Two isomorphous aza­stilbene derivatives: 1-(2-chloro­benz­yl)-4-[(E)-2-(4-hy­droxy­phenyl)ethenyl]pyridinium chloride and 1-(2-bromo­benzyl)-4-[(E)-2-(4-hy­droxy­phenyl)­ethenyl]­pyridinium bromide

The crystal structures of the two title (E)-stilbazolium halogenates, C₂₀H₁₇ClNO⁺·Cl⁻ and C₂₀H₁₇BrNO⁺·Br⁻, are isomorphous, with an isostructurality index of 0.985. The aza­styryl fragments are almost planar, with dihedral angles between the benzene and pyridine rings of ca 4.5°. The rings of the benzyl groups are, in turn, almost perpendicular to the aza­styryl planes, with dihedral angles larger than 80°. The cations and anions are connected by O—H...X⁻ (X = halogen) hydrogen bonds. The halide anions are `sandwiched' between the charged pyridinium rings of neighbouring mol­ecules, and weak C—H...O hydrogen bonds and C—H...X and C—H...π inter­actions also contribute to the crystal structures.

S1. Comment

The derivatives of (E)-stilbazolium and their salts have been used, for example, in the preparation of polymers (Bloch & Wright, 1989) and in nonlinear optics (e.g. Marder et al., 1989). Some interesting photochemical properties have been utilized in the testing of chromatographic stationary phases (Prukała et al., 2008). In particular, N-alkyl- and N-benzyl-substituted (E)-stilbazole derivatives show a broad spectrum of antimicrobial activity (e.g. Prukała & Kędzia, 1999; Klein et al., 2007).

In the course of our structural studies of the family of N-benzyl-stilbazole derivatives, we reported the isomorphous pair of halides 1-(2-chloro-benzyl)-4-[(E)-2-(3- hydroxyphenyl)ethenyl]pyridinium chloride hemihydrate and its 2-bromo- bromide analogue (Prukała et al., 2008). Here, we report the crystal structures of another isomorphous pair, this time without the solvent water, 1-(2-chlorobenzyl)-4-[(E)-2-(4-hydroxyphenyl)ethenyl]pyridinium chloride, (I), and 1-(2-bromobenzyl)-4-[(E)-2-(4-hydroxyphenyl)ethenyl]pyridinium bromide, (II).

Compounds (I) and (II) are highly isomorphous; they crystallize in the same space group, C2/c, and their unit-cell parameters and packing modes are similar. Kálmán et al. (1991) introduced the isostructurality index, which shows how close are the positions of the atoms in the two unit cells. In its simplest form, this index is defined as unity minus the sum of the squares of differences between the positions of the appropriate atoms, divided by the number of pairs. Consequently, it would be 1 for an ideal isostructural pair [there have been some attempts to put these values on more absolute scale, e.g. Kubicki & Szafrański (1998)]. In the case of (I) and (II), the value of this index is close to the ideal value, at 0.985. As in the previous related case (Prukała et al., 2008), the two molecules are so similar that the normal probability plots (International Tables for X-ray Crystallography, 1974, vol. IV, pp. 293–300; Abrahams & Keve, 1971) for bond lengths (without C—X bonds) and all bond angles show that the differences between the molecules are generally of a statistical nature; the correlation factors R² are 0.94 and 0.96 for bond lengths and angles, respectively.

Because the two compounds are highly isomorphous, the following discussion will be on the chloro compound, (I), only; all data for the bromo compound, (II), are available in the CIF, and in the discussion below numerical data for (II) will be given in square brackets after the appropriate values for (I).

The conformation of the molecule is very similar to the 3-hydroxy analogues described earlier. The values of the descriptors of the molecular conformation, i.e. the dihedral angles between the planar fragments [Fig. 1; three rings (chlorophenyl A, pyridine B and hydroxyphenyl C) and the C11—C14═C15—C16 bridge (D)] are almost identical. The dihedral angles within the azastyryl fragments are small; for instance, that between rings B and C is 4.35 (9)° [4.43 (18)°]. The planar benzyl group is, as in the majority of cases found in the Cambridge Structural Database (CSD; Allen, 2002), almost perpendicular to the azastyryl fragments; the dihedral angle between rings A and B is 84.66 (9)° [84.07 (18)°]. This particular value is significantly larger in the present case, by ca 10°, than in the 3-hydroxy series. The two almost perpendicular rings A and B look quite different from the perspective of the N12—C15—C16 bridge: ring A is almost coplanar with the bridge {dihedral angle 4.7 (2)° [2.8 (3)°]}, while ring B is almost perpendicular {82.2 (2)° [83.2 (3)°]}.

