organic compounds
n-Dodecylammonium bromide monohydrate
aCollege of Chemistry and Chemical Engineering, Liaocheng University, Shandong 252059, People's Republic of China
*Correspondence e-mail: diyouying@126.com
In the title compound, C12H28N+·Br−·H2O, the ionic pairs formed by n-dodecylammonium cations and bromide anions are arranged into thick layers; these layers are linked in a nearly perpendicular fashion [the angle between the layers is 85.84 (5)°] by hydrogen-bonding interactions involving the water molecules. The methylene part of the alkyl chain in the cation adopts an all-trans conformation. In the molecules are linked by intermolecular N—H⋯Br, O—H⋯Br and N—H⋯O hydrogen bonds.
Related literature
Long-chain n-alkylammonium halides are widely used as surfactants (Aratono et al., 1998; Tornblom et al., 2000) and as models for biological membranes (Ringsdorf et al., 1988). They exhibit at room temperature: for solid-solid phase transitions in n–alkylammonium chlorides, see: Terreros et al. (2000). For a related structure, see: Lundén (1974).
Experimental
Crystal data
|
Data collection: SMART (Siemens, 1996); cell SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536810010123/lx2141sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810010123/lx2141Isup2.hkl
n–Dodecylammonium bromide monohydrate was prepared by the addition of hydrobromic acid to an ethanol solution of n–dodecylamine. The resulting precipitate was filtered off and recrystallized several times from chloroform. Single crystals suitable for X–ray diffraction were prepared by evaporation of a solution of the title compound in chloroform at room temperature. Analysis, calculated for C12H30BrNO (Mr = 284.28): C 50.69, H 10.64, N 4.93, O 5.63, Br 28.11%; found: C 50.67, H 10.65, N 4.91, O 5.64, Br 28.13%.
The reported
was obtained by TWIN/BASF procedure in SHELXL (Sheldrick, 2008). Water molecule bound H atoms were located in difference Fourier maps and their positional parameters refined with a distance restraint [O1—H1 = 0.85 (5) & O1—H2 = 0.80 (5) Å] and a angle restraint. The H atoms of C and N atoms were positioned geometrically, with methylene C—H distances of 0.97 Å, methyl C—H distances of 0.96 Å, N—H 0.89 Å and refined as riding on their parent atoms. TheUiso(H) values were set at 1.2Ueq for the methylene H atoms and at 1.5Ueq for other H atoms.Data collection: SMART (Siemens, 1996); cell
SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C12H28N+·Br−·H2O | F(000) = 608 |
Mr = 284.28 | Dx = 1.217 Mg m−3 |
Monoclinic, Cc | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: C -2yc | Cell parameters from 1266 reflections |
a = 4.7921 (5) Å | θ = 2.9–25.0° |
b = 42.810 (4) Å | µ = 2.63 mm−1 |
c = 7.8573 (8) Å | T = 293 K |
β = 105.798 (2)° | Acicular, colourless |
V = 1551.0 (3) Å3 | 0.42 × 0.14 × 0.06 mm |
Z = 4 |
Siemens SMART CCD area-detector diffractometer | 2644 independent reflections |
