Two polymorphs of 2-(4-chloro­phenyl)-4-methyl­chromenium perchlorate

Crystallization (from ethyl acetate solution) of 2-(4-chloro­phenyl)-4-methyl­chromenium perchlorate, C₁₆H₁₂ClO⁺·;ClO₄⁻, (I), yields two monoclinic polymorphs with the space groups P2₁/n [polymorph (Ia)] and P2₁/c [polymorph (Ib)]; in both cases, Z = 4. Cations and anions, disordered in polymorph (Ib), form ion pairs in both polymorphs as a result of Cl—O...π inter­actions. Related by a centre of symmetry, neighbouring ion pairs in polymorph (Ia) are linked via π–π inter­actions between cationic fragments, and the resulting dimers are linked through a network of C—H...O(perchlorate) inter­actions between adjacent cations and anions. The ion pairs in polymorph (Ib), arranged in pairs of columns along the a axis, are linked through a network of C—H...O(perchlorate), C—Cl...π, π–π and C—Cl...O(perchlorate) inter­actions. The aromatic skeletons in polymorph (Ia) are parallel in the cationic fragments involved in dimers, but nonparallel in adjacent ion pairs not constituting dimers. In polymorph (Ib), these skeletons are parallel in pairs of columns, but non­parallel in adjacent pairs of columns; this is visible as a herring-bone pattern. Differences in the crystal structures of the polymorphs are most probably the cause of their different colours.

S1. Comment

2-Phenylchromenium salt-type systems occur in natural dyes (anthocyanides), exhibiting a distinctive biological significance (Gera, 1982). Owing to their strong absorption in the orange–red spectroscopic region, they are used as dyes, for example in the food industry (Timberlake & Bridle, 1980). Some 2-phenylchromenium salts exhibit intense luminescence and are used as lasing materials (Maeda, 1984; Deligeorgiev et al., 1987). Our investigations of the features of 2-phenylchromenium cations and their dimers and nucleophilic complexes (Roshal et al., 1998; Roshal et al., 2002) have shown that the spectroscopic properties of these species depend on their structure, mainly the angle between the chromenium and phenyl fragments (Roshal, 1999). The opportunity to investigate the influence of structure on spectroscopic features arose when we found two polymorphs of different colours following the crystallization of 2-(4-chlorophenyl)-4-methylchromenium perchlorate from ethyl acetate, subsequently designated (Ia) and (Ib). There is, to our knowledge, only one report in the Cambridge Structural Database (Version?; Allen, 2002) concerning 2-phenylchromenium derivatives (Busetta et al., 1974). The present work thus extends our knowledge of the crystal structures of this important group of compounds.

The parameters characterizing the geometry of the aromatic skeleton in both polymorphs are given in Tables 1 and 5. The relevant bond lengths, as well as the valence and dihedral angles, are comparable, except the C3—C2—C11—C12 angle, which differs by 2.0 (5)°. The angles between the mean planes of rings 1 (defined by atoms O1/C2–C4/C9/C10) and 2 (defined by atoms C5–C8/C9/C10) are 0.0 (2)° in polymorph (Ia) and 1.5 (5)° in polymorph (Ib). Furthermore, the angles between the mean planes of the chromenium skeleton (defined by atoms O1/C2–C10) and ring 3 (defined by atoms C11–C16) are 5.2 (2)° in polymorph (Ia) and 1.6 (5)° in polymorph (Ib). This implies that all three rings lie almost in one plane in both polymorphs.

In polymorph (Ia) (Fig. 1), the cations and the anions form ion pairs via Cl—O···π interactions (Fig. 2, Table 3). Adjacent ion pairs, related by a centre of symmetry, are linked via π–π interactions between cationic fragments (involving rings 1 and 3) (Table 4), and the resulting dimers are linked through a network of C—H···O(perchlorate) interactions (Table 2) between the cationic and anionic fragments of neighbouring ion pairs (Fig. 2). The angle between the mean planes defined by the whole aromatic skeleton [defined by atoms O1/C2–C16] is either 0°, in the case of the cationic fragments involved in dimers, or 32.6 (2)°, if we take into account the cationic fragments of adjacent ion pairs not constituting dimers.

