Zwitterionic 4-bromo-6-meth­oxy-2-{[tris­(hy­droxy­meth­yl)methyl]­iminiumyl­meth­yl}phenolate: crystal structure and Hirshfeld surface analysis

Lee, S.M.; Lo, K.M.; Tan, S.L.; Tiekink, E.R.T.

doi:10.1107/S2056989016012159

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Volume 72| Part 8| August 2016| Pages 1223-1227

https://doi.org/10.1107/S2056989016012159

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Zwitterionic 4-bromo-6-methoxy-2-{[tris(hydroxymethyl)methyl]iminiumylmethyl}phenolate: crystal structure and Hirshfeld surface analysis

See Mun Lee,^a ^* Kong Mun Lo,^a Sang Loon Tan ^a and Edward R. T. Tiekink ^a ^*

^aResearch Centre for Crystalline Materials, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia
^*Correspondence e-mail: annielee@sunway.edu.my, edwardt@sunway.edu.my

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 26 July 2016; accepted 26 July 2016; online 29 July 2016)

In the solid state, the title compound, C₁₂H₁₆BrNO₅ [systematic name: 4-bromo-2-((1E)-{[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]iminiumyl}methyl)-6-methoxybenzen-1-olate], C₁₂H₁₆BrNO₅, is found in the keto–amine tautomeric form, with an intramolecular iminium-N—H⋯O(phenolate) hydrogen bond and an E conformation about the C=N bond. Both gauche (two) and anti relationships are found for the methylhydroxy groups. In the crystal, a supramolecular layer in the bc plane is formed via hydroxy-O—H⋯O(hydroxy) and charge-assisted hydroxy-O—H⋯O(phenolate) hydrogen-bonding interactions; various C—H⋯O interactions provide additional cohesion to the layers, which stack along the a axis with no directional interactions between them. A Hirshfeld surface analysis confirms the lack of specific interactions in the inter-layer region.

Keywords: crystal structure; zwitterion; hydrogen bonding; Hirshfeld surface analysis.

CCDC reference: 1496206

1. Chemical context

Interest in molecules related to the title Schiff base compound derived from tris(hydroxymethyl)aminomethane (see Scheme) rests largely with the biological activity exhibited by their metal complexes. Thus, various species have been studied for their anticancer potential, e.g. vanadium (Back et al., 2012 ) and tin (Lee et al., 2015 ). The insulin-mimetic behaviour of vanadium complexes have been explored (Rehder et al., 2002 ), as has the catecolase activity of binuclear cobalt complexes (Dey & Mukherjee, 2014 ). More recently, the adipogenic (cell differentiation) capacity of vanadium (Halevas et al., 2015 ) and zinc complexes has been described (Tsave et al., 2015 ). Over and above these considerations, magnetochemistry motivates on-going investigations, especially single-molecule (Wu et al., 2007 ; Chandrasekhar et al., 2013 ; Dey et al., 2015 ) and lanthanide-containing species (Zou et al., 2015 ; Das et al., 2015 ). It was during on-going biological assays (Lee et al., 2015) that the title compound, (I), became available. Herein, the crystal and molecular structures of (I) are described, as well as a Hirshfeld surface analysis.

