N—C8—H8118.8
C6—C1—H1120.1C9—C8—H8118.8
C1—C2—C3120.5 (3)C14—C9—C10119.7 (2)
C1—C2—H2119.8C14—C9—C8119.8 (2)
C3—C2—H2119.8C10—C9—C8120.5 (2)
C2—C3—C4120.1 (3)O—C10—C11119.9 (2)
C2—C3—H3119.9O—C10—C9121.9 (2)
C4—C3—H3119.9C11—C10—C9118.2 (2)
C5—C4—C3121.2 (3)C12—C11—C10121.9 (2)
C5—C4—H4119.4C12—C11—Br2118.59 (17)
C3—C4—H4119.4C10—C11—Br2119.44 (16)
C4—C5—C6117.6 (3)C13—C12—C11118.8 (2)
C4—C5—C7121.2 (3)C13—C12—H12120.6
C6—C5—C7121.2 (3)C11—C12—H12120.6
C5—C6—C1120.7 (3)C14—C13—C12121.2 (2)
C5—C6—H6119.7C14—C13—Br1120.20 (18)
C1—C6—H6119.7C12—C13—Br1118.63 (18)
N—C7—C5110.7 (2)C13—C14—C9120.2 (2)
N—C7—H7A109.5C13—C14—H14119.9
C5—C7—H7A109.5C9—C14—H14119.9
N—C7—H7B109.5
C6—C1—C2—C31.5 (7)C8—C9—C10—O1.5 (3)
C1—C2—C3—C40.1 (6)C14—C9—C10—C111.1 (3)
C2—C3—C4—C51.0 (5)C8—C9—C10—C11177.7 (2)
C3—C4—C5—C60.6 (5)O—C10—C11—C12179.7 (2)
C3—C4—C5—C7179.6 (3)C9—C10—C11—C121.1 (3)
C4—C5—C6—C10.9 (5)O—C10—C11—Br22.4 (3)
C7—C5—C6—C1178.1 (3)C9—C10—C11—Br2176.78 (15)
C2—C1—C6—C52.0 (6)C10—C11—C12—C130.3 (3)
C8—N—C7—C5112.6 (3)Br2—C11—C12—C13177.68 (17)
C4—C5—C7—N95.3 (3)C11—C12—C13—C140.7 (3)
C6—C5—C7—N83.7 (3)C11—C12—C13—Br1179.63 (17)
C7—N—C8—C9178.1 (2)C12—C13—C14—C90.6 (4)
N—C8—C9—C14176.2 (2)Br1—C13—C14—C9179.65 (17)
N—C8—C9—C102.6 (3)C10—C9—C14—C130.3 (3)
C14—C9—C10—O179.7 (2)C8—C9—C14—C13178.5 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7A···Cgi0.972.883.526 (3)125
O—H1O···N0.821.882.601 (3)147
Symmetry code: (i) x+1, y+2, z+1.

Experimental details

Crystal data
Chemical formulaC14H11Br2NO
Mr369.07
Crystal system, space groupMonoclinic, P21/c
Temperature (K)296
a, b, c (Å)12.086 (2), 8.326 (1), 13.576 (2)
β (°) 93.126 (2)
V3)1364.1 (3)
Z4
Radiation typeMo Kα
µ (mm1)5.93
Crystal size (mm)0.34 × 0.30 × 0.25
Data collection
DiffractometerBruker APEXII area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2000)
Tmin, Tmax0.156, 0.231
No. of measured, independent and
observed [I > 2σ(I)] reflections
11566, 3156, 2339
Rint0.030
(sin θ/λ)max1)0.653
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.030, 0.073, 1.01
No. of reflections3156
No. of parameters164
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.45, 0.55

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7A···Cgi0.972.883.526 (3)125.2
O—H1O···N0.821.882.601 (3)146.8
Symmetry code: (i) x+1, y+2, z+1.
 

References

First citationBruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCohen, M. D., Schmidt, G. M. J. & Flavian, S. (1964). J. Chem. Soc. pp. 2041–2043.  CrossRef Web of Science Google Scholar
First citationSheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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ISSN: 2056-9890
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