The tetrahedral perchlorate anions in polymorph (Ib) occupy two positions, with occupancy factors of 0.557 (11) and 0.443 (11) for Cl19/O20–O23 and Cl9A/O20A–O23A, respectively (Fig. 3). Disordered perchlorate anions have been reported by others (e.g. Sun, 2006; Athimoolam & Rajaram, 2006), which suggests that disorder is not a feature unique to this entity. The cations and anions form ion pairs via Cl—O···π interactions (Figs. 4 and 5, Table 7). The ion pairs are arranged in columns extending along the a axis, in which the aromatic skeletons are parallel to one another (Fig. 4) and inclined at an angle of 63.6 (5)° relative to the bc plane. Cations of neighbouring ion pairs in columns are linked via π–π interactions, whereas cations and anions do so via C—H···O (perchlorate) interactions (Fig. 4, Tables 6 and 8). Adjacent columns are linked via C—Cl···π and π–π interactions between cations (Fig. 5, Tables 7 and 8), forming pairs of columns. Within a pair of columns, the aromatic skeletons are parallel. In adjacent pairs of columns, linked through C—H···O(perchlorate) interactions (Fig. 5, Table 6) and O···Cl contacts [Cl17···O23 = 3.26 (1) Å (symmetry code: 1 − x, y − 1/2, 1/2 − z); Fig. 4], the aromatic skeletons are at an angle of 66.1 (2)° [the angle between the mean planes defined by all the atoms of the aromatic skeletons of non-interacting cations], which produces a herringbone pattern.

The crystal structures of both polymorphs are stabilized by a network of the above-mentioned short-range interactions, as well as by long-range electrostatic interactions between ions.

All interactions demonstrated were found by PLATON (Spek, 2003). The C—H···O interactions exhibit a hydrogen-bond type nature (Steiner, 1999). Interactions between the perchlorate anion or electronegative Cl atom at ring 3, and rings 1 and 2, respectively identified as Cl—O···π and C—Cl···π interactions, should be of an attractive nature, since the chromenium system is positively charged (Dorn et al., 2005). An attractive nature should also be exhibited by the [Original meaning not clear - please check rephrasing] C—Cl···O(perchlorate) interactions (Allen et al., 1997) identified as O···Cl contacts.

To obtain some idea of how the chromenium (1 and 2) and phenyl (3) rings are mutually oriented in an isolated cation, we optimized its structure at the DFT(B 3LYP)/6–31 G^** level (GAUSSIAN98; Frisch et al., 1998) and calculated the angle between the mean planes of these fragments. The value obtained was 0.3°, which means that the whole aromatic system is planar. Distortion from planarity of the aromatic system in both polymorphs, apparent in the crystallographic data, may be the cause of their different spectroscopic behaviour.

Having optimized the structure of the cation, we calculated relative partial charges using a natural bond order (NBO) analysis (Reed et al., 1988), a Mulliken population analysis (Mulliken, 1955a,b) and the electrostatic potential (ESP) fit method (Besler et al., 1990). It is commonly believed that electron deficiency occurs at the ring O atom, but our calculations revealed the reverse situation: there was an excess negative charge at this atom [−0.416 (NBO), −0.488 (Mulliken) and −0.278 (EPS)]. It seems, therefore, that, in this case, traditional assumptions may have to be revised.

S2. Experimental

Compound (I) was synthesized by the method described in the literature (Czerney et al., 1995). The crude product was purified by recrystallization, initially from concentrated acetic acid and then from dichloromethane. The purity of the compound was confirmed chromatographically and its identity proven by IR and NMR spectroscopy. Crystals of the polymorphic forms (Ia) and (Ib) suitable for X-ray investigations were grown from ethyl acetate. They were separated manually.

S3. Refinement

All H atoms were positioned geometrically and refined using a riding model, with C—H distances of 0.93 Å and with U_iso(H) = 1.2U_eq(C), or C—H = 0.96 Å and U_iso(H) = 1.5U_eq(C) for the methyl group. The atoms of the perchlorate anion in polymorph (Ib) were located in a difference Fourier map and refined to an ideal tetrahedron, with restrained standard deviations of 0.01 and 0.03 Å for the Cl—O and O···O distances, respectively (SADI instruction in SHELXL97; Sheldrick, 1997) (Müller et al., 2006). Following refinement, the anisotropic displacement parameters of adjacent atoms were restrained to be similar (SIMU instruction), and the main directions of movements of covalently bonded atoms were likewise restrained (DELU instruction) (Müller et al., 2006). The occupancy ratio was determined by isotropic refinement for the disordered site and was refined freely during subsequent anisotropic refinement.

Computing details

For both compounds, data collection: P3 (Siemens, 1989); cell refinement: P3; data reduction: XDISK (Siemens, 1991); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Figures

