Halogen...halogen interactions in pressure-frozen ortho- and meta-dichlorobenzene isomers

Isomers 1,2-dichlorobenzene (o-DCB) and 1,3-dichlorobenzene (m-DCB) were high-pressure frozen in-situ in a Merrill–Bassett diamond–anvil cell and their structures determined at room temperature and at 0.18 (5) GPa for o-DCB, and 0.17 (5) GPa for m-DCB by single-crystal X-ray diffraction. The patterns of halogen...halogen intermolecular interactions in these structures can be considered to be the main cohesive forces responsible for the molecular arrangements in these crystals. The molecular packing of dichlorobenzene isomers, including three polymorphs of 1,4-dichlorobenzene (p-DCB), have been compared and relations between their molecular symmetry, packing arrangements, intermolecular interactions and melting points discussed. The topology of the crystal packing in dichlorobenzene isomers results from the interplay of the molecular shape, steric hindrances and intermolecular interactions. The non-planar arrangement of the dichlorobenzene molecules in the crystal structures can be justified by the distributions of the electrostatic potential on molecular surfaces, which determines electrostatic intermolecular interactions.

Computing details

For both compounds, data collection: CrysAlis CCD (Oxford Diffraction, 2004); cell refinement: CrysAlis RED (Oxford Diffraction, 2004); data reduction: CrysAlis RED (Oxford Diffraction, 2004); REDSHABS (Katrusiak, A. 2003); program(s) used to solve structure: SHELXS–97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL–97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1990); software used to prepare material for publication: SHELXL–97 (Sheldrick, 1997).

Figures

(oDCB) 1,2-dichlorobenzene ortho-dichlorobenzene

Crystal data

C6H4Cl2	F(000) = 296
Mr = 146.99	Dx = 1.558 Mg m^−3
Monoclinic, P21/n	Melting point: 256.4 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 3.9274 (4) Å	Cell parameters from 1765 reflections
b = 10.5678 (10) Å	θ = 2.3–25.7°
c = 15.199 (9) Å	µ = 0.91 mm^−1
β = 96.70 (2)°	T = 295 K
V = 626.5 (4) Å^3	Column, colourless
Z = 4	0.44 × 0.30 × 0.12 mm

Data collection

KM-4 CCD diffractometer	431 independent reflections
Radiation source: fine-focus sealed tube	133 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.069
ϕ– and ω–scans	θmax = 25.0°, θmin = 3.9°
Absorption correction: analytical Correction for absorption of the diamond-anvil cell and the sample were made using program REDSHABS (Katrusiak, A. (2003) REDSHABS. Adam Mickiewicz University Poznań; Katrusiak, A. (2004) Z. Kristallogr. 219, 461-467).	h = −4→4
Tmin = 0.43, Tmax = 0.79	k = −12→12
3835 measured reflections	l = −6→6

Refinement

Refinement on F^2	Primary atom site location: Patterson
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.037	H-atom parameters constrained
S = 0.63	w = 1/[σ^2(Fo^2) + (0.0138P)^2] where P = (Fo^2 + 2Fc^2)/3
431 reflections	(Δ/σ)max < 0.001
73 parameters	Δρmax = 0.21 e Å^−3
111 restraints	Δρmin = −0.22 e Å^−3

Special details

Experimental. Data were collected at pressure of 0.18 GPa (180000 kPa) with the crystal obtained by the in situ high-pressure crystallization technique Pressure was determined by monitoring the shift of the ruby R1-fluorescence line.

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.

The DAC imposes severe restrictions on which reflections can be collected, resulting in a low data:parameter ratio.