An O—H···X^- hydrogen bond connects the ionic fragments into a relatively tightly bound pair. In the crystal structure, the anions are `sandwiched' between the central pyridine (B) rings (Fig. 2). The Cg···X^- distances (Cg is the centroid of the ring) are 3.718 [3.736 Å] and 3.739 Å [3.739 Å], and the X^-(1 - x, -y, -z)···Cg···X^-(1 - x, y, -1/2 - z) angle of 161° [167°] indicates an almost linear disposition. Also, the Cg···X^-···Cg angles are close to linearity, at 160° [165°]. These interactions, in principle, can not be regarded as anion–π interactions, which are currently receiving increasing attention for their possible importance in e.g. template-based synthesis or biological processes (see, for instance, Vilar, 2003; de Hoog et al., 2004). In the light of the critical review by Hay & Custulcean (2009), the prerequisite for the existence of such an interaction is a neutral, not a charged, aromatic ring. In the CSD (Version 3.91 of November 2009, updated February 2010) there are 108 examples of such two-sided coordination of the halide anion by aromatic rings (organics only, R < 0.1, both X···centroid distances less than 4.0 Å). Only in 32 cases is the Cg···X^-···Cg angle larger than 140°, which shows the high degree of linearity of the coordination, and another 26 structures have limited linearity, with angles between 120 and 140°. The vast majority of these structures contain charged aromatic rings; within the group of hits showing linear coordination, we found only one example of an uncharged ring, 1,4-dibenzyl-1,4,8,11-tetraazoniacyclotetradecane tetrabromide dihydrate (Havlickova et al., 2008).

These contacts, together with O—H···Cl^- [Br^-] and relatively short C—H···Cl^- [Br^-] hydrogen bonds, effectively `trap' the anion in the structure (Table 1) and form infinite stacks of molecules along the [001] direction. A similar position of the Cl^- anion was observed in the structure of 1-methyl-3-hydroxypyridinium chloride (Szafran et al., 2007). Neighbouring stacks are connected by relatively short and directional C13—H···O hydrogen bonds. Table 1 also lists a number of relatively short C—H···Cl [Br] and C—H···Cl^- [Br^-] contacts. In the crystal structures, the hydroxyphenyl rings overlap significantly, with a Cg···Cg(1 - x, y, -1/2 - z) distance of 3.815Å [3.788 Å], which gives an interplanar distance of 3.54 Å [3.60 Å].

S2. Experimental

(E)-Azastilbenol-4' (5 mmol) was dissolved in boiling nitromethane (50 ml). Upon dissolution, the corresponding benzyl halide (25 mmol) was added. The reaction mixture was refluxed for 5 h and the precipitated solid was filtered off. Half the volume of nitromethane was then removed from the filtrate using a rotary evaporator. The residue was cooled for 24 h, and the precipitated solid was filtered off, washed with CH₃NO₂ and dried. The desired products were obtained by combining both fractions of solids and recrystallizing them from methanol.

S3. Refinement

H atoms were placed geometrically in idealized positions, with C—H = 0.93 and O—H = 0.82 Å [Please check added text], and refined as rigid groups, with U_iso(H) = 1.2U_eq(C,O).

Computing details

For both compounds, data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell refinement: CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

Fig. 1. The molecule of (I), with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. The dashed line indicates the hydrogen bond.

Fig. 2. The stacks of molecules of (I), connected by weak interactions that `trap' the Cl^- anions (see text for details). These interactions and relatively short C—H···O hydrogen bonds are drawn as dashed lines. [Symmetry codes: (i) x, -y, 1/2 + z; (ii) 1 - x, y, -1/2 - z; (iii) 1 - x, -y, -z; (iv) -1/2 - x, -1/2 - y, -1/2 + z; (v) -1/2 + x, -1/2 + y, z; (vi) 1/2 - x, -1/2 - y, -1 + z; (vii) 1/2 - x, -1/2 + y, -1/2 - z.]

