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A second, monoclinic, polymorph of the title compound, C14H8Cl2, has been found. In addition to the structure of this monoclinic form, the structure of the previously described ortho­rhom­bic form [Desvergne, Chekpo & Bouas-Laurent (1978). J. Chem. Soc. Perkin Trans. 2, pp. 84–87; Benites, Maverick & Fronczek (1996). Acta Cryst. C52, 647–648] has been redetermined at low temperature and using modern methods. The low-temperature structure of the ortho­rhom­bic form is of significantly higher quality than the previously published structure and additional details can be derived. A comparison of the crystal packing of the two forms with a focus on weak inter­molecular C—H...Cl inter­actions shows the monoclinic structure to have one such inter­action linking the mol­ecules into infinite ribbons, while two crystallographically independent C—H...Cl interactions give rise to an inter­esting infinite three-dimensional network in the ortho­rhom­bic crystal form.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113001790/gz3224sup1.cif
Contains datablocks I_mono, I_ortho, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270113001790/gz3224I_monosup2.hkl
Contains datablock mono

cdx

Chemdraw file https://doi.org/10.1107/S0108270113001790/gz3224I_monosup3.cdx
Supplementary material

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270113001790/gz3224I_monosup4.cml
Supplementary material

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270113001790/gz3224I_orthosup5.hkl
Contains datablock ortho

cdx

Chemdraw file https://doi.org/10.1107/S0108270113001790/gz3224I_orthosup6.cdx
Supplementary material

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270113001790/gz3224I_orthosup7.cml
Supplementary material

CCDC references: 925781; 925782

Comment top

One of the starting materials used in the context of our ongoing research into energy transfer in ternary complexes is the title compound, 1,8-dichloroanthracene, (I). Instead of the desired reaction product, crystals of (I) were obtained and the structure was determined to be a previously undescribed monoclinic polymorph of 1,8-dichloroanthracene.

The orthorhombic structure of (I) had originally been reported without coordinates by Desvergne et al. (1978) and was determined in space group Pnma (with Z = 4) from Weissenberg photographs collected at room temperature. This structure was later corrected by Benites et al. (1996) to space group Pna21 in essentially the same unit cell, determined based on point-detector data collected at room temperature, and refined against F values instead of F2. To better compare the two polymorphs and also to redetermine the structure with current methods, low-temperature data of the orthorhombic form were collected (the original bulk sample was still available) using a modern diffractometer equipped with an area detector. Figs. 1 and 2 show the molecules of the monoclinic and orthorhombic structures, respectively.

Comparison of the two structures shows that the monoclinic polymorph is somewhat denser than the orthorhombic crystal form (1.548 versus 1.533 Mg m-3), despite the fact that the orthorhombic unit cell was determined at a slightly lower temperature than the monoclinic one. To test for the possibility of a temperature-dependent phase transition, the unit cell of the monoclinic form was determined at 290 K from a fresh crystal (data not shown) and was found to be the same monoclinic cell as that reported herein. It also appears that the orthorhombic polymorph does not convert to the denser monoclinic one over time, at least not on a decade timescale, as the orthorhombic crystals used for this study were grown over 16 years ago.

Besides the obvious intramolecular C9—H9···Cl contacts occurring in both molecules, which are based more on molecular geometry than attractive forces between H and Cl, both structures show weak intermolecular C—H···Cl interactions. Using the sum of the van der Waals radii (3.0 Å; Standard reference?) as a cut-off and limiting the search to C—H···Cl angles near a chemically sensible value of 150°, the monoclinic structure has one crystallographically independent van der Waals interaction involving atom Cl1, while the orthorhombic structure has two crystallographically independent interactions of this kind, both involving atom Cl1. These interactions are listed as C—H···Cl hydrogen bonds in Tables 1 and 2.

In the monoclinic polymorph, the C4—H4···Cl1i interactions [symmetry code: (i) x, 5/2 - y, 1/2 + z] link the molecules into infinite zigzag ribbons extending along the c axis, in which neighboring molecules assume an angle of 55.891 (14)° to one another. When seen in projection along the a axis, the zigzag nature of the ribbons is shown (Fig. 3, panel A). A projection along the b axis shows the ribbon from the side (Fig. 3, panel B), while in a view along the axis of propagation, i.e. the c axis, a V-shaped groove presents itself (Fig. 3, panel C).