Radiation source: fine-focus sealed tube | 1665 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.047 |
Detector resolution: 10 pixels mm-1 | θmax = 27.0°, θmin = 1.9° |
ϕ and ω scans | h = −6→5 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −54→50 |
Tmin = 0.404, Tmax = 0.858 | l = −6→10 |
4760 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.043 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.081 | w = 1/[σ2(Fo2) + (0.0277P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.92 | (Δ/σ)max < 0.001 |
2644 reflections | Δρmax = 0.40 e Å−3 |
145 parameters | Δρmin = −0.24 e Å−3 |
5 restraints | Absolute structure: Flack (1983), 945 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.048 (19) |
C12H28N+·Br−·H2O | V = 1551.0 (3) Å3 |
Mr = 284.28 | Z = 4 |
Monoclinic, Cc | Mo Kα radiation |
a = 4.7921 (5) Å | µ = 2.63 mm−1 |
b = 42.810 (4) Å | T = 293 K |
c = 7.8573 (8) Å | 0.42 × 0.14 × 0.06 mm |
β = 105.798 (2)° |
Siemens SMART CCD area-detector diffractometer | 2644 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1665 reflections with I > 2σ(I) |
Tmin = 0.404, Tmax = 0.858 | Rint = 0.047 |
4760 measured reflections |
R[F2 > 2σ(F2)] = 0.043 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.081 | Δρmax = 0.40 e Å−3 |
S = 0.92 | Δρmin = −0.24 e Å−3 |
2644 reflections | Absolute structure: Flack (1983), 945 Friedel pairs |
145 parameters | Absolute structure parameter: 0.048 (19) |
5 restraints |
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 | 0.2086 (2) | 0.524590 (10) | 0.38293 (16) | 0.05643 (18) | |
O1 | 0.8268 (12) | 0.45062 (13) | 0.1580 (6) | 0.0760 (15) | |
H1 | 0.734 (13) | 0.4485 (18) | 0.053 (6) | 0.114* | |
H2 | 0.993 (11) | 0.4589 (15) | 0.124 (9) | 0.114* | |
N1 | 0.7249 (9) | 0.46990 (8) | 0.4809 (6) | 0.0502 (12) | |
H1A | 0.8831 | 0.4731 | 0.5697 | 0.075* | |
H1B | 0.6083 | 0.4864 | 0.4696 | 0.075* | |
H1C | 0.7755 | 0.4671 | 0.3810 | 0.075* | |
C1 | 0.5729 (12) | 0.44200 (13) | 0.5176 (8) | 0.0496 (17) | |
H1D | 0.3952 | 0.4392 | 0.4238 | 0.059* | |
H1E | 0.5212 | 0.4449 | 0.6276 | 0.059* | |
C2 | 0.7567 (11) | 0.41323 (10) | 0.5313 (7) | 0.0480 (14) | |
H2A | 0.9345 | 0.4161 | 0.6249 | 0.058* | |
H2B | 0.8084 | 0.4104 | 0.4213 | 0.058* | |
C3 | 0.6028 (11) | 0.38403 (11) | 0.5696 (7) | 0.0496 (14) | |
H3A | 0.5795 | 0.3855 | 0.6881 | 0.059* | |
H3B | 0.4108 | 0.3831 | 0.4875 | 0.059* | |
C4 | 0.7635 (11) | 0.35416 (10) | 0.5545 (7) | 0.0466 (14) | |
H4A | 0.7908 | 0.3531 | 0.4367 | 0.056* | |
H4B | 0.9540 | 0.3550 | 0.6382 | 0.056* | |
C5 | 0.6137 (11) | 0.32477 (11) | 0.5877 (7) | 0.0484 (14) | |
H5A | 0.5955 | 0.3254 | 0.7076 | 0.058* | |
H5B | 0.4194 | 0.3245 | 0.5082 | 0.058* | |
C6 | 0.7625 (11) | 0.29500 (11) | 0.5641 (7) | 0.0488 (14) | |
H6A | 0.9550 | 0.2951 | 0.6458 | 0.059* | |
H6B | 0.7859 | 0.2947 | 0.4453 | 0.059* | |
C7 | 0.6105 (11) | 0.26515 (11) | 0.5920 (7) | 0.0454 (13) | |
H7A | 0.5909 | 0.2651 | 0.7117 | 0.055* | |