	Fig. 1. The molecular structure of polymorph (Ia), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 25% probability level and H atoms are shown as small spheres of arbitrary radii. Cg1–Cg3 denote the ring centroids.
	Fig. 2. The arrangement of the ions of polymorph (Ia) in the unit cell, viewed approximately along the c axis. The C—H···O interactions are represented by dashed lines, and Cl—O···π and π–π interactions by dotted lines. H atoms not involved in interactions have been omitted. [Symmetry codes: (i) 1/2 − x, y − 1/2, 3/2 − z; (ii) −x, 1 − y, 2 − z.]
	Fig. 3. The molecular structure of polymorph (Ib), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 25% probability level and H atoms are shown as small spheres of arbitrary radii. The minor disorder component of the perchlorate anion is drawn with open bonds.
	Fig. 4. The arrangement of the ions of polymorph (Ib) in the unit cell, viewed along the b axis. The C—H···O interactions and O···Cl contacts are represented by dashed lines, and Cl—O···π and π–π interactions by dotted lines. H atoms not involved in interactions have been omitted. [Symmetry codes: (i) x − 1, y, z; (iii) 1 − x, −y, −z; (iv) 1 + x, y, z; (v) 1 − x, y − 1/2, 1/2 − z.] [No labels with symop (iii) are visible - can it be omitted from the caption?]
	Fig. 5. The arrangement of the ions of polymorph (Ib) in the unit cell, viewed along the a axis. The C—H···O interactions are represented by dashed lines, and C—Cl···π, Cl—O···π and π–π interactions by dotted lines. H atoms not involved in interactions have been omitted. [Symmetry codes: (ii) 1 − x, 1 − y, −z; (iii) 1 − x, −y, −z.]

(Ia) 2-(4-chlorophenyl)-4-methylchromenium perchlorate

Crystal data

C16H12ClO^+·ClO4^−	F(000) = 728
Mr = 355.16	Dx = 1.489 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 50 reflections
a = 11.0290 (19) Å	θ = 2.5–25.0°
b = 12.817 (2) Å	µ = 0.43 mm^−1
c = 11.2083 (18) Å	T = 290 K
β = 90.173 (13)°	Prism, green
V = 1584.4 (4) Å^3	0.3 × 0.3 × 0.2 mm
Z = 4

Data collection

Siemens P3/PC diffractometer	Rint = 0.025
Radiation source: fine-focus sealed X-ray tube	θmax = 25.0°, θmin = 2.5°
Graphite monochromator	h = 0→13
θ/2θ scans	k = 0→15
2915 measured reflections	l = −13→13
2763 independent reflections	2 standard reflections every 98 reflections
2124 reflections with I > 2σ(I)	intensity decay: 1.5%

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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.126	H-atom parameters constrained
S = 0.92	w = 1/[σ^2(Fo^2) + (0.0902P)^2] where P = (Fo^2 + 2Fc^2)/3
2763 reflections	(Δ/σ)max < 0.001
208 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.22 e Å^−3