2. Structural commentary

The molecular structure of (I) (Fig. 1) exists as a zwitterion in the solid state, with the iminium N atom being protonated and the phenolate O atom being deprotonated. The observed keto–amine tautomeric form for (I) is the common form for molecules of this type, see Database survey. The conformation about the iminium bond [1.295 (4) Å] is E and this residue is almost coplanar with the benzene ring, forming a C2—C1—C7—N1 torsion angle of 1.9 (4)°. This arrangement allows for the formation of a tight charge-assisted iminium-N—H⋯O(phenolate) hydrogen bond (Table 1). The conformations of the methylhydroxy groups are variable, with gauche relationships about the C8—C9 and C8—C11 bonds [N1—C8—C9—O2 is 45.9 (3)°, i.e. +synclinal, and N1—C8—C11—O4 is −80.2 (3)°, i.e. –synclinal], and an anti relationship about the C8—C10 bond [N1—C8—C10—O3 is 178.8 (2)°, i.e. +antiperiplanar]. The methoxy group is almost coplanar with the ring it is connected to, as seen in the value of the C12—O5—C3—C2 torsion angle of 177.7 (2)°.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O1	0.85 (2)	1.90 (2)	2.608 (3)	140 (3)
O2—H2O⋯O4ⁱ	0.82 (2)	1.93 (2)	2.741 (3)	170 (3)
O3—H3O⋯O2ⁱⁱ	0.81 (2)	1.91 (2)	2.704 (3)	167 (4)
O4—H4O⋯O1ⁱⁱⁱ	0.82 (3)	1.98 (3)	2.760 (3)	158 (3)
C7—H7⋯O1ⁱⁱⁱ	0.93	2.55	3.429 (4)	158
C9—H9B⋯O3ⁱ	0.97	2.51	3.242 (4)	132
C11—H11B⋯O1^iv	0.97	2.39	3.353 (3)	171
Symmetry codes: (i) $[-x+2, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) -x+2, -y+1, -z+1; (iii) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (iv) $[-x+2, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Figure 1
The molecular structure of (I)

, showing the atom-labelling scheme and displacement ellipsoids at the 70% probability level. The intramolecular N—H⋯O hydrogen bond is shown as a double-dashed line (see Table 1

)

3. Supramolecular features

As anticipated from the chemical composition of (I), there are considerable hydrogen-bonding interactions operating in the crystal; geometric characteristics of these are listed in Table 1. Each of the hydroxy O2 and O3 atoms participates in hydroxy-O—H⋯O(hydroxy) hydrogen-bonding interactions, while the hydroxy O4 atom forms a donor interaction with the phenolate O1 atom. The result is the formation of a supramolecular layer parallel to (100) (Fig. 2a). Within this framework are a number of C—H⋯O interactions, i.e. imine-C7—H⋯O(phenolate), methylene-C11—H⋯O(phenolate) and methylene-C9—H⋯O(hydroxy) (Fig. 2b). In accord with the distance criteria in PLATON (Spek, 2009 ), layers stack along the a axis with no directional interactions between them. In order to gain more insight into the molecular packing of (I), a Hirshfeld surface analysis was conducted.

Figure 2
The molecular packing in (I)

, showing (a) a view of the supramolecular layer sustained by O—H⋯O hydrogen bonding, shown as orange dashed lines, and (b) a view of the unit-cell contents shown in projection down the b axis, highlighting the stacking of layers along the a axis. In (a), only acidic H atoms are shown.

4. Analysis of the Hirshfeld surfaces

The Hirshfeld surface of (I) was mapped over the d_norm contact distance within the range of −0.67 to 1.31 Å through calculation of the internal (d_i) and external (d_e) Hirshfeld surface distances to the nearest nucleus (McKinnon et al., 2007 ; Spackman & Jayatilaka, 2009 ). Two-dimensional fingerprint plots associated with relevant close contacts were obtained through the plot of d_e versus d_i (Spackman & McKinnon, 2002 ). The electrostatic potential (ESP) of the crystal structure was mapped onto the Hirshfeld surface by an ab initio quantum modelling approach at the Hartree–Fock level of theory with the STO-3G basis set (HF/STO-3G) over the range of −0.122 to 0.189 au. All Hirshfeld surface and fingerprints plots were generated using Crystal Explorer (Wolff et al., 2012 ), while the ESP was calculated by TONTO (Spackman et al., 2008 ) as implemented in Crystal Explorer. Distances involving H atoms were normalized to the standard neutron diffraction bond lengths.