(I) 1-(2-chlorobenzyl)-4-[(E)-2-(4-hydroxyphenyl)ethenyl]pyridinium chloride

Crystal data

C20H17ClNO^+·Cl^−	F(000) = 1488
Mr = 358.25	Dx = 1.383 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 4261 reflections
a = 25.942 (4) Å	θ = 2.3–28.1°
b = 9.4027 (15) Å	µ = 0.38 mm^−1
c = 14.667 (2) Å	T = 295 K
β = 105.842 (15)°	Plate, pale yellow
V = 3441.8 (9) Å^3	0.2 × 0.15 × 0.15 mm
Z = 8

Data collection

Oxford Xcalibur Sapphire2, large Be window diffractometer	3867 independent reflections
Radiation source: Oxford Enhance (Mo) X-ray source	2368 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
Detector resolution: 8.1929 pixels mm^-1	θmax = 28.4°, θmin = 2.3°
ω scans	h = −33→33
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)	k = −12→12
Tmin = 0.938, Tmax = 1.000	l = −18→18
13504 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.094	H-atom parameters constrained
S = 0.94	w = 1/[σ^2(Fo^2) + (0.0502P)^2] where P = (Fo^2 + 2Fc^2)/3
3866 reflections	(Δ/σ)max = 0.001
218 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.23 e Å^−3

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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
C1	0.40214 (7)	−0.1748 (2)	−0.21975 (12)	0.0483 (5)
O1	0.35260 (5)	−0.21576 (15)	−0.26832 (10)	0.0695 (4)
H1	0.3339	−0.1453	−0.2860	0.083*
C2	0.41589 (7)	−0.0358 (2)	−0.20147 (13)	0.0558 (5)
H2	0.3907	0.0355	−0.2231	0.067*
C3	0.46692 (7)	−0.0019 (2)	−0.15108 (14)	0.0588 (5)
H3	0.4758	0.0933	−0.1386	0.071*
C4	0.50556 (7)	−0.10405 (19)	−0.11821 (11)	0.0441 (4)
C5	0.49075 (8)	−0.2435 (2)	−0.13738 (13)	0.0547 (5)
H5	0.5159	−0.3151	−0.1160	0.066*
C6	0.43984 (8)	−0.2791 (2)	−0.18724 (14)	0.0628 (5)
H6	0.4306	−0.3742	−0.1993	0.075*
C7	0.55872 (7)	−0.0587 (2)	−0.06602 (12)	0.0495 (5)
H7	0.5630	0.0387	−0.0557	0.059*
C8	0.60183 (7)	−0.13578 (19)	−0.03111 (11)	0.0472 (4)
H8	0.5993	−0.2334	−0.0415	0.057*
C9	0.65254 (7)	−0.07930 (19)	0.02204 (11)	0.0421 (4)
C10	0.66295 (7)	0.0653 (2)	0.03563 (13)	0.0524 (5)
H10	0.6363	0.1302	0.0076	0.063*
C11	0.71080 (7)	0.1140 (2)	0.08848 (12)	0.0507 (5)
H11	0.7167	0.2113	0.0965	0.061*
N12	0.74937 (6)	0.02268 (16)	0.12898 (10)	0.0458 (4)
C13	0.74120 (8)	−0.1175 (2)	0.11792 (13)	0.0539 (5)
H13	0.7685	−0.1799	0.1474	0.065*
C14	0.69443 (7)	−0.1700 (2)	0.06519 (12)	0.0515 (5)
H14	0.6900	−0.2679	0.0575	0.062*
C15	0.80054 (7)	0.0769 (2)	0.18814 (12)	0.0545 (5)
H15B	0.8129	0.0156	0.2430	0.065*
