In situ high-pressure crystallization and compression of halogen contacts in dichloromethane

The structure of dichloromethane, CH₂Cl₂, crystallized in situ in a diamond–anvil cell, has been determined by single-crystal X-ray diffraction at 1.33 and 1.63 GPa. The pressure-frozen crystal was determined to be orthorhombic, with the space group Pbcn, and isostructural with the low-temperature phase at 0.1 MPa. The CH₂Cl₂ molecules are located on one set of crystallographic twofold axes. The characteristics determined for the CH₂Cl₂ crystal (compression of the close intermolecular contacts, molecular association and the crystal habit of dichloromethane) suggest that the crystal cohesion forces are dominated by H...Cl interactions rather than by Cl...Cl attractions.

Computing details

For both compounds, data collection: CrysAlis (Oxford Diffraction, 2004); cell refinement: CrysAlis (Oxford Diffraction, 2004); data reduction: CrysAlis (Oxford Diffraction, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1990); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

(1dcm) dichloromethane

Crystal data

CH2Cl2	Dx = 1.920 Mg m^−3
Mr = 84.93	Melting point: 176 K
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 1459 reflections
a = 3.984 (1) Å	θ = 5–30°
b = 7.863 (2) Å	µ = 1.86 mm^−1
c = 9.357 (2) Å	T = 293 K
V = 293.12 (12) Å^3	Cylinder, colourless
Z = 4	0.42 × 0.42 × 0.15 × 0.21 (radius) mm
F(000) = 168

Data collection

Kuma KM4CCD κ geometry diffractometer	219 independent reflections
Radiation source: fine-focus sealed tube	188 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.096
ω scans	θmax = 29.6°, θmin = 5.2°
Absorption correction: analytical Katrusiak, A. (2003). REDSHADE - Program for correcting reflections intensities for DAC absorption, gasket shadowing and sample crystal absorption. Adam Mickiewicz University, Poznań. Katrusiak, A. (2004). Z. Kristallogr. 219, 461-467	h = −5→5
Tmin = 0.50, Tmax = 0.85	k = −10→10
2203 measured reflections	l = −5→5

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)] = 0.061	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.190	w = 1/[σ^2(Fo^2) + (0.1099P)^2 + 0.0415P] where P = (Fo^2 + 2Fc^2)/3
S = 1.28	(Δ/σ)max < 0.001
219 reflections	Δρmax = 0.30 e Å^−3
20 parameters	Δρmin = −0.29 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.11 (4)

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
Cl1	0.1889 (4)	0.14840 (17)	0.1165 (2)	0.0499 (16)
C1	0.0000	0.0223 (8)	0.2500	0.037 (4)
H1	0.184 (19)	−0.061 (11)	0.275 (18)	0.09 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0594 (12)	0.0515 (11)	0.039 (5)	−0.0122 (4)	−0.0052 (6)	0.0038 (8)
C1	0.050 (3)	0.040 (3)	0.020 (14)	0.000	0.002 (3)	0.000

Geometric parameters (Å, º)

Cl1—C1	1.765 (4)	C1—H1	1.01 (10)
Cl1^i—C1—Cl1	111.6 (3)	Cl1—C1—H1	103 (7)
Cl1^i—C1—H1	121 (9)

Symmetry code: (i) −x, y, −z+1/2.

(2dcm) dichloromethane

Crystal data

CH2Cl2	Dx = 1.972 Mg m^−3
Mr = 84.93	Melting point: 176 K
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 1495 reflections
a = 3.924 (1) Å	θ = 5–30°
b = 7.793 (2) Å	µ = 1.91 mm^−1
c = 9.335 (2) Å	T = 293 K
V = 285.46 (12) Å^3	Cylinder, colourless
Z = 4	0.42 × 0.42 × 0.14 × 0.21 (radius) mm
F(000) = 168

Data collection

Kuma KM4CCD κ geometry diffractometer	174 independent reflections
Radiation source: fine-focus sealed tube	157 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.068
ω scans	θmax = 29.9°, θmin = 5.2°
Absorption correction: analytical Katrusiak, A. (2003). REDSHADE - Program for correcting reflections intensities for DAC absorption, gasket shadowing and sample crystal absorption. Adam Mickiewicz University, Poznań. Katrusiak, A. (2004). Z. Kristallogr. 219, 461-467	h = −5→5
Tmin = 0.46, Tmax = 0.86	k = −10→10
2063 measured reflections	l = −4→4

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)] = 0.055	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.135	H atoms treated by a mixture of independent and constrained refinement
S = 1.25	w = 1/[σ^2(Fo^2) + (0.0601P)^2 + 0.5145P] where P = (Fo^2 + 2Fc^2)/3
174 reflections	(Δ/σ)max < 0.001
19 parameters	Δρmax = 0.29 e Å^−3
0 restraints	Δρmin = −0.28 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
Cl1	0.1903 (4)	0.14808 (17)	0.1156 (4)	0.0404 (19)
C1	0.0000	0.0202 (8)	0.2500	0.028 (9)
H1	0.181 (19)	−0.071 (9)	0.31 (2)	0.08 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0467 (9)	0.0424 (8)	0.032 (6)	−0.0098 (4)	−0.0013 (11)	0.0025 (9)
C1	0.049 (4)	0.029 (3)	0.01 (3)	0.000	−0.005 (7)	0.000

Geometric parameters (Å, º)

Cl1—C1	1.769 (4)	C1—H1	1.13 (12)
Cl1^i—C1—Cl1	111.4 (4)	Cl1—C1—H1	115 (7)
Cl1^i—C1—H1	107 (9)

Symmetry code: (i) −x, y, −z+1/2.