The C—H···Cl interaction pattern found in the orthorhombic structure is somewhat more complex. The first of the two C—H···Cl interactions [C4—H4···Cl1ii; symmetry code: (ii) -1/2 + x, 5/2 - y, z] links the molecules into infinite zigzag ribbons extending along the a direction (Fig. 4, panel A), with an angle between neighboring molecules of 55.816 (14)°. These ribbons are similar to those described for the monoclinic structure. Most notably, the angle between molecules is almost identical (only five s.u.s apart) and both ribbons are generated by glide planes (a c-glide in the monoclinic structure, corresponding to the propagation of the layer in the c direction, and an a-glide in the orthorhombic one, where the chain extends along a). It should be noted that the a axis in the monoclinic structure is only slightly longer than the c axis in the orthorhombic one [and d100 of the monoclinic form (18.136 Å) is almost identical to the length of the orthorhombic c axis], and the monoclinic c and orthorhombic a axes are also quite similar (as are, as an aside note, the two b axes, making the β angle the only notable difference between the two unit cells).

The second interaction in the orthorhombic structure, C7—H7···Cl1iii [symmetry code: (iii) 1 - x, 1 - y, -1/2 + z], adds an interesting dimension of complexity to the packing of that polymorph. When examined on its own, it connects the molecules into infinite zigzag chains extending along the c direction, perpendicular to the ribbons generated by the first interaction (Fig. 4, panel B). In those chains, the angle between neighboring molecules is 51.494 (13)°. In combination, the two independent C—H···Cl hydrogen bonds give rise to an infinite three-dimensional network (panel C of Fig. 4 shows a packing plot in projection along the b axis). Connection in the third dimension is generated by means of helices extending along the b direction (Fig. 4, panel D). These helices are built using all four symmetry operators of the space group (including x, y, z) and the four symmetry-equivalent molecules contribute to the helix in four different ways. One molecule binds to its neighbors through atoms H4 and H7, a second one through atoms H4 and Cl1, a third through atoms H7 and Cl1, and the fourth only through atom Cl1, which accepts hydrogen bonds from atoms H4 and H7 of neighboring molecules. Panel E of Fig. 4 shows the anatomy of the helix schematically. It is remarkable that, even in the comparatively simple space group Pna21, just two crystallographically independent hydrogen bonds can give rise to two infinite straight chains in two directions and a complex helix in the third, while interconnecting the molecules into a three-dimensional framework.

Fig. 5 shows packing plots of the two structures and the nearest Cl···H distances, in views approximately along the respective b axes. In both structures, both Cl atoms are near five H atoms, and all H atoms, except for atom H9 in both molecules, are involved. The respective Cl···H distances are quite similar in the two polymorphs. This statement does not refer to hydrogen bonds or van der Waals interactions, as most of those Cl···H distances are longer than the sum of the van der Waals radii. Nevertheless, the projections shown in Fig. 5 illustrate well the similarities between the two structures. A comparison of the Cl···H distances in the two structures also reflects the higher density found for the monoclinic structure, as the corresponding distances in the orthorhombic polymorph are significantly longer.

Simulated powder patterns of the two structures calculated using Mercury (Macrae et al., 2008) did not reveal any similarities between the two polymorphs besides those to be expected with such similar unit cells and packings as described in the paragraphs above.

It is interesting to note that the crystals of both polymorphs were derived by the same method and from the same solvent (slow evaporation from propan-2-ol). The presence of other components, namely Pd(PPh3)4 and possible reaction products, during the crystallization of the monoclinic form is the only tangible difference between the two crystallization procedures. However, recrystallization of the 16 year-old orthorhombic sample by slow evaporation from propan-2-ol yielded the monoclinic polymorph (data not shown). Exhaustive additional crystallization experiments should be carried out before a conclusive statement can be made. Nevertheless, it cannot be ruled out that this may be another example of a disappearing polymorph (Dunitz & Bernstein, 1995).

Related literature top

For related literature, see: Benites et al. (1996); Collman et al. (1992); Desvergne et al. (1978); Dunitz & Bernstein (1995); Flack (1983); Müller (2009); Macrae et al. (2008); Sheldrick (2008); Tauchert et al. (2010).