H15A	0.7950	0.1710	0.2108	0.065*
C16	0.84316 (7)	0.08488 (17)	0.13662 (11)	0.0418 (4)
C17	0.89415 (7)	0.12528 (18)	0.18475 (12)	0.0463 (4)
Cl1	0.90734 (2)	0.16295 (5)	0.30516 (3)	0.06218 (17)
C18	0.93464 (8)	0.1363 (2)	0.14159 (15)	0.0642 (6)
H18	0.9687	0.1644	0.1766	0.077*
C19	0.92525 (9)	0.1061 (3)	0.04707 (16)	0.0712 (6)
H19	0.9527	0.1121	0.0176	0.085*
C20	0.87484 (9)	0.0670 (2)	−0.00296 (14)	0.0614 (5)
H20	0.8677	0.0471	−0.0673	0.074*
C21	0.83438 (8)	0.05671 (19)	0.04132 (12)	0.0497 (5)
H21	0.8003	0.0300	0.0059	0.060*
Cl2	0.27482 (2)	0.02426 (6)	−0.33946 (3)	0.06820 (18)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0336 (9)	0.0569 (12)	0.0502 (10)	−0.0116 (9)	0.0044 (8)	−0.0058 (8)
O1	0.0394 (8)	0.0666 (9)	0.0882 (10)	−0.0159 (7)	−0.0071 (7)	−0.0092 (8)
C2	0.0344 (10)	0.0507 (12)	0.0723 (12)	0.0012 (9)	−0.0021 (9)	−0.0056 (9)
C3	0.0360 (10)	0.0445 (11)	0.0841 (14)	−0.0038 (9)	−0.0040 (10)	−0.0083 (9)
C4	0.0324 (9)	0.0483 (10)	0.0474 (9)	−0.0040 (8)	0.0041 (7)	−0.0026 (8)
C5	0.0427 (10)	0.0453 (11)	0.0680 (12)	0.0011 (9)	0.0016 (9)	0.0042 (9)
C6	0.0575 (13)	0.0442 (11)	0.0785 (13)	−0.0128 (11)	0.0048 (11)	−0.0049 (10)
C7	0.0359 (10)	0.0476 (10)	0.0591 (11)	−0.0040 (9)	0.0033 (8)	−0.0023 (8)
C8	0.0370 (10)	0.0472 (11)	0.0524 (10)	−0.0018 (9)	0.0041 (8)	−0.0011 (8)
C9	0.0311 (9)	0.0476 (11)	0.0451 (9)	0.0003 (8)	0.0063 (7)	0.0010 (8)
C10	0.0328 (10)	0.0481 (11)	0.0673 (12)	0.0029 (9)	−0.0016 (9)	0.0041 (9)
C11	0.0372 (10)	0.0486 (11)	0.0613 (11)	−0.0009 (9)	0.0049 (9)	0.0011 (8)
N12	0.0294 (8)	0.0587 (10)	0.0450 (8)	−0.0037 (7)	0.0030 (6)	0.0023 (7)
C13	0.0378 (10)	0.0563 (12)	0.0600 (11)	0.0073 (9)	0.0002 (8)	0.0102 (9)
C14	0.0390 (10)	0.0466 (11)	0.0628 (11)	0.0026 (9)	0.0037 (9)	0.0039 (9)
C15	0.0330 (10)	0.0773 (14)	0.0461 (10)	−0.0089 (10)	−0.0015 (8)	−0.0049 (9)
C16	0.0334 (9)	0.0371 (9)	0.0492 (10)	0.0009 (8)	0.0017 (7)	0.0043 (7)
C17	0.0373 (10)	0.0407 (10)	0.0536 (10)	−0.0016 (8)	0.0000 (8)	0.0070 (8)
Cl1	0.0527 (3)	0.0607 (3)	0.0587 (3)	−0.0109 (2)	−0.0093 (2)	−0.0018 (2)
C18	0.0350 (10)	0.0718 (15)	0.0791 (14)	−0.0053 (10)	0.0042 (10)	0.0156 (11)
C19	0.0481 (13)	0.0877 (16)	0.0825 (15)	0.0064 (12)	0.0259 (11)	0.0161 (12)
C20	0.0639 (14)	0.0639 (13)	0.0583 (12)	0.0063 (12)	0.0198 (11)	0.0014 (10)
C21	0.0418 (10)	0.0504 (11)	0.0521 (10)	−0.0010 (9)	0.0044 (8)	−0.0001 (8)
Cl2	0.0481 (3)	0.0974 (4)	0.0539 (3)	0.0053 (3)	0.0051 (2)	0.0046 (2)