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

	x	y	z	Uiso*/Ueq
Cl1	−0.0111 (6)	0.80323 (19)	0.7942 (5)	0.100 (4)
Cl2	−0.2769 (4)	0.99043 (12)	0.6415 (3)	0.0646 (19)
C1	0.0274 (16)	0.7634 (7)	0.6869 (15)	0.051 (4)
C2	−0.103 (3)	0.8469 (7)	0.6220 (11)	0.054 (5)
C3	−0.073 (2)	0.8126 (8)	0.5341 (13)	0.060 (5)
H3	−0.1529	0.8670	0.4882	0.072*
C4	0.0759 (13)	0.6978 (6)	0.5150 (10)	0.068 (4)
H4	0.0961	0.6751	0.4567	0.082*
C5	0.191 (2)	0.6195 (7)	0.5830 (10)	0.065 (5)
H5	0.2894	0.5425	0.5705	0.078*
C6	0.166 (2)	0.6512 (6)	0.6701 (11)	0.058 (5)
H6	0.2438	0.5963	0.7159	0.070*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.1007 (15)	0.0817 (13)	0.121 (14)	−0.0101 (12)	0.024 (3)	−0.002 (3)
Cl2	0.0658 (7)	0.0566 (8)	0.071 (6)	0.0029 (9)	0.0039 (11)	0.004 (2)
C1	0.044 (3)	0.060 (3)	0.047 (13)	−0.003 (3)	−0.002 (8)	−0.011 (6)
C2	0.050 (3)	0.051 (3)	0.063 (15)	−0.003 (3)	0.017 (8)	0.005 (6)
C3	0.052 (4)	0.070 (3)	0.054 (13)	−0.006 (3)	−0.009 (9)	0.004 (7)
C4	0.065 (4)	0.082 (3)	0.061 (13)	−0.014 (3)	0.024 (7)	−0.016 (6)
C5	0.056 (4)	0.061 (4)	0.079 (14)	0.002 (4)	0.018 (8)	−0.020 (5)
C6	0.055 (4)	0.051 (3)	0.068 (13)	0.000 (3)	0.008 (10)	−0.002 (5)

Geometric parameters (Å, º)

Cl1—C1	1.71 (2)	C4—C5	1.359 (16)
C1—C2	1.376 (18)	C5—C6	1.379 (17)
C1—C6	1.342 (10)	C3—H3	0.9300
Cl2—C2	1.704 (9)	C4—H4	0.9300
C2—C3	1.403 (19)	C5—H5	0.9300
C3—C4	1.391 (11)	C6—H6	0.9300
C1—C2—Cl2	124.7 (13)	C6—C1—C2	123.7 (17)
C1—C2—C3	116.8 (11)	C1—C6—H6	120.9
C1—C6—C5	118.2 (14)	C2—C3—H3	119.7
C2—C1—Cl1	117.3 (9)	C3—C4—H4	120.6
C3—C2—Cl2	118.4 (9)	C4—C3—H3	119.7
C4—C3—C2	120.6 (14)	C4—C5—H5	119.1
C4—C5—C6	121.8 (9)	C5—C4—H4	120.6
C5—C4—C3	118.8 (14)	C5—C6—H6	120.9
C6—C1—Cl1	118.9 (14)	C6—C5—H5	119.1
C1—C2—C3—C4	1.3 (17)	C6—C1—C2—Cl2	−179.4 (7)
C2—C1—C6—C5	2.3 (15)	Cl1—C1—C2—C3	−179.4 (10)
C2—C3—C4—C5	0.1 (16)	Cl1—C1—C6—C5	179.1 (8)
C3—C4—C5—C6	−0.4 (17)	Cl1—C1—C2—Cl2	3.9 (10)
C4—C5—C6—C1	−0.8 (18)	Cl2—C2—C3—C4	178.3 (4)
C6—C1—C2—C3	−2.6 (14)

(mDCB) 1,3-dichlorobenzene meta-dichlorobenzene

Crystal data

C6H4Cl2	F(000) = 592
Mr = 146.99	Dx = 1.541 Mg m^−3
Monoclinic, P21/c	Melting point: 248.3 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 3.9163 (6) Å	Cell parameters from 2167 reflections
b = 12.532 (5) Å	θ = 2.3–22.6°
c = 25.849 (5) Å	µ = 0.90 mm^−1
β = 93.098 (14)°	T = 295 K
V = 1266.8 (6) Å^3	Column, colourless
Z = 8	0.40 × 0.25 × 0.12 mm

Data collection

KM-4 CCD diffractometer	800 independent reflections
Radiation source: fine-focus sealed tube	627 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.091
ϕ– and ω–scans	θmax = 25.0°, θmin = 2.9°
Absorption correction: analytical Correction for absorption of the diamond-anvil cell and the sample were made using program REDSHABS (Katrusiak, A. (2003) REDSHABS. Adam Mickiewicz University Poznań; Katrusiak, A. (2004) Z. Kristallogr. 219, 461-467).	h = −4→4
Tmin = 0.40, Tmax = 0.82	k = −9→7
4205 measured reflections	l = −27→27