The Hirshfeld surface map provides a visual summary of any close contacts (shown as red) in contrast to relatively long contacts (shown as white and blue). As displayed in Fig. 3(a), there are several red spots observed on the Hirshfeld surface of (I), particularly around the O atoms, indicating close interactions at distances shorter than the sum of the van der Waals radii. A quantitative analysis of the decomposed two-dimensional fingerprint plot of the relevant O⋯H/H⋯O interactions reveals a distinctive reciprocal spike in the plot of d_e versus d_i (Fig. 3b), with the sum of contact distances being approximately 1.74 Å, signifying a strong intermolecular interaction. Such strong interactions constitute the second major contribution to the Hirshfeld surface, i.e. 25.4%, between the most prominent H⋯H (38.2%) and other major contacts, like C⋯H/H⋯C (15.2%) and Br⋯H/H⋯Br (14.3%) (Fig. 4). Their contributions to the overall Hirshfeld surface notwithstanding, as seen from Figs. 3(c) and 3(d), C⋯H and Br⋯H contacts are at distances greater than their respective van der Waals radii. Fig. 5 shows the O—H⋯O interactions formed between a reference molecule and symmetry-related molecules.

Figure 3
(a) Overall Hirshfeld surface and the two-dimensional fingerprint plot for (I)

, and d_norm surfaces and two-dimensional plots associated with (b) O⋯H/H⋯O, (c) Br⋯H/H⋯Br and (d) C⋯H/H⋯C interactions.

Figure 4
Percentage distribution of the corresponding close contacts to the Hirshfeld surface of (I)

Figure 5
The d_norm surface for (I)

, highlighting the O⋯H hydrogen-bonding interactions which connect molecules in the molecular packing.

In order to gain a qualitative insight into the electrostatic interaction and rationalize the packing motif of the structure, the ESP was mapped over the Hirshfeld surface. The result illustrated in Fig. 6(a), shows that the electronegative sites are predominantly converged on O atoms and that, upon crystallization, the electronegative and electropositive sites are connected (Fig. 6b). It is noteworthy that despite bromine being an electrophilic element, it did not form a significant non-covalent interaction with neighbouring molecules in the inter-layer region where these atoms are directed. The closest contact in this region occurs with methyl-C⋯H12Cⁱ, at 3.12 Å, i.e beyond the sum of the respective van der Waals radii (Spek, 2009) [symmetry code: (i) x, − $[{1\over 2}]$ − y, $[{1\over 2}]$ + z].

Figure 6
(a) The electrostatic potential map of (I)

within the range of −0.008 to 0.008 au and (b) the ESP mapped over the Hirshfeld surface, showing the attraction between the electronegative (red) and electropositive (blue) sites in (I)

5. Database survey

There are several closely related structures to (I) in the crystallographic literature (Groom et al., 2016 ). What might be termed the parent compound, i.e. with no substitution at the phenolate ring other than the imino group in the 2-position, (II), exists in the keto–amine tautomeric form and has been the subject of several investigations (Asgedom et al., 1996 ; Tatar et al., 2005 ). Similar zwitterionic structures are found in the 4-bromo, (III) (Martinez et al., 2011 ), and 6-methoxy, (IV) (Odabas˛oǧlu et al., 2003 ), derivatives, both closely related to (I), suggesting this is the most stable form for these molecules, at least in the solid state. Despite the similar electronic structures, conformational differences exist about the ring between (I) and (IV) as seen in the relative dispositions of the methoxy groups, i.e. C12—O5—C3—C2 is 177.7 (2)° in (I) but −165.75 (14)° in (IV) (Fig. 7). Differences in conformation of the methylhydroxy groups are also apparent, no doubt due to the different hydrogen-bonding patterns in the respective crystal structures.

Figure 7
Overlay diagrams for (I)

(red image), (II) (green), (III) (blue) and (IV) (pink). Images have been drawn so the benzene rings overlap.

