organic compounds
(E)-4-Bromo-2-[(2-hydroxyphenyl)iminiomethyl]phenolate
aSchool of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, bX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and cCrystal Materials Research Unit, Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand
*Correspondence e-mail: hkfun@usm.my
The title compound, C13H10BrNO2, crystallizes in a zwitterionic form. The zwitterion exists in a trans configuration about the C=N bond and is almost planar, the dihedral angle between the two benzene rings being 2.29 (9)°. An intramolecular N—H⋯O hydrogen bond formed between the iminium NH+ and the phenolate O− atoms generates an S(6) ring motif. In the crystal, the are linked through O—H⋯O hydrogen bonds into chains along [101] and these chains are further connected through C—H⋯Br interactions into a two-dimensional network perpendicular to (101). C⋯C [3.572 (3)–3.592 (3) Å] and C⋯Br [3.5633 (19)–3.7339 (18) Å] short contacts are observed. The crystal studied was a twin with 00, 00, 001 with a domain ratio of 0.09919 (2):0.90081 (2).
Related literature
For bond-length data, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995). For background to and their applications, see: Dao et al. (2000); Kagkelari et al. (2009); Karthikeyan et al. (2006); Sriram et al. (2006); Wei & Atwood (1998). For related structures, see: Eltayeb et al. (2009; 2010); Tan & Liu (2009). For the stability of the temperature controller used in the data collection, see Cosier & Glazer, (1986).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2009); cell SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S1600536810015230/rz2436sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810015230/rz2436Isup2.hkl
The title compound was synthesized by adding 5-bromo-2-hydroxybenzaldehyde (0.402 g, 2 mmol) to a solution of 2-aminophenol (0.218 g, 2 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for half an hour. The resultant yellow solution was filtered and the filtrate was evaporated to give a yellow solid product. Yellow needle-shaped single crystals of the title compound suitable for x-ray
were obtained from ethanol by slow evaporation at room temperature after nine days.Hydroxyl H atom was placed in calculated positions with d(O—H) = 0.82 Å and the Uiso values was constrained to be 1.5Ueq of the 1 0 0, 0 1 0, 0 0 1, leading to a distribution (refined BASF parameter) of 0.09919/0.90081 (2).
The remaining H atoms were located from the difference map and isotropically refined. The highest residual electron density peak is located at 0.80 Å from Br1 and the deepest hole is located at 0.99 Å from Br1. The crystal studied was a twin withMuch attention has been given to Schiff base ligands due to their applications such as in coordination chemistry (Kagkelari et al., 2009), chelated boron catalyst (Wei & Atwood, 1998), pharmacological activities, anticancer (Dao et al., 2000), anti-HIV (Sriram et al., 2006), antibacterial and antifungal (Karthikeyan et al., 2006) activities. We have reported the crystal structures of Schiff base ligands which existed in a zwitterionic form i.e 2-((E)-{2-[(E)-2,3-dihydroxybenzylideneamino]-5-methylphenyl}- iminiomethyl)-6-hydroxyphenolate (Eltayeb et al., 2009) and (E)-4-allyl-2-{[(2-hydroxyphenyl)iminio]methyl}-6-methoxyphenolate (Eltayeb et al., 2010). Herein we report the
of the title zwitterionic Schiff base ligand (I).The molecule of (I) (Fig. 1), C13H9BrNO2, crystallizes in a zwitterionic form with cationic iminium and anionic enolate, and exists in a trans configuration about the C═N bond [1.310 (2) Å]; the torsion angle C8–N1–C7–C6 is 179.25 (17)°. The molecule is almost planar with the dihedral angle between the two benzene rings of 2.31 (9)°. The hydroxy group is co-planar with the attached C8–C13 benzene ring with the r.m.s. of 0.0102 (2) Å for the seven non H atoms. Intramolecular N—H···O hydrogen bond between the NH+ and the phenolate O- generates an S(6) ring motif (Fig. 1; Table 1) which help to stabilize the planarity of the molecule (Bernstein et al., 1995). The bond distances are in normal ranges (Allen et al., 1987) and comparable with those found in related structures (Eltayeb et al., 2009, 2010; Tan & Liu, 2009).