Experimental top

For the orthorhombic crystals, compound (I) was prepared according to the procedure of Collman et al. (1992) and crystallized from propan-2-ol by slow evaporation. The crystals used for this study were, without recrystallization, taken from the original 16 year-old bulk sample from which a crystal had been used to derive the orthorhombic structure of (I) by Benites et al. (1996). For the monoclinic crystals, (I) was prepared according to the procedure of Tauchert et al. (2010), chromatographically purified and crystallized by slow evaporation from propan-2-ol in the presence of Pd(PPh3)4 and possible reaction products.

Refinement top

Both structures were refined against F2 on all data by full-matrix least squares using SHELXL97 (Sheldrick, 2008), following established refinement strategies (Müller, 2009). All H atoms were included in the model at geometrically calculated positions, with C—H = 0.95 Å, and refined using a riding model, with Uiso(H) = 1.2Ueq(C).

Four outlier reflections with Fo - Fc/σ > 10 were omitted from refinement of the monoclinic structure, and two low-resolution reflections with Fo << Fc (indicative of obstruction by the beam stop) were omitted from refinement of the orthorhombic structure. The Flack x parameter (Flack, 1983) of the orthorhombic structure was determined to be close to 0.5 and this structure was refined as a racemic twin. The twin ratio was refined freely and converged at 0.42 (3).