Special details

Experimental. no

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.09592 (13)	0.68936 (11)	0.94168 (11)	0.0614 (3)
C2	0.13088 (16)	0.59227 (15)	0.91970 (17)	0.0545 (4)
C3	0.1407 (2)	0.55907 (19)	0.80202 (18)	0.0672 (5)
H3	0.1632	0.4904	0.7869	0.081*
C4	0.1183 (2)	0.62429 (19)	0.70753 (19)	0.0704 (6)
C5	0.0521 (2)	0.8057 (2)	0.6461 (2)	0.0793 (7)
H5	0.0581	0.7897	0.5654	0.095*
C6	0.0176 (3)	0.9017 (2)	0.6788 (2)	0.0907 (8)
H6	−0.0013	0.9506	0.6203	0.109*
C7	0.0093 (3)	0.9297 (2)	0.7986 (3)	0.0936 (8)
H7	−0.0132	0.9972	0.8195	0.112*
C8	0.0348 (2)	0.85690 (18)	0.8865 (2)	0.0808 (7)
H8	0.0279	0.8742	0.9668	0.097*
C9	0.07982 (19)	0.72788 (18)	0.73236 (19)	0.0653 (5)
C10	0.07050 (18)	0.75861 (16)	0.85244 (18)	0.0595 (5)
C11	0.15580 (16)	0.53298 (14)	1.02693 (16)	0.0526 (4)
C12	0.1498 (2)	0.57924 (16)	1.13823 (18)	0.0650 (5)
H12	0.1295	0.6495	1.1440	0.078*
C13	0.1733 (2)	0.52337 (17)	1.24071 (18)	0.0693 (6)
H13	0.1692	0.5563	1.3146	0.083*
C14	0.20250 (19)	0.42021 (17)	1.23452 (18)	0.0638 (5)
C15	0.2072 (2)	0.36938 (18)	1.1256 (2)	0.0738 (6)
H15	0.2258	0.2987	1.1219	0.089*
C16	0.1841 (2)	0.42479 (19)	1.0230 (2)	0.0769 (6)
H16	0.1870	0.3909	0.9497	0.092*
Cl17	0.22578 (7)	0.35059 (5)	1.36519 (6)	0.0909 (2)
C18	0.1368 (3)	0.5869 (2)	0.5827 (2)	0.0977 (9)
H18A	0.1613	0.5150	0.5840	0.147*
H18B	0.1985	0.6281	0.5452	0.147*
H18C	0.0623	0.5935	0.5388	0.147*
Cl19	0.07323 (5)	0.23683 (4)	0.69382 (4)	0.06254 (15)
O20	0.1157 (3)	0.1597 (2)	0.6167 (2)	0.1595 (11)
O21	−0.04263 (19)	0.2684 (2)	0.6605 (2)	0.1340 (9)
O22	0.1506 (3)	0.3190 (3)	0.6782 (4)	0.1879 (14)
O23	0.0822 (3)	0.2113 (3)	0.8119 (2)	0.1573 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0699 (8)	0.0664 (8)	0.0479 (7)	0.0041 (7)	0.0012 (6)	−0.0047 (6)
C2	0.0478 (9)	0.0612 (10)	0.0544 (10)	−0.0062 (8)	−0.0003 (8)	−0.0111 (9)
C3	0.0696 (12)	0.0781 (13)	0.0539 (11)	−0.0048 (11)	−0.0034 (9)	−0.0108 (10)
C4	0.0767 (13)	0.0829 (14)	0.0516 (11)	−0.0109 (11)	−0.0049 (10)	−0.0141 (10)
C5	0.0929 (17)	0.0912 (16)	0.0539 (12)	−0.0090 (14)	−0.0063 (11)	0.0083 (11)
C6	0.112 (2)	0.0795 (16)	0.0801 (16)	−0.0020 (15)	−0.0172 (14)	0.0196 (13)
C7	0.119 (2)	0.0760 (15)	0.0851 (17)	0.0094 (15)	−0.0087 (16)	0.0047 (13)
C8	0.0989 (18)	0.0745 (14)	0.0690 (14)	0.0144 (13)	−0.0029 (13)	−0.0021 (11)
C9	0.0591 (11)	0.0845 (14)	0.0521 (10)	−0.0147 (10)	−0.0040 (9)	−0.0016 (10)
C10	0.0595 (11)	0.0634 (11)	0.0555 (11)	−0.0014 (9)	−0.0049 (9)	−0.0014 (9)
C11	0.0518 (10)	0.0547 (10)	0.0514 (10)	−0.0033 (8)	0.0028 (8)	−0.0070 (8)
C12	0.0900 (14)	0.0498 (10)	0.0553 (11)	−0.0033 (10)	−0.0013 (10)	−0.0037 (8)
C13	0.0933 (16)	0.0619 (12)	0.0527 (11)	0.0068 (11)	−0.0006 (10)	−0.0085 (9)
C14	0.0621 (11)	0.0700 (13)	0.0593 (11)	0.0040 (10)	0.0005 (9)	0.0039 (10)
C15	0.0822 (14)	0.0623 (12)	0.0769 (15)	0.0198 (11)	−0.0052 (11)	−0.0027 (10)
C16	0.0888 (15)	0.0805 (15)	0.0613 (12)	0.0219 (12)	0.0000 (11)	−0.0171 (11)
Cl17	0.1089 (5)	0.0873 (4)	0.0766 (4)	0.0176 (3)	−0.0068 (3)	0.0198 (3)
C18	0.140 (2)	0.1014 (19)	0.0517 (13)	−0.0027 (18)	0.0002 (14)	−0.0132 (13)
Cl19	0.0679 (3)	0.0617 (3)	0.0580 (3)	0.0092 (2)	−0.0010 (2)	−0.0016 (2)
O20	0.191 (2)	0.164 (2)	0.1225 (18)	0.1124 (18)	−0.0411 (16)	−0.0622 (15)
O21	0.0861 (13)	0.212 (2)	0.1038 (15)	0.0527 (14)	−0.0201 (11)	−0.0522 (16)
O22	0.182 (3)	0.152 (2)	0.231 (4)	−0.084 (2)	0.014 (3)	0.012 (2)
O23	0.209 (3)	0.188 (3)	0.0755 (14)	0.049 (2)	−0.0073 (16)	0.0258 (16)

Geometric parameters (Å, º)