H7B | 0.4168 | 0.2651 | 0.5117 | 0.055* | |
C8 | 0.7621 (11) | 0.23602 (11) | 0.5640 (7) | 0.0484 (14) | |
H8A | 0.9555 | 0.2361 | 0.6447 | 0.058* | |
H8B | 0.7827 | 0.2362 | 0.4446 | 0.058* | |
C9 | 0.6128 (11) | 0.20610 (11) | 0.5905 (7) | 0.0495 (14) | |
H9A | 0.4180 | 0.2062 | 0.5116 | 0.059* | |
H9B | 0.5957 | 0.2058 | 0.7107 | 0.059* | |
C10 | 0.7642 (12) | 0.17604 (11) | 0.5585 (7) | 0.0508 (14) | |
H10A | 0.7842 | 0.1766 | 0.4389 | 0.061* | |
H10B | 0.9579 | 0.1757 | 0.6387 | 0.061* | |
C11 | 0.6143 (13) | 0.14651 (12) | 0.5818 (8) | 0.0592 (16) | |
H11A | 0.5946 | 0.1459 | 0.7014 | 0.071* | |
H11B | 0.4205 | 0.1468 | 0.5016 | 0.071* | |
C12 | 0.7623 (15) | 0.11758 (13) | 0.5502 (9) | 0.080 (2) | |
H12A | 0.7850 | 0.1179 | 0.4325 | 0.121* | |
H12B | 0.6483 | 0.0998 | 0.5634 | 0.121* | |
H12C | 0.9496 | 0.1163 | 0.6342 | 0.121* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0519 (3) | 0.0577 (3) | 0.0587 (3) | 0.0057 (6) | 0.0134 (2) | 0.0063 (5) |
O1 | 0.078 (3) | 0.085 (4) | 0.069 (3) | 0.006 (3) | 0.025 (3) | 0.006 (3) |
N1 | 0.051 (3) | 0.038 (3) | 0.056 (3) | 0.006 (2) | 0.005 (2) | 0.0026 (19) |
C1 | 0.050 (4) | 0.032 (3) | 0.067 (5) | 0.001 (3) | 0.017 (3) | 0.004 (3) |
C2 | 0.052 (3) | 0.036 (3) | 0.057 (4) | −0.001 (3) | 0.016 (3) | 0.000 (2) |
C3 | 0.053 (4) | 0.043 (3) | 0.059 (4) | 0.001 (3) | 0.027 (3) | 0.007 (3) |
C4 | 0.047 (3) | 0.039 (3) | 0.056 (4) | 0.000 (3) | 0.017 (3) | 0.001 (3) |
C5 | 0.057 (4) | 0.041 (3) | 0.052 (3) | 0.001 (3) | 0.024 (3) | −0.005 (3) |
C6 | 0.053 (3) | 0.044 (3) | 0.049 (3) | −0.003 (3) | 0.013 (3) | 0.000 (3) |
C7 | 0.048 (3) | 0.036 (3) | 0.056 (3) | −0.001 (3) | 0.020 (3) | 0.001 (3) |
C8 | 0.050 (3) | 0.042 (3) | 0.055 (3) | −0.003 (3) | 0.017 (3) | −0.001 (3) |
C9 | 0.051 (4) | 0.046 (3) | 0.056 (4) | −0.007 (3) | 0.021 (3) | −0.001 (3) |
C10 | 0.058 (4) | 0.048 (3) | 0.047 (3) | 0.000 (3) | 0.015 (3) | 0.001 (3) |
C11 | 0.073 (4) | 0.041 (3) | 0.067 (4) | −0.011 (3) | 0.026 (3) | −0.001 (3) |
C12 | 0.104 (5) | 0.041 (4) | 0.097 (5) | 0.003 (4) | 0.028 (4) | −0.007 (3) |
O1—H1 | 0.83 (4) | C6—C7 | 1.516 (6) |
O1—H2 | 0.97 (4) | C6—H6A | 0.9700 |
N1—C1 | 1.468 (7) | C6—H6B | 0.9700 |
N1—H1A | 0.8900 | C7—C8 | 1.490 (6) |
N1—H1B | 0.8900 | C7—H7A | 0.9700 |
N1—H1C | 0.8900 | C7—H7B | 0.9700 |
C1—C2 | 1.501 (7) | C8—C9 | 1.509 (7) |
C1—H1D | 0.9700 | C8—H8A | 0.9700 |
C1—H1E | 0.9700 | C8—H8B | 0.9700 |
C2—C3 | 1.522 (6) | C9—C10 | 1.532 (7) |
C2—H2A | 0.9700 | C9—H9A | 0.9700 |
C2—H2B | 0.9700 | C9—H9B | 0.9700 |
C3—C4 | 1.514 (7) | C10—C11 | 1.490 (7) |
C3—H3A | 0.9700 | C10—H10A | 0.9700 |
C3—H3B | 0.9700 | C10—H10B | 0.9700 |
C4—C5 | 1.506 (6) | C11—C12 | 1.481 (8) |
C4—H4A | 0.9700 | C11—H11A | 0.9700 |
C4—H4B | 0.9700 | C11—H11B | 0.9700 |
C5—C6 | 1.496 (6) | C12—H12A | 0.9600 |
C5—H5A | 0.9700 | C12—H12B | 0.9600 |
C5—H5B | 0.9700 | C12—H12C | 0.9600 |
H1—O1—H2 | 91 (5) | C5—C6—H6B | 108.3 |