Geometric parameters (Å, º)

C1—O1	1.3447 (19)	C11—N12	1.329 (2)
C1—C2	1.362 (2)	C11—H11	0.9300
C1—C6	1.375 (3)	N12—C13	1.338 (2)
O1—H1	0.8200	N12—C15	1.465 (2)
C2—C3	1.366 (2)	C13—C14	1.342 (2)
C2—H2	0.9300	C13—H13	0.9300
C3—C4	1.377 (2)	C14—H14	0.9300
C3—H3	0.9300	C15—C16	1.502 (3)
C4—C5	1.374 (2)	C15—H15B	0.9700
C4—C7	1.447 (2)	C15—H15A	0.9700
C5—C6	1.365 (3)	C16—C17	1.372 (2)
C5—H5	0.9300	C16—C21	1.379 (2)
C6—H6	0.9300	C17—C18	1.370 (3)
C7—C8	1.314 (2)	C17—Cl1	1.7410 (18)
C7—H7	0.9300	C18—C19	1.370 (3)
C8—C9	1.435 (2)	C18—H18	0.9300
C8—H8	0.9300	C19—C20	1.364 (3)
C9—C10	1.390 (3)	C19—H19	0.9300
C9—C14	1.391 (2)	C20—C21	1.380 (3)
C10—C11	1.351 (2)	C20—H20	0.9300
C10—H10	0.9300	C21—H21	0.9300
O1—C1—C2	122.70 (18)	C11—N12—C13	120.48 (15)
O1—C1—C6	117.78 (17)	C11—N12—C15	119.32 (16)
C2—C1—C6	119.52 (17)	C13—N12—C15	120.17 (16)
C1—O1—H1	109.5	N12—C13—C14	121.39 (17)
C1—C2—C3	119.58 (18)	N12—C13—H13	119.3
C1—C2—H2	120.2	C14—C13—H13	119.3
C3—C2—H2	120.2	C13—C14—C9	120.50 (18)
C2—C3—C4	122.13 (18)	C13—C14—H14	119.8
C2—C3—H3	118.9	C9—C14—H14	119.8
C4—C3—H3	118.9	N12—C15—C16	113.08 (14)
C5—C4—C3	117.25 (16)	N12—C15—H15B	109.0
C5—C4—C7	124.23 (17)	C16—C15—H15B	109.0
C3—C4—C7	118.52 (16)	N12—C15—H15A	109.0
C6—C5—C4	121.28 (18)	C16—C15—H15A	109.0
C6—C5—H5	119.4	H15B—C15—H15A	107.8
C4—C5—H5	119.4	C17—C16—C21	116.35 (17)
C5—C6—C1	120.24 (18)	C17—C16—C15	119.59 (15)
C5—C6—H6	119.9	C21—C16—C15	124.04 (15)
C1—C6—H6	119.9	C18—C17—C16	122.42 (18)
C8—C7—C4	129.12 (17)	C18—C17—Cl1	119.34 (14)
C8—C7—H7	115.4	C16—C17—Cl1	118.24 (15)
C4—C7—H7	115.4	C19—C18—C17	120.31 (18)
C7—C8—C9	124.35 (17)	C19—C18—H18	119.8
C7—C8—H8	117.8	C17—C18—H18	119.8
C9—C8—H8	117.8	C20—C19—C18	118.7 (2)
C10—C9—C14	115.97 (16)	C20—C19—H19	120.7
C10—C9—C8	123.58 (16)	C18—C19—H19	120.7
C14—C9—C8	120.43 (16)	C19—C20—C21	120.4 (2)
C11—C10—C9	121.71 (17)	C19—C20—H20	119.8
C11—C10—H10	119.1	C21—C20—H20	119.8
C9—C10—H10	119.1	C16—C21—C20	121.81 (18)
N12—C11—C10	119.94 (18)	C16—C21—H21	119.1
N12—C11—H11	120.0	C20—C21—H21	119.1
C10—C11—H11	120.0
O1—C1—C2—C3	179.55 (19)	C11—N12—C13—C14	0.7 (3)
C6—C1—C2—C3	0.0 (3)	C15—N12—C13—C14	179.05 (17)
C1—C2—C3—C4	0.4 (3)	N12—C13—C14—C9	−1.4 (3)
C2—C3—C4—C5	−0.5 (3)	C10—C9—C14—C13	1.3 (3)
C2—C3—C4—C7	179.55 (19)	C8—C9—C14—C13	−177.44 (17)
C3—C4—C5—C6	0.2 (3)	C11—N12—C15—C16	−98.5 (2)
C7—C4—C5—C6	−179.88 (19)	C13—N12—C15—C16	83.2 (2)
C4—C5—C6—C1	0.2 (3)	N12—C15—C16—C17	−175.94 (16)
O1—C1—C6—C5	−179.89 (18)	N12—C15—C16—C21	5.5 (3)
C2—C1—C6—C5	−0.3 (3)	C21—C16—C17—C18	−0.5 (3)
C5—C4—C7—C8	2.6 (3)	C15—C16—C17—C18	−179.19 (18)
C3—C4—C7—C8	−177.5 (2)	C21—C16—C17—Cl1	179.69 (12)
C4—C7—C8—C9	−178.29 (18)	C15—C16—C17—Cl1	1.0 (2)
C7—C8—C9—C10	−5.7 (3)	C16—C17—C18—C19	−0.3 (3)
C7—C8—C9—C14	172.92 (18)	Cl1—C17—C18—C19	179.49 (15)
C14—C9—C10—C11	−0.6 (3)	C17—C18—C19—C20	0.9 (3)
C8—C9—C10—C11	178.05 (18)	C18—C19—C20—C21	−0.7 (3)
C9—C10—C11—N12	0.0 (3)	C17—C16—C21—C20	0.7 (3)
C10—C11—N12—C13	0.0 (3)	C15—C16—C21—C20	179.32 (18)
C10—C11—N12—C15	−178.38 (17)	C19—C20—C21—C16	−0.1 (3)