O1—C2	1.326 (2)	C11—C12	1.383 (3)
O1—C10	1.366 (2)	C11—C16	1.422 (3)
C2—C3	1.390 (3)	C12—C13	1.377 (3)
C2—C11	1.448 (3)	C12—H12	0.9300
C3—C4	1.371 (3)	C13—C14	1.363 (3)
C3—H3	0.9300	C13—H13	0.9300
C4—C9	1.422 (3)	C14—C15	1.385 (3)
C4—C18	1.493 (3)	C14—Cl17	1.733 (2)
C5—C6	1.339 (4)	C15—C16	1.375 (3)
C5—C9	1.422 (3)	C15—H15	0.9300
C5—H5	0.9300	C16—H16	0.9300
C6—C7	1.394 (4)	C18—H18A	0.9600
C6—H6	0.9300	C18—H18B	0.9600
C7—C8	1.385 (4)	C18—H18C	0.9600
C7—H7	0.9300	Cl19—O23	1.367 (2)
C8—C10	1.374 (3)	Cl19—O22	1.368 (3)
C8—H8	0.9300	Cl19—O21	1.391 (2)
C9—C10	1.406 (3)	Cl19—O20	1.395 (2)
O1—C2—C3	119.13 (18)	C12—C11—C2	120.96 (17)
O1—C2—C11	113.14 (15)	C16—C11—C2	121.82 (18)
C2—O1—C10	122.21 (15)	C13—C12—C11	121.33 (19)
C3—C2—C11	127.72 (19)	C13—C12—H12	119.3
C4—C3—C2	122.1 (2)	C11—C12—H12	119.3
C4—C3—H3	118.9	C14—C13—C12	120.4 (2)
C2—C3—H3	118.9	C14—C13—H13	119.8
C3—C4—C9	118.1 (2)	C12—C13—H13	119.8
C3—C4—C18	120.2 (2)	C13—C14—C15	120.7 (2)
C9—C4—C18	121.7 (2)	C13—C14—Cl17	119.40 (17)
C6—C5—C9	121.3 (2)	C15—C14—Cl17	119.79 (17)
C6—C5—H5	119.4	C16—C15—C14	119.1 (2)
C9—C5—H5	119.4	C16—C15—H15	120.4
C5—C6—C7	121.3 (2)	C14—C15—H15	120.4
C5—C6—H6	119.3	C15—C16—C11	121.2 (2)
C7—C6—H6	119.3	C15—C16—H16	119.4
C8—C7—C6	119.9 (3)	C11—C16—H16	119.4
C8—C7—H7	120.1	C4—C18—H18A	109.5
C6—C7—H7	120.1	C4—C18—H18B	109.5
C10—C8—C7	118.5 (2)	H18A—C18—H18B	109.5
C10—C8—H8	120.7	C4—C18—H18C	109.5
C7—C8—H8	120.7	H18A—C18—H18C	109.5
C10—C9—C4	118.1 (2)	H18B—C18—H18C	109.5
C10—C9—C5	116.0 (2)	O23—Cl19—O22	105.4 (2)
C4—C9—C5	125.9 (2)	O23—Cl19—O21	113.19 (17)
O1—C10—C8	116.78 (19)	O22—Cl19—O21	108.3 (2)
O1—C10—C9	120.22 (18)	O23—Cl19—O20	113.99 (17)
C8—C10—C9	123.0 (2)	O22—Cl19—O20	104.8 (2)
C12—C11—C16	117.20 (19)	O21—Cl19—O20	110.47 (15)
C10—O1—C2—C3	−0.8 (3)	C4—C9—C10—O1	−1.2 (3)
C10—O1—C2—C11	178.63 (16)	C5—C9—C10—O1	−179.68 (18)
O1—C2—C3—C4	1.7 (3)	C4—C9—C10—C8	179.7 (2)
C11—C2—C3—C4	−177.7 (2)	C5—C9—C10—C8	1.2 (3)
C2—C3—C4—C9	−2.2 (3)	O1—C2—C11—C12	−3.9 (3)
C2—C3—C4—C18	176.5 (2)	C3—C2—C11—C12	175.5 (2)
C9—C5—C6—C7	1.1 (4)	O1—C2—C11—C16	174.38 (18)
C5—C6—C7—C8	−1.3 (5)	C3—C2—C11—C16	−6.2 (3)
C6—C7—C8—C10	1.4 (4)	C16—C11—C12—C13	1.6 (3)
C3—C4—C9—C10	1.9 (3)	C2—C11—C12—C13	179.96 (19)
C18—C4—C9—C10	−176.8 (2)	C11—C12—C13—C14	−0.4 (4)
C3—C4—C9—C5	−179.7 (2)	C12—C13—C14—C15	−1.0 (4)
C18—C4—C9—C5	1.5 (4)	C12—C13—C14—Cl17	−177.48 (18)
C6—C5—C9—C10	−1.0 (4)	C13—C14—C15—C16	1.1 (4)
C6—C5—C9—C4	−179.3 (2)	C16—C15—C14—Cl17	177.59 (19)
C2—O1—C10—C8	179.83 (19)	C14—C15—C16—C11	0.1 (4)
C2—O1—C10—C9	0.6 (3)	C12—C11—C16—C15	−1.5 (3)
C7—C8—C10—O1	179.4 (2)	C2—C11—C16—C15	−179.8 (2)
C7—C8—C10—C9	−1.4 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O22	0.93	2.52	3.377 (5)	154

(Ib) 2-(4-chlorophenyl)-4-methylchromenium perchlorate

Crystal data

C16H12ClO^+·ClO4^−	F(000) = 728
Mr = 355.16	Dx = 1.497 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 50 reflections
a = 8.0631 (15) Å	θ = 2.5–25.0°
b = 11.873 (3) Å	µ = 0.43 mm^−1
c = 16.487 (2) Å	T = 290 K
β = 93.292 (14)°	Prism, olive-green
V = 1575.8 (5) Å^3	0.5 × 0.4 × 0.3 mm
Z = 4