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.109	H-atom parameters constrained
wR(F^2) = 0.129	w = 1/[σ^2(Fo^2) + (0.023P)^2 + 1.956P] where P = (Fo^2 + 2Fc^2)/3
S = 1.47	(Δ/σ)max < 0.001
800 reflections	Δρmax = 0.18 e Å^−3
146 parameters	Δρmin = −0.19 e Å^−3
222 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: Patterson	Extinction coefficient: 0.018 (2)

Special details

Experimental. Data were collected at pressure of 0.17 GPa (170000 kPa) with the crystal obtained by the in situ high-pressure crystallization technique Pressure was determined by monitoring the shift of the ruby R1-fluorescence line.

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.

The DAC imposes severe restrictions on which reflections can be collected, resulting in a low data:parameter ratio.

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

	x	y	z	Uiso*/Ueq
Cl1	0.2856 (7)	0.5602 (4)	0.09131 (11)	0.076 (2)
Cl2	−0.2206 (7)	0.2061 (4)	0.17370 (10)	0.0707 (19)
Cl3	0.4221 (7)	1.0049 (4)	0.25859 (9)	0.076 (2)
Cl4	0.3740 (7)	0.9352 (4)	0.05431 (10)	0.0797 (19)
C1	0.153 (2)	0.4284 (15)	0.0842 (4)	0.050 (4)
C2	0.030 (2)	0.3750 (13)	0.1259 (4)	0.045 (4)
H2	0.0177	0.4096	0.1576	0.054*
C3	−0.074 (2)	0.2716 (13)	0.1208 (4)	0.045 (4)
C4	−0.050 (2)	0.2198 (12)	0.0746 (4)	0.057 (4)
H4	−0.1155	0.1487	0.0710	0.069*
C5	0.074 (3)	0.2752 (13)	0.0334 (4)	0.063 (4)
H5	0.0860	0.2406	0.0017	0.076*
C6	0.180 (3)	0.3784 (14)	0.0373 (4)	0.061 (4)
H6	0.2684	0.4137	0.0093	0.074*
C7	0.510 (2)	0.9219 (13)	0.2060 (4)	0.048 (4)
C8	0.410 (2)	0.9590 (13)	0.1571 (3)	0.047 (4)
H8	0.2969	1.0235	0.1516	0.057*
C9	0.493 (2)	0.8925 (13)	0.1168 (4)	0.048 (4)
C10	0.664 (3)	0.7977 (13)	0.1237 (4)	0.058 (4)
H10	0.7198	0.7566	0.0954	0.069*
C11	0.752 (3)	0.7650 (13)	0.1732 (4)	0.062 (4)
H11	0.8634	0.7001	0.1788	0.074*
C12	0.677 (3)	0.8283 (13)	0.2149 (4)	0.057 (4)
H12	0.7392	0.8070	0.2486	0.069*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.074 (2)	0.067 (8)	0.088 (3)	−0.010 (3)	0.0043 (15)	0.008 (2)
Cl2	0.0676 (18)	0.070 (7)	0.075 (2)	−0.014 (2)	0.0054 (15)	0.014 (2)
Cl3	0.083 (2)	0.090 (7)	0.055 (2)	0.001 (2)	0.0121 (14)	−0.015 (2)
Cl4	0.101 (2)	0.086 (7)	0.052 (2)	−0.017 (3)	−0.0003 (15)	−0.0020 (19)
C1	0.041 (5)	0.057 (12)	0.053 (6)	−0.012 (7)	0.002 (5)	0.003 (6)
C2	0.036 (6)	0.054 (12)	0.045 (5)	−0.011 (7)	0.000 (4)	−0.004 (6)
C3	0.033 (6)	0.053 (12)	0.049 (5)	−0.011 (7)	−0.003 (5)	0.002 (6)
C4	0.056 (6)	0.055 (12)	0.062 (7)	−0.002 (7)	0.010 (5)	−0.013 (6)
C5	0.064 (7)	0.068 (12)	0.058 (6)	−0.003 (8)	0.012 (5)	−0.012 (7)
C6	0.062 (7)	0.071 (12)	0.052 (6)	−0.010 (8)	0.011 (5)	0.004 (7)
C7	0.048 (6)	0.050 (12)	0.047 (5)	−0.003 (7)	0.017 (5)	−0.001 (6)
C8	0.052 (5)	0.038 (12)	0.053 (6)	−0.006 (6)	0.010 (5)	0.003 (5)
C9	0.049 (6)	0.046 (12)	0.051 (6)	−0.012 (7)	0.010 (5)	−0.005 (6)
C10	0.063 (7)	0.044 (12)	0.067 (6)	−0.011 (7)	0.020 (6)	−0.007 (7)
C11	0.055 (6)	0.049 (12)	0.084 (7)	0.008 (7)	0.020 (6)	0.007 (6)
C12	0.056 (6)	0.057 (13)	0.060 (6)	0.002 (7)	0.006 (5)	0.010 (6)