Computing details top

Data collection: APEX2 (Bruker, 2011) for I_mono; COLLECT (Nonius, 2000) for I_ortho. Cell refinement: SAINT (Bruker, 2011) for I_mono; SCALEPACK (Otwinowski & Minor 1997) for I_ortho. Data reduction: SAINT (Bruker, 2011) for I_mono; DENZO and SCALEPACK (Otwinowski & Minor 1997) for I_ortho. For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) in its monoclinic form, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. The molecular structure of (I) in its orthorhombic form, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 3] Fig. 3. Three views of the infinite ribbon in the monoclinic structure of (I) generated by the C4—H4···Cl1i interactions [symmetry code: (i) x, 5/4 - y, 1/2 + z]. The symmetry operation relating the molecules in this ribbon is the c-glide, and the ribbon consequently extends along the c-direction. C—H···Cl interactions are drawn as dashed lines. The three panels show the ribbon in projections along a (panel A), b (panel B) and c (panel C). The angle between neighboring molecules is 55.891 (14)°.
[Figure 4] Fig. 4. Various packing views of the orthorhombic structure. C—H···Cl interactions are drawn as dashed lines. (a) The zigzag ribbon extending along the a axis, generated by the hydrogen bonds of atom H4. The angle between neighboring molecules is 55.816 (14)°. (b) The zigzag chain extending along the c axis, generated by the hydrogen bonds of atom H7. The angle between neighboring molecules is 51.494 (13)°. (c) A packing plot in projection along the b axis, providing a view down the helices that are formed by a combination of the motifs shown in (a) and (b). (d) A side view of the helix, which is built using all four general positions of space group Pna21 for each full turn. (e) Schematics of the anatomy of the helix, showing two turns. The molecules are represented by oval shapes and only those atoms directly interacting with a neighboring molecule protrude from the oval. Each of the four molecules in every full turn contributes to the helix in a different way: one molecule binds to its neighbors through atoms H4 and H7, a second one through atoms H4 and Cl1, a third through atoms H7 and Cl1, and the fourth only through atom Cl1. [Symmetry codes [in the centers of the ovals in part (e)]: (i) -x+1, -y+1, z-1/2; (ii) -x+1/2, y-3/2, z-1/2; (iii) x-1/2, -y-1/2, z; (iv) x-1/2, -y+5/2, z; (v) -y+1/2, y+3/2, z-1/2; (vi) -x+1, -y+4, z-1/2; (vii) x, y+3, z.]
[Figure 5] Fig. 5. Projections, approximately along the b axes, of (a) the monoclinic polymorph and (b) the orthorhombic polymorph, showing the nearest Cl···H distances in the packing of the two structures. Distances around the Cl atoms (in Å), in (a) Cl1···H2i = 2.98 Å, Cl1···H3i = 3.33 Å, Cl1···H4ii = 2.99 Å, Cl1···H4iii = 2.95 Å, Cl1···H10ii = 3.05 Å, Cl2···H5ii = 3.07 Å, Cl2···H6iv = 3.46 Å, Cl2···H7v = 3.28 Å, Cl2···H7iv = 3.16 Å and Cl2···H5vi = 2.95 Å; in (b) Cl1···H7vii = 2.93 Å, Cl1···H6vii = 3.88 Å, Cl1···H4viii = 2.84 Å, Cl1···H4ix = 3.24 Å, Cl1···H10ix = 3.01 Å, Cl2···H5ix = 3.04 Å, Cl2···H3x = 3.15 Å, Cl2···H2x = 3.23 Å, Cl2···H2xi = 3.46 Å and Cl2···H5xii = 3.10 Å. [Symmetry codes: (i) -x, y-1/2, -z+1/2; (ii) x, -y+3/2, z-1/2; (iii) x, -y+5/2, z-1/2; (iv) -x+1, -y+1, -z+1; (v) -x+1, -y, -z+1; (vi) x, -y+1/2, z-1/2; (vii) -x+1, -y+1, z+1/2; (viii) x+1/2, -y+5/2, z [Incomplete?]; (ix) x+1/2, -y+3/2, z; (x) -x+1, -y+2, z-1/2; (xi) -x+1, -y+1, z-1/2; (xii) x+1/2, -y+1/2, z [Incomplete?].]
(I_mono) 1,8-dichloroanthracene top
Crystal data top
C14H8Cl2F(000) = 504
Mr = 247.10Dx = 1.548 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 9433 reflections
a = 19.0070 (14) Åθ = 2.7–32.0°
b = 3.8621 (3) ŵ = 0.57 mm1
c = 15.1370 (11) ÅT = 100 K
β = 107.4103 (15)°Needle, colourless
V = 1060.25 (14) Å30.20 × 0.05 × 0.04 mm
Z = 4
Data collection top
Bruker SMART APEX2 CCD area-detector
diffractometer
3700 independent reflections
Radiation source: IµS micro-focus sealed tube3433 reflections with I > 2σ(I)
Incoatec IµS multilayer optics monochromatorRint = 0.027
Detector resolution: 8.3 pixels mm-1θmax = 32.0°, θmin = 2.3°
ϕ and ω scansh = 2828
Absorption correction: multi-scan
(SADABS; Sheldrick, 2009)
k = 55
Tmin = 0.894, Tmax = 0.977l = 2222
56651 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.028Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.083H-atom parameters constrained
S = 1.15 w = 1/[σ2(Fo2) + (0.0366P)2 + 0.5831P]
where P = (Fo2 + 2Fc2)/3
3700 reflections(Δ/σ)max = 0.001
145 parametersΔρmax = 0.53 e Å3
0 restraintsΔρmin = 0.20 e Å3
Crystal data top
C14H8Cl2V = 1060.25 (14) Å3
Mr = 247.10Z = 4
Monoclinic, P21/cMo Kα radiation
a = 19.0070 (14) ŵ = 0.57 mm1
b = 3.8621 (3) ÅT = 100 K
c = 15.1370 (11) Å0.20 × 0.05 × 0.04 mm
β = 107.4103 (15)°
Data collection top
Bruker SMART APEX2 CCD area-detector
diffractometer
3700 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2009)
3433 reflections with I > 2σ(I)
Tmin = 0.894, Tmax = 0.977Rint = 0.027
56651 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0280 restraints
wR(F2) = 0.083H-atom parameters constrained
S = 1.15Δρmax = 0.53 e Å3
3700 reflectionsΔρmin = 0.20 e Å3
145 parameters
Special details top

Experimental. Bruker X8 Kappa DUO four-circle diffractometer, Bruker APEX2 CCD. The instrument was purchased with the help of funding from the National Science Foundation (NSF) under Grant Number CHE-0946721.