6. Synthesis and crystallization

A solution of tris(hydroxymethyl)aminomethane (1.21 g, 0.01 mol) was added to an ethanolic solution of 5-bromo-3-methoxy-2-hydroxybenzaldehyde (2.31 g, 0.01 mol) and refluxed for 2 h. The solution was allowed to stand at room temperature, during which an orange solid formed. This was recrystallized by slow evaporation of its ethanol solution. Yield: 2.67 (80%). Yellow crystals. M.p. 465–466 K. Analysis calculated for C₁₂H₁₆BrNO₅: C 44.48, H 3.70, N 1.99%; found: C 44.81, H 3.42, N 1.64%. IR (cm⁻¹): 3330 (b) ν(N—H, O—H), 1640 (s) ν(C=N), 1528 (m) ν(—O—C=C—), 1066 (m) ν(C—O—C). ¹H NMR (400 MHz, CDCl₃): δ 8.35 [s, 1H, –N=C(H)], 7.01–7.10 (m, 1H, aryl H), 6.83–6.89 (m, 1H, aryl H), 5.06 (s, 3H, OH), 3.95 (s, 3H, OCH₃), 3.37–3.75 (m, 6H, aliphatic H).

7. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The carbon-bound H atoms were placed in calculated positions (C—H = 0.93–0.97 Å) and were included in the refinement in the riding-model approximation, with U_iso(H) set at 1.2–1.5U_eq(C). The O- and N-bound H atoms were located from difference Fourier maps and refined with distance restraints O—H = 0.82±0.01 Å and N—H = 0.86±0.01 Å, and with U_iso(H) set at 1.5U_eq(O) and U_iso(H) set at 1.2U_eq(N), respectively. Owing to poor agreement, several reflections, i.e. (−9 7 7), (−12 4 6), (−10 5 6) and (−3 3 2), were omitted from the final cycles of refinement.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₂H₁₆BrNO₅
M_r	334.17
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	12.2872 (9), 10.7186 (8), 10.5830 (8)
β (°)	108.462 (1)
V (Å³)	1322.06 (17)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	3.13
Crystal size (mm)	0.26 × 0.10 × 0.08

Data collection
Diffractometer	Bruker SMART APEX
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996 )
T_min, T_max	0.497, 0.788
No. of measured, independent and observed [I > 2σ(I)] reflections	5095, 2257, 1923
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.068, 1.04
No. of reflections	2257
No. of parameters	185
No. of restraints	4
Δρ_max, Δρ_min (e Å⁻³)	0.41, −0.54
Computer programs: SMART and SAINT (Bruker, 2008 ), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), ORTEP-3 for Windows (Farrugia, 2012 ), QMol (Gans & Shalloway, 2001 ), DIAMOND (Brandenburg, 2006 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1496206

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S2056989016012159/hb7605sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989016012159/hb7605Isup2.hkl

checkCIF report

Computing details top

Data collection: SMART (Bruker, 2008); cell refinement: SMART (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012), QMol (Gans & Shalloway, 2001), DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

4-Bromo-2-((1E)-{[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]iminiumyl}methyl)-6-methoxybenzen-1-olate top

Crystal data top

C₁₂H₁₆BrNO₅	F(000) = 680
M_r = 334.17	D_x = 1.679 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 12.2872 (9) Å	Cell parameters from 1493 reflections
b = 10.7186 (8) Å	θ = 2.6–27.9°
c = 10.5830 (8) Å	µ = 3.13 mm⁻¹
β = 108.462 (1)°	T = 293 K
V = 1322.06 (17) Å³	Prism, yellow
Z = 4	0.26 × 0.10 × 0.08 mm

Data collection top

Bruker SMART APEX diffractometer	2257 independent reflections
Radiation source: fine-focus sealed tube	1923 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.032
φ and ω scans	θ_max = 25.0°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→14
T_min = 0.497, T_max = 0.788	k = −12→12
5095 measured reflections	l = −9→12