Geometric parameters (Å, º)

Cl1—C1	1.739 (17)	Cl3—C7	1.761 (13)
C1—C2	1.380 (13)	C7—C8	1.383 (11)
C1—C6	1.373 (13)	C7—C12	1.357 (15)
Cl2—C3	1.719 (12)	Cl4—C9	1.741 (11)
C2—C3	1.362 (15)	C8—C9	1.384 (13)
C3—C4	1.368 (12)	C9—C10	1.372 (15)
C4—C5	1.382 (13)	C10—C11	1.369 (11)
C5—C6	1.360 (16)	C11—C12	1.383 (13)
C2—H2	0.9300	C8—H8	0.9300
C4—H4	0.9300	C10—H10	0.9300
C5—H5	0.9300	C11—H11	0.9300
C6—H6	0.9300	C12—H12	0.9300
C2—C3—Cl2	119.2 (9)	C8—C9—Cl4	116.8 (11)
C3—C2—C1	120.1 (12)	C7—C8—C9	114.8 (12)
C5—C6—C1	117.5 (13)	C7—C12—C11	119.0 (12)
C2—C1—Cl1	119.5 (10)	C8—C7—Cl3	116.8 (11)
C4—C3—Cl2	120.6 (11)	C10—C9—Cl4	119.4 (9)
C2—C3—C4	120.1 (11)	C10—C9—C8	123.8 (12)
C6—C5—C4	122.7 (13)	C10—C11—C12	120.2 (14)
C3—C4—C5	118.6 (14)	C11—C10—C9	118.5 (12)
C6—C1—Cl1	119.4 (10)	C12—C7—Cl3	119.5 (9)
C6—C1—C2	121.1 (15)	C12—C7—C8	123.7 (12)
C1—C2—H2	120.0	C7—C8—H8	122.6
C1—C6—H6	121.3	C7—C12—H12	120.5
C3—C2—H2	120.0	C9—C8—H8	122.6
C3—C4—H4	120.7	C9—C10—H10	120.7
C4—C5—H5	118.7	C10—C11—H11	119.9
C5—C4—H4	120.7	C11—C10—H10	120.7
C5—C6—H6	121.3	C11—C12—H12	120.5
C6—C5—H5	118.7	C12—C11—H11	119.9
C1—C2—C3—C4	1.5 (17)	C8—C9—C10—C11	1.7 (19)
C1—C2—C3—Cl2	179.0 (7)	C9—C10—C11—C12	−1.7 (18)
C2—C1—C6—C5	1.5 (18)	C10—C11—C12—C7	1.1 (17)
C2—C3—C4—C5	−1.5 (17)	Cl1—C1—C2—C3	−179.9 (10)
C3—C4—C5—C6	1.5 (18)	Cl1—C1—C6—C5	179.9 (11)
C4—C5—C6—C1	−2 (2)	Cl2—C3—C4—C5	−178.9 (8)
C6—C1—C2—C3	−1.5 (16)	C12—C7—C8—C9	0.3 (16)
C7—C8—C9—C10	−1.0 (17)	Cl3—C7—C8—C9	178.2 (8)
C7—C8—C9—Cl4	180.0 (8)	Cl3—C7—C12—C11	−178.2 (8)
C8—C7—C12—C11	−0.4 (19)	Cl4—C9—C10—C11	−179.3 (8)