(II) 1-(2-bromobenzyl)-4-[(E)-2-(4-hydroxyphenyl)ethenyl]pyridinium bromide

Crystal data

C20H17BrNO^+·Br^−	F(000) = 1776
Mr = 447.17	Dx = 1.658 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3219 reflections
a = 26.462 (3) Å	θ = 2.3–28.0°
b = 9.4974 (15) Å	µ = 4.53 mm^−1
c = 14.813 (2) Å	T = 295 K
β = 105.793 (15)°	Plate, pale yellow
V = 3582.3 (8) Å^3	0.15 × 0.1 × 0.1 mm
Z = 8

Data collection

Oxford Xcalibur Sapphire2, large Be window diffractometer	3299 independent reflections
Radiation source: Oxford Enhance (Mo) X-ray Source	2046 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
Detector resolution: 8.1929 pixels mm^-1	θmax = 25.5°, θmin = 2.3°
ω scans	h = −31→32
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)	k = −11→11
Tmin = 0.494, Tmax = 1.000	l = −17→17
8330 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.083	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.04P)^2] where P = (Fo^2 + 2Fc^2)/3
3299 reflections	(Δ/σ)max = 0.001
218 parameters	Δρmax = 0.41 e Å^−3
0 restraints	Δρmin = −0.38 e Å^−3

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
C1	0.41025 (14)	−0.1957 (5)	−0.2096 (3)	0.0509 (10)
O1	0.36115 (10)	−0.2377 (3)	−0.2576 (2)	0.0729 (9)
H1	0.3411	−0.1701	−0.2654	0.087*
C2	0.42226 (15)	−0.0605 (5)	−0.1916 (3)	0.0695 (13)
H2	0.3967	0.0083	−0.2126	0.083*
C3	0.47243 (15)	−0.0223 (4)	−0.1421 (3)	0.0731 (14)
H3	0.4800	0.0724	−0.1291	0.088*
C4	0.51150 (14)	−0.1204 (4)	−0.1116 (2)	0.0481 (10)
C5	0.49828 (15)	−0.2592 (4)	−0.1313 (3)	0.0546 (10)
H5	0.5236	−0.3289	−0.1119	0.066*
C6	0.44829 (16)	−0.2957 (5)	−0.1791 (3)	0.0666 (12)
H6	0.4399	−0.3902	−0.1912	0.080*
C7	0.56391 (14)	−0.0726 (4)	−0.0607 (3)	0.0533 (10)
H7	0.5668	0.0240	−0.0503	0.064*
C8	0.60728 (13)	−0.1428 (4)	−0.0274 (2)	0.0464 (10)
H8	0.6060	−0.2394	−0.0381	0.056*
C9	0.65720 (13)	−0.0847 (4)	0.0246 (2)	0.0410 (9)
C10	0.66615 (14)	0.0588 (4)	0.0387 (3)	0.0518 (10)
H10	0.6393	0.1218	0.0121	0.062*
C11	0.71328 (13)	0.1092 (5)	0.0906 (2)	0.0518 (10)
H11	0.7182	0.2058	0.0991	0.062*
N12	0.75244 (10)	0.0216 (3)	0.12914 (19)	0.0414 (7)
C13	0.74520 (14)	−0.1168 (4)	0.1171 (3)	0.0497 (10)
H13	0.7727	−0.1773	0.1446	0.060*
C14	0.69905 (13)	−0.1722 (4)	0.0660 (2)	0.0473 (10)
H14	0.6954	−0.2692	0.0587	0.057*
C15	0.80260 (12)	0.0768 (5)	0.1889 (2)	0.0505 (10)