Refinement top

Refinement on F²	4 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.030	w = 1/[σ²(F_o²) + (0.0206P)² + 0.8903P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.068	(Δ/σ)_max < 0.001
S = 1.04	Δρ_max = 0.41 e Å⁻³
2257 reflections	Δρ_min = −0.54 e Å⁻³
185 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.45516 (2)	−0.01276 (3)	0.80991 (3)	0.01835 (11)
O1	0.79706 (16)	0.09687 (18)	0.52558 (18)	0.0134 (4)
O2	1.05037 (18)	0.27428 (18)	0.60436 (19)	0.0141 (5)
H2O	1.083 (2)	0.2087 (17)	0.632 (3)	0.021*
O3	0.96322 (18)	0.60240 (19)	0.62300 (19)	0.0174 (5)
H3O	0.948 (3)	0.641 (3)	0.5535 (19)	0.026*
O4	0.85256 (17)	0.54263 (18)	0.83553 (19)	0.0132 (4)
H4O	0.824 (3)	0.517 (3)	0.891 (2)	0.020*
O5	0.70096 (17)	−0.12504 (18)	0.49502 (19)	0.0153 (5)
N1	0.8572 (2)	0.2954 (2)	0.6738 (2)	0.0118 (5)
H1N	0.865 (3)	0.245 (2)	0.615 (2)	0.014*
C1	0.7122 (2)	0.1554 (3)	0.6915 (3)	0.0125 (6)
C2	0.7298 (2)	0.0719 (3)	0.5940 (3)	0.0110 (6)
C3	0.6701 (2)	−0.0452 (3)	0.5783 (3)	0.0122 (6)
C4	0.5921 (2)	−0.0711 (3)	0.6427 (3)	0.0133 (6)
H4	0.5531	−0.1467	0.6289	0.016*
C5	0.5715 (2)	0.0190 (3)	0.7308 (3)	0.0146 (6)
C6	0.6309 (2)	0.1276 (3)	0.7580 (3)	0.0140 (6)
H6	0.6186	0.1835	0.8193	0.017*
C7	0.7801 (2)	0.2645 (3)	0.7279 (3)	0.0109 (6)
H7	0.7689	0.3161	0.7933	0.013*
C8	0.9361 (2)	0.4026 (3)	0.7066 (3)	0.0110 (6)
C9	1.0558 (2)	0.3539 (3)	0.7151 (3)	0.0129 (6)
H9A	1.1060	0.4239	0.7159	0.016*
H9B	1.0878	0.3079	0.7975	0.016*
C10	0.8904 (2)	0.4963 (2)	0.5932 (3)	0.0120 (6)
H10A	0.8904	0.4597	0.5094	0.014*
H10B	0.8124	0.5201	0.5856	0.014*
C11	0.9462 (2)	0.4610 (3)	0.8413 (3)	0.0121 (6)
H11A	0.9492	0.3952	0.9052	0.014*
H11B	1.0175	0.5076	0.8725	0.014*
C12	0.6500 (3)	−0.2459 (3)	0.4763 (3)	0.0216 (7)
H12A	0.6684	−0.2879	0.5606	0.032*
H12B	0.6791	−0.2933	0.4170	0.032*
H12C	0.5683	−0.2380	0.4388	0.032*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.01640 (17)	0.01891 (18)	0.02421 (18)	−0.00122 (13)	0.01279 (13)	0.00285 (13)
O1	0.0139 (11)	0.0159 (11)	0.0136 (10)	−0.0018 (8)	0.0089 (9)	−0.0016 (8)
O2	0.0205 (12)	0.0093 (10)	0.0139 (11)	0.0039 (9)	0.0075 (9)	0.0016 (8)
O3	0.0284 (13)	0.0112 (11)	0.0141 (11)	−0.0034 (9)	0.0091 (10)	0.0029 (8)
O4	0.0141 (11)	0.0153 (11)	0.0145 (11)	0.0004 (8)	0.0108 (9)	−0.0009 (9)
O5	0.0192 (12)	0.0123 (10)	0.0173 (11)	−0.0026 (9)	0.0099 (9)	−0.0049 (9)
N1	0.0151 (13)	0.0091 (12)	0.0109 (13)	−0.0001 (10)	0.0034 (11)	−0.0023 (10)
C1	0.0106 (15)	0.0127 (15)	0.0145 (15)	−0.0002 (12)	0.0043 (12)	0.0015 (12)
C2	0.0079 (14)	0.0123 (15)	0.0110 (14)	0.0025 (11)	0.0008 (12)	0.0037 (12)
C3	0.0094 (15)	0.0149 (15)	0.0126 (15)	0.0007 (12)	0.0038 (12)	−0.0008 (12)
C4	0.0132 (16)	0.0104 (14)	0.0142 (15)	−0.0009 (12)	0.0013 (12)	0.0009 (12)
C5	0.0122 (15)	0.0180 (16)	0.0147 (15)	−0.0013 (12)	0.0060 (12)	0.0054 (12)
C6	0.0140 (15)	0.0140 (15)	0.0145 (15)	0.0035 (12)	0.0052 (12)	0.0007 (12)
C7	0.0121 (15)	0.0098 (14)	0.0115 (14)	0.0028 (11)	0.0049 (12)	0.0025 (11)
C8	0.0124 (15)	0.0105 (14)	0.0114 (14)	−0.0008 (11)	0.0055 (12)	−0.0004 (11)
C9	0.0137 (16)	0.0124 (15)	0.0137 (15)	−0.0019 (12)	0.0056 (12)	−0.0010 (11)
C10	0.0132 (14)	0.0117 (14)	0.0118 (14)	0.0021 (12)	0.0052 (11)	−0.0028 (12)
C11	0.0123 (15)	0.0117 (14)	0.0128 (15)	0.0016 (12)	0.0048 (12)	−0.0002 (11)
C12	0.0263 (19)	0.0138 (16)	0.0267 (18)	−0.0091 (13)	0.0112 (15)	−0.0070 (13)