In the crystal packing (Fig. 2), the
are linked through O2–H1O2···O1 hydrogen bonds into chains along the [101] and these chains are further connected through C11—H11A···Br1 interactions into a 2-D network perpendicular to the (101)-plane. The crystal is stabilized by O—H···O and weak C—H···Br interactions (Table 1). C···C [3.572 (3)-3.592 (3) Å] and C···Br [3.5633 (19)-3.7339 (18) Å] short contacts are observed.For bond-length data, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995). For background to
and their applications, see: Dao et al. (2000); Kagkelari et al. (2009); Karthikeyan et al. (2006); Sriram et al. (2006); Wei & Atwood (1998). For related structures, see: Eltayeb et al. (2009; 2010); Tan & Liu (2009). For the stability of the temperature controller used in the data collection, see Cosier & Glazer, (1986).Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).C13H10BrNO2 | F(000) = 292 |
Mr = 291.12 | Dx = 1.773 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 3120 reflections |
a = 4.6387 (3) Å | θ = 1.1–30.0° |
b = 18.9379 (13) Å | µ = 3.74 mm−1 |
c = 6.2270 (4) Å | T = 100 K |
β = 90.144 (3)° | Needle, yellow |
V = 547.02 (6) Å3 | 0.43 × 0.14 × 0.14 mm |
Z = 2 |
Bruker APEXII DUO CCD area-detector diffractometer | 3120 independent reflections |
Radiation source: sealed tube | 3034 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.026 |
φ and ω scans | θmax = 30.0°, θmin = 1.1° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −6→6 |
Tmin = 0.295, Tmax = 0.628 | k = −26→26 |
8575 measured reflections | l = −8→8 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.018 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.041 | w = 1/[σ2(Fo2) + (0.0035P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max < 0.001 |
3120 reflections | Δρmax = 0.59 e Å−3 |
191 parameters | Δρmin = −0.29 e Å−3 |
1 restraint | Absolute structure: Flack (1983), 1480 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.027 (7) |
C13H10BrNO2 | V = 547.02 (6) Å3 |
Mr = 291.12 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 4.6387 (3) Å | µ = 3.74 mm−1 |
b = 18.9379 (13) Å | T = 100 K |
c = 6.2270 (4) Å | 0.43 × 0.14 × 0.14 mm |
β = 90.144 (3)° |
Bruker APEXII DUO CCD area-detector diffractometer | 3120 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 3034 reflections with I > 2σ(I) |
Tmin = 0.295, Tmax = 0.628 | Rint = 0.026 |
8575 measured reflections |
R[F2 > 2σ(F2)] = 0.018 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.041 | Δρmax = 0.59 e Å−3 |
S = 1.02 | Δρmin = −0.29 e Å−3 |
3120 reflections | Absolute structure: Flack (1983), 1480 Friedel pairs |