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 (Å2) top
xyzUiso*/Ueq
Cl20.382516 (13)0.29325 (7)0.371481 (17)0.01727 (7)
Cl10.130329 (14)0.83680 (7)0.229521 (17)0.01825 (7)
C10.12833 (5)0.9344 (3)0.34099 (7)0.01406 (17)
C20.06746 (6)1.0937 (3)0.35174 (7)0.01650 (18)
H20.02701.14730.29910.020*
C30.06480 (6)1.1791 (3)0.44184 (8)0.01791 (19)
H30.02201.28640.44940.021*
C40.12310 (6)1.1087 (3)0.51775 (7)0.01679 (18)
H40.12091.17190.57750.020*
C50.37151 (6)0.6169 (3)0.65498 (7)0.01720 (19)
H50.37020.68260.71500.021*
C60.43164 (6)0.4487 (3)0.64500 (7)0.01874 (19)
H60.47190.39800.69820.022*
C70.43488 (6)0.3484 (3)0.55613 (8)0.01731 (19)
H70.47710.23090.55000.021*
C80.37733 (5)0.4207 (3)0.47958 (7)0.01412 (17)
C90.25283 (5)0.6755 (3)0.40811 (7)0.01312 (17)
H90.25460.61210.34820.016*
C100.24777 (6)0.8657 (3)0.58497 (7)0.01515 (18)
H100.24630.93210.64480.018*
C110.19057 (5)0.8459 (3)0.41776 (7)0.01298 (17)
C120.18742 (5)0.9407 (3)0.50812 (7)0.01414 (17)
C130.31246 (5)0.5974 (3)0.48543 (7)0.01290 (16)
C140.31032 (6)0.6954 (3)0.57603 (7)0.01411 (17)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl20.01612 (11)0.01846 (12)0.01843 (12)0.00085 (8)0.00698 (8)0.00174 (8)
Cl10.01790 (12)0.02263 (13)0.01357 (11)0.00230 (9)0.00371 (8)0.00045 (8)
C10.0140 (4)0.0139 (4)0.0146 (4)0.0012 (3)0.0049 (3)0.0002 (3)
C20.0145 (4)0.0151 (4)0.0201 (4)0.0000 (3)0.0054 (3)0.0005 (4)
C30.0161 (4)0.0167 (5)0.0232 (5)0.0009 (3)0.0093 (4)0.0015 (4)
C40.0184 (4)0.0159 (4)0.0190 (4)0.0007 (4)0.0101 (4)0.0019 (4)
C50.0195 (4)0.0165 (5)0.0136 (4)0.0032 (4)0.0018 (3)0.0009 (4)
C60.0192 (4)0.0163 (5)0.0172 (4)0.0020 (4)0.0001 (3)0.0016 (4)
C70.0147 (4)0.0154 (4)0.0201 (4)0.0006 (3)0.0026 (3)0.0011 (4)
C80.0136 (4)0.0132 (4)0.0156 (4)0.0012 (3)0.0044 (3)0.0002 (3)
C90.0126 (4)0.0138 (4)0.0132 (4)0.0016 (3)0.0042 (3)0.0003 (3)
C100.0174 (4)0.0155 (4)0.0134 (4)0.0031 (3)0.0059 (3)0.0009 (3)
C110.0134 (4)0.0126 (4)0.0136 (4)0.0020 (3)0.0051 (3)0.0002 (3)
C120.0162 (4)0.0130 (4)0.0148 (4)0.0025 (3)0.0071 (3)0.0013 (3)
C130.0130 (4)0.0124 (4)0.0135 (4)0.0023 (3)0.0043 (3)0.0001 (3)
C140.0161 (4)0.0132 (4)0.0128 (4)0.0035 (3)0.0040 (3)0.0000 (3)
Geometric parameters (Å, º) top
Cl2—C81.7395 (10)C6—C71.4190 (16)
Cl1—C11.7404 (10)C6—H60.9500
C1—C21.3624 (14)C7—C81.3633 (14)
C1—C111.4297 (14)C7—H70.9500
C2—C31.4187 (15)C8—C131.4350 (14)
C2—H20.9500C9—C131.3970 (13)
C3—C41.3638 (16)C9—C111.3995 (14)
C3—H30.9500C9—H90.9500
C4—C121.4295 (14)C10—C121.3980 (14)
C4—H40.9500C10—C141.4003 (15)
C5—C61.3616 (16)C10—H100.9500
C5—C141.4287 (14)C11—C121.4343 (14)
C5—H50.9500C13—C141.4348 (14)
C2—C1—C11122.45 (9)C7—C8—C13122.05 (9)
C2—C1—Cl1118.64 (8)C7—C8—Cl2118.99 (8)