Geometric parameters (Å, º) top

Br1—C5	1.902 (3)	C4—C5	1.420 (4)
O1—C2	1.287 (3)	C4—H4	0.9300
O2—C9	1.434 (3)	C5—C6	1.355 (4)
O2—H2O	0.818 (10)	C6—H6	0.9300
O3—C10	1.419 (3)	C7—H7	0.9300
O3—H3O	0.815 (10)	C8—C11	1.525 (4)
O4—C11	1.432 (3)	C8—C10	1.529 (4)
O4—H4O	0.819 (10)	C8—C9	1.536 (4)
O5—C3	1.365 (3)	C9—H9A	0.9700
O5—C12	1.425 (3)	C9—H9B	0.9700
N1—C7	1.295 (4)	C10—H10A	0.9700
N1—C8	1.473 (4)	C10—H10B	0.9700
N1—H1N	0.856 (10)	C11—H11A	0.9700
C1—C7	1.417 (4)	C11—H11B	0.9700
C1—C6	1.424 (4)	C12—H12A	0.9600
C1—C2	1.432 (4)	C12—H12B	0.9600
C2—C3	1.438 (4)	C12—H12C	0.9600
C3—C4	1.369 (4)

C9—O2—H2O	109 (2)	N1—C8—C10	106.1 (2)
C10—O3—H3O	105 (2)	C11—C8—C10	111.4 (2)
C11—O4—H4O	107 (2)	N1—C8—C9	107.2 (2)
C3—O5—C12	117.3 (2)	C11—C8—C9	107.0 (2)
C7—N1—C8	127.9 (2)	C10—C8—C9	112.1 (2)
C7—N1—H1N	115 (2)	O2—C9—C8	111.0 (2)
C8—N1—H1N	117 (2)	O2—C9—H9A	109.4
C7—C1—C6	118.9 (3)	C8—C9—H9A	109.4
C7—C1—C2	120.1 (3)	O2—C9—H9B	109.4
C6—C1—C2	121.0 (3)	C8—C9—H9B	109.4
O1—C2—C1	123.0 (3)	H9A—C9—H9B	108.0
O1—C2—C3	120.8 (3)	O3—C10—C8	107.6 (2)
C1—C2—C3	116.2 (3)	O3—C10—H10A	110.2
O5—C3—C4	125.2 (3)	C8—C10—H10A	110.2
O5—C3—C2	112.7 (2)	O3—C10—H10B	110.2
C4—C3—C2	122.1 (3)	C8—C10—H10B	110.2
C3—C4—C5	119.2 (3)	H10A—C10—H10B	108.5
C3—C4—H4	120.4	O4—C11—C8	112.6 (2)
C5—C4—H4	120.4	O4—C11—H11A	109.1
C6—C5—C4	121.8 (3)	C8—C11—H11A	109.1
C6—C5—Br1	119.3 (2)	O4—C11—H11B	109.1
C4—C5—Br1	118.8 (2)	C8—C11—H11B	109.1
C5—C6—C1	119.3 (3)	H11A—C11—H11B	107.8
C5—C6—H6	120.3	O5—C12—H12A	109.5
C1—C6—H6	120.3	O5—C12—H12B	109.5
N1—C7—C1	122.7 (3)	H12A—C12—H12B	109.5
N1—C7—H7	118.6	O5—C12—H12C	109.5
C1—C7—H7	118.6	H12A—C12—H12C	109.5
N1—C8—C11	113.2 (2)	H12B—C12—H12C	109.5

