Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270111056265/lg3074sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270111056265/lg3074Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270111056265/lg3074IIsup3.hkl |
CCDC references: 867009; 867010
For related literature, see: Bond (2003); Bruker (2000); Choudhury et al. (2004); Crawford et al. (2009); Daniel & McHale (1997); Etter et al. (1990); Ibberson et al. (2008); Spackman & McKinnon (2002); Thomas et al. (1966); Vasylyeva et al. (2010); Wiechert & Mootz (1999); Yufit & Howard (2005, 2010, 2012).
Mixtures of CF and DCM with DMSO (in 3:1 and 4:1 molar ratios, respectively) were sealed in 0.3 mm borosilicate glass capillaries which were mounted on a diffractometer using a special attachment (Yufit & Howard, 2005). The first mixture was cooled to 130 K and then warmed to 161 K when spontaneous crystallization occurred. The polycrystalline sample of (I) obtained was warmed slowly to 198 K until only a few crystalline seeds could be seen in the capillary, and was then cooled slowly to 185 K. At this temperature, the data were collected. In the case of the second mixture, it solidified at 130 K and a suitable crystal of (II) grew at 167 K. The data were collected at this temperature. In both cases, several spatially separated crystals were present in the capillaries and the reflections from one of them were manually picked up for indexing and subsequent integration using the program RLATT (Bruker, 2000).
In both cases, the data were collected using two 180° ω scans in 0.3° steps. Between scans, the crystal was manually rotated by 180° around the ω axis. This data-collection mode is necessary because of the design of the mounting attachment and does not provide full coverage (Yufit & Howard, 2005); the data coverage was 0.795 of a full sphere for (I) (θ < 30°) and 0.770 (θ < 29.99°) of a full sphere for (II). Two and eight reflections for structures (I) and (II), respectively, were omitted from the refinement as they overlapped with reflections from other crystals present in the capillaries.
The H atoms of (I) were located in a difference Fourier map and freely isotropically refined. The H atoms in (II) were placed in calculated positions and refined using a riding model, with C—H distances of 0.99 or 0.98 Å, and with Uiso(H) = 1.2 or 1.5Ueq(C), for methylene and methyl groups, respectively.
For both compounds, data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003). Program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) for (I); smtbx-flip (Bourhis et al., 2009) for (II). For both compounds, program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).
2CHCl3·C2H6OS | Dx = 1.693 Mg m−3 |
Mr = 316.86 | Melting point = 197–199 K |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 5.9679 (3) Å | Cell parameters from 2605 reflections |
b = 9.0041 (6) Å | θ = 2.4–30.9° |
c = 23.1424 (15) Å | µ = 1.51 mm−1 |
β = 91.63 (1)° | T = 185 K |
V = 1243.07 (13) Å3 | Cylinder, colourless |
Z = 4 | 0.4 × 0.3 × 0.3 × 0.15 (radius) mm |
F(000) = 632 |
Bruker SMART 6000 CCD area-detector diffractometer | 2883 independent reflections |