Data collection

Siemens P3/PC diffractometer	Rint = 0.036
Radiation source: fine-focus sealed X-ray tube	θmax = 25.0°, θmin = 3.0°
Graphite monochromator	h = 0→9
θ/2θ scans	k = 0→14
2957 measured reflections	l = −19→19
2748 independent reflections	3 standard reflections every 200 reflections
1814 reflections with I > 2σ(I)	intensity decay: 2.0%

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.123	H-atom parameters constrained
S = 0.85	w = 1/[σ^2(Fo^2) + (0.0849P)^2] where P = (Fo^2 + 2Fc^2)/3
2748 reflections	(Δ/σ)max < 0.001
255 parameters	Δρmax = 0.20 e Å^−3
261 restraints	Δρmin = −0.26 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.2075 (4)	0.2599 (3)	0.0201 (2)	0.0598 (10)
C2	0.3229 (6)	0.2015 (4)	0.0620 (3)	0.0535 (12)
C3	0.2964 (7)	0.1688 (5)	0.1409 (3)	0.0594 (13)
H3	0.3769	0.1260	0.1693	0.071*
C4	0.1551 (7)	0.1978 (5)	0.1782 (3)	0.0620 (14)
C5	−0.1185 (7)	0.3010 (6)	0.1628 (4)	0.0756 (18)
H5	−0.1460	0.2836	0.2154	0.091*
C6	−0.2228 (7)	0.3635 (6)	0.1144 (5)	0.0808 (19)
H6	−0.3218	0.3884	0.1345	0.097*
C7	−0.1882 (8)	0.3913 (6)	0.0372 (5)	0.0788 (18)
H7	−0.2633	0.4349	0.0059	0.095*
C8	−0.0461 (7)	0.3565 (5)	0.0050 (4)	0.0680 (15)
H8	−0.0225	0.3750	−0.0479	0.082*
C9	0.0331 (6)	0.2617 (5)	0.1336 (3)	0.0586 (14)
C10	0.0627 (6)	0.2925 (4)	0.0538 (3)	0.0540 (12)
C11	0.4674 (6)	0.1736 (4)	0.0170 (3)	0.0547 (13)
C12	0.4785 (7)	0.2071 (6)	−0.0632 (4)	0.0743 (17)
H12	0.3918	0.2480	−0.0885	0.089*
C13	0.6150 (8)	0.1812 (6)	−0.1060 (4)	0.0733 (17)
H13	0.6200	0.2025	−0.1601	0.088*
C14	0.7415 (6)	0.1241 (5)	−0.0676 (3)	0.0586 (13)
C15	0.7351 (7)	0.0868 (5)	0.0110 (4)	0.0661 (15)
H15	0.8223	0.0454	0.0354	0.079*
C16	0.5967 (7)	0.1117 (5)	0.0532 (3)	0.0598 (14)
H16	0.5904	0.0867	0.1064	0.072*
Cl17	0.9189 (2)	0.09293 (14)	−0.12047 (11)	0.0814 (6)
C18	0.1337 (9)	0.1610 (7)	0.2631 (4)	0.086 (2)
H18C	0.2286	0.1178	0.2823	0.130*
H18B	0.0354	0.1156	0.2648	0.130*
H18A	0.1232	0.2260	0.2971	0.130*
Cl19	0.3290 (14)	0.4978 (8)	0.2129 (8)	0.062 (3)	0.557 (13)
O20	0.4875 (15)	0.4668 (16)	0.2428 (9)	0.140 (5)	0.557 (13)
O21	0.347 (2)	0.6112 (10)	0.2286 (10)	0.134 (5)	0.557 (13)
O22	0.218 (2)	0.4929 (15)	0.1468 (8)	0.145 (6)	0.557 (13)
O23	0.2414 (16)	0.4457 (10)	0.2719 (6)	0.126 (5)	0.557 (13)