C7—C1—C2—O1	−7.6 (4)	C2—C1—C6—C5	1.7 (4)
C6—C1—C2—O1	175.5 (2)	C8—N1—C7—C1	−177.2 (3)
C7—C1—C2—C3	170.7 (2)	C6—C1—C7—N1	178.9 (3)
C6—C1—C2—C3	−6.2 (4)	C2—C1—C7—N1	1.9 (4)
C12—O5—C3—C4	−1.6 (4)	C7—N1—C8—C11	16.6 (4)
C12—O5—C3—C2	177.7 (2)	C7—N1—C8—C10	−105.8 (3)
O1—C2—C3—O5	5.3 (4)	C7—N1—C8—C9	134.3 (3)
C1—C2—C3—O5	−173.1 (2)	N1—C8—C9—O2	45.9 (3)
O1—C2—C3—C4	−175.4 (3)	C11—C8—C9—O2	167.6 (2)
C1—C2—C3—C4	6.2 (4)	C10—C8—C9—O2	−70.0 (3)
O5—C3—C4—C5	177.5 (3)	N1—C8—C10—O3	178.8 (2)
C2—C3—C4—C5	−1.8 (4)	C11—C8—C10—O3	55.2 (3)
C3—C4—C5—C6	−3.2 (4)	C9—C8—C10—O3	−64.6 (3)
C3—C4—C5—Br1	175.5 (2)	N1—C8—C11—O4	−80.2 (3)
C4—C5—C6—C1	3.2 (4)	C10—C8—C11—O4	39.2 (3)
Br1—C5—C6—C1	−175.5 (2)	C9—C8—C11—O4	162.0 (2)
C7—C1—C6—C5	−175.2 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O1	0.85 (2)	1.90 (2)	2.608 (3)	140 (3)
O2—H2O···O4ⁱ	0.82 (2)	1.93 (2)	2.741 (3)	170 (3)
O3—H3O···O2ⁱⁱ	0.81 (2)	1.91 (2)	2.704 (3)	167 (4)
O4—H4O···O1ⁱⁱⁱ	0.82 (3)	1.98 (3)	2.760 (3)	158 (3)
C7—H7···O1ⁱⁱⁱ	0.93	2.55	3.429 (4)	158
C9—H9B···O3ⁱ	0.97	2.51	3.242 (4)	132
C11—H11B···O1^iv	0.97	2.39	3.353 (3)	171

Symmetry codes: (i) −x+2, y−1/2, −z+3/2; (ii) −x+2, −y+1, −z+1; (iii) x, −y+1/2, z+1/2; (iv) −x+2, y+1/2, −z+3/2.

Acknowledgements

The authors are grateful to Sunway University, the University of Malaya for financial assistance (grant No. RP017B-14AFR) and the Ministry of Higher Education of Malaysia (MOHE) Fundamental Research Grant Scheme (grant No. FP033-2014B) for supporting this research.

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