Radiation source: sealed X-ray tube | 2481 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.020 |
Detector resolution: 5.6 pixels mm-1 | θmax = 30.0°, θmin = 1.8° |
ω scans | h = −5→5 |
Absorption correction: multi-scan (SADABS; Bruker, 2006) | k = −12→12 |
Tmin = 0.437, Tmax = 0.745 | l = −29→32 |
10789 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.022 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.056 | All H-atom parameters refined |
S = 1.04 | w = 1/[σ2(Fo2) + (0.020P)2 + 0.4P] where P = (Fo2 + 2Fc2)/3 |
2883 reflections | (Δ/σ)max = 0.001 |
141 parameters | Δρmax = 0.26 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
2CHCl3·C2H6OS | V = 1243.07 (13) Å3 |
Mr = 316.86 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 5.9679 (3) Å | µ = 1.51 mm−1 |
b = 9.0041 (6) Å | T = 185 K |
c = 23.1424 (15) Å | 0.4 × 0.3 × 0.3 × 0.15 (radius) mm |
β = 91.63 (1)° |
Bruker SMART 6000 CCD area-detector diffractometer | 2883 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2006) | 2481 reflections with I > 2σ(I) |
Tmin = 0.437, Tmax = 0.745 | Rint = 0.020 |
10789 measured reflections |
R[F2 > 2σ(F2)] = 0.022 | 0 restraints |
wR(F2) = 0.056 | All H-atom parameters refined |
S = 1.04 | Δρmax = 0.26 e Å−3 |
2883 reflections | Δρmin = −0.25 e Å−3 |
141 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 1.04736 (8) | 0.94036 (5) | 0.416255 (18) | 0.04988 (12) | |
Cl2 | 1.01737 (9) | 0.69537 (5) | 0.49621 (2) | 0.05408 (12) | |
Cl3 | 0.61483 (8) | 0.84486 (5) | 0.455619 (17) | 0.04890 (12) | |
Cl4 | 1.01457 (8) | 0.40462 (5) | 0.200390 (19) | 0.04952 (12) | |
Cl5 | 0.58598 (7) | 0.27670 (5) | 0.228415 (16) | 0.04463 (11) | |
Cl6 | 0.99018 (8) | 0.17774 (5) | 0.288015 (19) | 0.05099 (12) | |
S1 | 0.53475 (7) | 0.44368 (4) | 0.407369 (14) | 0.03611 (10) | |
O1 | 0.7434 (2) | 0.48489 (12) | 0.37599 (5) | 0.0439 (3) | |
C1 | 0.4874 (4) | 0.25087 (18) | 0.39297 (8) | 0.0451 (4) | |
C1S | 0.8853 (3) | 0.78752 (16) | 0.43748 (6) | 0.0349 (3) | |
C2 | 0.3064 (3) | 0.5153 (2) | 0.36466 (8) | 0.0470 (4) | |
C2S | 0.8522 (3) | 0.33089 (15) | 0.25588 (6) | 0.0330 (3) | |
H1A | 0.483 (3) | 0.236 (2) | 0.3534 (8) | 0.051 (5)* | |
H1B | 0.604 (4) | 0.201 (2) | 0.4115 (9) | 0.060 (6)* | |
H1C | 0.351 (4) | 0.225 (2) | 0.4100 (9) | 0.068 (6)* | |
H1S | 0.871 (3) | 0.7209 (18) | 0.4073 (6) | 0.031 (4)* | |
H2A | 0.320 (4) | 0.621 (3) | 0.3671 (9) | 0.072 (7)* | |
H2B | 0.321 (3) | 0.481 (2) | 0.3253 (9) | 0.060 (6)* | |
H2C | 0.168 (4) | 0.481 (2) | 0.3789 (9) | 0.057 (6)* | |
H2S | 0.830 (3) | 0.4018 (18) | 0.2853 (7) | 0.034 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0547 (3) | 0.0445 (2) | 0.0506 (2) | −0.01352 (18) | 0.00350 (18) | 0.00219 (16) |
Cl2 | 0.0571 (4) | 0.0422 (2) | 0.0622 (3) | 0.00923 (18) | −0.0102 (2) | 0.01043 (18) |
Cl3 | 0.0377 (3) | 0.0632 (3) | 0.0460 (2) | 0.00891 (19) | 0.00367 (17) | 0.00106 (17) |
Cl4 | 0.0512 (3) | 0.0434 (2) | 0.0549 (2) | 0.00108 (17) | 0.01816 (19) | 0.00968 (16) |
Cl5 | 0.0396 (3) | 0.0499 (2) | 0.04394 (19) | −0.00377 (17) | −0.00553 (16) | 0.00267 (15) |
Cl6 | 0.0510 (3) | 0.0449 (2) | 0.0564 (2) | 0.00523 (18) | −0.00885 (19) | 0.01383 (17) |