191 parameters | Absolute structure parameter: 0.027 (7) |
1 restraint |
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. |
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. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.00526 (4) | 0.442840 (15) | 0.87673 (2) | 0.01554 (4) | |
O1 | 0.5191 (3) | 0.66300 (7) | 0.29008 (19) | 0.0152 (2) | |
O2 | 1.1314 (3) | 0.70088 (8) | 1.0194 (2) | 0.0166 (3) | |
H1O2 | 1.2697 | 0.6925 | 1.0976 | 0.025* | |
N1 | 0.8565 (3) | 0.69973 (8) | 0.6076 (2) | 0.0121 (3) | |
H1N1 | 0.802 (6) | 0.6976 (16) | 0.470 (5) | 0.026 (7)* | |
C1 | 0.4132 (4) | 0.61426 (10) | 0.4149 (3) | 0.0126 (3) | |
C2 | 0.1934 (4) | 0.56695 (10) | 0.3446 (3) | 0.0140 (3) | |
H2A | 0.133 (6) | 0.5756 (14) | 0.207 (4) | 0.020 (6)* | |
C3 | 0.0797 (4) | 0.51628 (10) | 0.4781 (3) | 0.0138 (3) | |
H3A | −0.064 (6) | 0.4852 (14) | 0.440 (4) | 0.021 (6)* | |
C4 | 0.1776 (4) | 0.51058 (9) | 0.6919 (3) | 0.0129 (3) | |
C5 | 0.3894 (4) | 0.55482 (9) | 0.7685 (3) | 0.0125 (3) | |
H5A | 0.450 (6) | 0.5535 (16) | 0.905 (4) | 0.026 (7)* | |
C6 | 0.5112 (4) | 0.60653 (9) | 0.6331 (3) | 0.0122 (3) | |
C7 | 0.7261 (4) | 0.65154 (9) | 0.7227 (3) | 0.0123 (3) | |
H7A | 0.787 (5) | 0.6470 (12) | 0.868 (4) | 0.009 (5)* | |
C8 | 1.0707 (4) | 0.74911 (9) | 0.6695 (3) | 0.0117 (3) | |
C9 | 1.2064 (4) | 0.74952 (9) | 0.8722 (3) | 0.0125 (3) | |
C10 | 1.4149 (4) | 0.80132 (10) | 0.9137 (3) | 0.0148 (3) | |
H10A | 1.494 (6) | 0.8047 (15) | 1.048 (5) | 0.022 (6)* | |
C11 | 1.4940 (4) | 0.84982 (10) | 0.7569 (3) | 0.0159 (3) | |
H11A | 1.639 (6) | 0.8847 (13) | 0.786 (4) | 0.018 (6)* | |
C12 | 1.3635 (4) | 0.84799 (10) | 0.5548 (3) | 0.0160 (3) | |
H12A | 1.427 (7) | 0.8788 (17) | 0.453 (5) | 0.036 (8)* | |
C13 | 1.1523 (4) | 0.79797 (9) | 0.5130 (3) | 0.0139 (3) | |
H13A | 1.045 (5) | 0.7956 (13) | 0.368 (3) | 0.014 (6)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.01876 (7) | 0.01522 (7) | 0.01262 (6) | −0.00425 (9) | −0.00307 (5) | 0.00324 (8) |
O1 | 0.0161 (6) | 0.0183 (6) | 0.0113 (5) | −0.0031 (5) | −0.0034 (5) | 0.0033 (5) |
O2 | 0.0167 (6) | 0.0224 (7) | 0.0106 (6) | −0.0044 (5) | −0.0054 (5) | 0.0042 (5) |
N1 | 0.0122 (7) | 0.0140 (7) | 0.0102 (7) | −0.0004 (5) | −0.0033 (5) | 0.0003 (5) |
C1 | 0.0122 (7) | 0.0150 (8) | 0.0106 (7) | 0.0001 (6) | −0.0012 (5) | −0.0002 (6) |
C2 | 0.0156 (8) | 0.0172 (8) | 0.0092 (8) | −0.0007 (6) | −0.0030 (6) | −0.0007 (6) |
C3 | 0.0136 (8) | 0.0141 (8) | 0.0137 (8) | −0.0022 (6) | −0.0024 (6) | −0.0018 (6) |
C4 | 0.0142 (8) | 0.0120 (7) | 0.0126 (8) | −0.0007 (6) | −0.0003 (6) | 0.0015 (6) |