C11—C1—Cl1118.91 (8)C13—C8—Cl2118.96 (7)
C1—C2—C3119.71 (10)C13—C9—C11120.90 (9)
C1—C2—H2120.1C13—C9—H9119.5
C3—C2—H2120.1C11—C9—H9119.5
C4—C3—C2120.66 (10)C12—C10—C14121.73 (9)
C4—C3—H3119.7C12—C10—H10119.1
C2—C3—H3119.7C14—C10—H10119.1
C3—C4—C12120.57 (10)C9—C11—C1123.20 (9)
C3—C4—H4119.7C9—C11—C12119.83 (9)
C12—C4—H4119.7C1—C11—C12116.98 (9)
C6—C5—C14120.57 (10)C10—C12—C4121.53 (9)
C6—C5—H5119.7C10—C12—C11118.86 (9)
C14—C5—H5119.7C4—C12—C11119.60 (9)
C5—C6—C7120.76 (10)C9—C13—C14119.73 (9)
C5—C6—H6119.6C9—C13—C8123.21 (9)
C7—C6—H6119.6C14—C13—C8117.06 (9)
C8—C7—C6119.89 (10)C10—C14—C5121.40 (9)
C8—C7—H7120.1C10—C14—C13118.94 (9)
C6—C7—H7120.1C5—C14—C13119.66 (10)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···Cl1i0.952.953.8233 (11)154
Symmetry code: (i) x, y+5/2, z+1/2.
(I_ortho) 1,8-dichloroanthracene top
Crystal data top
C14H8Cl2F(000) = 504
Mr = 247.10Dx = 1.533 Mg m3
Orthorhombic, Pna21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2nCell parameters from 4800 reflections
a = 15.331 (2) Åθ = 2.5–36.5°
b = 3.8621 (5) ŵ = 0.57 mm1
c = 18.087 (2) ÅT = 90 K
V = 1070.9 (2) Å3Lath, yellow
Z = 40.33 × 0.20 × 0.08 mm
Data collection top
Nonius KappaCCD area-detector
diffractometer
4919 independent reflections
Radiation source: fine-focus sealed tube4717 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.027
ϕ and ω scansθmax = 36.5°, θmin = 2.9°
Absorption correction: multi-scan
(SCALEPACK; Otwinowski & Minor 1997)
h = 2524
Tmin = 0.835, Tmax = 0.956k = 46
24420 measured reflectionsl = 3029
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.028H-atom parameters constrained
wR(F2) = 0.072 w = 1/[σ2(Fo2) + (0.0379P)2 + 0.2409P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
4919 reflectionsΔρmax = 0.37 e Å3
146 parametersΔρmin = 0.27 e Å3
1 restraintAbsolute structure: Flack (1983), with 2320 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.42 (3)
Crystal data top
C14H8Cl2V = 1070.9 (2) Å3
Mr = 247.10Z = 4
Orthorhombic, Pna21Mo Kα radiation
a = 15.331 (2) ŵ = 0.57 mm1
b = 3.8621 (5) ÅT = 90 K
c = 18.087 (2) Å0.33 × 0.20 × 0.08 mm
Data collection top
Nonius KappaCCD area-detector
diffractometer
4919 independent reflections
Absorption correction: multi-scan
(SCALEPACK; Otwinowski & Minor 1997)
4717 reflections with I > 2σ(I)
Tmin = 0.835, Tmax = 0.956Rint = 0.027
24420 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.028H-atom parameters constrained
wR(F2) = 0.072Δρmax = 0.37 e Å3
S = 1.06Δρmin = 0.27 e Å3
4919 reflectionsAbsolute structure: Flack (1983), with 2320 Friedel pairs
146 parametersAbsolute structure parameter: 0.42 (3)
1 restraint
Special details top