Cl9A	0.3313 (17)	0.4974 (12)	0.2044 (11)	0.072 (4)	0.443 (13)
O20A	0.454 (2)	0.5737 (16)	0.2278 (12)	0.116 (6)	0.443 (13)
O21A	0.216 (2)	0.5735 (14)	0.1764 (11)	0.121 (5)	0.443 (13)
O22A	0.3500 (19)	0.4442 (11)	0.1304 (8)	0.104 (5)	0.443 (13)
O23A	0.410 (2)	0.4010 (13)	0.2292 (12)	0.135 (6)	0.443 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.060 (2)	0.061 (2)	0.058 (2)	−0.0049 (18)	−0.0038 (17)	0.0004 (17)
C2	0.050 (3)	0.056 (3)	0.054 (3)	−0.010 (2)	−0.006 (2)	0.001 (2)
C3	0.060 (3)	0.065 (3)	0.053 (3)	−0.002 (3)	−0.006 (2)	0.009 (2)
C4	0.060 (3)	0.068 (3)	0.058 (3)	−0.013 (3)	0.003 (3)	−0.011 (3)
C5	0.064 (4)	0.082 (4)	0.081 (4)	−0.021 (3)	0.006 (3)	−0.025 (3)
C6	0.051 (3)	0.096 (5)	0.096 (5)	0.005 (3)	0.001 (3)	−0.024 (4)
C7	0.069 (4)	0.071 (4)	0.095 (5)	0.004 (3)	−0.014 (3)	−0.007 (4)
C8	0.065 (4)	0.067 (4)	0.071 (4)	−0.001 (3)	−0.002 (3)	−0.008 (3)
C9	0.053 (3)	0.060 (3)	0.063 (3)	−0.015 (3)	0.001 (2)	−0.016 (3)
C10	0.053 (3)	0.051 (3)	0.057 (3)	−0.005 (2)	−0.009 (2)	−0.008 (2)
C11	0.058 (3)	0.051 (3)	0.054 (3)	−0.005 (2)	−0.001 (2)	−0.003 (2)
C12	0.062 (3)	0.100 (5)	0.061 (3)	0.004 (3)	0.009 (3)	0.029 (3)
C13	0.076 (4)	0.093 (5)	0.052 (3)	0.004 (3)	0.014 (3)	0.023 (3)
C14	0.058 (3)	0.063 (3)	0.056 (3)	−0.014 (3)	0.011 (2)	−0.002 (3)
C15	0.065 (3)	0.062 (3)	0.070 (4)	−0.002 (3)	−0.003 (3)	−0.008 (3)
C16	0.066 (3)	0.056 (3)	0.056 (3)	−0.005 (3)	−0.008 (3)	0.006 (2)
Cl17	0.0782 (10)	0.0779 (11)	0.0906 (12)	−0.0014 (8)	0.0272 (8)	0.0017 (8)
C18	0.098 (5)	0.102 (5)	0.059 (4)	−0.005 (4)	0.010 (3)	0.005 (3)
Cl19	0.064 (5)	0.055 (4)	0.067 (4)	0.003 (4)	0.002 (3)	−0.008 (3)
O20	0.122 (9)	0.158 (15)	0.139 (11)	−0.013 (9)	−0.004 (7)	0.006 (10)
O21	0.173 (15)	0.104 (9)	0.124 (10)	−0.025 (8)	0.001 (11)	−0.016 (7)
O22	0.179 (14)	0.144 (14)	0.108 (9)	−0.066 (13)	−0.024 (10)	−0.006 (9)
O23	0.142 (10)	0.132 (9)	0.104 (8)	−0.045 (8)	0.002 (7)	0.006 (6)
Cl9A	0.065 (7)	0.074 (7)	0.075 (6)	−0.016 (5)	−0.008 (4)	−0.016 (4)
O20A	0.114 (11)	0.106 (12)	0.126 (12)	−0.027 (10)	−0.016 (11)	−0.011 (10)
O21A	0.116 (11)	0.120 (12)	0.126 (13)	−0.001 (9)	−0.008 (9)	0.000 (10)
O22A	0.105 (10)	0.103 (10)	0.103 (8)	−0.028 (7)	0.007 (7)	−0.021 (6)
O23A	0.146 (15)	0.101 (10)	0.156 (12)	−0.035 (9)	−0.021 (11)	0.012 (10)