C5 | 0.0150 (8) | 0.0137 (8) | 0.0087 (8) | 0.0011 (6) | −0.0030 (6) | 0.0007 (6) |
C6 | 0.0116 (7) | 0.0140 (7) | 0.0109 (7) | 0.0014 (6) | −0.0014 (6) | −0.0021 (6) |
C7 | 0.0123 (8) | 0.0139 (8) | 0.0108 (8) | 0.0003 (6) | −0.0020 (6) | −0.0007 (6) |
C8 | 0.0114 (7) | 0.0114 (7) | 0.0122 (7) | 0.0001 (6) | −0.0033 (5) | −0.0010 (6) |
C9 | 0.0127 (7) | 0.0146 (8) | 0.0103 (7) | 0.0003 (6) | −0.0012 (6) | −0.0007 (6) |
C10 | 0.0146 (8) | 0.0174 (9) | 0.0123 (8) | −0.0012 (6) | −0.0044 (6) | −0.0020 (6) |
C11 | 0.0141 (8) | 0.0154 (8) | 0.0182 (8) | −0.0021 (7) | −0.0016 (7) | −0.0017 (6) |
C12 | 0.0172 (9) | 0.0147 (8) | 0.0161 (8) | −0.0007 (7) | −0.0011 (6) | 0.0022 (7) |
C13 | 0.0128 (8) | 0.0160 (8) | 0.0129 (8) | 0.0008 (6) | −0.0026 (6) | 0.0011 (6) |
Br1—C4 | 1.9011 (18) | C5—C6 | 1.411 (2) |
O1—C1 | 1.304 (2) | C5—H5A | 0.89 (2) |
O2—C9 | 1.346 (2) | C6—C7 | 1.424 (2) |
O2—H1O2 | 0.8200 | C7—H7A | 0.95 (2) |
N1—C7 | 1.310 (2) | C8—C13 | 1.397 (2) |
N1—C8 | 1.417 (2) | C8—C9 | 1.409 (2) |
N1—H1N1 | 0.89 (3) | C9—C10 | 1.401 (2) |
C1—C2 | 1.425 (2) | C10—C11 | 1.391 (3) |
C1—C6 | 1.439 (2) | C10—H10A | 0.92 (3) |
C2—C3 | 1.376 (3) | C11—C12 | 1.396 (3) |
C2—H2A | 0.91 (3) | C11—H11A | 0.96 (3) |
C3—C4 | 1.409 (2) | C12—C13 | 1.387 (3) |
C3—H3A | 0.92 (3) | C12—H12A | 0.91 (3) |
C4—C5 | 1.376 (3) | C13—H13A | 1.03 (2) |
C9—O2—H1O2 | 109.5 | N1—C7—C6 | 121.74 (16) |
C7—N1—C8 | 129.42 (16) | N1—C7—H7A | 116.6 (14) |
C7—N1—H1N1 | 111.3 (19) | C6—C7—H7A | 121.6 (14) |
C8—N1—H1N1 | 119.2 (18) | C13—C8—C9 | 120.02 (16) |
O1—C1—C2 | 122.15 (15) | C13—C8—N1 | 115.98 (15) |
O1—C1—C6 | 121.08 (16) | C9—C8—N1 | 123.97 (16) |
C2—C1—C6 | 116.76 (16) | O2—C9—C10 | 122.23 (15) |
C3—C2—C1 | 121.85 (16) | O2—C9—C8 | 119.39 (15) |
C3—C2—H2A | 125.0 (16) | C10—C9—C8 | 118.39 (16) |
C1—C2—H2A | 113.1 (17) | C11—C10—C9 | 121.08 (16) |
C2—C3—C4 | 120.08 (16) | C11—C10—H10A | 119.3 (18) |
C2—C3—H3A | 124.6 (16) | C9—C10—H10A | 119.6 (17) |
C4—C3—H3A | 115.3 (16) | C10—C11—C12 | 120.15 (17) |
C5—C4—C3 | 120.59 (16) | C10—C11—H11A | 120.5 (15) |
C5—C4—Br1 | 120.14 (13) | C12—C11—H11A | 119.4 (15) |
C3—C4—Br1 | 119.24 (13) | C13—C12—C11 | 119.38 (17) |
C4—C5—C6 | 120.14 (16) | C13—C12—H12A | 122 (2) |
C4—C5—H5A | 122 (2) | C11—C12—H12A | 118 (2) |
C6—C5—H5A | 118 (2) | C12—C13—C8 | 120.94 (16) |
C5—C6—C7 | 117.51 (15) | C12—C13—H13A | 122.2 (13) |
C5—C6—C1 | 120.57 (16) | C8—C13—H13A | 116.8 (13) |
C7—C6—C1 | 121.89 (16) | ||
O1—C1—C2—C3 | −179.04 (17) | C1—C6—C7—N1 | −3.8 (3) |
C6—C1—C2—C3 | 0.1 (3) | C7—N1—C8—C13 | −175.04 (17) |
C1—C2—C3—C4 | 0.8 (3) | C7—N1—C8—C9 | 7.1 (3) |
C2—C3—C4—C5 | −0.8 (3) | C13—C8—C9—O2 | −178.12 (16) |