Experimental. Nonius KappaCCD. The diffractometer was purchased through grant No. LEQSF(1999–2000)-ENH-TR-13, administered by the Louisiana Board of Regents.

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 (Å2) top
xyzUiso*/Ueq
Cl10.604407 (15)0.89356 (7)0.499979 (15)0.01757 (5)
Cl20.551245 (16)0.33625 (6)0.248928 (15)0.01766 (5)
C10.49318 (6)0.9843 (3)0.50488 (6)0.01308 (15)
C20.46168 (7)1.1505 (3)0.56601 (6)0.01533 (16)
H20.50001.21540.60490.018*
C30.37096 (8)1.2256 (3)0.57101 (6)0.01685 (17)
H30.34881.33880.61370.020*
C40.31555 (7)1.1368 (3)0.51515 (6)0.01620 (17)
H40.25521.18810.51940.019*
C50.26485 (7)0.6215 (3)0.26894 (6)0.01811 (18)
H50.20460.67720.27220.022*
C60.29585 (8)0.4562 (3)0.20762 (6)0.01972 (19)
H60.25700.39830.16860.024*
C70.38568 (8)0.3698 (3)0.20149 (6)0.01817 (18)
H70.40670.25550.15850.022*
C80.44159 (7)0.4517 (3)0.25761 (6)0.01466 (16)
C90.46959 (6)0.7135 (3)0.38141 (5)0.01289 (15)
H90.52980.65740.37790.015*
C100.29172 (7)0.8810 (3)0.39160 (6)0.01500 (16)
H100.23160.93900.39490.018*
C110.43834 (6)0.8835 (2)0.44444 (5)0.01204 (14)
C120.34733 (6)0.9675 (3)0.45031 (5)0.01332 (15)
C130.41335 (7)0.6252 (2)0.32344 (5)0.01301 (15)
C140.32225 (7)0.7117 (3)0.32837 (5)0.01399 (15)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.01212 (9)0.02056 (10)0.02002 (9)0.00001 (7)0.00155 (8)0.00242 (9)
Cl20.01851 (10)0.01666 (9)0.01781 (9)0.00126 (8)0.00319 (8)0.00108 (9)
C10.0122 (3)0.0125 (3)0.0145 (4)0.0002 (3)0.0002 (3)0.0011 (3)
C20.0178 (4)0.0132 (4)0.0149 (4)0.0002 (3)0.0002 (3)0.0000 (3)
C30.0204 (4)0.0141 (4)0.0160 (4)0.0017 (3)0.0041 (3)0.0001 (3)
C40.0151 (4)0.0146 (4)0.0189 (4)0.0019 (3)0.0042 (3)0.0020 (3)
C50.0173 (4)0.0160 (4)0.0210 (4)0.0015 (3)0.0057 (3)0.0034 (3)
C60.0242 (5)0.0156 (4)0.0194 (4)0.0016 (4)0.0077 (4)0.0012 (3)
C70.0249 (5)0.0149 (4)0.0148 (4)0.0013 (3)0.0030 (3)0.0008 (3)
C80.0173 (4)0.0122 (3)0.0146 (4)0.0003 (3)0.0004 (3)0.0010 (3)
C90.0127 (4)0.0124 (4)0.0136 (3)0.0003 (3)0.0005 (3)0.0015 (3)
C100.0122 (4)0.0145 (4)0.0183 (4)0.0001 (3)0.0004 (3)0.0027 (3)
C110.0122 (3)0.0108 (3)0.0131 (3)0.0004 (3)0.0010 (3)0.0015 (3)
C120.0125 (3)0.0122 (4)0.0153 (3)0.0003 (3)0.0015 (3)0.0029 (3)
C130.0142 (4)0.0112 (4)0.0136 (3)0.0005 (3)0.0007 (3)0.0022 (3)
C140.0136 (4)0.0120 (4)0.0164 (4)0.0013 (3)0.0019 (3)0.0030 (3)
Geometric parameters (Å, º) top
Cl1—C11.7431 (10)C6—C71.4214 (18)
Cl2—C81.7463 (11)C6—H60.9500
C1—C21.3666 (15)C7—C81.3657 (15)
C1—C111.4330 (15)C7—H70.9500
C2—C31.4237 (17)C8—C131.4334 (14)
C2—H20.9500C9—C131.3996 (14)
C3—C41.3637 (16)C9—C111.4001 (14)
C3—H30.9500C9—H90.9500
C4—C121.4284 (15)C10—C141.3981 (15)
C4—H40.9500C10—C121.4022 (15)
C5—C61.3650 (17)C10—H100.9500
C5—C141.4322 (15)C11—C121.4364 (14)
C5—H50.9500C13—C141.4388 (15)
C2—C1—C11122.51 (9)C7—C8—C13122.42 (10)
C2—C1—Cl1118.77 (8)C7—C8—Cl2118.57 (8)
C11—C1—Cl1118.72 (8)C13—C8—Cl2119.00 (8)
C1—C2—C3119.49 (10)C13—C9—C11120.89 (9)
C1—C2—H2120.3C13—C9—H9119.6
C3—C2—H2120.3C11—C9—H9119.6
C4—C3—C2120.68 (10)C14—C10—C12121.83 (9)
C4—C3—H3119.7C14—C10—H10119.1
C2—C3—H3119.7C12—C10—H10119.1
C3—C4—C12120.72 (10)C9—C11—C1123.21 (9)
C3—C4—H4119.6C9—C11—C12119.90 (9)
C12—C4—H4119.6C1—C11—C12116.89 (9)
C6—C5—C14120.64 (11)C10—C12—C4121.57 (9)
C6—C5—H5119.7C10—C12—C11118.74 (9)
C14—C5—H5119.7C4—C12—C11119.69 (9)
C5—C6—C7120.70 (10)C9—C13—C8123.37 (9)
C5—C6—H6119.6C9—C13—C14119.68 (9)
C7—C6—H6119.6C8—C13—C14116.95 (9)
C8—C7—C6119.72 (10)C10—C14—C5121.47 (10)
C8—C7—H7120.1C10—C14—C13118.96 (9)
C6—C7—H7120.1C5—C14—C13119.57 (10)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···Cl1i0.952.843.7207 (11)154
C7—H7···Cl1ii0.952.933.7870 (12)151
Symmetry codes: (i) x1/2, y+5/2, z; (ii) x+1, y+1, z1/2.