H15B	0.8154	0.0140	0.2418	0.061*
H15A	0.7964	0.1681	0.2133	0.061*
C16	0.84405 (12)	0.0918 (3)	0.1376 (2)	0.0370 (8)
C17	0.89346 (13)	0.1365 (4)	0.1861 (2)	0.0415 (9)
Br1	0.907886 (15)	0.18033 (5)	0.31580 (3)	0.05851 (16)
C18	0.93296 (15)	0.1512 (4)	0.1440 (3)	0.0603 (12)
H18	0.9660	0.1812	0.1785	0.072*
C19	0.92344 (16)	0.1210 (5)	0.0493 (3)	0.0685 (13)
H19	0.9502	0.1301	0.0201	0.082*
C20	0.87485 (15)	0.0782 (5)	−0.0007 (3)	0.0579 (11)
H20	0.8681	0.0597	−0.0646	0.069*
C21	0.83569 (14)	0.0622 (4)	0.0434 (3)	0.0469 (10)
H21	0.8028	0.0308	0.0090	0.056*
Br2	0.279252 (15)	0.01449 (5)	−0.33589 (3)	0.06195 (16)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.033 (2)	0.060 (3)	0.056 (2)	−0.017 (2)	0.0062 (17)	−0.015 (2)
O1	0.0385 (15)	0.068 (2)	0.099 (2)	−0.0164 (16)	−0.0046 (15)	−0.0138 (19)
C2	0.031 (2)	0.060 (3)	0.104 (4)	−0.005 (2)	−0.005 (2)	−0.010 (3)
C3	0.039 (2)	0.037 (2)	0.125 (4)	−0.004 (2)	−0.009 (2)	−0.021 (2)
C4	0.033 (2)	0.054 (3)	0.052 (2)	0.001 (2)	0.0035 (17)	−0.002 (2)
C5	0.047 (2)	0.040 (2)	0.071 (3)	−0.003 (2)	0.007 (2)	−0.001 (2)
C6	0.051 (3)	0.048 (3)	0.090 (3)	−0.012 (2)	0.001 (2)	−0.002 (2)
C7	0.039 (2)	0.040 (2)	0.073 (3)	−0.007 (2)	0.0015 (19)	−0.005 (2)
C8	0.036 (2)	0.043 (2)	0.056 (2)	−0.0017 (19)	0.0055 (18)	0.0022 (19)
C9	0.0296 (19)	0.049 (2)	0.046 (2)	−0.0003 (19)	0.0123 (16)	0.0058 (19)
C10	0.031 (2)	0.046 (2)	0.070 (3)	0.0044 (19)	0.0000 (19)	0.010 (2)
C11	0.037 (2)	0.053 (3)	0.062 (3)	0.001 (2)	0.0076 (19)	0.007 (2)
N12	0.0257 (15)	0.052 (2)	0.0426 (17)	−0.0043 (16)	0.0031 (13)	−0.0066 (16)
C13	0.035 (2)	0.052 (3)	0.056 (2)	0.005 (2)	0.0018 (18)	0.000 (2)
C14	0.038 (2)	0.038 (2)	0.060 (2)	−0.0032 (19)	0.0048 (18)	0.003 (2)
C15	0.0292 (19)	0.076 (3)	0.040 (2)	−0.013 (2)	−0.0027 (16)	−0.006 (2)
C16	0.0313 (18)	0.033 (2)	0.042 (2)	0.0044 (17)	0.0037 (16)	0.0092 (17)
C17	0.037 (2)	0.030 (2)	0.052 (2)	0.0014 (17)	0.0032 (17)	0.0058 (17)
Br1	0.0485 (2)	0.0596 (3)	0.0565 (3)	−0.0083 (2)	−0.00428 (18)	−0.0053 (2)
C18	0.035 (2)	0.069 (3)	0.073 (3)	−0.006 (2)	0.007 (2)	0.010 (3)
C19	0.046 (3)	0.088 (4)	0.079 (3)	0.004 (3)	0.030 (2)	0.010 (3)
C20	0.054 (3)	0.071 (3)	0.051 (3)	0.007 (2)	0.018 (2)	−0.002 (2)
C21	0.038 (2)	0.045 (2)	0.053 (2)	0.0002 (19)	0.0053 (19)	0.001 (2)
Br2	0.0485 (2)	0.0810 (3)	0.0526 (3)	0.0006 (2)	0.00739 (19)	0.0012 (2)