C2—C3—C4—Br1 | 177.31 (14) | N1—C8—C9—O2 | −0.3 (3) |
C3—C4—C5—C6 | 0.0 (3) | C13—C8—C9—C10 | 2.3 (3) |
Br1—C4—C5—C6 | −178.09 (13) | N1—C8—C9—C10 | −179.92 (17) |
C4—C5—C6—C7 | 178.93 (16) | O2—C9—C10—C11 | 178.26 (18) |
C4—C5—C6—C1 | 0.8 (3) | C8—C9—C10—C11 | −2.1 (3) |
O1—C1—C6—C5 | 178.25 (17) | C9—C10—C11—C12 | 0.6 (3) |
C2—C1—C6—C5 | −0.8 (2) | C10—C11—C12—C13 | 0.8 (3) |
O1—C1—C6—C7 | 0.2 (3) | C11—C12—C13—C8 | −0.6 (3) |
C2—C1—C6—C7 | −178.85 (16) | C9—C8—C13—C12 | −0.9 (3) |
C8—N1—C7—C6 | 179.25 (17) | N1—C8—C13—C12 | −178.91 (16) |
C5—C6—C7—N1 | 178.12 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H1O2···O1i | 0.82 | 1.76 | 2.5641 (19) | 169 |
N1—H1N1···O1 | 0.89 (3) | 1.84 (3) | 2.6129 (18) | 143 (3) |
C7—H7A···O2 | 0.95 (2) | 2.12 (2) | 2.794 (2) | 127.1 (18) |
C11—H11A···Br1ii | 0.96 (3) | 2.89 (3) | 3.6982 (19) | 143.1 (19) |
Symmetry codes: (i) x+1, y, z+1; (ii) −x+2, y+1/2, −z+2. |
Experimental details
Crystal data | |
Chemical formula | C13H10BrNO2 |
Mr | 291.12 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 100 |
a, b, c (Å) | 4.6387 (3), 18.9379 (13), 6.2270 (4) |
β (°) | 90.144 (3) |
V (Å3) | 547.02 (6) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 3.74 |
Crystal size (mm) | 0.43 × 0.14 × 0.14 |
Data collection | |
Diffractometer | Bruker APEXII DUO CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2009) |
Tmin, Tmax | 0.295, 0.628 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8575, 3120, 3034 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.018, 0.041, 1.02 |
No. of reflections | 3120 |
No. of parameters | 191 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.59, −0.29 |
Absolute structure | Flack (1983), 1480 Friedel pairs |
Absolute structure parameter | 0.027 (7) |
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H1O2···O1i | 0.82 | 1.76 | 2.5641 (19) | 169 |
N1—H1N1···O1 | 0.89 (3) | 1.84 (3) | 2.6129 (18) | 143 (3) |
C7—H7A···O2 | 0.95 (2) | 2.12 (2) | 2.794 (2) | 127.1 (18) |
C11—H11A···Br1ii | 0.96 (3) | 2.89 (3) | 3.6982 (19) | 143.1 (19) |
Symmetry codes: (i) x+1, y, z+1; (ii) −x+2, y+1/2, −z+2. |
Acknowledgements
The authors thank the Malaysian Government, the Ministry of Science, Technology and Innovation (MOSTI) and Universiti Sains Malaysia for the RU research grants (PKIMIA/815002 and PKIMIA/811120). NEE would like to acknowledge Universiti Sains Malaysia for a post-doctoral fellowship. The International University of Africa (Sudan) is acknowledged for providing study leave to NEE. The authors thank the Malaysian Government and Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.