S1 | 0.0391 (3) | 0.03771 (17) | 0.03165 (16) | −0.00507 (15) | 0.00339 (14) | −0.00669 (13) |
O1 | 0.0342 (8) | 0.0440 (6) | 0.0539 (6) | −0.0092 (5) | 0.0079 (5) | −0.0125 (5) |
C1 | 0.0588 (15) | 0.0351 (8) | 0.0417 (8) | −0.0067 (7) | 0.0036 (8) | 0.0016 (6) |
C1S | 0.0355 (11) | 0.0320 (6) | 0.0371 (7) | −0.0007 (6) | −0.0002 (6) | −0.0058 (5) |
C2 | 0.0395 (13) | 0.0440 (9) | 0.0577 (10) | −0.0003 (7) | 0.0042 (8) | 0.0023 (7) |
C2S | 0.0352 (10) | 0.0314 (6) | 0.0325 (6) | 0.0011 (6) | 0.0014 (6) | −0.0005 (5) |
Cl1—C1S | 1.7599 (15) | C1—H1A | 0.924 (19) |
Cl2—C1S | 1.7595 (16) | C1—H1B | 0.93 (2) |
Cl3—C1S | 1.7571 (16) | C1—H1C | 0.94 (2) |
Cl4—C2S | 1.7605 (15) | C1S—H1S | 0.922 (15) |
Cl5—C2S | 1.7632 (17) | C2—H2A | 0.95 (2) |
Cl6—C2S | 1.7601 (15) | C2—H2B | 0.97 (2) |
S1—O1 | 1.5057 (12) | C2—H2C | 0.95 (2) |
S1—C1 | 1.7888 (16) | C2S—H2S | 0.945 (16) |
S1—C2 | 1.781 (2) | ||
O1—S1—C1 | 106.13 (8) | Cl3—C1S—H1S | 107.9 (10) |
O1—S1—C2 | 105.86 (8) | S1—C2—H2A | 105.4 (14) |
C2—S1—C1 | 97.67 (10) | S1—C2—H2B | 108.5 (12) |
S1—C1—H1A | 108.9 (12) | S1—C2—H2C | 110.4 (13) |
S1—C1—H1B | 105.9 (13) | H2A—C2—H2B | 111.2 (17) |
S1—C1—H1C | 107.3 (13) | H2A—C2—H2C | 112.1 (17) |
H1A—C1—H1B | 112.7 (17) | H2B—C2—H2C | 109.1 (17) |
H1A—C1—H1C | 112.2 (18) | Cl4—C2S—Cl5 | 110.52 (8) |
H1B—C1—H1C | 109.6 (19) | Cl4—C2S—H2S | 111.2 (10) |
Cl1—C1S—H1S | 109.7 (10) | Cl5—C2S—H2S | 107.8 (10) |
Cl2—C1S—Cl1 | 110.29 (9) | Cl6—C2S—Cl4 | 110.07 (9) |
Cl2—C1S—H1S | 107.9 (10) | Cl6—C2S—Cl5 | 109.96 (8) |
Cl3—C1S—Cl1 | 110.65 (8) | Cl6—C2S—H2S | 107.2 (10) |
Cl3—C1S—Cl2 | 110.39 (8) |
D—H···A | D—H | H···A | D···A | D—H···A |
C1S—H1S···O1 | 0.922 (15) | 2.365 (16) | 3.1779 (18) | 146.9 (13) |
C2—H2C···O1i | 0.95 (2) | 2.53 (2) | 3.389 (2) | 149.9 (17) |
C2S—H2S···O1 | 0.945 (16) | 2.301 (16) | 3.1897 (17) | 156.4 (13) |
Symmetry code: (i) x−1, y, z. |
CH2Cl2·C2H6OS | F(000) = 168 |
Mr = 163.05 | Dx = 1.467 Mg m−3 |
Triclinic, P1 | Melting point = 168–170 K |
a = 6.6800 (12) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 7.7862 (13) Å | Cell parameters from 1764 reflections |
c = 8.0017 (15) Å | θ = 2.6–30.0° |
α = 78.019 (10)° | µ = 1.06 mm−1 |
β = 80.008 (10)° | T = 167 K |
γ = 65.665 (10)° | Cylinder, colourless |
V = 369.13 (11) Å3 | 0.4 × 0.3 × 0.3 × 0.15 (radius) mm |
Z = 2 |
Bruker SMART 6000 CCD area-detector diffractometer | 1658 independent reflections |
Radiation source: sealed X-ray tube | 1306 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.021 |
Detector resolution: 5.6 pixels mm-1 | θmax = 30.0°, θmin = 2.6° |
ω scans | h = −9→9 |
Absorption correction: multi-scan (SADABS; Bruker, 2006) | k = −10→10 |
Tmin = 0.590, Tmax = 0.970 | l = −11→11 |
3271 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.040 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.113 | H-atom parameters constrained |
S = 1.01 | w = 1/[σ2(Fo2) + (0.060P)2 + 0.180P] where P = (Fo2 + 2Fc2)/3 |
1658 reflections | (Δ/σ)max < 0.001 |
66 parameters | Δρmax = 0.33 e Å−3 |
0 restraints | Δρmin = −0.44 e Å−3 |
CH2Cl2·C2H6OS | γ = 65.665 (10)° |
Mr = 163.05 | V = 369.13 (11) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.6800 (12) Å | Mo Kα radiation |