Geometric parameters (Å, º)

O1—C2	1.323 (6)	C12—H12	0.9300
O1—C10	1.376 (6)	C13—C14	1.351 (8)
C2—C3	1.386 (7)	C13—H13	0.9300
C2—C11	1.455 (7)	C14—C15	1.374 (8)
C3—C4	1.369 (8)	C14—Cl17	1.757 (5)
C3—H3	0.9300	C15—C16	1.381 (8)
C4—C9	1.415 (8)	C15—H15	0.9300
C4—C18	1.485 (8)	C16—H16	0.9300
C5—C6	1.349 (9)	C18—H18C	0.9600
C5—C9	1.418 (8)	C18—H18B	0.9600
C5—H5	0.9300	C18—H18A	0.9600
C6—C7	1.359 (9)	Cl19—O22	1.370 (11)
C6—H6	0.9300	Cl19—O21	1.377 (11)
C7—C8	1.355 (8)	Cl19—O23	1.380 (13)
C7—H7	0.9300	Cl19—O20	1.393 (11)
C8—C10	1.383 (8)	Cl9A—O21A	1.360 (12)
C8—H8	0.9300	Cl9A—O23A	1.360 (13)
C9—C10	1.400 (8)	Cl9A—O20A	1.382 (13)
C11—C16	1.383 (7)	Cl9A—O22A	1.390 (14)
C11—C12	1.388 (8)	O22A—O23A	1.75 (2)
C12—C13	1.376 (8)
O1—C2—C3	119.7 (5)	C11—C12—H12	119.3
O1—C2—C11	114.4 (4)	C14—C13—C12	118.5 (5)
C2—O1—C10	121.6 (4)	C14—C13—H13	120.7
C3—C2—C11	125.9 (5)	C12—C13—H13	120.7
C4—C3—C2	121.9 (5)	C13—C14—C15	122.3 (5)
C4—C3—H3	119.0	C13—C14—Cl17	119.2 (4)
C2—C3—H3	119.0	C15—C14—Cl17	118.4 (5)
C3—C4—C9	118.2 (5)	C14—C15—C16	118.8 (6)
C3—C4—C18	119.7 (6)	C14—C15—H15	120.6
C9—C4—C18	122.1 (5)	C16—C15—H15	120.6
C6—C5—C9	120.0 (6)	C15—C16—C11	120.5 (5)
C6—C5—H5	120.0	C15—C16—H16	119.8
C9—C5—H5	120.0	C11—C16—H16	119.8
C5—C6—C7	122.3 (6)	C4—C18—H18C	109.5
C5—C6—H6	118.9	C4—C18—H18B	109.5
C7—C6—H6	118.9	H18C—C18—H18B	109.5
C8—C7—C6	121.1 (6)	C4—C18—H18A	109.5
C8—C7—H7	119.5	H18C—C18—H18A	109.5
C6—C7—H7	119.5	H18B—C18—H18A	109.5
C7—C8—C10	117.6 (6)	O22—Cl19—O21	104.3 (11)
C7—C8—H8	121.2	O22—Cl19—O23	101.8 (11)
C10—C8—H8	121.2	O21—Cl19—O23	111.0 (11)
C10—C9—C4	118.5 (5)	O22—Cl19—O20	144.4 (16)
C10—C9—C5	115.5 (5)	O21—Cl19—O20	96.3 (11)
C4—C9—C5	125.9 (6)	O23—Cl19—O20	97.4 (11)
O1—C10—C8	116.4 (5)	O21A—Cl9A—O23A	163.7 (15)
O1—C10—C9	120.0 (5)	O21A—Cl9A—O20A	97.3 (13)
C8—C10—C9	123.6 (5)	O23A—Cl9A—O20A	98.8 (13)
C16—C11—C12	118.4 (5)	O21A—Cl9A—O22A	96.4 (14)
C16—C11—C2	120.4 (5)	O23A—Cl9A—O22A	79.0 (12)
C12—C11—C2	121.2 (5)	O20A—Cl9A—O22A	115.5 (15)
C13—C12—C11	121.4 (6)	Cl9A—O22A—O23A	49.8 (7)
C13—C12—H12	119.3	Cl9A—O23A—O22A	51.3 (8)
C10—O1—C2—C3	2.0 (7)	C4—C9—C10—C8	−178.8 (5)
C10—O1—C2—C11	179.7 (4)	C5—C9—C10—C8	−0.2 (7)
O1—C2—C3—C4	−1.7 (8)	O1—C2—C11—C16	−179.3 (4)
C11—C2—C3—C4	−179.1 (5)	C3—C2—C11—C16	−1.8 (8)
C2—C3—C4—C9	0.8 (8)	O1—C2—C11—C12	0.0 (7)
C2—C3—C4—C18	−179.6 (5)	C3—C2—C11—C12	177.5 (5)
C9—C5—C6—C7	−0.1 (10)	C16—C11—C12—C13	−0.8 (9)
C5—C6—C7—C8	0.3 (10)	C2—C11—C12—C13	179.9 (6)
C6—C7—C8—C10	−0.5 (9)	C11—C12—C13—C14	−1.6 (10)
C3—C4—C9—C10	−0.2 (7)	C12—C13—C14—C15	3.1 (9)
C18—C4—C9—C10	−179.7 (5)	C12—C13—C14—Cl17	−178.6 (5)
C3—C4—C9—C5	−178.6 (5)	C13—C14—C15—C16	−2.2 (9)
C18—C4—C9—C5	1.8 (9)	Cl17—C14—C15—C16	179.5 (4)
C6—C5—C9—C10	0.1 (8)	C14—C15—C16—C11	−0.3 (8)
C6—C5—C9—C4	178.5 (5)	C12—C11—C16—C15	1.7 (8)
C2—O1—C10—C8	177.9 (4)	C2—C11—C16—C15	−179.0 (5)
C2—O1—C10—C9	−1.4 (7)	O21A—Cl9A—O22A—O23A	−164.2 (17)
C7—C8—C10—O1	−178.9 (5)	O20A—Cl9A—O22A—O23A	94.6 (15)
C7—C8—C10—C9	0.4 (8)	O21A—Cl9A—O23A—O22A	75 (7)
C4—C9—C10—O1	0.5 (7)	O20A—Cl9A—O23A—O22A	−114.4 (15)
C5—C9—C10—O1	179.1 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O20^i	0.93	2.60	3.476 (17)	156
C13—H13···O21^ii	0.93	2.50	3.213 (16)	133

Symmetry codes: (i) x−1, y, z; (ii) −x+1, −y+1, −z.