Geometric parameters (Å, º)

C1—C2	1.332 (5)	C11—N12	1.330 (4)
C1—O1	1.360 (4)	C11—H11	0.9300
C1—C6	1.368 (5)	N12—C13	1.333 (5)
O1—H1	0.8200	N12—C15	1.477 (4)
C2—C3	1.379 (5)	C13—C14	1.356 (5)
C2—H2	0.9300	C13—H13	0.9300
C3—C4	1.374 (5)	C14—H14	0.9300
C3—H3	0.9300	C15—C16	1.502 (4)
C4—C5	1.375 (5)	C15—H15B	0.9700
C4—C7	1.459 (5)	C15—H15A	0.9700
C5—C6	1.364 (5)	C16—C17	1.377 (4)
C5—H5	0.9300	C16—C21	1.380 (5)
C6—H6	0.9300	C17—C18	1.362 (5)
C7—C8	1.303 (5)	C17—Br1	1.900 (3)
C7—H7	0.9300	C18—C19	1.386 (5)
C8—C9	1.445 (5)	C18—H18	0.9300
C8—H8	0.9300	C19—C20	1.360 (6)
C9—C14	1.387 (5)	C19—H19	0.9300
C9—C10	1.389 (5)	C20—C21	1.376 (5)
C10—C11	1.361 (5)	C20—H20	0.9300
C10—H10	0.9300	C21—H21	0.9300
C2—C1—O1	121.9 (4)	C11—N12—C13	119.5 (3)
C2—C1—C6	119.3 (3)	C11—N12—C15	120.2 (3)
O1—C1—C6	118.8 (4)	C13—N12—C15	120.2 (3)
C1—O1—H1	109.5	N12—C13—C14	122.2 (4)
C1—C2—C3	120.2 (4)	N12—C13—H13	118.9
C1—C2—H2	119.9	C14—C13—H13	118.9
C3—C2—H2	119.9	C13—C14—C9	120.3 (4)
C4—C3—C2	121.7 (4)	C13—C14—H14	119.9
C4—C3—H3	119.1	C9—C14—H14	119.9
C2—C3—H3	119.1	N12—C15—C16	113.0 (3)
C3—C4—C5	117.1 (3)	N12—C15—H15B	109.0
C3—C4—C7	118.9 (4)	C16—C15—H15B	109.0
C5—C4—C7	124.0 (4)	N12—C15—H15A	109.0
C6—C5—C4	120.6 (4)	C16—C15—H15A	109.0
C6—C5—H5	119.7	H15B—C15—H15A	107.8
C4—C5—H5	119.7	C17—C16—C21	117.3 (3)
C5—C6—C1	121.2 (4)	C17—C16—C15	119.0 (3)
C5—C6—H6	119.4	C21—C16—C15	123.7 (3)
C1—C6—H6	119.4	C18—C17—C16	122.0 (3)
C8—C7—C4	130.7 (4)	C18—C17—Br1	118.2 (3)
C8—C7—H7	114.7	C16—C17—Br1	119.8 (3)
C4—C7—H7	114.7	C17—C18—C19	119.4 (4)
C7—C8—C9	126.1 (4)	C17—C18—H18	120.3
C7—C8—H8	116.9	C19—C18—H18	120.3
C9—C8—H8	116.9	C20—C19—C18	119.9 (4)
C14—C9—C10	116.0 (3)	C20—C19—H19	120.1
C14—C9—C8	120.7 (3)	C18—C19—H19	120.1
C10—C9—C8	123.3 (3)	C19—C20—C21	119.8 (4)
C11—C10—C9	121.5 (4)	C19—C20—H20	120.1
C11—C10—H10	119.3	C21—C20—H20	120.1
C9—C10—H10	119.3	C20—C21—C16	121.6 (3)
N12—C11—C10	120.6 (4)	C20—C21—H21	119.2
N12—C11—H11	119.7	C16—C21—H21	119.2
C10—C11—H11	119.7
O1—C1—C2—C3	179.5 (4)	C11—N12—C13—C14	0.4 (6)
C6—C1—C2—C3	−0.6 (7)	C15—N12—C13—C14	177.2 (3)
C1—C2—C3—C4	1.3 (8)	N12—C13—C14—C9	−0.4 (6)
C2—C3—C4—C5	−0.9 (7)	C10—C9—C14—C13	0.4 (5)
C2—C3—C4—C7	179.1 (4)	C8—C9—C14—C13	−177.9 (3)
C3—C4—C5—C6	−0.1 (6)	C11—N12—C15—C16	−98.5 (4)
C7—C4—C5—C6	179.8 (4)	C13—N12—C15—C16	84.7 (4)
C4—C5—C6—C1	0.8 (7)	N12—C15—C16—C17	−177.2 (3)
C2—C1—C6—C5	−0.4 (7)	N12—C15—C16—C21	2.4 (5)
O1—C1—C6—C5	179.4 (4)	C21—C16—C17—C18	−0.2 (5)
C3—C4—C7—C8	−177.7 (4)	C15—C16—C17—C18	179.4 (4)
C5—C4—C7—C8	2.3 (7)	C21—C16—C17—Br1	179.6 (2)
C4—C7—C8—C9	−178.2 (4)	C15—C16—C17—Br1	−0.8 (5)
C7—C8—C9—C14	172.3 (4)	C16—C17—C18—C19	0.3 (6)
C7—C8—C9—C10	−5.8 (6)	Br1—C17—C18—C19	−179.5 (3)
C14—C9—C10—C11	−0.3 (5)	C17—C18—C19—C20	0.4 (7)
C8—C9—C10—C11	177.9 (4)	C18—C19—C20—C21	−1.3 (7)
C9—C10—C11—N12	0.3 (6)	C19—C20—C21—C16	1.4 (6)
C10—C11—N12—C13	−0.3 (5)	C17—C16—C21—C20	−0.7 (5)
C10—C11—N12—C15	−177.2 (3)	C15—C16—C21—C20	179.7 (4)