b = 7.7862 (13) Å | µ = 1.06 mm−1 |
c = 8.0017 (15) Å | T = 167 K |
α = 78.019 (10)° | 0.4 × 0.3 × 0.3 × 0.15 (radius) mm |
β = 80.008 (10)° |
Bruker SMART 6000 CCD area-detector diffractometer | 1658 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2006) | 1306 reflections with I > 2σ(I) |
Tmin = 0.590, Tmax = 0.970 | Rint = 0.021 |
3271 measured reflections |
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.113 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.33 e Å−3 |
1658 reflections | Δρmin = −0.44 e Å−3 |
66 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.40924 (15) | 0.48685 (12) | 0.81142 (10) | 0.0549 (3) | |
Cl2 | 0.04694 (13) | 0.40720 (12) | 0.73867 (11) | 0.0565 (3) | |
S1 | 0.20809 (10) | 1.07024 (9) | 0.35061 (7) | 0.0298 (2) | |
O1 | 0.2881 (3) | 0.8844 (3) | 0.4687 (2) | 0.0357 (4) | |
C1 | 0.2734 (4) | 0.4690 (4) | 0.6491 (3) | 0.0380 (6) | |
H1A | 0.2209 | 0.5925 | 0.5718 | 0.046* | |
H1B | 0.3786 | 0.3711 | 0.5799 | 0.046* | |
C2 | 0.4465 (4) | 1.0900 (4) | 0.2224 (3) | 0.0386 (6) | |
H2A | 0.5437 | 1.0995 | 0.2956 | 0.058* | |
H2B | 0.4012 | 1.2043 | 0.1356 | 0.058* | |
H2C | 0.5256 | 0.9770 | 0.1654 | 0.058* | |
C3 | 0.0888 (4) | 1.0322 (4) | 0.1860 (3) | 0.0397 (7) | |
H3A | 0.1950 | 0.9207 | 0.1352 | 0.060* | |
H3B | 0.0509 | 1.1448 | 0.0971 | 0.060* | |
H3C | −0.0449 | 1.0100 | 0.2353 | 0.060* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0668 (6) | 0.0508 (6) | 0.0520 (4) | −0.0266 (5) | −0.0170 (4) | −0.0014 (3) |
Cl2 | 0.0479 (5) | 0.0524 (6) | 0.0673 (5) | −0.0276 (5) | 0.0018 (3) | 0.0061 (4) |
S1 | 0.0315 (3) | 0.0317 (5) | 0.0253 (3) | −0.0134 (3) | −0.0001 (2) | −0.0026 (2) |
O1 | 0.0377 (10) | 0.0363 (12) | 0.0297 (8) | −0.0156 (10) | −0.0024 (7) | 0.0039 (7) |
C1 | 0.0379 (14) | 0.0375 (18) | 0.0350 (12) | −0.0152 (14) | 0.0008 (10) | −0.0007 (11) |
C2 | 0.0395 (14) | 0.0501 (19) | 0.0334 (12) | −0.0291 (15) | −0.0022 (10) | 0.0021 (11) |
C3 | 0.0354 (14) | 0.054 (2) | 0.0344 (12) | −0.0223 (15) | −0.0070 (10) | −0.0023 (11) |
Cl1—C1 | 1.766 (3) | C2—H2A | 0.9800 |
Cl2—C1 | 1.765 (3) | C2—H2B | 0.9800 |
S1—O1 | 1.4975 (18) | C2—H2C | 0.9800 |
S1—C2 | 1.784 (2) | C3—H3A | 0.9800 |
S1—C3 | 1.783 (2) | C3—H3B | 0.9800 |
C1—H1A | 0.9900 | C3—H3C | 0.9800 |
C1—H1B | 0.9900 | ||
O1—S1—C2 | 106.35 (12) | S1—C2—H2C | 109.5 |
O1—S1—C3 | 106.25 (12) | H2A—C2—H2B | 109.5 |
C3—S1—C2 | 97.39 (12) | H2A—C2—H2C | 109.5 |
Cl1—C1—H1A | 109.5 | H2B—C2—H2C | 109.5 |
Cl1—C1—H1B | 109.5 | S1—C3—H3A | 109.5 |
Cl2—C1—Cl1 | 110.90 (14) | S1—C3—H3B | 109.5 |
Cl2—C1—H1A | 109.5 | S1—C3—H3C | 109.5 |
Cl2—C1—H1B | 109.5 | H3A—C3—H3B | 109.5 |
H1A—C1—H1B | 108.0 | H3A—C3—H3C | 109.5 |
S1—C2—H2A | 109.5 | H3B—C3—H3C | 109.5 |
S1—C2—H2B | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···O1 | 0.99 | 2.45 | 3.291 (3) | 143 |
C1—H1B···O1i | 0.99 | 2.33 | 3.243 (3) | 153 |
C2—H2A···O1ii | 0.98 | 2.40 | 3.363 (3) | 166 |
C3—H3C···O1iii | 0.98 | 2.70 | 3.373 (3) | 126 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1; (iii) −x, −y+2, −z+1. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | 2CHCl3·C2H6OS | CH2Cl2·C2H6OS |
Mr | 316.86 | 163.05 |