References
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CSD CrossRef Web of Science Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107. CrossRef CAS Web of Science IUCr Journals Google Scholar
Dao, V.-T., Gaspard, C., Mayer, M., Werner, G. H., Nguyen, S. N. & Michelot, R. J. (2000). Eur. J. Med. Chem. 35, 805–813. Web of Science CrossRef PubMed CAS Google Scholar
Eltayeb, N. E., Teoh, S. G., Chantrapromma, S. & Fun, H.-K. (2010). Acta Cryst. E66, o934–o935. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Eltayeb, N. E., Teoh, S. G., Yeap, C. S., Fun, H.-K. & Adnan, R. (2009). Acta Cryst. E65, o2065–o2066. Web of Science CSD CrossRef IUCr Journals Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Kagkelari, A., Papaefstahiou, G. S., Raptopoulou, C. P. & Zafiropoulos, T. F. (2009). Polyhedron, 28, 3279–3283. Web of Science CSD CrossRef CAS Google Scholar
Karthikeyan, M. S., Prasad, D. J., Poojary, B., Bhat, K. S., Holla, B. S. & Kumari, N. S. (2006). Bioorg. Med. Chem. 14, 7482–7489. Web of Science CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sriram, D., Yogeeswari, P., Myneedu, N. S. & Saraswat, V. (2006). Bioorg. Med. Chem. Lett. 16, 2127–2129. Web of Science CrossRef PubMed CAS Google Scholar
Tan, G.-X. & Liu, X.-C. (2009). Acta Cryst. E65, o559. Web of Science CSD CrossRef IUCr Journals Google Scholar
Wei, P. & Atwood, D. A. (1998). Inorg. Chem. 37, 4934–4938. Web of Science CSD CrossRef PubMed CAS Google Scholar
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Much attention has been given to Schiff base ligands due to their applications such as in coordination chemistry (Kagkelari et al., 2009), chelated boron catalyst (Wei & Atwood, 1998), pharmacological activities, anticancer (Dao et al., 2000), anti-HIV (Sriram et al., 2006), antibacterial and antifungal (Karthikeyan et al., 2006) activities. We have reported the crystal structures of Schiff base ligands which existed in a zwitterionic form i.e 2-((E)-{2-[(E)-2,3-dihydroxybenzylideneamino]-5-methylphenyl}- iminiomethyl)-6-hydroxyphenolate (Eltayeb et al., 2009) and (E)-4-allyl-2-{[(2-hydroxyphenyl)iminio]methyl}-6-methoxyphenolate (Eltayeb et al., 2010). Herein we report the crystal structure of the title zwitterionic Schiff base ligand (I).
The molecule of (I) (Fig. 1), C13H9BrNO2, crystallizes in a zwitterionic form with cationic iminium and anionic enolate, and exists in a trans configuration about the C═N bond [1.310 (2) Å]; the torsion angle C8–N1–C7–C6 is 179.25 (17)°. The molecule is almost planar with the dihedral angle between the two benzene rings of 2.31 (9)°. The hydroxy group is co-planar with the attached C8–C13 benzene ring with the r.m.s. of 0.0102 (2) Å for the seven non H atoms. Intramolecular N—H···O hydrogen bond between the NH+ and the phenolate O- generates an S(6) ring motif (Fig. 1; Table 1) which help to stabilize the planarity of the molecule (Bernstein et al., 1995). The bond distances are in normal ranges (Allen et al., 1987) and comparable with those found in related structures (Eltayeb et al., 2009, 2010; Tan & Liu, 2009).
In the crystal packing (Fig. 2), the zwitterions are linked through O2–H1O2···O1 hydrogen bonds into chains along the [101] and these chains are further connected through C11—H11A···Br1 interactions into a 2-D network perpendicular to the (101)-plane. The crystal is stabilized by O—H···O and weak C—H···Br interactions (Table 1). C···C [3.572 (3)-3.592 (3) Å] and C···Br [3.5633 (19)-3.7339 (18) Å] short contacts are observed.