C1—N1—H1A | 109.5 | C7—C6—H6B | 108.3 |
C1—N1—H1B | 109.5 | H6A—C6—H6B | 107.4 |
H1A—N1—H1B | 109.5 | C8—C7—C6 | 114.3 (4) |
C1—N1—H1C | 109.5 | C8—C7—H7A | 108.7 |
H1A—N1—H1C | 109.5 | C6—C7—H7A | 108.7 |
H1B—N1—H1C | 109.5 | C8—C7—H7B | 108.7 |
N1—C1—C2 | 111.6 (5) | C6—C7—H7B | 108.7 |
N1—C1—H1D | 109.3 | H7A—C7—H7B | 107.6 |
C2—C1—H1D | 109.3 | C7—C8—C9 | 114.9 (4) |
N1—C1—H1E | 109.3 | C7—C8—H8A | 108.5 |
C2—C1—H1E | 109.3 | C9—C8—H8A | 108.5 |
H1D—C1—H1E | 108.0 | C7—C8—H8B | 108.5 |
C1—C2—C3 | 112.4 (4) | C9—C8—H8B | 108.5 |
C1—C2—H2A | 109.1 | H8A—C8—H8B | 107.5 |
C3—C2—H2A | 109.1 | C8—C9—C10 | 115.3 (4) |
C1—C2—H2B | 109.1 | C8—C9—H9A | 108.5 |
C3—C2—H2B | 109.1 | C10—C9—H9A | 108.5 |
H2A—C2—H2B | 107.9 | C8—C9—H9B | 108.5 |
C4—C3—C2 | 113.2 (4) | C10—C9—H9B | 108.5 |
C4—C3—H3A | 108.9 | H9A—C9—H9B | 107.5 |
C2—C3—H3A | 108.9 | C11—C10—C9 | 115.3 (4) |
C4—C3—H3B | 108.9 | C11—C10—H10A | 108.5 |
C2—C3—H3B | 108.9 | C9—C10—H10A | 108.5 |
H3A—C3—H3B | 107.8 | C11—C10—H10B | 108.5 |
C5—C4—C3 | 114.6 (4) | C9—C10—H10B | 108.5 |
C5—C4—H4A | 108.6 | H10A—C10—H10B | 107.5 |
C3—C4—H4A | 108.6 | C12—C11—C10 | 114.8 (5) |
C5—C4—H4B | 108.6 | C12—C11—H11A | 108.6 |
C3—C4—H4B | 108.6 | C10—C11—H11A | 108.6 |
H4A—C4—H4B | 107.6 | C12—C11—H11B | 108.6 |
C6—C5—C4 | 115.1 (4) | C10—C11—H11B | 108.6 |
C6—C5—H5A | 108.5 | H11A—C11—H11B | 107.5 |
C4—C5—H5A | 108.5 | C11—C12—H12A | 109.5 |
C6—C5—H5B | 108.5 | C11—C12—H12B | 109.5 |
C4—C5—H5B | 108.5 | H12A—C12—H12B | 109.5 |
H5A—C5—H5B | 107.5 | C11—C12—H12C | 109.5 |
C5—C6—C7 | 115.9 (4) | H12A—C12—H12C | 109.5 |
C5—C6—H6A | 108.3 | H12B—C12—H12C | 109.5 |
C7—C6—H6A | 108.3 | ||
N1—C1—C2—C3 | 179.9 (4) | C5—C6—C7—C8 | 178.9 (4) |
C1—C2—C3—C4 | 170.6 (5) | C6—C7—C8—C9 | −179.7 (5) |
C2—C3—C4—C5 | −178.7 (4) | C7—C8—C9—C10 | 178.9 (4) |
C3—C4—C5—C6 | 177.0 (5) | C8—C9—C10—C11 | −179.1 (5) |
C4—C5—C6—C7 | −178.4 (4) | C9—C10—C11—C12 | 179.9 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···Br1i | 0.89 | 2.53 | 3.380 (4) | 159 |
N1—H1B···Br1 | 0.89 | 2.47 | 3.340 (4) | 166 |
N1—H1C···O1 | 0.89 | 1.97 | 2.834 (7) | 165 |
O1—H1···Br1ii | 0.83 (4) | 2.76 (6) | 3.329 (5) | 128 (6) |
O1—H2···Br1iii | 0.97 (4) | 2.49 (5) | 3.361 (5) | 149 (5) |
Symmetry codes: (i) x+1, −y+1, z+1/2; (ii) x, −y+1, z−1/2; (iii) x+1, −y+1, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C12H28N+·Br−·H2O |
Mr | 284.28 |
Crystal system, space group | Monoclinic, Cc |
Temperature (K) | 293 |
a, b, c (Å) | 4.7921 (5), 42.810 (4), 7.8573 (8) |
β (°) | 105.798 (2) |
V (Å3) | 1551.0 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.63 |
Crystal size (mm) | 0.42 × 0.14 × 0.06 |
Data collection | |
Diffractometer | Siemens SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.404, 0.858 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4760, 2644, 1665 |
Rint | 0.047 |
(sin θ/λ)max (Å−1) | 0.639 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.081, 0.92 |