Crystal system, space group | Monoclinic, P21/n | Triclinic, P1 |
Temperature (K) | 185 | 167 |
a, b, c (Å) | 5.9679 (3), 9.0041 (6), 23.1424 (15) | 6.6800 (12), 7.7862 (13), 8.0017 (15) |
α, β, γ (°) | 90, 91.63 (1), 90 | 78.019 (10), 80.008 (10), 65.665 (10) |
V (Å3) | 1243.07 (13) | 369.13 (11) |
Z | 4 | 2 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 1.51 | 1.06 |
Crystal size (mm) | 0.4 × 0.3 × 0.3 × 0.15 (radius) | 0.4 × 0.3 × 0.3 × 0.15 (radius) |
Data collection | ||
Diffractometer | Bruker SMART 6000 CCD area-detector diffractometer | Bruker SMART 6000 CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2006) | Multi-scan (SADABS; Bruker, 2006) |
Tmin, Tmax | 0.437, 0.745 | 0.590, 0.970 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10789, 2883, 2481 | 3271, 1658, 1306 |
Rint | 0.020 | 0.021 |
(sin θ/λ)max (Å−1) | 0.703 | 0.703 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.056, 1.04 | 0.040, 0.113, 1.01 |
No. of reflections | 2883 | 1658 |
No. of parameters | 141 | 66 |
H-atom treatment | All H-atom parameters refined | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.26, −0.25 | 0.33, −0.44 |
Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), smtbx-flip (Bourhis et al., 2009), SHELXL97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
C1S—H1S···O1 | 0.922 (15) | 2.365 (16) | 3.1779 (18) | 146.9 (13) |
C2—H2C···O1i | 0.95 (2) | 2.53 (2) | 3.389 (2) | 149.9 (17) |
C2S—H2S···O1 | 0.945 (16) | 2.301 (16) | 3.1897 (17) | 156.4 (13) |
Symmetry code: (i) x−1, y, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···O1 | 0.99 | 2.45 | 3.291 (3) | 143.0 |
C1—H1B···O1i | 0.99 | 2.33 | 3.243 (3) | 152.6 |
C2—H2A···O1ii | 0.98 | 2.40 | 3.363 (3) | 165.6 |
C3—H3C···O1iii | 0.98 | 2.70 | 3.373 (3) | 126.1 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1; (iii) −x, −y+2, −z+1. |
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The cryocrystallization method for the structural study of compounds which are not solid under ambient conditions has attracted increasing attention in recent years. This technique, consisting of in situ crystallization of the system under investigation followed by single-crystal X-ray study of the crystals obtained, is nowadays used not only for studying pure compounds, but also for the synthesis of new polymorphs (Choudhury et al., 2004; Ibberson et al., 2008) and co-crystals (Wiechert & Mootz, 1999; Bond, 2003) and for studies of isotope effects (Crawford et al., 2009; Vasylyeva et al., 2010). Liquid chemical systems are usually made up of relatively small molecules and thus represent good models for theoretical calculations. They also reveal a variety of intermolecular interactions and their structures are far from being intuitively predictable. Previously, we have shown that the common organic solvents chloroform (trichloromethane, CF) and dichloromethane (DCM) are able to form low-melting molecular complexes (LmMCs) with various small organic ketones, 1,4-dioxane, triethylamine and N,N-dimethylformamide (Yufit & Howard, 2010, 2012). Here, we report the synthesis and structures of two new LmMCs of dimethyl sulfoxide (DMSO) with CF, (I), and DCM, (II).