Experimental details

(I_mono)(I_ortho)
Crystal data
Chemical formulaC14H8Cl2C14H8Cl2
Mr247.10247.10
Crystal system, space groupMonoclinic, P21/cOrthorhombic, Pna21
Temperature (K)10090
a, b, c (Å)19.0070 (14), 3.8621 (3), 15.1370 (11)15.331 (2), 3.8621 (5), 18.087 (2)
α, β, γ (°)90, 107.4103 (15), 9090, 90, 90
V3)1060.25 (14)1070.9 (2)
Z44
Radiation typeMo KαMo Kα
µ (mm1)0.570.57
Crystal size (mm)0.20 × 0.05 × 0.040.33 × 0.20 × 0.08
Data collection
DiffractometerBruker SMART APEX2 CCD area-detector
diffractometer
Nonius KappaCCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2009)
Multi-scan
(SCALEPACK; Otwinowski & Minor 1997)
Tmin, Tmax0.894, 0.9770.835, 0.956
No. of measured, independent and
observed [I > 2σ(I)] reflections
56651, 3700, 3433 24420, 4919, 4717
Rint0.0270.027
(sin θ/λ)max1)0.7460.836
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.028, 0.083, 1.15 0.028, 0.072, 1.06
No. of reflections37004919
No. of parameters145146
No. of restraints01
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.53, 0.200.37, 0.27
Absolute structure?Flack (1983), with 2320 Friedel pairs
Absolute structure parameter?0.42 (3)

Computer programs: APEX2 (Bruker, 2011), COLLECT (Nonius, 2000), SAINT (Bruker, 2011), DENZO and SCALEPACK (Otwinowski & Minor 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) for (I_mono) top
D—H···AD—HH···AD···AD—H···A
C4—H4···Cl1i0.952.953.8233 (11)154.1
Symmetry code: (i) x, y+5/2, z+1/2.
Hydrogen-bond geometry (Å, º) for (I_ortho) top
D—H···AD—HH···AD···AD—H···A
C4—H4···Cl1i0.952.843.7207 (11)154.3
C7—H7···Cl1ii0.952.933.7870 (12)150.7
Symmetry codes: (i) x1/2, y+5/2, z; (ii) x+1, y+1, z1/2.
 

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