No. of reflections | 2644 |
No. of parameters | 145 |
No. of restraints | 5 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.40, −0.24 |
Absolute structure | Flack (1983), 945 Friedel pairs |
Absolute structure parameter | 0.048 (19) |
Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 1998), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···Br1i | 0.89 | 2.53 | 3.380 (4) | 159.4 |
N1—H1B···Br1 | 0.89 | 2.47 | 3.340 (4) | 166.4 |
N1—H1C···O1 | 0.89 | 1.97 | 2.834 (7) | 164.6 |
O1—H1···Br1ii | 0.83 (4) | 2.76 (6) | 3.329 (5) | 128 (6) |
O1—H2···Br1iii | 0.97 (4) | 2.49 (5) | 3.361 (5) | 149 (5) |
Symmetry codes: (i) x+1, −y+1, z+1/2; (ii) x, −y+1, z−1/2; (iii) x+1, −y+1, z−1/2. |
Acknowledgements
We acknowledge financial support by the National Natural Science Foundations of China (20673050 and 20973089).
References
Aratono, M., Villeneuve, M., Takiue, T., Ikeda, N. & Iyota, H. (1998). J. Colloid Interface Sci. 200, 161–171. Web of Science CrossRef CAS Google Scholar
Brandenburg, K. (1998). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Lundén, B.-M. (1974). Acta Cryst. B30, 1756–1760. CSD CrossRef IUCr Journals Web of Science Google Scholar
Ringsdorf, H., Schlarb, B. & Venzmer, J. (1988). Angew. Chem. Int. Ed. Engl. 27, 113–158. CrossRef Web of Science Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Siemens (1996). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar
Terreros, A., Galera–Gomez, P. J. & Lopez–Cabarcos, E. (2000). J. Therm. Anal. Calorim. 61, 341–350. Web of Science CrossRef CAS Google Scholar
Tornblom, M., Sitnikov, R. & Henriksson, U. (2000). J. Phys. Chem. B, 104, 1529–1538. Web of Science CrossRef Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Long-chain n-alkylammonium halides are widely used as surfactants (Aratono et al., 1998; Tornblom et al., 2000) and as models for biological membranes (Ringsdorf et al., 1988). They exhibit polymorphism at room temperature; solid-solid phase transitions occurred in n-alkylammonium chlorides (Terreros et al., 2000). As a part of the studies on novel potential phase transfer materials with the thermochemical properties such as n-alkylammonium chlorides, we report the crystal structure of the title compound (Fig. 1).
Atoms C3–C12 are coplanar in the title compound; however, atoms C2–C12 are coplanar in n–dodecylammonium bromide (Ludén, 1974). Although the methylene chain had the extended all–trans conformation, it is slightly curved in the vicinity of the ammonium group, to accommodate the hydrogen–bonding interactions. The hydrogen bonds of n–dodecylammonium bromide monohydrate are more stronger than that of n–dodecylammonium bromide because of N—H···O and O—H···Br hydrogen bonds. Only torsion angle C1–C2–C3–C4 deviates significantly from 180 °, with a value of 170.6 (5)°. The crystal packing (Fig. 2) is stabilized by intermolecular N—H···Br, N—H···O and O—H···Br hydrogen bonds (Table 1).