The LmMC (I) (crystallized from a 3:1 molar ratio mixture of CF and DMSO) contains two CF molecules per one molecule of DMSO (Fig. 1). Interestingly enough, the existence of 2:1 CF:DMSO aggregates linked by Cl3C—H···O interactions in solution has been predicted by spectroscopic methods (Daniel & McHale, 1997), although their exact geometry remained unknown. According to the spectroscopic data, 1:1 aggregates are also present in solution, but all our attempts to crystallize them have failed so far: any increase in the relative concentration of DMSO in the mixture results in the crystallization of pure α-DMSO. The CF molecules of (I) are indeed connected to the DMSO molecule by weak Cl3C—H···O hydrogen bonds. A similar motif has been observed before in the LmMC of CF with butan-2-one (methylethyl ketone, MEK) (Yufit & Howard, 2012), in which these interactions were different for CF molecules located in and out of the plane of the MEK molecule. In the case of (I), the geometry of both contacts is almost identical. The DMSO molecules in (I) are linked together in chains parallel to the [100] direction by C—H···O(-1 + x, y, z) contacts (Fig. 2). A similar arrangement of DMSO molecules was found in the structure of α-DMSO (Thomas et al., 1966), where a number of other contacts of various types also exist. There are no direction-specific interactions between adjacent chains, the shortest inter-chain contact being Cl2···Cl2(-x + 2, -y + 1, -z + 1) = 3.5290 (9) Å. This distance is slightly shorter than the shortest contact in the structure of pure CF [3.5669 (3) Å; Yufit & Howard, 2010].
In contrast with (I), the LmMC (II) contains only one DCM molecule per DMSO molecule (Fig. 3), in spite of the fact that (II) was crystallized from a 4:1 molar ratio mixture of the components. Similar to the crystallization of (I), an increase in the relative concentration of DMSO in the mixture results in the crystallization of pure α-DMSO. The 1:1 composition of complex (II) reflects the difference between the H-donor capacity of CF (one available H atom) and DCM (two H atoms). The components of (II) are also connected by Cl2C—H···O interactions but they are slightly longer than those in (I), which is consistent with the lower H-acidity of DCM compared with that of CF. These contacts bind the components into centrosymmetric rings of R24(8)type (Etter et al., 1990) (Fig. 4), similar to those found previously in the LmMC of DCM with cyclohexanone (Yufit & Howard, 2012). These cyclic dimers are linked into a three-dimensional network by interactions between the DMSO molecules. These interactions are of two types: a pair of C—H···O(-x + 1, -y + 1, -z + 1) contacts connects DMSO molecules in the [110] direction, while in the [100] direction the S═O groups of adjacent DMSO molecules are anti-parallel and the corresponding S···O(-x, -y + 2, -z + 1) distance is 3.2852 (19) Å. This implies the presence of a dipole–dipole interaction between these molecules. Remarkably, both types of contact are also present in the structure of α-DMSO (Thomas et al., 1966). These interactions combine the centrosymmetric rings into layers parallel to the [110] direction (Fig. 4). The shortest contact between the layers is Cl1···Cl1(-x + 1, -y + 1, -z + 2) = 3.5149 (16) Å.
As noted earlier (Yufit & Howard, 2012), in some cases co-crystals retain particular structural features of the crystal structures of the pure components and the composition of these particular fragments depends on the co-crystallization partner. In the case of the LmMCs (I) and (II), the CF `selects' the chains of DMSO molecules from the structure of pure DMSO, while co-crystallization with DMC keeps the layers of DMSO molecules intact, breaking down the chains. The difference in the crystal environment of the DMSO molecules in (I), (II) and pure DMSO (Thomas et al., 1966) becomes more apparent in Fig. 5, where a comparison of fingerprint plots of Hirshfeld surfaces (Spackman & McKinnon, 2002) is presented. The plots represent points on the Hirshfeld surface as a function of the closest distance from said point to nuclei inside (di) and outside (de) the surface, thus showing all intermolecular interactions simultaneously. The plots for (I) and (II) are distinctively asymmetrical, which is typical for co-crystals. It is easy to see that the shortest intermolecular contacts in (I) and (II), the characteristic spurs on the plots, corresponding to ClC—H···O interactions, are shorter than the shortest C—H···O contacts in pure DMSO (Thomas et al., 1966).